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The Independent Monthly Newspaper for Anesthesiologists AnesthesiologyNews.com • J u n e 2 0 1 2 • Volume 38 Number 6

Anesthesia Training Shorts Practice Issues

M

ost anesthesiologists believe residency programs do a poor job of training young doctors in practice management, according to results of a recent survey of the specialty. The results, presented at this year’s American Society of Anesthesiologists (ASA) Conference on Practice Management, showed that most respondents felt see  practice  page 29

40th Anniversary

Femoral Blocks a Boon For Hip, Knee Surgery

F

emoral blocks offer wide-ranging benefits after knee and hip replacement, from reducing pain during early recovery to lowering health care costs, new research has found. Three new studies presented at the 2012 annual meeting of the American Academy of Orthopaedic Surgeons highlighted the advantages of femoral blocks over other anesthetic approaches in these patients. They showed that femoral blockade can spare patients from opioid-related adverse effects, reduce the need for joint manipulation after surgery and hasten discharge from the postanesthesia care unit (PACU). see  femoral  page 26

New App Predicts Chronic Pain After Inguinal Hernia Surgery New York—Surgeons and patients considering hernia surgery can now use a free app that predicts a person’s chance of experiencing chronic pain after inguinal hernia repair, based on the outcomes of nearly 1,700 patients treated over the last five years. The app, the Carolinas Equation of Quality of Life (CeQOL), was officially launched at the 5th International Hernia Congress and is available for free download on smartphones, tablets and desktop computers. The app will help educate

patients about the risks for chronic pain, an issue sometimes glossed over in preoperative discussions between physicians and patients, said B. Todd Heniford, MD, the senior researcher of the team that designed the app and chair of gastrointestinal and minimally invasive surgery at Carolinas Medical Center, in Charlotte, N.C. “This app opens up the discussion about the chance of chronic discomfort following inguinal hernia surgery and gives patients a very specific idea of risk,” Dr. Heniford said. “It’s a tool that

INside 08 | COMMENTARY Avoid the wrong bet on P4P.

12 | Pain Medicine Researchers explore combat-related pain.

24 | CLinical Anesthesiology Overweight patients may receive excessive neuromuscular blockade.

sets the stage for what we should strive for with every operation: an objective plan to obtain personal quality-of-life outcomes for postoperation and therapy.” see  app  page 14

30  |  Policy & Management Transfusions a wild card for hip replacement.

Educational Review

Ultrasound-Guided Central Vein Cannulation: Current Recommendations and Guidelines, see insert at page 16.

CME: PreAnesthetic Assessment

Lesson 297, Part 2: PreAnesthetic Assessment of the Patient Undergoing Thoracic Endovascular Aneurysm Repair, see page 18.

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4  I  AnesthesiologyNews.com

June 2012

Comment on these and other articles @ AnesthesiologyNews.com.

Heard Here First: The long commitment of anesthesiologists to

protecting patients and advancing the specialty through research, guidelines and education is worthy of support. Payment experiments that

June 2012

The five most-viewed articles last month on AnesthesiologyNews.com 1. Cancelled Surgeries Costing Hospitals Millions 2. Current Concepts in the Management of the Difficult Airway (Educational Review) 3. Calif. Ruling on CRNA Practice Promises Nationwide Tremors 4. Anesthesiologists Take on Central Role in Stroke Care 5. Neuromuscular Blockers Linked to Post-op Breathing Problems

distract from clinical care

are not. Anesthesiologists should double down on meaningful quality improvements and double back on care distractions.

Register for free @ AnesthesiologyNews.com to read these and other articles.

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PONV prevention:

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PONV prevention that covers the entire at-risk period from post-op to PACU discharge Priming dose starts early Unique transdermal delivery system provides a priming dose of scopolamine upon application Statistically significant reduction in nausea, vomiting, and retching 2 to 4 hours post-op1

Continuous release keeps working Extended release delivers a near constant dose over 24 hours2 66% of Transderm Scop® patch patients vs. 46% for placebo reported no retching/vomiting within the 24-hour period postadministration

Stays late. 1. Kotelko DM, Rottman RL, Wright WC, et al. Transdermal scopolamine decreases nausea and vomiting following cesarean section in patients receiving epidural morphine. Anesthesiology. 1989;71:675-678. 2. Transderm Scop® [package insert]. New Providence, NJ: Baxter Healthcare Corporation; 2006.

Indications and Important Risk Information for the Transderm Scop® patch (scopolamine 1.5 mg) Transdermal Therapeutic System

Indications The Transderm Scop® patch is indicated in adults for prevention of nausea and vomiting associated with recovery from anesthesia and surgery. The patch should be applied only to skin in the postauricular area. Important Risk Information The Transderm Scop® patch is contraindicated in: Persons who are hypersensitive to the drug scopolamine or to other belladonna alkaloids or to any ingredient or component in the formulation or delivery system. Patients with angle-closure (narrow-angle) glaucoma. The Transderm Scop® patch should not be used in children. The Transderm Scop® patch should be used with caution in the elderly or in individuals with impaired liver or kidney function; patients with pyloric obstruction, urinary bladder neck obstruction, or in patients suspected of having intestinal obstruction. Also use with caution in patients with a history of seizures or psychosis.

Since drowsiness, disorientation and confusion may occur, patients should not drive, operate dangerous machinery, or participate in activities that require alertness. Patients should not use alcohol. Use with caution in patients taking other drugs that can cause CNS effects, such as sedatives or tranquilizers. Rarely, idiosyncratic reactions have occurred. The most serious that have been reported include acute toxic psychosis, confusion, agitation, rambling speech, hallucinations, paranoid behavior and delusions. Since scopolamine can cause dilation of pupils and blurred vision upon direct eye contact, patients should be strongly advised to wash hands thoroughly with soap and water immediately after handling the patch. Because of an aluminized layer in the delivery system, it is recommended to remove The Transderm Scop® patch prior to undergoing an MRI. Skin burns have been reported at the patch site during an MRI.

Monitor glaucoma therapy in patients with chronic open-angle (wide-angle) glaucoma.

In five postoperative nausea and vomiting clinical studies, the most commonly reported adverse events were dry mouth (29%) and dizziness (12%).

Please see full prescribing information on the following page.

01/12 720254

Baxter is a registered trademark of Baxter International Inc. Transderm Scop is a registered trademark of Novartis AG.


6  I  AnesthesiologyNews.com

June 2012

IN BRIEF

T

U.S. Survey Shows Decline in Postsurgical Deaths

he number of inpatient deaths within 30 days of surgery in the United States declined by just over 15% between 1996 and 2006, according to a nationwide report published in Surgery (2012;151:171-182). Before this analysis, national rates and patterns of death after surgery were unknown.

Investigators from the Harvard School of Public Health and the Center for Surgery and Public Health at Brigham and Women’s Hospital, in Boston, compared deaths that occurred within 30 days of admission among patients undergoing surgery in 1996 and 2006. Using the Nationwide Inpatient Sample, which covers

approximately 20% of hospitals in the United States, the researchers examined the inpatient 30-day death rate for all surgical procedures, procedures with the most deaths, and high-risk cardiovascular and cancer procedures, and for patients who suffered a recorded complication. The researchers found that hospital admissions involving surgical procedures increased by 14.4% (from just over 12.5 million in 1996 to more than 14.3 million in 2006), while deaths within 30 days of admission dropped by 15.4% (from 224,111 in 1996 to 189,690 in 2006). The adjusted 30-day inpatient mortality rate decreased from 1.68% to 1.32% during that period (P<0.001). “The decline in the number of deaths may have occurred through reduced mortality of individual procedures, reductions in the volume of high-risk procedures and the rescue of patients who had a complication,” the authors wrote. The investigators identified 21 procedures associated with the most deaths in 1996 (accounting for 3,160,643 admissions and 101,146 deaths) and found that, in 2006, the same procedures accounted for 26.5% fewer deaths (3,339,722 admissions and 74,254 deaths). The inpatient 30-day mortality rate for patients who had a complication decreased from 12.10% to 9.84% (P<0.001). Mortality decreased for nine of 14 high-risk cardiovascular and cancer procedures. The incidence of sepsis and pneumonia increased from 1996 to 2006, but the failure-to-rescue rate declined during the study period for both groups (sepsis, from 18.69% to 14.03%; pneumonia, from 8.54% to 7.34%). Overall, the investigators estimated that 51,000 fewer people died in 2006 than would have if the postsurgical mortality rate from 1996 had continued. The authors noted that “additional research to determine the underlying causes for decreased mortality is warranted.��� —Victoria Stern

Baxter Healthcare Corporation | 95 Spring Street | New Providence, NJ 07974 1-800-ANA-DRUG (1-800-262-3784) | 01/12 720254| www.baxter.com


June 2012

AnesthesiologyNews.com  I  7

The following advertorial has been provided by I-Flow, LLC, and is designed to support the advertisement presented below.

The ON-Q* T-bloc*, from I-Flow Q. Who is I-Flow, and what do they offer anesthesiologists? A. I-Flow, LLC, a Kimberly-Clark Health Care Company, is a global market leader in acute pain and ambulatory medication delivery, driving innovative clinical applications for surgical procedures and regional anesthesia that improve outcomes and advance patient care. Building on I-Flow’s industry leadership in postsurgical pain relief systems, I-Flow provides to customers ongoing, in-depth training, education, consultation and clinical support on its products—a total solution. I-Flow has long been recognized as an innovator in pain management and drug delivery technology and has expanded its offerings to become the trusted total solution provider for pain management and nerve block procedures.

A set of needles, catheters and accessories completes the ON-Q* nerve block solution, meeting the varying needs of physicians by providing them with a comprehensive suite of tools for use in most regional nerve block procedures.

Q. How can customers purchase the ON-Q* T-bloc* trays and kits and additional line of needles, catheters and accessories? A. The ON-Q* T-bloc* trays and kits and additional line of needles, catheters and accessories are available

for purchase and evaluation samples. Interested customers can contact I-Flow at (800) 448-3569 to place an order or for full product listings. * Registered trademark of Kimberly Clark Worldwide, Inc.

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Q. What do these new product suites include? A. Specifically, the newest additions to the I-Flow product suite include: The ON-Q* T-bloc* product suite, designed to meet the product needs for performing most continuous upper- and lower-extremity and truncal blocks. The product suite will help to streamline the process of adequately stocking the block room. The ON-Q* T-bloc* trays and kits contain everything needed for use in delivering ultrasound-guided nerve blocks.

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8  I  AnesthesiologyNews.com

June 2012

C OMM E NT A R Y

Time To Double Back—Not Down—on P4P Spate of new studies expose flaws in performance-based payments

P

ay for performance, at least the government version, does not work well. That is the conclusion of several studies published recently in the New England Journal of Medicine and Health Affairs. Pay for performance, also known as P4P, seeks to improve the quality of health care by paying bonuses to physicians and hospitals that meet various performance measures. Health care is continuing to improve despite the ineffectiveness of P4P, or its renaming as value-based purchasing. We should double back on this payment confusion and bureaucracy before reformists and regulators double down on it again. The reality is that P4P has never worked well, especially in anesthesiology, where every patient is seen preoperatively, each anesthetic is delivered personally and safety defines the choices.

bonus payment programs and only about 12% receive bonuses. Keeping patients warm also qualifies for a P4P payment. Numerous studies established the value of normothermia during surgery, and clinical Robert E. Johnstone, MD guidelines promoted its use, before the Centers for Medicare & Medicaid Services adopted it into its bonus program. Most anesthesiologists keep their patients normothermic because it makes anesthesia safer and smoother, and most do not know how to code and report it for P4P funds. Anesthesiologists perform anesthetics as best they can, and hope their administrator knows when and where to add codes 4255F and 4250F, and how to report them. The major problem with P4P for anesthesiologists is that the bonus payment program does not improve patient care or reduce health care costs, any more than does simply paying for the care. Continuing research on anesthesia techniques and outcomes, education on what techniques work best, and feedback to practitioners on how they are doing are all that is needed. Checklists and facilitated communications, two recent quality innovations, will improve care more than bonus payments. P4P is at best irrelevant, and at worst distracting, to the provision of quality care. The model also creates an expensive bureaucracy. Eliminating P4P might even reduce the overall cost of health care. The long commitment of anesthesiologists to protecting patients and advancing the specialty through research, guidelines and education is worthy of support. Payment experiments that distract from clinical care are not. Anesthesiologists should double down on meaningful quality improvements and double back on care distractions.

comparing them with 780 hospitals not participating in the demonstration project. After five years, the quality scores of the two groups had increased—but to the same degree. These two studies corroborated the results of a third analysis by a team from the Rand Corporation, who looked at performance reports of physician groups contracting with a large network health maintenance organization to compare clinical quality before and after the implementation of P4P. Yet again, they failed to find evidence that this P4P initiative resulted in any major improvements in quality of care. Of course, lack of evidence has not slowed down reformers committed to implementing P4P. Several sections of the Patient Protection and Affordable Care Act establish new payment plans that hinge on performance measurements. Accountable care organizations, for instance—a current reform rage— History of Anesthesia Instructive demand the inclusion of 33 measures of care coordiAnesthesiologists have a history of improving nation, patient safety, preventive health services, care patient safety and clinical care that long predates the for at-risk populations and patient experience to earn P4P fad. Clinicians can find a hundred standards, any shared savings. There is now a P4P industry, with guidelines, advisories and other practice parameters national meetings, newsletters, software, specialists —Robert E. Johnstone, MD on the Web site of the American Society of Anesthe- and agendas for growth. Dr. Johnstone is professor of anesthesiology at West Virginia siologists (ASA) under “Patient Quality and Safety.” Patient Expectations, University, in Morgantown. He comments frequently on health care None was developed for extra pay. politics. This commentary represents his personal views. Not Bonus Pay, Driving Care Trying to jerry-rig guideline steps into bonus payment formulas to improve quality is an errand for Extra pay for physicians and hospitals that do good Suggested Reading fools. Early studies of P4P showed little gain in work makes sense, in theory. But it is too far removed quality for the money spent, as well as evidence from clinical decision-making to affect care, and 1. Jha AK, Joynt KE, Orav EJ, Epstein AM. The long-term effect of premier pay for performance on patient outcomes. N Engl J Med. that suggested unintended consequences, such as good care is expected anyway. 2012;366:1606-1615. the avoidance of high-risk patients when payment Anesthesiologists who report that they adminisKJ, Frank RG, Rosenthal MB. Can you get what you pay for? depends on outcome improvements. tered the correct prophylactic antibiotic to a surgical 2. Mullen Pay-for-performance and the quality of healthcare providers. Rand J The latest data are more bad news for advocates patient during the hour before incision, or two hours Econ. 2010;41:64-91. of value-based purchasing in health care. Among the for a fluoroquinolone antibiotic, can qualify for an 3. Rosenthal MB, Frank RG, Li Z, Epstein AM. Early experience with payrecently published studies, researchers at the Harvard extra 0.5% of the allowed Medicare payment. Yet for-performance: from concept to practice. JAMA. 2005:294:1788-1793. School of Public Health compared outcomes among anesthesiologists administer the antibiotic whether AM, Blustein J, Casalino LP. Medicare’s flagship test of pay-for252 hospitals participating in the Medicare Premier they file for, or receive, the extra payment. Surveys 4. Ryan performance did not spur more rapid quality improvement among Hospital Quality Incentive Demonstration and 3,363 that predate P4P payments show an intensive level low-performing hospitals. Health Aff. 2012;31:797-805. others outside the project. They found no evidence of involvement by anesthesiologists in the adminis5. Warters RD, Szmuk P, Pivalizza EG, et al. The role of anesthesiologists that hospital-based P4P programs decrease 30-day tration of perioperative antibiotics. Infection prophyin the selection and administration of perioperative antibiotics: mortality, and concluded that any expectations laxis is just part of good anesthesia and surgery. A survey of the American Association of Clinical Directors. Anesth Analg. 2006;102:1177-1182. for programs modeled after these programs should Filing for bonuses primarily measures whether the remain modest. extra payment in any system is worth the extra has- 6. Werner RM, Kolstad JT, Stuart EA, Polsky D. The effect of pay-forperformance in hospitals: lessons for quality improvement. Meanwhile, researchers at the University of Penn- sle. Only about 20% of eligible physicians and health Health Aff. 2011;30:690-698. sylvania studied 260 hospitals in Medicare P4P, professionals now participate in Medicare quality


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June 2012

AnesthesiologyNews.com  I  11

PR N

Unreported Clinical Trial Data Rampant, Lead to Research Bias

C

linical drug trials often are hailed as the standard for relevant and reliable information on potential new products. But a recent editorial in the British Medical Journal suggests that researchers often fail to report relevant trial data (BMJ 2012;344:d8158). “We are not dealing here with trial design, hidden bias or problems of data analysis—we are talking simply about the absence of the data,” the authors wrote. This behavior, in turn, biases research, wastes health care resources and may harm patients, the editorialists argued. “Moreover, researchers or others who deliberately conceal trial results have breached their ethical duty to trial participants,” they wrote. In fact, a slew of studies accompanying the editorial in the journal “confirm the fact that a large proportion of evidence from human trials is unreported, and much of what is reported is done so inadequately,” the editorial argued. The studies explore the extent and consequences of leaving out data from clinical trials. In one study, investigators showed that the addition of unpublished data to published meta-analyses of drug trials often changed the results (BMJ 2012;344:d7202). The researchers integrated previously unpublished data into existing meta-analyses of nine FDA-approved drugs and showed that the recalibrated trial data produced identical estimates of drug efficacy in three of 41 cases (7%), but 46% greater and 46% lower drug efficacy in the remaining 38 cases (19 for each). The editorialists acknowledged that “it is sometimes assumed that incorporation of missing data will reduce estimates of drug benefits, but this study shows that ‘publication bias’ can cut both ways. Each increment of data can change the overall picture, but in most cases with no certainty that the picture is complete.” Not only is evidence frequently missing from trials, but the requirements for mandatory trial registration and appropriately timed sharing of results often are not followed properly. Another study found that fewer than half of trials funded by the National Institutes of Health (NIH) are published in a peer-reviewed journal within 30 months of trial completion, and even at 51 months, one-third of results remained unpublished (BMJ 2012;344:d7292). Furthermore, in the

United States, in 2009, only 22% of drug trials subject to mandatory

Pat El-Hinnawy, an FDA spokes- submission requirement.” woman, said a delay in publishing data Elizabeth Loder, MD, MPH, a BMJ may result if the sponsor of a editor and co-author of the editorial, clinical trial is seek- noted that most clinical interventions in ing approval of a new use today are based on trials carried out use of a drug or device. before the era of mandatory registration. “FDA has identified a “And here the task of data retrieval by number of factors that systematic reviewers and national adviskew the data and impact sory bodies becomes impossible,” the the percentage of results editorialists wrote. “Our patients will Prayle [et al] reported,” have to live with the consequences of reporting requireMs. El-Hinnawy said. these failures for many years to come.” ments disclosed their As for enforcement, Potential solutions to the probresults within the Ms. El-Hinnawy said that the lem of underreporting of data have required one year after agency has focused on providing infor- been proposed. Dr. Prayle suggested the trial ended (BMJ 2012;​ 3 44:​ mation and assistance “to encourage that “a greater awareness of the reportd7373). compliance and to ensure an under- ing requirement will go a long way.” “So it seems that most trials haven’t standing of the responsibilities.” Dr. Jefferson added, “Reform and transreported results, which we think is seriFrederick Stearns, JD, partner at parency are needed across the board.” ous,” said lead author Andrew P. Prayle, Keller and Heckman LLP, in WashDr. Loder proposed a harsher soluBMedSci, clinical research fellow at ington, D.C., said he suspected that tion: “Penalties for not reporting trial the University of Nottingham, in the policing the clinical trial reporting data need to be enforced,” adding that United Kingdom. requirements “is a lower-priority issue, academic institutions and professional A recent Cochrane review provided given all of the other matters the agency organizations need to be involved, and an example of allegedly unreported is responsible for.” In addition, he said, researchers doing meta-analyses need to data (Cochrane Database Syst Rev the $10,000 per day monetary pen- look beyond published trials. 2012;1:CD008965). Attempting to alty may seem “unduly harsh for a data —George Ochoa study the anti-influenza antiviral drugs zanamivir (Relenza, GlaxoSmithKline) and oseltamivir (Tamiflu, Genentech USA, Inc., member of the Roche Group), the researchers received cooperation from GlaxoSmithKline, but reported that they were “unable to obtain the full set of clinical study reports or obtain verification of data” from Roche despite five requests between June 2010 and February 2011. Tom Jefferson, MD, an independent epidemiologist in Rome, leader of the study, said his group had reached “tentative conclusions which are at odds with the manufacturers’ statements,” but “full testing of all these findings, which may have a profound public health impact, cannot be done in the absence of the complete data set.” Perspectives in Chronic Pain: Evidence Into Practice Roche maintained that it does make NL1131 expires July 29, 2012 “detailed clinical trial reports” available and that it “stands behind the robustness and integrity of our data supporting the efficacy and safety of Tamiflu.” E-Journal Exchange: Current and Emerging Therapies in Chronic Pain WE1113 The lack of reporting appears to vioexpires November 16, 2012 late the FDA Amendments Act of 2007. That prompted Rep. Henry A. Waxman (D-Calif.) and congressioOptimizing the Selection and Use Of Topical Hemostats nal colleagues to write to the heads of expires April 1, 2013 the NIH and the FDA, for an explanation, and an answer to why the penalty Go to: topical-hemostats.com of $10,000 per day for violating the law had apparently not been enforced. The NIH declined to comment Malignant Hyperthermia: Diagnosis, Treatment, and Prevention and said it would respond to the IP112 expires December 1, 2013 representatives.

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12  I  AnesthesiologyNews.com

June 2012

P A I N M E DI C I NE

Pain Care in War Zones Mostly Not Battle-Related New Orleans—Traumatic injuries among service members in Iraq and Afghanistan have received considerable attention, but the major cause of unit attrition in modern warfare involves painful injuries sustained beyond the field of battle. And managing those injuries represents a major challenge for military clinicians, experts said. “Non–battle-related injuries are the No. 1 cause [of attrition],” said Col. Steven P. Cohen, MD, professor at the Uniformed Services University of the Health Sciences in Bethesda, Md., and associate professor of anesthesiology and critical care at Johns Hopkins School of Medicine, in Baltimore. “As military medicine evolves, pain management capabilities will take on an increasingly vital role.” Noninterventional strategies used to prevent chronic pain—resumption of normal activities, immediacy,

expectancy, avoidance of sick role and secondary gain—should be emphasized, with early, aggressive treatment administered, Dr. Cohen said at a session on pain medicine and combatrelated injuries at the spring meeting of the American Society of Regional Anesthesia and Pain Medicine.

reservists, about half of whom had no history of low back problems, showed that back pain became frequent over 18 months of duty. Among the 154 patients who never reported an episode of back pain either by history or over a three-year run-up to the monthly surveillance, pain scores of 2 or greater on the Oswestry DisMusculoskeletal ability Index (with 0 being the lowComplaints Common est possible score) were reported by In one study, Dr. Cohen and his 84%, scores of 4 to 9 were reported colleagues found that musculoskeletal by 64% and scores of 10 or greater and connective tissue disorders were were reported by 14%; at least 25% the most common reasons for medical scored 10 or greater (Spine 2009;​34:​ evaluation, documented among 24% 978-983). Among deployed solders, of the 34,006 personnel who were Dr. Cohen said, “back pain is the rule.” medically evacuated during Opera- Joining the military, he added, is assotion Iraqi Freedom and Operation ciated with a 200% increase in the risk Enduring Freedom (Lancet 2010;​375:​ for back problems. 301-309). Spinal pain was reported by Risk factors for back pain in another 7%. deployed soldiers include increased A five-year prospective study, activity level, carrying heavy gear, which included 285 special operation psychosocial stress, post-traumatic

stress disorder and combat stress, reduced coping mechanisms and secondary gain or poor job satisfaction. Only 13% of soldiers with back pain

Illness and Injury in Combat Zones: Return-to-Duty Rates Can Be Improved Knowledge of the risk factors that prevent return to duty, and aggressive interventions, can help motivated soldiers stay in theater New Orleans—For service members who become ill or are injured, returnto-duty rates historically have been low. But recognition of risk factors impeding their return, and aggressive interventions for pain, can result in the majority of these individuals resuming active duty, according to one expert. Col. Steven Cohen, MD, said that pain treatment in the U.S. armed forces focuses on two key goals: returning battle-wounded soldiers to their premorbid state and treating and preventing injuries unrelated to battle. Knowledge of the risk factors that prevent return to duty and aggressive interventions can help motivated soldiers stay in theater, he said. Dr. Cohen is professor at the Uniformed Services University of the Health Sciences in Bethesda, Md., and associate professor of anesthesiology and critical care medicine at the Johns Hopkins School of Medicine, in Baltimore. Dr. Cohen spoke at a session on combat-related injuries at the spring meeting of the American Society of Regional Anesthesia and Pain

Medicine. He described a study he co-authored on medical diagnoses among 162 soldiers serving in Operation Iraqi Freedom who were referred to two large pain treatment centers outside the theaters of combat (Anesth Analg 2005;101:1098-1103). Fifty-three percent presented with either radicular or axial low back pain, with lumbar herniated disk being the most frequently diagnosed condition (24%). The two most implicated etiologies were exacerbation of a previous pain condition treated with surgery (15%) and motor vehicle accidents (12%). Only 17% of patients were injured in combat. “With the exception of battle-related injuries, the pain conditions suffered during modern warfare reflect what we see in the typical civilian pain clinics,” Dr. Cohen said. Treatment primarily consisted of nonsteroidal anti-inflammatory drugs (NSAIDs; 56%), short-acting opioids (43%), physical therapy (34%) and anticonvulsants (31%).

Aggressive Management Makes a Difference “Among the 49 patients in whom data were available, only 2% returned to combat duty in Iraq,” Dr. Cohen said. “What matters most in the military is whether you can do your job. And this is an abysmal outcome.” But according to Dr. Cohen, when aggressive pain management strategies are used in forward-deployed areas (where troops must be ready for action), high return-to-duty rates can be achieved. This was shown in another prospective observational study that Dr. Cohen co-authored with Ron White, MD (Anesthesiology 2007;107:1003-1008), involving 113 coalition forces. Most had lumbar radiculopathy (56%); the rest had thoracic pain (12%), cervical radiculopathy (7%), groin pain (7%), nonradicular leg pain (7%) and axial low back pain (6%). Epidural steroid injections were by far the most frequently performed treatment, followed by trigger point injections, lumbar facet

blocks and groin blocks. Most patients also received NSAIDs; 25% were referred to physical therapy. The return-to-duty rate for these service members reached 94.7%, “a dramatic difference from our previous study,” Dr. Cohen noted. “These were motivated patients who wanted to stay in theater.” In a recent prospective cohort study, Dr. Cohen further determined factors that predicted which service members are most likely to be returned to duty, based on 34,006 personnel medically


June 2012

AnesthesiologyNews.com  I  13

P a i n M e d i c i ne evacuated out of theaters of operation returned to duty in a 2009 study he conducted (Arch Intern Med 2009;​ 169:​1916-1923). Factors associated with negative outcomes were being in the Navy or Marines, having a psychiatric diagnosis and not being treated

evacuated during Operation Iraqi Freedom and Operation Enduring Freedom (Lancet 2010;375:301-309). Musculoskeletal complaints and connective tissue disorders were the main reasons for medical evaluation (24%), followed by combat injuries (14%), neurologic disorders (10%), psychiatric diagnoses (9%) and spinal pain (7%), the study found. Factors most strongly associated with return to duty were being a senior officer, having a disease and non-battle injury (DNBI), and presenting with

in a pain clinic. workload after returning to duty, parAmong multiple risk factors for ticularly stand out, Dr. Cohen said. back pain–associated disability, havPost-Amputation Pain ing high job stress, a physically Growing Problem demanding job, poor coping skills, high anxiety levels and, importantly, Injury resulting from improvised lacking the opportunity for a reduced explosive devices is common in the Iraq and Afghanistan wars and is the main cause of wartime amputations. Post-amputation pain (e.g., phantom limb pain [PLP] and residual limb pain), which occurs in between 60% and 80% of major limb amputees, is a treatment challenge. Treatment of pain in the residual limb should address the underlying cause and may include revision surgery, neuroma injections, sympathetic blocks, pharmacotherapy, different prosthetics and complementary and alternative medicine. As a means of preventing PLP after amputation, results have been equivocal for epidural injections and preemptive nerve blocks “but they weakly favor preemptive analgesia,” Dr. Cohen said. Some studies have shown that good preoperative and postoperative pain control may decrease PLP and that the benefits may be greater if epidural analgesia is started early. Studies were more likely to detect differences when the “control” group was not optimally managed, he said. “The effect may be small, and limited to select patients, but there are other advantages to epidurals, such as a reduced need for opioids and anesthesia during the procedure,” he added. PLP is treated similarly to other forms of neuropathic pain; evidence is strongest for the use of opioids, although the long-term use of opioids can have significant adverse effects in

young people with concomitant psychological conditions. The incidence of PLP diminishes over time, and about 17% of service members return to duty post-amputation, Dr. Cohen said. “This is far higher than was seen 15 years ago, when just 2.3% returned to duty.” Other therapies for post-amputation pain include transcutaneous electrical stimulation, massage and physiotherapy, sensory discrimination training, acupuncture, biofeedback and selfhypnosis, visual feedback with mirrors, spinal cord and motor cortex stimulation and electroconvulsive therapy. There is no firm evidence that chronic pain can be prevented through preemptive analgesic agents, although there are some positive data for gabapentinoids and the antidepressant venlafaxine (Effexor, Eli Lilly), he added. Rick Fisher, DO, a physician fellow in interventional pain management at Walter Reed, agreed that managing post-amputation patients with PLP requires the pain specialist to be especially attentive to special needs. “We have large numbers of patients who do fairly well after amputation, but others have very real problems and take a lot of your time. I see these patients almost every day in my clinic,” Dr. Fisher said. “We use all the modalities we can and try to strike a balance between doing enough and doing too much. A lot of what we do is talk to them about the process, and encourage them to give the treatments time to work. It’s ‘expectations management.’”

Beaumont Army Medical Center/ Texas Tech University Health Sciences Center in El Paso, also has observed that within combat zones, the contributions of DNBI are frequently overlooked and significantly underreported. “These have historically accounted for a far greater proportion of casualties than all other categories combined,” said Dr. Belmont, who also is associate professor of surgery at the Uniformed Services University of the Health Sciences. In a study he led, musculoskeletal non–battle-related injuries accounted for more than 50% of the total DNBI casualties and more than 25% of the DNBI casualties requiring subsequent

medical evacuation (Mil Med 2010;​ 175:​469-476). “Dr. Cohen’s report [in Anesthesiology] detailing the aggressive treatment of mainly spinal conditions with a combination of epidural steroid injections, trigger point injections, facet blocks, NSAIDs and physical therapy holds great promise in the treatment of those musculoskeletal DNBI casualties because they were able to achieve a return-to-duty rate of greater than 90%,” and the effort allowed deployed units to ‘conserve their fighting strength,’” Dr. Belmont said.

chest or abdominal pain, a gastrointestinal disorder or genitourinary disorder. Factors associated with a decreased probability of return were serving in the Navy, Coast Guard or Marines, and presenting with a combat injury, psychiatric disorder, musculoskeletal or connective tissue disorder, spinal pain or other wound. Efforts Applauded U.S. Army Lt. Col. Philip J. Belmont Jr., MD, director of the Orthopaedic Surgery Residency Program at William

—Caroline Helwick

—Caroline Helwick


14  I  AnesthesiologyNews.com

June 2012

T ec h nolo g y App  continued from page 1 Between 8% and 40% of patients who undergo inguinal hernia repair have chronic pain after surgery, according to previous studies. And that pain often triggers legal action against physicians and hospital systems. In the United Kingdom, chronic pain following hernia repair is the No. 1 cause of malpractice suits. In the United States, 35% of all malpractice case law that relates to hernia

repair is related to chronic pain or discomfort. Bruce Ramshaw, MD, a hernia surgeon and chief medical officer for the Transformative Care Institute, in Daytona Beach, Fla., said the app marks a change in the way outcomes after medical and surgical care are measured. “This app is great because it’s focused on patient quality of life and outcomes from the patient perspective. That’s the direction we are going as a hernia society.”

The app is based on an algorithm developed by Igor Belyansky, MD, a fellow in laparoscopic surgery at Carolinas Medical Center. Dr. Belyansky and colleagues studied data collected between September 2007 and September 2011 by the International Hernia Mesh Registry, a prospectively collected multicenter database that includes data on patients from 30 sites in Canada, the United States, Europe and Australia. Patients submit data to the registry, by mail or email, and answer questions

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regarding quality of life, Carolinas Comfort Scale scores and postoperative complications. Researchers studied 2,146 inguinal hernia patients, after excluding cases where more than 10 tacks were used in the repair. (An earlier study, from the same group, showed that the use of more than 10 tacks increases long-term pain [Ann Surg 2011;254:709-714]). The average age of the patients was 56.4±14.6 years; 94% were male and 38% underwent laparoscopic repair. Overall, 20% of patients had bilateral repair and 12% were treated for a recurrent hernia. Almost 58% of patients reported preoperative pain. Patients were queried at regular intervals for a year after their hernia repair (77.7% follow-up rate). One month after surgery, just over onefourth of patients (26.1%) reported postoperative pain. That figure dropped by more than half over the next year, with 12.5% reporting postoperative pain one year after surgery. The investigators found that younger age, female sex, bilateral repair, recurrent inguinal hernia repair, preoperative pain, postoperative hematoma, postoperative recurrence and postoperative urinary tract problems all were predictive of chronic pain. Based on these results, the researchers developed an algorithm to predict chronic pain. They used a random sample of 80% of patients in the database to develop the algorithm and confirmed the results in the remaining 20% of patients. A Harvard statistician independently tested the equation, and confirmed its sensitivity and specificity. The app was developed to make the algorithm more practical for use by physicians and patients. It is the first app for medical and surgical outcomes, Dr. Heniford said. According to CeQOL, a young asymptomatic patient with no preoperative pain has about a 10% risk for discomfort one year after surgery. Patients with preoperative pain, bilateral inguinal hernias and recurrent hernias have an increased risk for developing chronic pain after surgery. Interestingly, older patients are less likely to have symptoms of chronic pain than younger patients. Dr. Belyansky said the app will help identify high-risk individuals who may benefit from a multidisciplinary treatment approach. “Furthermore, in a preoperative or pretreatment setting, full disclosure of postoperative qualityof-life expectations should become a standard part of the counseling and consent process for surgery and major


June 2012

AnesthesiologyNews.com  I  15

T ec h nolo g y “The team should be congratulated for pioneering an app that bridges evolving technology and patient care outcomes. As CeQOL gets used by multiple surgeons and patients, its validity and usefulness will be tested,” said Brian Jacob, MD, attending surgeon at Mount Sinai Medical Center, in New York City. “Pain complaints after hernia surgery, in general, are very subjective, and often factor in many variables that are dependent on any given surgeon’s technique,

patient population and follow-up regimen,” he said. “Such variables make it tough for an app to reliably account for things like the type of hernia repair being performed, the surgeon’s experience with the technique and the location or type of pain complaint being reported. Therefore, the risks that CeQOL produces might have a chance to overestimate or generalize.” Dr. Jacob said he does plan to use the app in his own practice and see “how reliable it is with my patients.”

The research team plans to recheck the algorithm and update it as needed as more information on quality of life is collected. They also are designing trials for patients with a high risk for chronic discomfort after inguinal hernia repair to perform patient-directed care instead of hernia-directed care. Dr. Belyansky won the World Hernia Congress Resident/Fellow Research Award for 2012 for this project. —Christina Frangou

‘It’s a tool that sets the stage for what we should strive for with every operation: an objective plan to obtain personal quality-oflife outcomes for postoperation and therapy.’ —B. Todd Heniford, MD medical treatments,” he said. Surgeons at Carolinas currently use the app for all inguinal hernia patients who come into the clinic. Surgeons fill in the app as they speak to patients, or patients do it themselves on an iPad. New products come into the hernia field at rapid speed but data on outcomes follow much more slowly, said Shirin Towfigh, MD, associate professor of surgery at Cedars-Sinai Medical Center, in Los Angeles, and assistant professor of surgery at the University of Southern California. The new app keeps the focus on patients, she said. “What this app helps quantify in very real terms, and for the first time ever, is how much chronic pain a typical patient may suffer based on simple preoperative symptoms,” Dr. Towfigh said. “Surgeons can help use this app to educate their patients about the risks and benefits of hernia repair.” Dr. Heniford, who is the outgoing president of the American Hernia Society, encouraged clinicians and their patients to use the app. Currently, the app applies only to men, because of a shortage of outcomes data following hernia repair in women. He said CeQOL represents a paradigm shift in which the success of a procedure is judged not only by recurrence rates, which are quite low, but also by patients’ quality of life.

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June 2012

AnesthesiologyNews.com  I  17

CL I N I CA L A N E S T H E SI OL O G Y

Obese Patients Experience Fewer Post-op Complications

O

bese adults have fewer compli- Table. Complications and Mortality After non-Bariatric Surgery “At my clinic, perioperative nurses folcations following non-bariatric low a protocol specifically designed to Normal-Weight Obese Severely Adults Adults Obese Adults surgery than their leaner peers, look for complications such as hypoxia, a according to a review of more than hypercarbia, early signs of bleeding or 30-day all-cause mortality 1.10% 0.80% 0.70% 230,000 patients. infection, which our morbidly obese Major postoperative complications 15.60% 15.80% 12.70%b “These findings are the opposite patients are at highest risk for,” Dr. Beer of what we would expect to see,” said a P<0.001 for obese and severely (morbidly) obese versus normal; b P<0.001 for severely (morbidly) obese versus normal said. “I suspect clinicians across the Thomas Beer, MD, an anesthesiologist country are equally as vigilant and these in Scottsdale, Ariz., who specializes in However, Dr. Beer said obese patients perioperative period, which may reduce results likely reflect that.” bariatric medicine but was not involved may be observed more closely in the complications and deaths. —David Wild in the study. Olubukola Nafiu, MD, assistant professor of anesthesiology at the University of Michigan, in Ann Arbor, and several colleagues, analyzed data from 235,076 general and vascular inpatient surgeries conducted between 2005 and 2008. Dr. Nafiu’s team compared the incidence of postoperative complications among older and younger normal-weight, obese and morbidly obese patients. The researchers excluded underweight patients from their analysis, as this population often has comorbidities—such as cancer—that increase their risk for morGet the latest news from the tality. They also excluded patients undergoing outpatient surgeries, who typically best-read anesthesiology are healthier than hospitalized patients. publication in the country The researchers found that 16% of all patients suffered a major postoperadelivered directly to your tive complication and 2% of all patients died within 30 days of surgery (Table). computer or mobile device Normal-weight adults younger than age for free! 65 years had significantly higher odds of death and major postoperative complications than did obese and morbidly obese Each installment adults. contains articles from the Although the mortality rate for the current month’s issue ahead elderly population was still signifiof print, as well as links to podcasts cantly lower in obese patients compared with normal-weight patients, morbidly and other Web-exclusive content obese patients enjoyed no such protecScan this QR code to register for free tion, the researchers found (4.7% for normal weight, 3% for obese and 3.7% for morbidly obese; P<0.001 for all). Major postoperative complications in the elderly followed a similar J-curve, according to the researchers, occurring in 25.3%, 23.8% and 25.6% of normalweight, obese and severely obese older patients, respectively (P<0.001). The study is not the first to describe an “obesity paradox.” Obese patients with heart failure and stroke, as well as Download it for free from the App Store those in the surgical intensive care unit, seem to have better outcomes than their normal-weight peers, Dr. Nafiu said. “The reasons for the obesity paradox are still largely unresolved,” Dr. Nafiu said. “Some of the reasons may be physiologic, such as having higher nutritional buffers of inflammation or earlier manifestations of symptoms.”

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18

CONTINUING MEDICAL EDUCATION

This lesson is available online at www.mssm.procampus.net

JUNE 2012

Lesson 297: PreAnesthetic Assessment of the Patient Undergoing Thoracic Endovascular Aneurysm Repair: Part 2 WRITTEN BY:

LEARNING OBJECTIVES

Jayanta Mukherji, MBBS Associate Professor, Department of Anesthesiology, Loyola University Medical Center, Maywood, Illinois

At the end of this activity, the participant should be able to: 1. Outline the causes of aortic dissection and natural history of descending thoracic aneurysm. 2. Describe the criteria and technique used for performing thoracic endovascular aneurysm repair (TEVAR). 3. Prescribe the preanesthetic assessment of the patient undergoing TEVAR. 4. Evaluate the anesthetic implications for the patient undergoing endovascular graft deployment. 5. Tabulate the criteria for TEVAR. 6. List common comorbidities in vascular patients. 7. Recognize the off-label status of endovascular stents when used in the treatment of aortic dissection. 8. List the indications for stent graft placement. 9. Identify perioperative goals. 10. Describe the intraoperative use of adenosine.

Michael Trembowicz, DO Fellow in Cardiothoracic Anesthesia, Department of Anesthesiology, Loyola University Medical Center, Maywood, Illinois

REVIEWED BY: Pierre Levan, MD Professor, Department of Anesthesiology, Loyola University Medical Center, Maywood, Illinois (In Part 1 of this 2-part series, the causes of thoracic aneurysms and the noninvasive treatment by stent placement are described. In Part 2, the complications of this therapy and monitoring requirements will be outlined.) DISCLOSURES The authors, editor, and reviewer have declared no conflict of interest related to financial disclosures, research, and written presentation of this manuscript.

PROFESSIONAL GAPS Thoracic endovascular aneurysm repair represents a technique with special considerations that may not be known by many practicing anesthesiologists. This lesson aims to explain these changes and developments.

CALL FOR WRITERS If you would like to write a CME lesson for Anesthesiology News, please send an email to Elizabeth A.M. Frost, MD, at ElzFrost@aol.com.

TARGET AUDIENCE Anesthesiologists

CASE HISTORY A 67-year-old woman presented to the emergency room with severe back pain and diaphoresis. She had a history of hypertension and coronary artery disease (CAD). Computed tomography (CT) angiogram revealed an aortic dissection involving the descending thoracic aorta distal to the left subclavian artery origin extending to the aortic bifurcation. There was a 6-cm dilatation of the proximal region of the descending thoracic aorta with evidence of extravasation. There was no disruption of blood flow to the celiac axis, superior mesenteric, and renal vessels on angiogram. Cardiac catheterization revealed nonobstructive CAD and an ejection fraction of 40%. Transthoracic echo revealed left ventricular hypertrophy with normal aortic root and ascending aorta. On physical examination, the patient had no neurologic deficits; blood pressure (BP) was 170/110 mm Hg; heart rate was 110 beats per minute; and all peripheral pulses were palpable. She was scheduled to undergo thoracic endovascular stent placement to create a seal at the area of extravasation.

Preanesthetic Considerations for TEVAR

T

he goal of preoperative evaluation is to optimize the patient’s medical status and plan an anesthetic technique that minimizes complications. Aortic surgery and emergency operations are independent risk factors for major complications. The anesthetic approach to the patient with a thoracic aortic aneurysm (TAA) is selected based on the urgency of repair. An unstable hemodynamic presentation suggests ongoing hemorrhage from a leaking aneurysm, cardiac tamponade, myocardial ischemia, or heart failure. Prior to surgery, it is important to discuss with the surgeon the operative procedure, cannulation strategy (if applicable), and whether evoked potential monitoring is planned. Symptomatic patients with leaking aneurysms require urgent intervention, and there generally is little time to perform more than the most basic preoperative assessment.

PREANESTHETIC ASSESSMENT Dr. Elizabeth A.M. Frost, who is the editor of this continuing medical education series, is clinical professor of anesthesiology at the Mount Sinai School of Medicine in New York City. She is the author of Clinical Anesthesia in Neurosurgery (Butterworth-Heinemann, Boston) and numerous articles. Dr. Frost is past president of the Anesthesia History Association and former editor of the journal of the New York State Society of Anesthesiologists, Sphere. She is also editor of the book series based on this CME program, Preanesthetic Assessment, Volumes 1 through 3 (Birkhäuser, Boston) and 4 through 6 (McMahon Publishing, New York City). A COURSE OF STUDY FOR AMA PRA CATEGORY 1 CREDIT(S)™ Read this article, reflect on the information presented, then go online (www.mssm.procampus.net) and complete the lesson

post-test and course evaluation before June 30, 2013. (CME credit is not valid past this date.) You must achieve a score of 80% or better to earn CME credit. TIME TO COMPLETE ACTIVITY: 2 hours RELEASE DATE: June 1, 2012 TERMINATION DATE: June 30, 2013 ACCREDITATION STATEMENT The Mount Sinai School of Medicine is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. CREDIT DESIGNATION STATEMENT The Mount Sinai School of Medicine designates this enduring material for a maximum of 2.0 AMA PRA Category 1 Credit(s).™

All antihypertensive and antianginal medications should be continued until the time of surgery. Systemic hypertension contributes to expansion and rupture of TAA. Strict control of hypertension is initially a top priority and is immediately implemented. The first-line management of hypertension includes a short-acting β-blocker such as esmolol. By lowering the heart rate and slowing the force of contraction, β-blockade reduces the shear force exerted on the dissection. The likelihood of propagation of the dissection is decreased. Second-line agents include vasodilators such as nitroprusside, which lower systolic blood pressure (BP), aortic wall stress, and the possibility of rupture. Preoperative sedation should be based on the patient’s clinical condition and concurrent medical diseases. Anxiolysis helps reduce hypertension and tachycardia, thus lowering the risk for myocardial ischemia and aneurysm rupture.

Physicians should only claim credit commensurate with the extent of their participation in the activity. DISCLOSURE STATEMENT It is the policy of Mount Sinai School of Medicine to ensure objectivity, balance, independence, transparency, and scientific rigor in all CME-sponsored educational activities. All faculty participating in the planning or implementation of a sponsored activity are expected to disclose to the audience any relevant financial relationships and to assist in resolving any conflict of interest that may arise from the relationship. Presenters must also make a meaningful disclosure to the audience of their discussions of unlabeled or unapproved drugs or devices. This information will be available as part of the course material.


CONTINUING MEDICAL EDUCATION

JUNE 2012

Patients undergoing an elective TEVAR need a detailed workup encompassing every organ system. Cardiovascular System Patients undergoing TEVAR are subjected to less hemodynamic stress, as the aorta is not cross-clamped and the anesthesiologist does not have to contend with major fluid shifts and blood loss. Clinicians should assess for the presence of comorbidities, such as coexisting hypertension, atherosclerotic disease, coronary artery disease, and congestive heart failure. The chart is reviewed for previous hospitalizations and procedures, including pacemakers, coronary artery bypass, and percutaneous stent placements. Specific preoperative studies should include the following: • Electrocardiography (ECG), which may reveal evidence of ischemia or prior myocardial infarction, left ventricular hypertrophy, and conduction blocks • Echocardiography, which is used to determine the size, location, and extent of the aneurysm, assess the functional status of the valves, and evaluate biventricular function • Computed tomography angiography or magnetic resonance angiogram (MRA), which determines the size, location, and extent of the aneurysm. Pulmonary System Preoperative pulmonary evaluation includes ascertaining the presence and severity of chronic obstructive pulmonary disease (COPD), smoking history, and functional status. There is less concern for respiratory failure in patients undergoing TEVAR than in those undergoing open descending thoracic aneurysm repairs, because there is less pulmonary insult from massive fluid shifts, transfusion of blood products, and one-lung ventilation. Respiratory failure is a likely sequela of TEVAR if the patient has baseline pulmonary insufficiency. If feasible, active smokers should refrain from smoking for at least 4 weeks before surgery. Patients with poor diffusing capacity or severe COPD may require preoperative optimization, despite not being subjected to prolonged ventilation. Dyspnea or stridor may be signs of tracheal or bronchial compression on physical examination. Hemoptysis may be a sign of aneurysmal leakage into the airway. Patients should be evaluated for a history of recurrent laryngeal nerve damage because there is potential for damage to the left recurrent laryngeal nerve if the procedure is converted to open repair. Central Nervous System Preexisting neurologic deficits in the central nervous system must be determined. A history of transient ischemic attacks, stroke, and seizures should be specifically sought preoperatively because of the potential for neurologic complications after surgery. Carotid angiography or duplex studies may be appropriate in selected patients with a history of stroke or severe atherosclerosis. Renal System Baseline renal insufficiency is related to hypertension, diabetes, and atherosclerotic disease and is an independent predictor of postoperative renal failure. The angiographic contrast dye used preoperatively during CT imaging and during the intraoperative evaluation of the aneurysm often causes transient abnormalities of renal function. Elective repairs should be delayed until these values have normalized.

Table 1. Risk Factors for Spinal Cord Ischemia After TEVAR Emergency surgery Previous abdominal aortic aneurysm repair Intraoperative hypotension More extensive coverage of the thoracic aorta by graft Coverage and occlusion of the left subclavian artery or hypogastric arteries by graft Severe peripheral vascular disease Severe atherosclerosis of the thoracic aorta Aortic dissections Anemia TEVAR, thoracic endovascular aneurysm repair

Hematologic System Preoperatively, it is routine to discontinue antiplatelet medications and warfarin. Point-of-care testing is used to guide transfusion of blood products. Coagulopathy following TEVAR is uncommon but is likely to occur in the setting of hypothermia, and in the use of heparin. Gastrointestinal and Hepatic Systems Aneurysmal involvement of the celiac and mesenteric arteries can predispose to bowel ischemia. Abnormal liver function tests should be noted. Radiologic Evaluation The extent and location of the aneurysm is determined by reviewing the CT or MRA. It may be beneficial to locate the origin of the artery of Adamkiewicz (ARM) preoperatively by angiography if TEVAR is converted to open repair, as identification and reimplantation of ARM reduces the risk for paraplegia by 5%. However, the significance of identifying the origin of ARM for endovascular aneurysm repairs is not known.

Anesthetic Considerations in Endovascular Graft Deployment Although endovascular repair is a less-invasive procedure, patients should be anesthetized with the possibility that open surgical repair may be necessary. The risk has decreased with improvements in endovascular devices and with greater surgical experience. Endovascular aortic repair should be classified, similar to aortic and peripheral vascular surgery, as a higher-risk procedure. Vascular patients are likely to have significant comorbid conditions such as hypertension, hyperlipidemia, stroke, ischemic heart disease, COPD, and diabetes. Preoperative assessment needs to address the typical issues associated with a general anesthetic in a vascular patient.8 Perioperative goals during TEVAR are to provide hemodynamic stability while preserving cardiac, spinal, and splanchnic flow and maintaining intravascular volume, adequate oxygenation, and body temperature. Both general and regional techniques have been used successfully. However, with the increasing use of neurologic monitoring and transesophageal echocardiogram (TEE) during TEVAR, general anesthesia is an appropriate choice.

Although epidural anesthesia can be used, it may be difficult to distinguish the effects of central neuroaxial blockade by local anesthetics from spinal cord ischemia (SCI). The use of epidural anesthesia is disadvantageous if lower extremity weakness ensues following operations involving the thoracic aorta. Neurologic examination is performed immediately upon emergence from general anesthesia. Any neurologic deficit detected should be considered to be SCI until ruled out. In early cases of TEVAR, surgeons preferred a “still” field during stent graft deployment, accomplished by the use of adenosine to achieve transient bradycardia or ventricular asystole. With the availability of newer self-deploying stents, this technique is no longer necessary. Various imaging modalities such as angiography, fluoroscopy, and TEE may be used to confirm the position of the stent. The proximal and distal ends of the endograft are then sealed to the aortic wall by endoluminal balloon inflation. The transient balloon inflation may cause a short-lived hemodynamic change that usually will not require any intervention. However, even this ephemeral increase in afterload may be poorly tolerated in patients with severe ventricular dysfunction. Blood loss may be difficult to quantify, as it often is lost around the sheaths and catheters and can be retroperitoneal in the case of injury to femoral or iliac vessels. A retroperitoneal approach is an alternative technique used in cases with failed femoral access. However, this approach results in higher chances of retroperitoneal bleeding and a longer procedure time. Large-bore IV access is useful in resuscitating unstable patients with rapid, ongoing blood loss. Because of the difficulty associated with accurate prediction of substantial blood loss and the possible need for allogeneic blood transfusion, it is appropriate to set up a cell salvage device in a backup mode. Intraoperative cell salvage and reinfusion can obviate allogeneic blood transfusion and its attendant risks. After graft deployment, vasopressors and inotropes are needed to manage hemodynamic emergencies and maintain higher mean arterial pressures (MAPs).9 Spinal Cord Ischemia The risk for SCI is lower after TEVAR than after open procedures but the complication still occurs, with an incidence of approximately 4% to 7%.10 A Crawford type II thoracoabdominal aortic aneurysm involves most of the descending thoracic aorta and the entire abdominal aorta; this type of aneurysm has the highest incidence of neurologic complications following endovascular repair (19%). There are other risk factors for SCI related to patients’ underlying conditions and the nature of the surgery (Table 1). The anatomic peculiarity of spinal blood supply explains the susceptibility of the spinal cord to ischemia. A single anterior spinal artery supplies the anterior twothirds of the spinal cord, which represents the motor region. In the cervical region, the vertebral arteries mainly supply the anterior spinal artery. In general, very few radicular arteries bolster the anterior spinal blood flow. It is critical to maintain the patency of the largest supplier, known as the ARM, as major SCI is likely with its occlusion. Other noteworthy collaterals improving anterior spinal flow arise from intercostal and lumbar segmental arteries that are branches off the descending thoracic aorta. In severe atherosclerosis, in which these collaterals are occluded, the anterior spinal blood supply may be derived from lumbar and perivertebral vessels and the pelvic circulation. Thus, the collateral network is dynamic and can supply blood to the spinal cord from another source when one is reduced. The posterior third of the spinal cord is

19


20

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This lesson is available online at www.mssm.procampus.net

Table 2. Avoiding Complications With Lumbar Drains Verify adequate coagulation, including platelet function, before catheter insertion. Monitor and maintain CSF pressure of 10 to 12 mm Hg to maintain spinal cord perfusion. Use intermittent CSF drainage rather than continuous drainage to avoid intracranial hypotension or subdural hematoma. Prevent infection by maintaining a closed CSF collection system. Occlude lumbar catheter for 24 hours before removal. Supervise catheter removal; place patients in lateral decubitus position for removal to avoid catheter fracture. Adapted from Pokhrel B, et al. Neurosurgery 2002;51:1414-1421.

predominantly a sensory region supplied by 2 posterior spinal arteries. Although the incidence of paraplegia is definitively lower with endovascular procedures, it remains one of the most dreaded complications. The cause differs from that encountered in open surgery, as no aortic cross-clamping is employed, and is most likely because of permanent coverage of important collateral arteries and intercostals supplying the spinal cord. With the recognition of this risk, cerebrospinal fluid (CSF) drainage during the perioperative period is an important consideration when extensive lengths of descending thoracic aorta are to be covered and in patients who had previous aortic repair.

Monitoring Considerations in TEVAR In patients at high risk for SCI, additional intraoperative neurologic monitoring with transcranial motor evoked potentials (MEPs) and/or somatosensory evoked potentials (SSEP) is useful. Patients are prepared for evoked potential monitoring with baseline measurements following induction of general anesthesia. Both inhalational and IV anesthetic agents have effects on neural synaptic and axonal functional activities. Intraoperative neurophysiologic monitoring can be challenging, because recording SSEP and MEP signals requires critical anesthetic choices and attention to temperature changes. The anesthetic effect on any given response depends on the pathway affected and the mechanism of action of the anesthetic agent. Inhaled anesthetics decrease the waveform amplitude and increase latency to a greater extent than IV anesthetics. Halogenated agents and nitrous oxide also depress MEP signals more than total IV anesthesia. An IV propofolâ&#x20AC;&#x201C; based anesthetic is preferred because it causes less suppression of cortical SSEPs with better preservation of SSEP amplitude at an equivalent depth of anesthesia compared with isoflurane.11 The management of pharmacologic neuromuscular blockade is crucial to myogenic MEP recording, as some blockade may be desirable for surgery, but excessive blockade may eliminate responses. Monitoring helps in the early detection of SCI and permits intervention before ischemia evolves to infarction.12 Decreased SSEP and MEP amplitudes have been shown to correlate with SCI, but the sensitivity and specificity of

these techniques remain to be determined. Intraoperative loss of SSEP or MEP signals is not necessarily caused by SCI. SSEP latency is increased and the magnitude is reduced by benzodiazepines and normal clinical concentrations of volatile anesthetic agents. SSEP detects lateral and posterior column ischemia but is a poor monitor for anterior motor column. A potential limitation of SSEP monitoring is that SCI confined to the anterior spinal cord may cause a selective motor deficit with intact sensation. Impaired peripheral nerve functioning from ischemia may affect the associated SSEPs or MEPs. Intraoperative strokes and lower limb ischemia from vascular insufficiency are known to cause loss of peripheral SSEPs or MEPs in the absence of SCI.

Techniques To Improve Spinal Cord Perfusion Because spinal cord perfusion pressure (SCPP) is equal to the MAP minus the lumbar CSF pressure, close attention is given to CSF drainage if lumbar CSF pressure is increased. Spinal cord perfusion is improved by augmenting the arterial pressure alone or in combination with lumbar CSF drainage. Vasopressor agents such as norepinephrine have been used to maintain a MAP of 80 mm Hg or greater to assure an SCPP of at least 70 mm Hg. Patients at risk for SCI may even need a higher MAP to improve SCPP. Attention needs to be given to optimizing oxygen delivery by improving cardiac output, correcting anemia, and maintaining a normal central venous pressure. CSF is drained by the percutaneous insertion of a silastic catheter into the subarachnoid space. It is performed on an awake patient in the lumbar position. CSF is drained passively to reduce lumbar CSF pressure to approximately 10 to 12 mm Hg during the operation. The catheter is usually left in place for 48 to 72 hours postoperatively. Emergent CSF drainage has been performed postoperatively to reverse delayed-onset paraplegia in combination with augmentation of MAP up to 100 mm Hg.13 Hypotension should be assiduously avoided, as it worsens SCI. It results from bleeding, anesthetics, and an underlying cardiac condition. SCI, which may itself

JUNE 2012

contribute to hypotension, is a neurogenic shock associated with autonomic dysfunction. Immediate treatment of hypotension is a priority, as prolonged ischemia may progress to spinal cord infarction. The various options for spinal cord revascularization that exist in open repairs are not available in TEVAR. Here, the preservation of spinal artery blood flow by segmental vessels is not feasible if the aneurysm is excluded by the stent graft. In some situations, the left subclavian artery may need to be covered by the endovascular stent graft in order to exclude the aneurysm. Because subclavian arterial flow contributes substantially to anterior spinal artery supply, a prior transposition of the subclavian artery onto the left carotid artery is required. Another method used to preserve left subclavian artery flow in TEVAR is to perform a left carotid to subclavian bypass graft with subsequent coil embolization of the proximal left subclavian artery stump during TEVAR.14 Because coverage of the left subclavian artery without bypass has been independently associated with paraplegia, many centers now perform elective left subclavian revascularization before TEVAR if the preoperative plan involves coverage of this artery in order to obtain an adequate proximal seal zone. Lumbar CSF drainage is performed in patients who will subsequently require anticoagulation with boluses of heparin for endovascular stent placement. It is generally deemed safe, although complications related to intraspinal or epidural hematoma may exist with a traumatic drain placement. Rapid drainage of CSF is another cause of serious complications such as subdural hematoma, intracranial hemorrhage, and remote cerebellar hemorrhage. Precautions such as continuous measurement of CSF pressure, controlled intermittent drainage of CSF, and assessment of coagulation function may decrease the risks associated with lumbar CSF drainage (Table 2).15

Renal Concerns With TEVAR TEVAR patients encounter exposure to large volumes of radiographic contrast to assist in suitable deployment of the graft and to ensure that the aneurysmal sac is completely excluded. Prevention is emphasized, as there is no specific treatment for contrast-induced acute renal failure

Table 3. Use of Intraoperative TEE for TEVAR Procedures Confirming aortic pathology

Define the extent and size of aneurysm, check presence of coexisting aortic aneurysms.

Detect the presence of widespread atherosclerotic plaques

Severe plaques in landing zone make graft deployment difficult. Detached plaques can embolize to brain.

Endograft imaging

Guide precise placement to ensure exclusion of the aneurysmal sac.

Differentiate true from false lumen in dissections

Confirm position of guide wire in true lumen.

TEE probe used as a marker during fluoroscopy

Serves as a marker of aortic level on fluoroscopy without contrast.

Monitoring cardiac performance

Monitor during a brief period of aortic occlusion because of inflation of the endovascular balloon; enables fixation of the endograft to the aortic wall.

Regional wall motion abnormality

Seen with CAD, severe ventricular dysfunction.

Check for endoleaks after graft deployment

Define type and severity of endoleaks.

CAD, coronary artery disease; TEE, transesophageal echocardiography; TEVAR, thoracic endovascular aneurysm repair


CONTINUING MEDICAL EDUCATION

JUNE 2012

Table 4. Causes of Endoleak Causes of Endoleak

Endoleaks Related to

Misplacement of endograft

Technical error consequential to techniques used for endograft placement

Poor sizing of endograft Material fatigue

Device failure

Displacement or distortion of endograft Reactions to the endograft within the aneurysmal sac environment

Patient factors

Table 5. Types of Endoleak and Treatment Type Description of Endoleak

Treatment

I

• Persistent flow around the attachment site (proximal and distal) of the endograft due to inadequate seal • Most frequent complication after stent graft placement for aneurysm (24%)

• Technical error leading to failure of stenting • Additional stent graft deployment needed for sealing

II

• Retrograde flow into the aneurysmal sac from a patent collateral branch vessel

• Not a major concern, as it does not impede remodeling and thrombosis in the false lumen • Resolves spontaneously after 5 to 6 months

III

• Endovascular placement of a covered stent to • Flow into the aneurysmal sac because of tear or reline the failing endograft defect in the endograft fabric or because of leakage between modular segments of an endograft • Early or late graft material fatigue is caused by greater hemodynamic stress • More common in the thoracic region

IV

• Flow detected in the aneurysmal sac after completion of angiography • Occurs due to highly porous graft material rather than device failure

(ARF). Preexisting renal failure and diabetes place patients at highest risk for contrast-induced ARF. Measures include hydration with isotonic sodium bicarbonate along with the administration of the antioxidant acetylcysteine to reduce the risk for contrast-induced ARF. Diuretics and/or mannitol have no role in the prevention of contrast-induced ARF.

Role of TEE in TEVAR The proximity of the esophagus to the aorta in the intrathoracic space makes TEE an appealing imaging modality for detection of aortic pathology. During TEVAR, intraoperative TEE provides valuable feedback regarding the extent and severity of the aortic pathology, guiding placement of the endograft, monitoring cardiac performance during and following aortic occlusion caused by transient balloon, and detecting endoleaks after endograft deployment. Cardiac performance may be monitored by TEE during the acute hemodynamic disturbances of stent deployment. Diastolic dysfunction is the end result of perioperative myocardial injury that remains undetected by any other monitoring modality (Table 3).16 An endoleak is a unique complication of TEVAR and occurs when blood flows outside the lumen of the endograft but within an aneurysm sac. The causes of endoleak are described in Table 4. Endoleaks have been classified into types I to IV based on the underlying cause and anatomic

• Difficult to distinguish from other types of graft leakage • Diagnosis is made after exclusion of any identifiable source of endoleak

site of origin. Accurate detection and classification are essential for proper management because the method of endoleak treatment is determined by its source.17 In general, high-pressure leaks (types I and III) require urgent management because of the relatively high shortterm risk for sac rupture. Observational management of type II endoleaks may be associated with continued sac expansion, requiring close monitoring (Table 5). Lowpressure lesions (type II) are considered less urgent but may require continued endovascular evaluation if there is impending growth of the aneurysm sac. Endoleaks requiring correction include all type I and III lesions as well as type II lesions associated with aneurysm enlargement. Techniques used incorporate extension endografts or cuff, balloon angioplasty, and bare stents. Type II endoleak continues to be the most common but also the most controversial in terms of evaluation, need for treatment, and methods of treatment. Postoperative lifelong follow-up with CT imaging is needed.18

Management of the Case Presented This patient has a type B aortic dissection complicated by periaortic leakage but with no evidence of organ malperfusion or limb ischemia. Surgical or endovascular repair was indicated for the periaortic leak with potential for aortic rupture. Maintaining BP control and hemodynamic stability is of critical importance, with the goal of

keeping systolic BP below 120 mm Hg while maintaining sufficient organ perfusion to the brain, heart, and kidneys. The patient was given esmolol and sodium nitroprusside infusions preoperatively for strict BP control and to minimize the shear forces on the aorta. She was not receiving anticoagulants or clopidogrel, so after discussion with the surgeon, a decision was made to place a lumbar drain, as the surgeon was planning to cover a large area of the thoracic aorta. The risk for SCI was anticipated for this procedure, and a plan was made to monitor her neurologic status intraoperatively using SSEPs and MEPs. Prior to the patient’s arrival in the operating room, a right radial arterial cannula was placed for close BP monitoring and frequent blood gas sampling, along with a large-bore peripheral IV. The right radial artery was chosen for arterial line placement due to the possibility of the proximal landing zone covering the left subclavian artery, thereby inhibiting flow to the left radial artery. The patient received premedication with IV midazolam and was brought to the operating room, where standard monitors were placed. A lumbar drain was placed atraumatically in sitting position. Opening CSF pressures were normal. CSF pressures were transduced and fluid intermittently drained if CSF pressure exceeded 10 mm Hg. Anesthesia was induced with sufentanil, propofol, and succinylcholine, and she was maintained with propofol and sufentanil infusions along with 0.5% inspired isoflurane. After induction, central venous access was obtained by a right internal jugular vein 9 Fr introducer for potential central venous pressure monitoring and for rapid infusion. A central line is recommended for rapid fluid administration from acute blood loss secondary to procedure-related complications or aortic pathology. It provides portals for pharmacologic therapy with pressors or inotropes, and for insertion of invasive monitors, such as a pulmonary artery catheter if necessary, to optimize hemodynamic status in hypotensive states. Although there are concerns about central line–related complications leading to pneumothorax, hematoma, infection, and thrombosis, we routinely place a central line for this procedure using ultrasound guidance and remove the catheter early if it is not required. Pulse pressure variations are dynamic preload indicators and also can be used to assess volume responsiveness in ventilated patients. TEE probe was placed atraumatically to provide rapid real-time assessment of cardiac structures, with a view to assessing functional status and treating hemodynamic instability. Pericardial effusion and aortic valve abnormalities were excluded, and aortic pathology comprising aneurysm and intimal flap in descending thoracic aorta was identified. True and false lumens were confirmed, and the location of guide wire in the true lumen was checked. The aortogram demonstrated a descending thoracic aortic aneurysm with a portion of the posterior aorta showing extravasation. Both proximal and distal landing zones were observed, and it was determined that the left subclavian artery would not be covered by the endograft. A 34 mm ×10 cm TAG device was chosen based on the aortogram, and was advanced over the guide wire and brought into position and deployed. This was followed by ballooning of the proximal and distal portions of the graft. A proximal type I endoleak was noted distally by TEE, so the balloon was reinserted and inflated along the length of the graft. The balloon inflation resolved the endoleak on TEE. A final aortogram revealed adequate seal of the proximal and distal landing zones. TEE helped to guide administration of fluids and pressors. Patient had decreased end-diastolic volume on transgastric short axis view, with increased contractility and no

21


CONTINUING MEDICAL EDUCATION

22

JUNE 2012

This lesson is available online at www.mssm.procampus.net

regional wall motion abnormality. Fluid boluses and norepinephrine infusion helped achieve a MAP between 80 and 90 mm Hg for adequate spinal cord perfusion after the stent deployment. The patient was successfully extubated in the operating room, and her neurologic exam was normal. She was monitored in the intensive care unit, and MAPs were maintained between 80 and 90 mm Hg. The spinal drain was removed after 48 hours. A follow-up CT angiogram was performed and confirmed adequate placement of the endograft with no evidence of extravasation or displacement. She was transferred to floor, in stable condition.

Conclusions TEVAR is emerging as the treatment of choice for acute surgical emergencies involving the descending thoracic aorta. The data support the safety and efficacy of TEVAR for aortic pathologies with a low mortality rate. We described a case of successful anesthetic management of a patient who presented with acute aortic dissection Stanford type B associated with periaortic hematoma and aortic dilatation necessitating surgical intervention. Her BP was initially controlled while further workup and imaging studies were performed. The patient met the surgical criteria for endovascular stent placement and had no complications related to organ malperfusion. She was considered at high risk for SCI, and a lumbar drain with CSF pressure and intraoperative neurologic monitoring were done. Invasive hemodynamic monitoring and TEE were additionally employed. We conclude that perioperative workup and anesthetic

technique need to be tailored to the patient’s underlying comorbidities and aortic pathology. Current endograft technology has evolved sufficiently to allow for successful treatment for emergent conditions involving the descending thoracic aorta.

References 1.

Ramanath VS, Oh JK, Sundt TM 3rd, Eagle KA. Acute aortic syndromes and thoracic aortic aneurysm. Mayo Clin Proc. 2009;84(5):465-481.

2.

Davies RR, Goldstein LJ, Coady MA, et al. Yearly rupture or dissection rates for thoracic aortic aneurysms: simple prediction based on size. Ann Thorac Surg. 2002;73(1):17-27.

3.

Mitchell ME, Rushton FW Jr, Boland AB, Byrd TC, Baldwin ZK. Emergency procedures on the descending thoracic aorta in the endovascular era. J Vasc Surg. 2011;54(5):1298-1302.

considerations for thoracoabdominal aortic aneurysm repair. Anesthesiology. 2011;115(5):1093-1102. 10. Conrad MF, Cambria RP. Contemporary management of descending thoracic and thoracoabdominal aortic aneurysms: endovascular versus open. Circulation. 2008;117(6):841-852. 11. Liu EH, Wong HK, Chia CP, Lim HJ, Chen ZY, Lee TL. Effects of isoflurane and propofol on cortical somatosensory evoked potentials during comparable depth of anaesthesia as guided by bispectral index. Br J Anaesth. 2005;94(2):193-197. 12. Cheung AT, Pochettino A, McGarvey ML, et al. Strategies to manage paraplegia risk after endovascular stent repair of descending thoracic aortic aneurysms. Ann Thorac Surg. 2005;80(4):1280-1288. 13. Sinha AC, Cheung AT. Spinal cord protection and thoracic aortic surgery. Curr Opin Anaesthesiol. 2010;23(1):95-102. 14. Wynn MM, Mell MW, Tefera G, Hoch JR, Acher CW. Complications of spinal fluid drainage in thoracoabdominal aortic aneurysm repair: a report of 486 patients treated from 1987 to 2008. J Vasc Surg. 2009;49(1):29-34.

4.

Sachs T, Pomposelli F, Hagberg R, et al. Open and endovascular repair of type B aortic dissection in the Nationwide Inpatient Sample. J Vasc Surg. 2010;52(4):860-866.

5.

Hughes GC, Sulzer CF, McCann RL, Swaminathan M. Endovascular approaches to complex thoracic aortic disease. Semin Cardiothorac Vasc Anesth. 2008;12(4):298-319.

15. Dardik A, Perler BA, Roseborough GS, Williams GM. Subdural hematoma after thoracoabdominal aortic aneurysm repair: an underreported complication of spinal fluid drainage? J Vasc Surg. 2002;36(1):47-50.

6.

Falkenberg M, Lönn L, Schroeder T, Delle M. TEVAR and covering the celiac artery. Is it safe or not? J Cardiovasc Surg (Torino). 2010;51(2):177-182.

16. Rocchi G, Lofiego C, Biagini E, et al. Transesophageal echocardiography-guided algorithm for stent-graft implantation in aortic dissection. J Vasc Surg. 2004;40(5):880-885.

7.

Fanelli F, Dake MD. Standard of practice for the endovascular treatment of thoracic aortic aneurysms and type B dissections. Cardiovasc Intervent Radiol. 2009;32(5):849-860.

17. Parmer SS, Carpenter JP, Stavropoulos SW, et al. Endoleaks after endovascular repair of thoracic aortic aneurysms. J Vasc Surg. 2006;44(3):447-452.

8.

Gutsche JT, Szeto W, Cheung AT. Endovascular stenting of thoracic aortic aneurysm. Anesthesiol Clin. 2008;26(3):481-499.

9.

Vaughn SB, Lemaire SA, Collard CD. Case scenario: anesthetic

18. Cao P, De Rango P, Verzini F, Parlani G. Endoleak after endovascular aortic repair: classification, diagnosis and management following endovascular thoracic and abdominal aortic repair. J Cardiovasc Surg (Torino). 2010;51(1):53-69.

Visit www.mssm.procampus.net today for instant online processing of your CME post-test and evaluation form. There is a registration fee of $15 for this non–industry-supported activity. For assistance with technical problems, including questions about navigating the Web site, call toll-free customer service at (888) 345-6788 or send an email to Customer.Support@ProCEO.com.

For inquiries about course content only, send an email to ram.roth@mssm.edu. Ram Roth, MD, is director of PreAnesthetic Assessment Online and assistant professor of anesthesiology at The Mount Sinai School of Medicine, New York, NY.

Post-Test 1.

The indications for surgical intervention in Stanford type B aortic dissection include _____ a. b. c. d.

2.

extravasation of blood from the aorta rapidly expanding false aneurysm hypertension obstruction of renal vessels

4.

Using the technique of thoracic endovascular aneurysm repair (TEVAR) to manage descending thoracic aneurysm entails the following anesthetic plan: a. Use of one-lung ventilation to visualize the descending aorta. b. Radial line can be placed in either upper extremity. c. Mean arterial pressures (MAPs) need to be maintained higher than 80 mm Hg before stent graft is deployed. d. Monitoring blood loss, as significant loss can occur from groin and retroperitoneal hematomas.

3.

c. endograft coverage may span coverage between left common carotid artery and celiac axis d. the celiac axis must never be covered to achieve an adequate distal landing zone

The surgical considerations for endovascular repair of thoracic aortic aneurysm include all of the following EXCEPT: a. adequate proximal and distal landing zones b. access to femoral or iliac vessels

Anesthetic considerations for endovascular graft deployment include all of the following EXCEPT:

6.

a. b. c. d.

7.

a. consideration should always be given to the idea of an open procedure being needed. b. the procedure is performed on vascular patients with significant comorbidities. c. regional techniques are preferred, as they facilitate neurologic examination. d. vasopressors and inotropes should be immediately available for management of hemodynamic emergencies.

5.

<12 mm Hg 12-15 mm Hg 15-17 mm Hg 17-20 mm Hg

Each of the following is a method of treatment or prevention of spinal cord ischemia during TEVAR EXCEPT: a. early detection of ischemia by intraoperative monitoring with somatosensory evoked potential and motor evoked potential (MEP). b. augmentation of spinal cord perfusion by elevated blood pressure and CSF drainage. c. performing an elective subclavian revascularization if the subclavian artery needs to be covered by endovascular stent graft. d. MAP may be kept lower and lumbar drain is not needed in treating type II Crawford thoracoabdominal aortic aneurysm.

A lumbar drain a. should be routinely used in all patients undergoing TEVAR. b. may be placed postoperatively if there is delayed-onset paraparesis. c. should not be used if heparin is given intraoperatively during TEVAR. d. should be continuously drained to prevent spinal cord ischemia.

Cerebrospinal fluid (CSF) pressures during TEVAR should be maintained at _____

8.

_____ can be used to maintain adequate MEP signals intraoperatively. a. Nondepolarizing muscle relaxants

b. High-dose volatile anesthetics c. Propofol infusion d. Succinylcholine

9.

All of the following are true regarding aortic aneurysms EXCEPT: a. they are classified according to location, morphology, and etiology. b. location is NOT used to determine surgical approach. c. aortic dissection may be associated with an aneurysm. d. true aneurysms involve all layers of the aortic wall.

10. Which of the statements regarding endoleaks is true? a. A type I endoleak is a diagnosis of exclusion, and a contrast angiography is not needed for its diagnosis. b. Most type II leaks should only be observed if they are associated with continued sac expansion. c. A type I leak occurs due to reactions of the endograft within the aneurysmal sac environment. d. Transesophageal echocardiography is not helpful in the detection of type I endoleaks.


24  I  AnesthesiologyNews.com

June 2012

C L I N I C A L A N E S T H E SI O LO G Y

Overweight Patients Often Receive Excessive NMBAs “Here in Florida, we have one of the highest reintubation rates in the country,” said Lalitha V. Sundararaman, MD, an anesthesiology resident at the University of Miami’s Jackson Memorial Hospital. “To help get to the root of this issue at our institution, Drs. Michael Vigoda, Luis Rodriguez and I started looking at iatrogenic factors that may contribute to

reintubation.” Previous research showed that using total body weight to determine dose in obese patients may increase the duration of action of neuromuscular blockers. Dr. Sundararaman and her colleagues analyzed the electronic medical records of 3,004 elective cases performed by senior anesthesiology providers in all subspecialties. Patients

were aged between 3 and 80 years, and their body surface area ranged from 25 to 32 kg/m2. Calculations of ideal body weight were adjusted for age and sex. Intubation doses of vecuronium and rocuronium were compared with the traditional maximum accepted doses of 0.1 and 1.2  mg/kg, respectively. “We found that we are sadly overdosing our patients,” said Dr. Sundararaman, who reported the results at the 2011 annual meeting of the American Society of Anesthesiologists (abstract 440). In the 1,921 patients who received rocuronium, the maximum acceptable dose was exceeded in 3.59% of cases when total body weight was used to calculate appropriate doses. Vecuronium was used in 1,071 cases. In those patients, the maximum acceptable dose was exceeded in 23% of patients when total body weight was used. The difference was found to be statistically significant (P<0.01) in both the rocuronium and vecuronium groups. The investigators also tracked dosing based on sex, and found that 70% of the patients who received higher-than-maximum doses were women. “I think the reason we overdose vecuronium so much is that it is so short-acting, and we tend to be more

1000

Rocuronium (1.2 mg/kg)  < Recommended  > Recommended

800

Number of Cases

Chicago—A significant proportion of overweight patients receiving vecuronium are being overdosed, a practice that may increase rates of reintubation, Florida researchers have found. The investigators concluded that because the use of total body weight results in excessive dosing, ideal body weight may be a more desirable guide to administering the drug.

600

P<0.01

400

200

3.59% 0

Dose/BW

6.42%

Dose/IBW

Figure. Nearly a quarter of vecuronium doses by total body weight exceeded upper limit. BW, body weight; IBW, ideal body weight


June 2012

AnesthesiologyNews.com  I  25

CL I N I CA L A N E S T H E SI OL O G Y liberal with it,” Dr. Sundararaman told Anesthesiology News. “We think our patients will come out quickly and it won’t be a problem. But that’s not really a good strategy, because there are always some patients in whom the surgery finishes early and we’re caught red-handed. So it’s always better to give the right dose.” Making estimates of ideal body weight is a tricky undertaking at the best of times, so Dr. Sundararaman recommended several free smartphone applications that help do the job. “Then you can note the patient’s ideal body weight in the preoperative chart, so it’s readily available when you need it,” she said. Although the researchers have yet to report if their efforts have affected reintubation rates, Dr. Sundararaman said these and other changes can serve only to improve patient care at the institution. “We also made it mandatory that anesthesiologists have to check the 100-Hz fade to tetanus before they extubate,” she said. “There is a significant iatrogenic component to all of this, and one we think can actually be corrected easily.” Michael Higgins, MD, MPH, professor of anesthesiology, surgery and biomedical informatics at Vanderbilt University School of Medicine, in Nashville, Tenn., said anesthesiologists could take a few lessons from the pediatric subspecialty.

100

“Not to insult anyone, but in pediatrics—because of the variable weights of our patients—we keep dosing sheets for the typical medications in every operating room,” Dr. Higgins said. “Well, we’re sort of entering into that realm with adult patients now, with high variability and extremes of weight. And maybe it’s not too inconceivable to think of doing the same thing with adults.”

@

Contact

the editor of Anesthesiology News

amarcus@mcmahonmed.com

—Michael Vlessides

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OFIRMEV reduces opioid consumption*1 • OFIRMEV 1 g (Q6h) + PCA morphine significantly reduced morphine consumption vs placebo + PCA morphine (–46% over 6 h, P<0.01; –33% over 24 h, P<0.01)1 • The clinical benefit of reduced opioid consumption was not demonstrated

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Indication OFIRMEV is indicated for the management of mild to moderate pain; the management of moderate to severe pain with adjunctive opioid analgesics; and the reduction of fever.

Number of Cases

80

60

Important Safety Information OFIRMEV is contraindicated in patients with severe hepatic impairment, severe active liver disease or with known hypersensitivity to acetaminophen or to any of the excipients in the formulation. Acetaminophen should be used with caution in patients with the following conditions: hepatic impairment or active hepatic disease, alcoholism, chronic malnutrition, severe hypovolemia, or severe renal impairment.

P<0.01

40 26.33% 20

0

23%

Do not exceed the maximum recommended daily dose of acetaminophen. Administration of acetaminophen by any route in doses higher than recommended may result in hepatic injury, including the risk of severe hepatotoxicity and death. OFIRMEV should be administered only as a 15-minute intravenous infusion.

Discontinue OFIRMEV immediately if symptoms associated with allergy or hypersensitivity occur. Do not use in patients with acetaminophen allergy. The most common adverse reactions in patients treated with OFIRMEV were nausea, vomiting, headache, and insomnia in adult patients and nausea, vomiting, constipation, pruritus, agitation, and atelectasis in pediatric patients. OFIRMEV is approved for use in patients ≥2 years of age. The antipyretic effects of OFIRMEV may mask fever in patients treated for postsurgical pain. To report SUSPECTED ADVERSE REACTIONS, contact Cadence Pharmaceuticals, Inc. at 1-877-647-2239 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.com. Please see Brief Summary of Prescribing Information on adjacent page or full Prescribing Information at OFIRMEV.com.

*Randomized, double-blind, placebo-controlled, single- and repeated-dose 24-h study (n=101). Patients received OFIRMEV 1 g + PCA morphine or placebo + PCA morphine the morning following total hip or knee replacement surgery. Primary endpoint: pain relief measured on a 5-point verbal scale over 6 h. Morphine rescue was administered as needed. †SPID24=sum of pain intensity differences, based on VAS score, from baseline, at 0 to 24 h.

Dose/BW

Dose/IBW

References: 1. Sinatra RS, Jahr JS, Reynolds LW, Viscusi ER, Groudine SB, Payen-Champenois C. Efficacy and safety of single and repeated administration of 1 gram intravenous acetaminophen injection (paracetamol) for pain management after major orthopedic surgery. Anesthesiology. 2005;102:822-831. 2. Data on file. Cadence Pharmaceuticals, Inc.

©2012 Cadence Pharmaceuticals, Inc. All rights reserved.

OFIRMEV and the OFIRMEV dot design are trademarks of Cadence Pharmaceuticals, Inc.

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June 2012

C L I N I C A L A N E S T H E SI O LO G Y Femoral  continued from page 1 “I applaud the efforts of these investigators, because we need more data on the benefits and risks of femoral nerve blocks,” said Brian M. Ilfeld, MD, MS, associate professor of anesthesiology at the University of California, San Diego, who was not involved in the studies. “We recognize there are sometimes complications with any invasive procedure, including regional anesthetics, so the more data

we have, the more information we can provide patients.” Femoral Blockade Versus Periarticular Injection One of the studies (abstract P201) compared two widely used protocols for perioperative pain management after total knee arthroplasty (TKA). The prospective, randomized controlled trial enrolled 90 patients. Half received epidural analgesia plus femoral nerve block (PCEA/FNB); the rest

received periarticular injections plus oral opioids (PAI). Patients in both protocols had similar lengths of stay in the hospital and similar postoperative pain scores. However, patients who received PCEA/FNB reported significantly less pain with ambulation on postoperative day 1, and less pain with regard to quality of recovery. Patients in both groups reported similar pain levels on the second and third days after surgery. The researchers also found no significant differences between the groups in global quality of recovery scores, patient satisfaction or opioid intake. “We were surprised that PAI worked almost as well as PCEA/FNB,” said Geoffrey H. Westrich, MD, orthopedic surgeon at the Hospital for Special Surgery in New York City, who led the research. “We can now tell smaller hospitals that don’t have our level of expertise that PAI works extremely well; much better than just giving pain pills after surgery.” The PAI approach also is less expensive than PCEA/FNB, and Dr. Westrich noted that he would consider trying the protocol in his surgical practice. However, he added, a multimodal approach to pain management works best. “One of the most common concerns patients have is how much pain they’ll experience and how we’ll treat it. They like the control they have with a pain pump,” he said. Dr. Ilfield said the study was an important addition to the data set on FNB. “It has become a trend for


June 2012

AnesthesiologyNews.com  I  27

CL I N I CA L A N E S T H E SI OL O G Y orthopedic surgeons to try high-dose local anesthetics,” Dr. Ilfeld said. “But we don’t have adequate data. This study sheds more light on what’s optimal for patients after TKA for pain control.”

Congratulations to Robert Toney O’Bannon III, MD, winner of this year’s Readex ad survey!

Easier Recovery In a second, unrelated study (abstract P195), researchers at New England Baptist Hospital, in Boston, found that regional anesthesia, including continuous FNB, significantly improved patients’ postoperative range of motion and reduced their need for manipulation following TKA. The retrospective review looked at 1,091 TKA procedures performed by two surgeons using identical prostheses, postoperative rehabilitation protocols and surgical techniques. The surgeries occurred both before and after the hospital’s anesthesiologists began using continuous femoral nerve catheters. Before the catheters became routine, 12% of TKA patients required manipulation after surgery. That figure fell to 6% once the catheters became widely used. The decrease was independent of the surgeon. “Because manipulation is expensive—if you avoid it, you easily more than make up the cost of the infusion,” Dr. Ilfeld said. “The results demonstrate a need for a large, prospective randomized trial.” Femoral Block or Morphine? In a third, unrelated study (abstract 666), researchers at the Hospital for Joint Diseases at NYU Langone Medical Center, in New York City, found that single-injection FNBs are an excellent alternative to routine narcotic pain medication after hip arthroscopy. In the study, 40 patients were randomized into two groups once they reached the PACU. Half received routine IV opioids if their pain scores were 7 or greater; the rest received a femoral block for pain of the same severity. Patients who received opioids stayed in the PACU longer, were more likely to report postoperative nausea and reported being less satisfied with their postoperative pain control than patients in the FNB group. “An hour decrease of PACU time is enormous, and provides a huge cost savings,” Dr. Ilfeld said. “These are important results because we don’t have a lot of data looking at post-op outcomes other than pain, and how they benefit patients and the entire health care system.” —Dana Hawkins-Simons

Dr. O’Bannon, an instructor in the Department of Anesthesiology and Perioperative Medicine at Georgia Health Sciences University, in Augusta, will receive a $500 gift card from American Express.

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June 2012

C L I N I C A L A N E S T H E SI O LO G Y

PONV Steroids Seen Safe for Wound Healing After Cancer Surgery Chicago—Dexamethasone for the prevention of postoperative nausea and vomiting does not increase the risk for wound complications after laparotomy for endometrial cancer, a recent study has found. “Corticosteroids such as dexamethasone have been associated with delayed wound healing and increased risk for wound infection when high and

moderate doses were given immediately after cellular injury,” said Corey S. Bolac, MD, anesthesia resident at Duke University Medical Center, in Durham, N.C., who led the study. “Nevertheless, the current literature is inconclusive on whether the use of single-dose dexamethasone increases the risk for postoperative wound complications.”

Dr. Bolac’s group analyzed medical records from 431 women who underwent laparotomy for endometrial cancer at Duke between 2002 and 2007 (median age, 60 years; median body mass index [BMI], 34 kg/m2; median surgical time, 160 minutes). The investigators looked for reports of cellulitis, surgical site infection, superficial wound separation or fascial

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dehiscence. They also analyzed baseline characteristics and perioperative details that have been found to be independently associated with wound infections after surgery. Baseline characteristics included BMI, age, diabetes, immunosuppression and smoking status; perioperative details included use of preoperative antibiotics, duration of surgery, lymph node dissection, surgical closure, estimated blood loss, intraoperative temperature and other variables. Roughly 30% (134) of patients developed a wound complication after their procedure. Yet the researchers found no link between dexamethasone and poor wound healing: 27.6% of patients who received dexamethasone (53 of 192) developed an infection, compared with 33.9% of patients who did not receive dexamethasone (81 of 239; P=0.16). Nor did escalating dose appear to have an effect. “Our study was performed in a high-risk patient population for surgical site infections,” Dr. Bolac said. “These patients all had cancer with its associated immunocompromised state, tended to be obese, primarily underwent large midline laparotomy and had longer operative durations. These characteristics would seem to make them more susceptible to the immunosuppressive effects of corticosteroids, but we could find no such association.” Not particularly surprising, the researchers said, was the finding that BMI and smoking were the most significant predictors of wound infection in this patient population—and the only ones to remain after multivariate analysis. Narinder Rawal, MD, professor of anesthesiology and intensive care at Örebro University Hospital in Örebro, Sweden, said the researchers’ definitions of wound infection as “anything requiring extra care,” might have confounded their findings. That happens to be what the Centers for Disease Control and Prevention recommends for defining such complications, Dr. Bolac noted, although it leaves a substantial amount of discretion to clinicians. The researchers reported their findings at the 2011 annual meeting of the American Society of Anesthesiologists (abstract 785). —Michael Vlessides


June 2012

AnesthesiologyNews.com  I  29

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POL I CY & M A N A G E M E N T Practice  continued from page 1 residents receive inadequate exposure to key issues in billing, reimbursement, liability, contracts and other aspects of running their practice. At the same time, most respondents agreed that these issues are “important” in their workday. “Physicians are trained well in clinical sciences, but we don’t get a lot of training in some of the business and practice management areas that are also an important part of being a physician,” said study author Philip Kalarickal, MD, MPH, clinical assistant professor of anesthesiology at Tulane University School of Medicine, in New Orleans. Dr. Kalarickal and his colleagues convened a working group of practicing anesthesiologists, including some on the ASA committee on practice management, to compile a list of topics that they believe should be an important part of any curriculum in practice management (abstract PM19). The researchers then mailed a survey to the entire ASA membership, asking them if they had received adequate training in these areas, and collected responses from May through October 2011. More than 3,600 clinicians responded, for a response rate of 12%. The majority said they did not believe

‘Current anesthesiology trainees who believe they are going to make a comfortable living just providing OR anesthesia, I think are going to be sorely disappointed with their careers.’ —David Mackey, MD residency programs included enough training in practice management. “Our working hypothesis was it would indeed be the case that there were deficiencies,” Dr. Kalarickal told Anesthesiology News. “But I was surprised at how strong they were.” For instance, between 68% and 88% of respondents said they thought residents were inadequately exposed to billing issues; 71% said there was not enough training in insurance reimbursement. However, the majority of all participants—at least 84% in every bracket of experience—agreed that training in practice management could help improve patient care and outcomes, quality, safety and containment of health care costs. More than half of respondents said they believed residents got enough exposure to the topics of quality assurance/improvement and

scheduling in the operating room (OR). And residency program directors were least likely to say that training failed to address issues in practice management. That makes sense, Dr. Kalarickal said, for obvious reasons. “Their perception is that they may be doing a better job than they actually are.” Dr. Kalarickal said he hoped the findings will encourage program directors to look more critically at their curricula, and add more time and expertise to program management. “We hope that residency programs, based on this, recognize that there is a need for more training in these areas.” David Mackey, MD, professor in the Department of Anesthesiology and Perioperative Medicine at the University of Texas MD Anderson Cancer Center, in Houston, said he agreed with the gist of the survey findings. Anesthesia trainees are not getting

enough exposure to practice management, said Dr. Mackey, who was not involved in the study. “I think trainees understand this better than program directors do.” Health care has changed dramatically in recent years, Dr. Mackey added. Programs need to help anesthesiology residents transition from simply working in the OR to taking on a broader role in health care by leading and managing the delivery of procedural services in integrated systems. “Current anesthesiology trainees who believe they are going to make a comfortable living just providing OR anesthesia, I think are going to be sorely disappointed with their careers.” Private practices, especially at places like Mayo Clinic and the Cleveland Clinic, are transitioning to integrated health care delivery more easily than traditional academic centers, Dr. Mackey noted. He recommended that leaders of private practices form a standing group to create a practice management curriculum that would give trainees exposure and hands-on experience in business and interpersonal skills. “OR skills are as important as ever,” Dr. Mackey said, “but business management and leadership skills are becoming equally important.” —Alison McCook


30  I  AnesthesiologyNews.com

June 2012

P OL I C Y & M A NA G EMENT

The following advertorial has been provided by Preferred Physicians Medical and is designed to support the advertisement presented on the adjacent page.

Transfusions a Wild Card For Hip Replacement Study highlights need for standards

W

hich patients will receive blood transfusion during hip replacement surgery is a significant area of uncertainty in the operating room—leading to unnecessary costs and potential risks for harm, according to a new abstract presented at this year’s American Society of Anesthesiologists Conference on Practice Management (abstract PM20). After reviewing more than 2,000 hip replacements for osteoarthritis that took place over 15 months in 2009 and 2010, Pittsburgh anesthesiologist Jonathan Waters, MD, and his co-author found that roughly 40% of patients received blood products during the procedure. Some surgeons were much more likely to administer transfusions than others— one surgeon had a 4% transfusion rate, whereas another transfused nearly 90% of patients. “We found hugely varying blood use among surgeons for the exact same procedure,” Dr. Waters, chief of anesthesia at Magee-Women’s Hospital, told Anesthesiology News. And those transfusions carry consequences. The average cost of hip replacement reached $82,480 when patients received blood transfusions (range, $36,732 to $213,740), but only $64,766 without transfusion (range, $35,703 to $121,190), according to the researchers. Patients who received blood products also had longer hospital length of stay (LOS) following surgery—3.5 days with transfusion, 3.2 without. The differences in both cost and LOS were statistically significant (P<0.05). The ultimate goal of the study is to help standardize transfusion practices, explained Dr. Waters. In most cases, patients undergoing hip replacement do not need a blood product. “Probably in the vast majority of circumstances, blood is used outside of an indication. So we’ve been trying to cut back on overuse,” he said. Every year, the University of Pittsburgh Medical Center (UPMC)—of which Magee-Women’s Hospital is a part—spends $52 million purchasing blood products, Dr. Waters said. When the cost of administering the blood and all the other expenses involved with obtaining and storing the fluid are considered, transfusions likely cost the entire hospital system $250 million per

year, he said. That’s a lot of money to spend on something that often is unnecessary, Dr. Waters noted, adding that the Joint Commission recently deemed transfusion of red blood cells one of the most overused procedures in medicine. To evaluate how often transfusions occur during one procedure in the UPMC health system, Dr. Waters and his co-author Trent Emerick, MD, reviewed how often red blood cell transfusions were included in hip replacements procedures. They selected this procedure, Dr. Waters explained, because “it should be a really similar surgical procedure.” Even if patients are anemic, he explained, that problem should be managed before surgery so it does not become an issue. Alternatively, surgeons can avoid transfusions during surgery by administering drugs that minimize the loss of blood, or perform bloodsalvaging procedures that let doctors return lost blood back to patients. Aryeh Shander, MD, chief of the Department of Anesthesiology and Critical Care at Englewood Hospital Medical Center in Englewood, N.J., agreed that the ultimate aim of this research should be to reduce transfusion rates—particularly because they are associated with infections and other potential risks to patients. “There are not only financial implications for unnecessary transfusions, there may be many other clinical implications,” Dr. Shander said. Dr. Shander, who is also the chair of the Committee of Blood Management for the American Society of Anesthesiologists, said the substantial variability in the use of transfusion among UPMC doctors was unsurprising. “There’s enormous variability in transfusion practice across the United States and across multiple surgical procedures,” he said. Dr. Shander noted, however, that the authors did not state if there was any stratification of patients, suggesting that some of those who received transfusions required additional care that might have been unrelated to the transfusion, which independently added to cost and prolonged hospitalization. —Alison McCook

Preferred Physicians Medical Q. Who is Preferred Physicians Medical?

Q. What makes PPM unique?

Q. Will PPM settle a claim without the insured physician’s consent?

A. PPM is the only company of its kind in America—the only company founded by and for anesthesiologists exclusively. As well, PPM has historically turned down more than 25% of its applicants. A condition of insurance is that all physicians meet or exceed the American Society of Anesthesiologists (ASA) Standards of Care when practicing, thereby creating what we believe to be the safest risk pool in the country. No other company requires this of their insureds. Although only 4% of the total physician population is anesthesiologists, 100% of PPM’s clients are anesthesiologists, so 100% of our time is spent developing products and services specific to the professional liability needs of anesthesia practices. This is especially important in risk management efforts.

A. No. PPM’s policy states that the company will not settle a claim without the insured physician’s consent.

Q. Can you comment on your risk management efforts?

A. Preferred Physicians Medical (PPM) is an anesthesiologist-only professional liability insurance company.

Q. How many years has PPM been in business? A. 2012 marks PPM’s 25th year in business.

Q. Who owns the company? A. PPM is a stock company owned exclusively by the anesthesiologists it insures.

Q. How is PPM different from its multispecialty competitors? A. Most notably, we are anesthesia-specific and do not have multiple agendas or try to be all-encompassing to all physicians. The nature and practice of anesthesia are vastly different from the nature and practice of obstetrics, neurosurgery, radiology, cardiology and other specialties, and represent unique and different exposures from a liability standpoint. We spend our entire day, every day, servicing anesthesia practices exclusively. No other company in America does this.

Q. How much anesthesia loss experience data does the company have? A. We believe PPM possesses the most extensive anesthesia claims database in existence. Collectively, our policyholders have generated a database comprising well over 65,000 doctor-years of anesthesia practice, including more than 44,000 since joining the company. This includes prior-acts coverage back to 1980. Since 1987, we have reviewed the claims history of more than 16,000 practicing anesthesiologists. In addition, PPM’s claims department has investigated more than 11,000 adverse incident outcomes, and more than 3,000 claim or litigation files. With this information, PPM has an unparalleled ability to identify and address loss trends. PPM uses this data to establish fair and appropriate premium levels, manage claim files and provide anesthesia-specific risk management advice to its policyholders in the form of seminars, publications such as Anesthesia & the Law and through a policyholder-only resource area on our Web site.

A. Risk management is one of PPM’s strong areas, and, again, is unique insofar as it is entirely anesthesia-specific. PPM’s five in-house attorneys spend all day, every day overseeing, managing and defending anesthesia claims exclusively. These same attorneys conduct our site-specific risk management seminars every year for our insured owners. Some examples of topics at the seminars include but are not limited to causes and prevention of intraoperative fires, implementation of the new ASA Standard for Basic Anesthesia Monitoring, postoperative drug-induced respiratory depression, securing narcotics and medication in the operating room, top 10 anesthesia claims and how to avoid them, and more. PPM’s risk management is proactive, designed for each insured group’s specific practice and provides practical, thoughtful advice. With a claims database in excess of 64 million administered anesthetics, more than 11,000 adverse incident reports and more than 3,000 claim reports, PPM’s policyholders are assured they are receiving insightful, valuable and important information they can use to mitigate their exposures moving forward and apply immediately in their practice setting.

Q. What else should I know? A. You should know that it costs nothing to evaluate your options. If you are not currently sharing risk with other ASA Standard of Care clinicians, isn’t it worth five minutes of your time to learn what PPM can offer that your existing carrier may be unable to provide? Don’t settle—Own! Call us at (800) 562-5589 and let us show you who we are and what we can do for you!


Preferred Physicians Medical (PPM) formed in 1987 to exclusively insure anesthesiologists and their practices. From day one, each new policyholder also became an owner of PPM, so it’s no surprise that protecting our physicians’ professional reputation is at the core of everything we do. Our substantial database of more than 11,000 adverse anesthesia events collected over the last quarter of a century arms our physician owners with practical, anesthesia-specific strategies to effectively identify and manage risk, including: On-site, anesthesia-specific risk management seminars Exclusive online access to timely and useful risk management resources A subscription to Anesthesia & the Law, our industry-respected risk management newsletter In-house Claims Attorneys and Claims Specialists skilled in using this data to effectively develop defense strategies and resolve claims without indemnity payment Don’t wait another year. Take ownership of your own reputation by calling PPM today.

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Ultrasound-Guided Central Vein Cannulation: Current Recommendations and Guidelines JULIE A. GAYLE, MD Assistant Professor of Clinical Anesthesiology Louisiana State University School of Medicine New Orleans, Louisiana

ALAN DAVID KAYE, MD, PHD Professor and Chairman Department of Anesthesiology Louisiana State University School of Medicine New Orleans, Louisiana The authors report no relevant financial conflicts.

U

ltrasound technology has become an essential tool

for the everyday practice of anesthesiology. Some of the many uses include

the placement of central, arterial, and peripheral lines, as well as peripheral nerve blocks. Until recently, neither a national standard for ultrasound use nor a wellaccepted standard in training for ultrasound-guided central venous cannulation (CVC) existed. In the past few years, several specialty societies and national organizations—including the American Society of Anesthesiologists, the American Society of Echocardiography, the Society of Cardiovascular Anesthesiologists, and the Centers for Disease Control and Prevention (CDC)—have published guidelines and recommendations regarding ultrasound-guided vascular cannulation.

I N D E P E N D E N T LY D E V E L O P E D B Y M C M A H O N P U B L I S H I N G

A N E ST H E S I O LO GY N E WS • J U N E 2 0 1 2

1


Catheterization of venous vessels allows access for hemodynamic monitoring; administration of drugs, fluids, and parenteral nutrition; placement of a difficult peripheral IV; and hemodialysis. The internal jugular vein (IJV) and subclavian and femoral veins are the vessels of choice when acquiring central access. For many anesthesiologists, the IJV is a first choice. Historically, entry into the IJV has been facilitated by the visualization and palpation of certain anatomic landmarks. Additional techniques include the use of a smaller bore “finder needle” to first locate the IJV prior to cannulation with a larger bore needle; an indirect ultrasound method, in which the practitioner marks the path of the vein prior to cannulation; and a direct ultrasound technique, in which the vein is visualized using sonography during cannulation.1 The risk for complications during CVC is reported to be between 2% and 15%.2 This rate varies significantly depending on several factors, including the experience of the practitioner and the overall status of the patient.3,4 Among the more frequently encountered complications of CVC, and their respective incidences, are pneumothorax (0-6.6%), carotid artery puncture (6%), subclavian artery puncture (0.5%-4%), and hemothorax (1%).1 In addition, the overall rate of unsuccessful central venous cannulation of the IJV is approximately 12%.5 Earlier studies showed that the use of ultrasound may increase the rate of success of central venous catheter placement and may reduce the incidence of traumatic complications.6 More recent literature has confirmed that ultrasound guidance during insertion of a central venous catheter in the IJV improves the likelihood of first-pass cannulation and decreases the incidence of injury to adjacent arterial vessels.7

History In 1978, Ullman and Stoelting described the first use of ultrasonography for accessing central veins. They used Doppler localization to mark the skin overlying the IJV. They reported that using an ultrasound Doppler blood-flow detector took the “guesswork” out of finding the vein and allowed them to locate the IJV as it traversed the neck. According to the authors, this new technique would increase the success rate of IJV catheterization and decrease accidental puncture of the carotid artery compared with the traditional technique using only anatomic landmarks.8 In 1986, Yonei et al reported on the use of real-time ultrasonographic guidance for IJV cannulation.9 In 2001, the Agency for Healthcare Research and Quality (AHRQ) reported that use of ultrasonography during central venous access deserved widespread implementation based on the strength of evidence in the literature.10 The AHRQ recommended the use of ultrasound guidance for the placement of central lines as one of 11 evidence-based

2

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practices most likely to improve patient safety. In 2002, the National Institute for Clinical Excellence stated that ultrasound guidance was the preferred method for insertion of central venous catheters into the IJV, and recommended that all clinicians involved in placing these catheters receive appropriate training.11 In 2011, the CDC recommended use of ultrasound guidance to place central venous catheters to reduce the number of cannulation attempts and mechanical complications. Furthermore, in its publication, Guidelines for the Prevention of Intravascular CatheterRelated Infections, the CDC stated that ultrasound guidance should only be used by those clinicians fully trained in the technique.12

Static Versus Dynamic Imaging Static, or indirect, ultrasound imaging during central venous access allows the operator to identify an entry point on the skin over the vessel prior to sterile preparation of the site. Anatomic variations and vital structures may be noted. Compared with the traditional anatomic landmark approach, use of static ultrasound for marking the skin site before cannulation of the IJV is more likely to result in a successful insertion into the vessel.13 Dynamic, or direct, imaging during CVC allows for needle observation as the needle approaches the target vessel. In addition to being more likely to result in a successful insertion on the first attempt, real-time imaging during cannulation of the IJV also reduces access time and the rate of arterial puncture and has a higher overall success rate.14-16

Training The evidence clearly indicates that the use of ultrasound imaging during central venous catheterization, particularly of the IJV, improves success and safety during cannulation. However, the technique also has a well-recognized learning curve. Knowledge of the anatomy of the vessels and surrounding structures is imperative. Interpreting 2-dimensional images of vessels and the surrounding structures takes practice. It takes more practice to perform the 3-dimensional task of placing a needle into the target vessel and developing the eyehand coordination required to direct the probe to optimize visualization of the needle. Although individuals acquire the necessary knowledge and skills at different rates, it has been suggested that a minimum of 10 ultrasound-guided vascular access procedures be supervised to demonstrate competency in the technique.7 Kaye et al identified a “critical” number of central line insertions to differentiate the “experienced” ultrasound user from the novice. They found that anesthesiologists who had performed at least 20 central line insertions under ultrasound guidance had significantly fewer complications than inexperienced clinicians (Figure 1).1


Simulation has proven to be a beneficial training tool for developing proficiency in the use of ultrasound guidance for placing a CVC. Simulation-based ultrasound training results in improved identification of the target vessel with ultrasound compared with landmark techniques and helps inexperienced operators achieve higher rates of successful central line placement with an improved safety profile.17,18 Studies looking specifically at simulation-based training and various outcomes of CVC support its use as a teaching method. These outcomes include successful first cannulation, fewer needle passes, successful catheter insertion, and fewer pneumothoraces.19,20

Site Selection Recommendations regarding selection of a site for placing a line for central venous access involve considerations such as risk for infection, thrombosis, hematoma, pneumothorax, and arrhythmias. To minimize the risks for infection and thrombosis, insertion sites in the upper body, IJV, and subclavian vein are preferred to the femoral vein. The insertion site should be free of contamination or potential contamination. Sites in close proximity to wounds, burns, saliva, excrement, and infections should be avoided.

The subclavian vein is the preferred site for longerdwelling catheters because it has the lowest rate of infection and thrombosis. Although ultrasound guidance for insertion of a catheter in the IJV has overwhelming support in the literature, the use of ultrasound for cannulation of the subclavian vein is more complicated. The clavicle obscures visualization of the vessel, making dynamic imaging during cannulation difficult. However, patients in whom external landmarks are hard to identify, such as the morbidly obese or those who have local scarring from surgery or radiation in the neck, static ultrasound imaging prior to cannulation may help to visualize the vessel and rule out thrombosis.7 The femoral vein is a frequent site of catheterization during cardiac procedures, emergent central access, and other therapies that require short-term access to a vessel. Reliable anatomic landmarks and relatively quick and safe access are advantages of femoral vein cannulation. Ultrasound examination of the anatomy prior to cannulation reveals the location of the vessels and surrounding structures. However, real-time ultrasound imaging during femoral vein catheterization has not been shown to improve outcomes, and evidence currently does not support routine use of ultrasound imaging during this procedure.7

Confirmation of Location „ Non-experienced „ Experienced „ National average

Complication Rates, %

7

6.6 6.0

6 5

4.6

4 3 2 1

0.9

1.0 0.0

0

Carotid Puncture

Pneumothorax

Figure 1. Complication rates of experienced versus non-experienced ultrasound practitioners. National average represents blind technique. Experienced ultrasound practitioners had significantly reduced complication rates. Experienced practitioners were defined as those clinicians taught with ultrasound for central line insertion on a minimum of 20 different patients.1

Unintentional dilation of an artery during CVC is best avoided by confirming location of the guide wire prior to dilating the vessel. Real-time ultrasound guidance is a reliable way to determine if the wire sits in a vein.22 The technology is particularly helpful for avoiding dilation of the carotid artery while attempting catheterization of the IJV (Figure 2). Ultrasound visualization of the guide wire in the longitudinal view, or long axis, of the vein is less ambiguous than the cross-sectional, or short axis, view by itself (Figures 3 and 4). Aligning the ultrasound probe to view the long axis of a central vein and the wire within takes less than a minute for most users and provides another safety measure to avoid arterial injury.7 Manometry, transesophageal echocardiography, direct pressure transduction, analysis of blood gases, fluoroscopy, and electrocardiography also can help confirm the location of a wire in a vein.23 When available, these techniques provide a more definitive, although time-consuming, confirmation that the wire is in a central blood vessel. Confirmation of the correct location of the catheter tip following CVC requires chest radiography or fluoroscopy. Removal of a catheter following inadvertent arterial cannulation carries risks for serious complications including stroke, hemothorax, and arteriovenous fistula. In this situation, the catheter should be left in place and a general or vascular surgeon should be consulted immediately for optimal removal.24

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Figure 2. Cervical ultrasound anatomy relevant to internal jugular venipuncture. Left. Operator’s view of the 4 right-sided ultrasound probe positions; inset shows a magnified view of the region of the sternocleidomastoid triangle and the locations of the 6 right-sided cutaneous vantage points (Vs). Right. Composite diagram of overlapping transverse ultrasonic images obtained from the 3 rightsided cricoid-level ultrasound probe positions of one subject (head rotated 45° to the left). Key to color coding of rectangles indicating standard ultrasound probe positionings: blue=high anterior; yellow=high middle; orange=high posterior; gray=low middle. 45, head rotated 45° away from the side of measurement; a, overlying the anterior (medial) portion of SCMM; aa, medial to SCMM; ant, anterior; b, base of neck; c, cricoid level; CCA, common carotid artery; IJV, internal jugular vein; LN, lymph node; m, overlying the mid portion of the SCMM (transverse plane) or between its sternal and clavicular heads; OmHM, omohyoid muscle; p, overlying the posterior (lateral) portion of the SCMM; post, posterior; pp, posterior to the SCMM; R, right side of neck; rt, right; SCMM, sternocleidomastoid muscle; StHM, sternohyoid muscle; StTM, sternothyroid muscle; Thy, thyroid gland; Trach, trachea.21 Reprinted with permission.

Infection Control Evidence-based recommendations for the prevention of bloodstream infections associated with central lines emphasize education and training of the health care providers inserting and maintaining the catheters, aseptic technique, maximum sterile barrier precautions during insertion, and use of an alcoholic formulation of chlorhexidine for skin disinfection and manipulation of the vascular line.12 To prevent infection, routine placement of central venous catheters should be avoided. If such a catheter is necessary, an insertion site in the upper body should be considered first. To minimize the risk for infection, insertion into the subclavian vein is preferable. Use of a bio-occlusive dressing is recommended, and only qualified personnel should be involved in the changing and care of the

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catheter.12 Central venous catheters should be removed promptly when no longer necessary. In the event of a catheter-related infection, a new catheter should be placed at a new site rather than changing the catheter over a guide wire.24 Use of ultrasound guidance for CVC has not been shown to increase the rate of catheter-related infections; no published study has noted this complication. Sterile needle guides and probe sleeves are widely available and should be used to maintain sterile technique during insertion of the catheter.

Cost and Implementation Despite overwhelming evidence that the use of ultrasound guidance for CVC improves patient safety and clinical outcomes, the technology must be available to the practitioner. The typical cost of


an ultrasound machine, including probes, is $20,000 to $30,000. Therefore, it is important to consider the potential cost savings associated with use of ultrasound for CVC. Ultrasound guidance for catheterization of the IJV consistently results in higher rates of successful cannulation, a lower incidence of complications and cannulation attempts, and a reduction in time spent trying to successfully place a catheter.25 The estimated cost of a pneumothorax resulting from landmark-guided insertion of a central line is approximately $134 per patient. Based on a conservative estimate of 1.5 pneumothoraces per 100 patients using the landmark technique, this complication translates into $5 million to $10 million per year nationally in avoidable expenditures.26 Reductions in failure rates and number of attempts improve efficiency and help demonstrate the economic benefits of ultrasound. Furthermore, ultrasound guidance plays a role in other procedures. The technology has a clearly established role in the placement of peripheral nerve blocks and arterial lines.27,28 Overall cost savings can be realized through a reduction in complications, improved efficiency of health care providers, and increased patient safety.

Conclusion Current literature supports the use of real-time ultrasound guidance for cannulation of the IJV whenever possible to improve success rates and reduce complications. Evidence also clearly indicates that proper training is necessary to achieve better clinical outcomes and improve patient safety.

Future Directions The possibility that ultrasound could create an unhealthy dependence on technology for future generations of anesthesiologists has been the subject of recent debate. It has been suggested that if ultrasound guidance becomes the standard of care for CVC, the anatomic landmark technique might be abandoned. As a consequence, practitioners would lose their skills and trainees would never acquire the ability to place a central line by anatomic landmarks alone. In the event that an ultrasound device is unavailable or not working properly, complications and decreased success rates might result. Advocates of the anatomic landmark technique argue that every anesthesiologist should be able to place a central venous catheter without ultrasound and still achieve a low incidence of complications and a high rate of success.29 Some authors have tried to reconcile the 2 seemingly opposing techniques, suggesting that training programs should teach the landmark technique alongside ultrasound guidance. But, is it realistic to require trainees to learn the landmark technique when it is unlikely they will use it enough to become skillful or even remain competent in the method?30 Real-time ultrasound guidance has become standard practice for cannulation of the IJV and has an expanding role in securing other sites for vascular access. The importance of training in ultrasound guidance for CVC to achieve improved clinical outcomes has been demonstrated repeatedly. Training, therefore, would perhaps be better spent mastering the ultrasound guidance of CVC.31

Figure 3. Long-axis view of internal jugular vein and carotid artery.

Figure 4. Short-axis view of internal jugular vein in close proximity to carotid artery.

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References 1.

Kaye AD, Fox CJ, Hymel BJ, et al. The importance of training for ultrasound guidance in central vein catheterization. MEJ Anesthesiol. 2011;21(1):61-66.

16. Mallory DL, McGee WT, Shawker TH, et al. Ultrasound guidance improves the success rate of internal jugular vein cannulation: A prospective, randomized trial. Chest. 1990;98(1):157-160.

2. Domino KB, Bowdle TA, Posner KI, Spitellie PH, Lee LA, Cheney FW. Injuries and liability related to central vascular catheters: a closed claims analysis. Anesthesiology. 2004;100(6):1411-1418.

17. Hirvela E, Parsa C, Aalmi O, Kelly E, Goldstein L. Skills and risk assessment of central line placement using bedside simulation with 3-dimensional ultrasound guidance system. Crit Care Med. 2000;28:A78.

3. Bo-Linn GW, Anderson DJ, Anderson KC, McGoon MD. Percutaneous central venous catheterization performed by medical house officers: a prospective study. Cathet Cardiovasc Diagn. 1982;8(1):23-29.

18. Sekiguchi H, Tokita JE, Minami T, Eisen LA, Mayo PH, Narasimhan M. A prerotational, simulation-based workshop improves the safety of central venous catheter insertion: results of a successful internal medicine house staff-training program. Chest. 2011;140(3):652-658.

4. Eisenhauer ED, Derveloy RJ, Hastings PR. Prospective evaluation of central venous pressure (CVP) catheters in a large city/county hospital. Ann Surg. 1982;196(5):560-564.

19. Evans LV, Dodge KL, Shah TD, et al. Simulation training in central venous catheter insertion: improved performance in clinical practice. Acad Med. 2010;85(9):1462-1469.

5. Denys BG, Uretsky BF, Reddy PS. Ultrasound-assisted cannulation of the internal jugular vein. A prospective comparison to the external landmark-guided technique. Circulation. 1993;87(5):1557-1562. 6. Ruesch S, Walder B, Tramèr MR. Complications of central venous catheters: internal jugular versus subclavian access—a systematic review. Crit Care Med. 2002;30(2):454-460. 7. Troianos CA, Hartman GS, Glas KE, et al. Guidelines for performing ultrasound guided vascular cannulation: recommendations of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr. 2011;24(12):1291-1318. 8. Ullman JI, Stoelting RK. Internal jugular vein location with the ultrasound Doppler blood flow detector. Anesth Analg. 1978;57(1):118. 9. Yonei A, Nonoue T, Sari A. Real-time ultrasonic guidance for percutaneous puncture of the internal jugular vein. Anesthesiology. 1986;64(6):830-831. 10. Rothschild JM. Ultrasound guidance of central vein catheterization. In: Making Health Care Safer: A Critical Analysis of Patient Safety Practices. AHRQ Publication No 01-EO58. Rockville, MD: Agency for Healthcare Research and Quality; 2001:245-253. 11. National Institute for Health and Clinical Excellence. NICE Technology Appraisal No 49: Guidance on the use of ultrasound locating devices for placing central venous catheters. http://www.nice.org. uk/nicemedia/live/11474/32461/32461.pdf. Accessed March 2012. 12. O’Grady NP, Alexander M, Burns LA, et al. Healthcare Infection Control Practices Advisory Committee. Guidelines for the prevention of intravascular catheter related infections. Am J Infect Control. 2011;39(4 Suppl 1):S1-S34. 13. Milling TJ Jr, Rose J, Briggs WM et al. Randomized, controlled clinical trial of point-of-care limited ultrasonography assistance of central venous cannulation: The Third Sonography Outcomes Assessment Program (SOAP-3) Trial. Crit Care Med. 2005;33(8):1764-1769. 14. Bansal R, Agarwal SK, Tiwari SC, Dash SC. A prospective randomized study to compare ultrasound-guided with non-ultrasound guided double lumen internal jugular catheter insertion as a temporary hemodialysis access. Ren Fail. 2005;27(5):561-564. 15. Karakitsos D, Labropoulos N, De Groot E, et al. Real-time ultrasound-guided catheterization of the internal jugular vein: A prospective comparison with the landmark technique in critical care patients. Crit Care. 2006;10(6):R162.

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20. Ma IW, Brindle ME, Ronksley PE, Lorenzetti DL, Sauve RS, Ghali WA. Use of simulation-based education to improve outcomes of central venous catheterization: a systematic review and metaanalysis. Acad Med. 2011;86(9):1137-1147. 21. Riopelle JM, Ruiz DP, Hunt JP, et al. Circumferential adjustment of ultrasound probe position to determine the optimal approach to the internal jugular vein: a noninvasive geometric study in adults. Anesth Analg. 2005;100(2):514. 22. Stone MB, Nagdev A, Murphy MC, Sisson CA. Ultrasound detection of guidewire position during central venous catheterization. Am J Emerg Med. 2010;28(1):82-84. 23. Ezaru CS, Mangione MP, Oravitz TM, Ibinson JW, Bjerke RJ. Eliminating arterial injury during central venous catheterization using manometry. Anesth Analg. 2009;109(1):130-134. 24. Rupp SM, Apfelbaum JL, Blitt C, et al. Practice guidelines for central venous access: a report by the American Society of Anesthesiologists Task Force on Central Venous Access. Anesthesiology. 2012;116(3):539-573. 25. Hind D, Calvert N, McWilliams R, et al. Ultrasonic locating devices for central venous cannulation: meta-analysis. BMJ. 2003;327(7411):361. 26. Kinsella S, Young N. Ultrasound-guided central line placement as compared with standard landmark technique: some unpleasant arithmetic for the economics of medical innovation. Value Health. 2009;12(1):98-100. 27. Domingo-Triadó V, Selfa S, Martínez F, et al. Ultrasound guidance for lateral midfemoral sciatic nerve block: a prospective comparative, randomized study. Anesth Analg. 2007;104(5):1270-1274. 28. Shiver S, Blaivas M, Lyon M. A prospective comparison of ultrasound-guided and blindly placed radial arterial catheters. Acad Emerg Med. 2006;13(12):1275-1279. 29. Hessel EA 2nd. Con: we should not enforce the use of ultrasound as a standard of care for obtaining central venous access. J Cardiothorac Vasc Anesth. 2009;23(5):725-728. 30. O’Leary R, Bodenham A. Future directions in ultrasound-guided central venous access. Eur J Anaesthesiol. 2011;28(5):327-328. 31. Ridley S. Farewell to history (editorial). Anaesthesia. 2010;65(9):877-879.


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The June 2012 Digital Edition of Anesthesiology News