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THE INDEPENDENT MONTHLY NEWSPAPER FOR ANESTHESIOLOGISTS AnesthesiologyNews.com • F e b r u a r y 2 0 1 3 • Volume 39 Number 2

Registry Sheds Light On Poor Outcomes Of Nerve Blocks San Diego—Although the techniques of regional anesthesia have advanced dramatically in recent decades, the practice is still not without its complications—complications all anesthesiologists should be aware of if they are to fine-tune their practice and improve patient safety. Thanks to a database from Australia, the variety and scope of these events are becoming clearer. In a symposium at the 2012 spring meeting of the American Society of Regional Anesthesia and Pain Medicine, Michael

To Do Less Harm, Know What You Don’t Know Hint: It’s more than you might think New York—Most anesthesiologists understand th he significance of medical errors and their effect on n clinical practice. But are they willing to admit that their own long-held assumptions—even those acquired through years of apparently successful patient care—may be as much a part of the problem as negligence or ignorance? In a far-rangingg discussion at the recent PostGraduate Assembly in Anesthesiology (PGA), four speakers argued that factors such as poor communication, teamwork and leadership, as welll as flawed or biased decision making, might cauuse more medical errors than “technical” mistakes or lack of clinical knowledge.

see complications page 23

see retthink page 16

Two ‘Lows’ Better Than Three For Anesthesia Outcomes Results from cardiac surgery study differ from earlier analysis in other patients Washington—Patients who experience a “double mortality in non-cardiac patients (see Anesthesiology low” of blood pressure and brain function during car- News, November 2009, page 1). diac surgery do not appear to be at higher “Anesthesiologists are increasingly risk for perioperative death, a recent study involved in controlling intraoperative varisuggests. ables that impact postoperative outcomes, including hypothermia, transfusion and The findings diverge from previous research showing that a “triple low” of glucose control,” said Ankit Maheshwari, mean arterial pressure (MAP) and low MD, an anesthesia resident at Cleveland bispectral index (BIS; Covidien) values Clinic, in Ohio, who helped conduct the during low minimum alveolar concenlatest study. “In addition, very low blood tration (MAC) is a strong predictor of see double page 26

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INSIDE 08 | COMMENTARY Botched drugs, broken trust: lessons from the New England compounding scandal.

10 | PAIN MEDICINE The economic tab of chronic post-op pain.

11 | PAIN MEDICINE Cochrane review: Nerve blocks prevent chronic pain after major surgery.

15 | CLINICAL ANESTHESIOLOGY Desaturation and cardiac output go separate ways in one-lung ventilation study.

CME: PREANESTHETIC ASSESSMENT Lesson 302: PreAnesthetic Considerations For a Patient With Hereditary Hemorrhagic Telangiectasia, see page 19.


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Heard Here First: From an economic point of view,

preventing February 2013

long-term

postoperative pain will be

The five most-viewed articles last month on AnesthesiologyNews.com

increasingly important with

1. Seven Red Flags for Outpatient Surgery 2. Canadian Study Reveals High Rate of Residual Paralysis 3. CMS Ruling Exposes Organizational Rift Between Anesthesiologists, CRNAs 4. Meta-Analysis: IV Analgesic Reduces PONV When Given Early 5. Preventable Injuries Frequent in Anesthesia

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accountable care organizations,

provider reimbursements are where

tied to quality metrics that could include pain scores and likely

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to become specialty board-certified as a condition of licensure or licensure renewal. The MOL framework requires neither specialty certificaDear Editor: MOL “framework requires physicians take examinations in order to comply tion nor Maintenance of Certification he Federation of State Medical to pass periodic tests of their knowledge with MOL. While an exam may be an (MOC) or Osteopathic Continuous Boards (FSMB) would like to and skills” could be misinterpreted by option some physicians wish to use to Certification (OCC). However, MOC clarify two points in your arti- some readers to imply that physicians demonstrate their knowledge and skills or OCC may be an option some physicle about its proposed Maintenance will have to take a high-stakes exam in in their area of practice, we are advo- cians wish to use to demonstrate comof Licensure (MOL) initiative (“Ohio order to comply with MOL. cating that such an exam should not be pliance with MOL. Physicians Deal Setback to Push for The FSMB is working closely with We would like to reiterate that the mandatory. Broader Licensing Rules,” December MOL framework proposed by FSMB, The article also cites concerns of the house of medicine and practic2012, page 1). The statement that the in fact, does not require physicians to some physicians that they may have ing physicians to ensure that MOL supports a doctor’s commitment to lifelong learning and is not redundant or burdensome. Most physicians are already involved in activities that could meet a state’s proposed MOL requirements.

T

Read the #1 anesthesiology publication in the country anywhere, anytime.

—Humayun J. Chaudhry, DO President and CEO Federation of State Medical Boards To the Editor: egarding the article, “Ohio Physicians Deal Setback to Push for Broader Licensing Rules” (Anesthesiology ( News, December 2012, page 1), in my lifetime I have held in my own hand my own Social Security card, with the written promise upon it that stated “Not to be used for identification.” Of course, we now know that that was a lie. It’s used all over the place as de facto ID. More recently, I’ve seen the board certification process go from being optional to being mandatory, since no hospital around here will grant privileges to an anesthesiologist who is not board-certified. So, as far as I’m concerned, regardless of promises made or to be made regarding the maintenance of certification initiative, count on it becoming not only mandatory but also expensive enough in both the financial and time/ energy sense to become a means of subjecting doctors to even greater control by those outside the profession. Without commenting on whether the maintenance of certification initiative is good or bad, speaking for myself, thanks to publications such as this one and the numerous medical meetings that take place around the world, I am quite happy to take charge of my own continuing medical education and would just as soon not be nagged or mandated by anyone else to do it. Sincerely,

R

—Peter Rivera, MD Dr. Rivera is an anesthesiologist in private practice in Puerto Rico.


FEBRUARY 2013

AnesthesiologyNews.com I 7

I N BRI EF

GlideScope Reduces Laryngospasm in Peds

T

he use of the GlideScope (Verathon Medical) is associated with a lower incidence of laryngospasm during nasal intubation in children, researchers have found. A retrospective survey of records from 1,200 pediatric dental cases from a single site found that laryngospasm occurred in four of the patients intubated with the GlideScope video laryngoscope (GVL). Among the children who underwent direct laryngoscopy with a Miller laryngoscope, 16 experienced laryngospasm. All of the children were anesthetized by Alexander G. Targ, MD, who practices at a mobile dental anesthesia facility in Palo Alto, Calif. Dr. Targg and his colleagues presented his findings at the 2012 annual meeting of the International Anesthesia Research Society (abstract 389). Dr. Targg called the setting of his high-volume practice “chaotic.” Before using the GVL, he said, between 2% and 2.5% of his patients experienced laryngospasm “despite how careful and attentive I was.” With the GVL, “my laryngospasm incidence vanished. I did hundreds more cases and it never returned,” he said. Children are twice as likely as adults to experience perioperative laryngospasm; one study found a rate of 28

cases per 1,000 patients among children aged 0 to 9 years compared with 11.7 per 1,000 patients for middleaged adults (Acta ( Anaesthesiol Scand 1984;28:567-575). However, the California-based researchers noted that no study had looked at the use of the GVL for assisted pediatric nasal intubation, despite previous findings that the use of the device is “equal or superior to” direct laryngoscopy for viewing the glottis and insertion of an endotracheal tube. The researchers examined the records of 1,200 patients younger than age 12 years. Each patient underwent “a standardized induction,” defined as administration of sevoflurane (8%) followed by placement, as needed, of a supraglottic airway device. While noting the limitations of retrospective research, John Doyle, MD, PhD, professor of anesthesiology at the Cleveland Clinic Lerner College of Medicine, in Ohio, said the study addressed a common problem in children. “The insight it provides is intriguing and it provides us with a conceptual basis for designing future trials,” said Dr. Doyle, a member of the editorial board of Anesthesiology News. —Tinker Ready


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C OMM E NT A R Y

Botched Drugs, Broken Trust Fallout of the fungal meningitis catastrophe

W

ho knew that insects could crawl around a manufacturing site for anesthesia drugs? Or that birds might fly inside that facility? Or that fungi and bacteria would contaminate unopened anesthetic vials and syringes? Or that government inspectors would take two years to notify the manufacturer of detected unsafe practices? Or that hundreds of local compounding pharmacies could manufacture and sell drugs nationally, with woefully little oversight? I learned all this and more after epidurally injected steroids produced by the New England Compounding Center (NECC), of Framingham, Mass., caused fungal meningitis in hundreds of patients throughout the country. When the FDA and the Centers for Disease Control and Prevention (CDC) investigated the NECC production site, they found air-conditioningg ducts, autoclaves and drug vials contaminated with greenish black and white filamentous matter. Even the “clean room” showed growths of bacteria and mold. Then the FDA investigated Ameridose, a sister company of NECC and found similar quality problems, including insects and birds inside the manufacturing facility. Ameridose manufactures many anesthesia injectables, including ropivacaine, fentanyl and succinylcholine. The CDC discovered bacteria, such as bacillus, and fungal species, such as aspergillus, in unopened vials of betamethasone, cardioplegia and triamcimolone. My hospital, as did many in the United States, stocked Ameridose drugs, and I used them. I had always assumed that a sealed drug vial from a pharmaceutical company contained only the labeled drug and its preservatives, that it had passed multiple inspections and assays. Now I feel as violated as the patients, and pray that no one I anesthetized was harmed by tainted drugs. The CDC reports that these contaminated steroids have sickened hundreds and killed dozens—37 so far. Further investigations seem likely to detect more drug contamination and injury. Reports of delayed injection site infections from the steroids are already appearing. I watched televised excerpts of a Congressional committee hearing on the contaminated NECC drugs. The company founder outrageously refused to testify how this could happen, citing his right not to incriminate himself. Although not in jail, he will probably have to spend his ill-gotten gains on lawyers to stay out. So far his brother, an anesthesiologist who also is a top official in the family web of pharmacy companies, has managed to stay out of the spotlight. Botching drugs did not mean booking losses, or personal privation. The four family members who cofounded NECC collected $16 million last year, including $8.7 million to the anesthesiologist, before closing the company, according to a report in the Boston Globe. The FDA does not look much better in this mess. It took the agency 684 days to warn NECC officials that it had uncovered serious issues at their manufacturing plant. Testimony by the FDA commissioner at

Robert E. Johnstone, MD

the Congressional committee about how this could happen was defensive and vague—and quite unreassuring. Anesthesia patients in the United States may fare better than others, however, because pharmaceutical experts estimate more than 100,000 people per year die globally from substandard and fake medicines. I am learning a lot from this catastrophe. Pharmacists use state laws allowing compounding of medicines for individuals to manufacture large batches of drugs and sell them nationally. Pharmaceutical companies pay others not to compete with them. If pharmaceutical companies put ethics ahead of profits, their drugs would be safer. If regulators acted on their observations, innocent patients would be alive. As an anesthesiologist, I administer drugs daily, often more than a dozen per patient, throughout the perioperative period. I have learned to review indications, double-check labels, wear gloves, clean injection ports and dispose of syringes after each use. As an academic anesthesiologist I teach the pharmacology, administration and documentation of anesthetic drugs. Never did I worry that the drugs themselves might be contaminated and cause unpredictable complications, or that pharmaceutical executives and government regulators could be cavalier and incompetent.

sensitivities to drugs. Now I need to factor in biological contamination, and consider that if drugs are manufactured and inspected so carelessly, they may not even contain the labeled drug in the proper dosage. Several times during my career I have witnessed no anesthesia after the subarachnoid administration of a local anesthetic, with visible cerebrospinal fluid before and after injection. I assumed the needle tip moved from the proper site during injection. Incorrect concentrations in the drug vial now seem as likely as inaccurate placement of the spinal needle. Another aspect of profiteering and incompetence in the pharmaceutical manufacturing and regulation industries is the nonavailability of mainstay drugs. Many of these are the generics that we depend on daily, such as propofol, rocuronium and neostigmine. I have recently had to induce anesthesia with etomidate, intubate without muscle relaxants and reverse muscle relaxation with physostigmine—all second- or thirdrate choices for the planned surgeries and anesthetics. As large pharmaceutical companies have dropped low– profit margin drugs, it has apparently enabled small pharmacies to sell their compounds nationally. My trust of the pharmaceutical industry is broken, and I see little happening now that might regain it. Action is needed on many levels. At my practitioner level, I will never again naively believe company Idiosyncratic—or Iatrogenic? labels. And I will swirl vials before using them, to disThe unexpected occurs occasionally in periopera- card those with visible fungi, bugs and bird droppings. tive patients—flushing after injection of induction —Robert E. Johnstone, MD drugs, wheezing and tachycardia during an anesthetic, or delirium postoperatively. I have ascribed these Dr. Johnstone is professor of anesthesiology at West Virginia to patient idiosyncrasies, the bell-shaped curves of University, in Morgantown.


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P A IN M E D I C I NE

Chronic Post-op Pain Takes Toll Resources Washington—Chronic pain after surgery takes a substantial toll on the health care system—not to mention the patients who must endure it—driving up the use of resources and services and increasing costs, researchers have found. The findings, from Dutch researchers, come from a large prospective study assessing the prevalence and predictive factors of both acute and chronic postsurgical pain in a large group of outpatients treated at Maastricht University Medical Center. As in the United States, 50% to 60% of all surgical procedures in the Netherlands are performed on an ambulatory basis. Marco Marcus, MD, PhD, professor of anesthesiology and perioperative care at Maastricht, and his colleagues enrolled 1,275 patients over an 18-month period. Patients answered questionnaires administered one week before surgery, as well as four days and one year after the procedure.

Pain scores were measured using an 11-point numeric rating scale. A score above 4 was considered moderate to severe pain. Health care consumption was measured by asking patients about the number of visits to general practitioners, medical specialists, emergency departments and other clinicians. The prevalence of moderate to severe pain was 14.8%, according to the researchers, who presented their findings at the 2012 annual meeting of the American Society of Anesthesiologists (abstract 977). Patients with chronic postoperative pain were sub- Table. Health Care Visits by Site for Patients With and Without Chronic Pain stantially more likely to report having visited a clinician or emergency departGeneral Medical Emergency ment, Dr. Marcus’ group found (Table). Practitioner Specialist Department Other To determine the number of visits that patients made to other health care Chronic pain 2.7 3.48 0.20 18.49 professionals, patients were asked how No chronic pain 1.13 1.22 0.14 5.86 often they visited other care providers because of pain, such as a chiropractor or physical therapist. Moreover, the researchers found that of anesthesia and health research and while average health care costs for all policy at Stanford University School patients in the study population were of Medicine, in Stanford, Calif., said 540 euros (approximately US$700) per that findings highlight the importance patient, they were 1,221 euros (approx- of developing an accurate method of imately US$1,577) for patients with predicting patients most likely to have chronic pain—significantly more than surgery-related pain a year after operthe 421 euros (approximately US$545) ation. “In addition to the intensity of that patients without pain spent acute postoperative pain, there may be other variables that could be part of (P<0.001). “We had expected health care use such a risk score, including high pain to be higher in patients with mild to scores before surgery, the use of premoderate pain compared to patients scribed opioids preoperatively, anxiety with no or mild pain,” Dr. Marcus told or depressive symptoms, and the type Anesthesiology News. “But we did not of surgical procedure,” Dr. Macario expect differences to be this high.” said. Dr. Marcus said that a “full economic “From an economic point of view, evaluation” would be needed to assess preventing long-term postoperative not only direct health costs but the inci- pain will be increasingly important dental impact, such as time lost from with accountable care organizations [ACOs], where provider reimbursework, of chronic pain after surgery. Can anesthesiologists intervene early ments are tied to quality metrics in the postoperative period to prevent that could include pain scores and chronic pain? The answer is unclear. likely will be fixed per case,” added But Dr. Marcus suggested that improv- Dr. Macario, a member of the editoing patients’ compliance with the anal- rial board of Anesthesiology News. “So, gesics they are prescribed after surgery if a patient consumes more health care Optimizing the Selection and Use Of Topical Hemostats could help. “Furthermore, identify- resources—as was shown in the study— ing patients with an increased risk the ACO’s bottom line would be expires April 1, 2013 for developing [chronic postsurgical affected. As a result, high-riskk patients Go to: topical-hemostats.com pain]—such as those with severe pre- for chronic postoperative pain, once operative pain—during the preoper- able to be identified accurately before ative phase deserves special interest,” surgery, could have a specific multiDr. Marcus added. “This way, the anes- modal treatment plan to attempt to Malignant Hyperthermia: Diagnosis, Treatment, and Prevention IP112 thesiologist and surgeon could try to prevent the chronic pain.” expires December 1, 2013 attempt to reduce these risk factors.” Alex Macario, MD, MBA, professor —Michael Vlessides

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AnesthesiologyNews.com I 11

PA IN M E D ICIN E

Review: Nerve Blocks Prevent Pain After Major Surgery Miami Beach—Administration of local or regional anesthesia before some major surgeries can prevent longterm pain for patients at five to six months postoperatively, according to a recent meta-analysis. “A large percentage of people have pain at six months, especially after thoracotomy, breast cancer surgery and cesarean section,” said Michael H. Andreae, MD, of the Department of Anesthesiology at Montefiore Medical Center/Albert Einstein College of Medicine, in New York City. Dr. Andreae and his wife, Doerthe A. Andreae, MD, PhD, an immunologist, identified 23 double-blind, randomized controlled trials in the literature that compared local or regional anesthesia technology (epidural, spinal or local blocks) with conventional treatment of pain (nonsteroidal antiinflammatoryy drugs [NSAIDs] or morphine) and grouped them according to the surgical intervention. Many studies showed that local or regional anesthesia can prevent chronic pain after different surgical interventions, but a meta-analysis could only be performed if there was more than one study in a surgical subgroup.

find the results were so clear; this is important because chronic pain after thoracotomy is so difficult to treat.” The analysis of 89 patients who underwent surgery for breast cancer found that those who received a paravertebral block were less likely to experience pain five or six months postoperatively (OR, 0.37). Put another way, an epidural for

thoracotomy or a paravertebral block for breast cancer surgery can prevent chronic pain in one patient for approximately every four to five patients treated. “Chronic pain can have a tremendous impact on quality of life; this is why prevention is paramount,” Dr. Andreae said. These and other findings were published Oct. 17, 2012 in the Cochrane Database of Systematic

Reviews (2012, Issue 10. Art. No.: CD007105. doi: 10.1002/14651858. CD007105.pub2.). “We as anesthesiologists have to become perioperative physicians and take a role in what happens after surgery,” Dr. Andreae said. Dr. Andreae also has a message for surgeons. “Chronic pain after surgery see Cochrane page 12

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P A IN M E D I C I NE COCHRANE

CONTINUED FROM PAGE 11

is underappreciated by surgeons, but it’s very important to the patient,” he said (see article, page 11). Some surgeons don’t realize pain can persist this far into the postoperative period, he added, or that prevention of pain with just a small amount of regional anesthesia can be very effective. “Even use of a single paravertebral block or a single-shot intervention” can alleviate significant pain.

Simple infiltration of a wound before closure can be beneficial as well. “This doesn’t cost more and doesn’t increase [the rate of ] infection,” he added. Many patients also need education, Dr. Andreae said. “When we tell them about a block, some say ‘just knock me out.’” Some patients may not understand how regional anesthesia works or— as this study points out—how it can be advantageous in the long run, he said.

“Dr. Andreae’s review is extremely important in that it clearly demonstrates that chronic pain is reduced when regional anesthesia and analgesia are used, which is a very important argument for the widespread use of these techniques,” said Arthur Atchabahian, MD, of the Department of Anesthesiology at New York University Langone Medical Center, in New York City.

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“A next step might be to evaluate possible long-term benefits from other modalities of acute postoperative pain control, such as multimodal pharmacologic analgesia,” said Dr. Atchabahian, who was not involved with the current study. The dichotomous responder analysis (patients either had pain or did not) made for a very clean study, “but chronic pain is a very complex concept that is not well captured by a yes/ no answer,” Dr. Andreae said. Another potential limitation was the intermediate quality of the studies included in the meta-analysis, and the authors cautioned against overinterpretation of findings based on a small number of studies. The investigators only included studies of adults. In the future, Dr. Andreae said he would like to assess chronic pain in children after surgery, as well as expand his current findings to another meta-analysis that looks at different types of surgical procedures. —Damian McNamara Drs. Andreae and Atchabahian reported no relevant financial conflicts.

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Hyperglycemia Tied to Increased Orthopedic Surgery Infections Findings highlight role of anesthesiologists in controlling blood glucose

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wo recently published studies are the latest in a growing body of evidence emphasizing that one of the central roles of operating room anesthesiologists is to manage the patient’s blood sugar levels. The research found that hyperglycemia, even in the absence of diagnosed diabetes, increases the risk for surgical site infections (SSIs) by nearly five times in patients undergoing orthopedic and joint surgery. “The scope of our practice as true perioperative physicians is expanding and the postoperative consequences of uncontrolled hyperglycemia are one of a set of variables, including appropriate pain management and measures to reduce delirium, that lie within the realm of our care and have implications well beyond the operating room,” said Laura Clark, MD, director of acute pain and regional anesthesia and professor of anesthesia at the University of Louisville School of Medicine, in Kentucky. The two papers appeared in the Journal of Bone Joint Surgery of America. In one, researchers at Vanderbilt University, in Nashville, Tenn., retrospectively examined the incidence of SSIs within 30 days of orthopedic surgery as well as blood glucose levels in 790 surgery patients treated at the institution between 2004 and 2009 (2012;94:1181-1186). The patients did not have a history of diabetes, injuries to other body systems, corticosteroid use or admission to the ICU immediately following injury. More than 37% (294) of the patients in the study had glucose levels of 200 mg/dL or greater on at least two random glucose tests, the researchers found. Of these patients, 17% (134) met a separate criterion quantifying glucose control during an entire hospital stay as the area under the curve of all glucose values acquired during the patient’s hospitalization. An index score of at least 1.76 (≥140 mg/dL) is considered hyperglycemic. The researchers found 4.4% (13 of 294) of those with glucose at or above 200 mg/dL on at least two tests had an SSI within 30 days of surgery compared with 1.6% (eight of 496) of those who did not (P=0.02). Approximately 8% (10 of 134) of patients with hyperglycemia developed an SSI during that period compared with 1.7% (11 of 656) of those without elevated blood sugar (P<0.001).

Multivariable analyses controlling for the effects of open fractures confirmed the association, showing hyperglycemic patients were 3.2 to 4.9 times more likely than nonhyperglycemic patients to develop an SSI within 30 days, depending on the definition of hyperglycemia used.

“The link between hyperglycemia and postoperative complications has been established in other surgical disciplines, including general surgery, but ours is one of the first to look at non-diabetic, non-ICU patients,” said Justin Richards, MD, an anesthesia resident at Vanderbilt, who led the study.

“Given that up to one-third of patients admitted to hospital without a diagnosis of diabetes have hyperglycemia, these findings are very significant.” The increased risk for SSIs in patients without diabetes but who have high glucose levels was confirmed in the second see SSIs page 14

NAROPIN® delivers a faster return of motor function than bupivacaine.1,2 A Block Well Done. NAROPIN provides 8 to 10 hours faster return of motor function following total knee replacement 1 than bupivacaine (P<0.05). P

Using NAROPIN beyond recommended doses to increase motor block or duration of sensory block may negate its favorable cardiovascular advantages, in the event that an inadvertent intravascular injection occurs.

To learn more about the clinical benefits of NAROPIN, visit www.naropin-us.com.

Important Safety Information There have been adverse event reports of chondrolysis in patients receiving intra-articular infusions of local anesthetics following arthroscopic and other surgical procedures. NAROPIN is not approved for this use. Please see dosage and administration details in Prescribing Information at www.naropin-us.com.

Like all amide-type local anesthetics, NAROPIN may be associated with adverse reactions. In clinical trials, side effects were mild and transient and may reflect the procedures, patient health status, and/or other medications used. Adverse events reported at a rate of ≥5%: hypotension, nausea, vomiting, bradycardia, fever, pain, postoperative complications, anemia, paresthesia, headache, pruritus, and back pain.

Please see accompanying brief summary of Prescribing Information. www.naropin-us.com NAROPIN is indicated for the production of regional or local anesthesia for surgery and for acute pain management. References: 1. Beaulieu P, Babin D, Hemmerling T. The pharmacodynamics of ropivacaine and bupivacaine in combined sciatic and femoral nerve blocks for total knee arthroplasty. Anesth Analg. 2006;103:768-774. 2. Morrison LM, Emanuelsson BM, McClure JH, et al. Efficacy and kinetics of extradural ropivacaine: comparison with bupivacaine. Br J Anaesth. 1994;72:164-169. Naropin® and logo are trademarks of Fresenius Kabi USA, LLC. APP ® and are trademarks of Fresenius Kabi USA, LLC. ©2012, Fresenius Kabi USA, LLC. All Rights Reserved. 0155-NAR-05-2/11

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study, a single-center analysis of 7,181 patients with osteoarthritis who underwent primary hip and knee replacements in Finland ((J Bone Joint Surg Am 2012;94:e101). The Finnish investigators found that 1.15% of those who did not have a diabetes diagnosis but did have preoperative glucose levels of at least 122 mg/dL experienced a periprosthetic joint infection compared with 0.28% of nondiabetics with lower

glucose levels (P=0.002). The association did not persist after multivariate analyses controlled for age, sex, physical status, surgical site or body mass index. A limitation of both studies is that most patients had blood glucose measured at random, said Dr. Clark, a specialist in orthopedic anesthesia who was not involved in the research. Furthermore, the blood glucose cutoff level of 122 mg/dL used in the Finnish study is “a relatively low definition of hyperglycemia,” she noted. “They

Naropin

®

(ropivacaine HCl) Injection BRIEF SUMMARY INDICATIONS AND USAGE Naropin is indicated for the production of local or regional anesthesia for surgery and for acute pain management. Surgical Anesthesia: epidural block for surgery including cesarean section; major nerve block; local infiltration. Acute Pain Management: epidural continuous infusion or intermittent bolus, e.g., postoperative or labor; local infiltration. CONTRAINDICATIONS Naropin is contraindicated in patients with a known hypersensitivity to ropivacaine or to any local anesthetic agent of the amide type. WARNINGS In performing Naropin blocks, unintended intravenous injection is possible and may result in cardiac arrhythmia or cardiac arrest. The potential for successful resuscitation has not been studied in humans. There have been rare reports of cardiac arrest during the use of Naropin for epidural anesthesia or peripheral nerve blockade, the majority of which occurred after unintentional accidental intravascular administration in elderly patients and in patients with concomitant heart disease. In some instances, resuscitation has been difficult. Should cardiac arrest occur, prolonged resuscitative efforts may be required to improve the probability of a successful outcome. Naropin should be administered in incremental doses. It is not recommended for emergency situations, where a fast onset of surgical anesthesia is necessary. Historically, pregnant patients were reported to have a high risk for cardiac arrhythmias, cardiac/ circulatory arrest and death when 0.75% bupivacaine (another member of the amino amide class of local anesthetics) was inadvertently rapidly injected intravenously. Prior to receiving major blocks the general condition of the patient should be optimized and the patient should have an i.v. line inserted. All necessary precautions should be taken to avoid intravascular injection. Local anesthetics should only be administered by clinicians who are well versed in the diagnosis and management of dose-related toxicity and other acute emergencies that may arise from the block to be employed, and then only after ensuring the immediate (without delay) availability of oxygen, other resuscitative drugs, cardiopulmonary resuscitative equipment, and the personnel resources needed for proper management of toxic reactions and related emergencies (See also ADVERSE REACTIONS, PRECAUTIONS, and MANAGEMENT OF LOCAL ANESTHETIC EMERGENCIES). Delay in proper management of dose-related toxicity, underventilation from any cause, and/or altered sensitivity may lead to the development of acidosis, cardiac arrest and, possibly, death. Solutions of Naropin should not be used for the production of obstetrical paracervical block anesthesia, retrobulbar block, or spinal anesthesia (subarachnoid block) due to insufficient data to support such use. Intravenous regional anesthesia (bier block) should not be performed due to a lack of clinical experience and the risk of attaining toxic blood levels of ropivacaine. Intra-articular infusions of local anesthetics followingg arthroscopic p and other surgical g pprocedures is an unapproved pp use,, and there have been ppost-marketingg reports p of chondrolysis y in patients p receivingg such infusions. The majority j y of reported p cases of chondrolysis y have involved the shoulder jjoint;; cases of ggleno-humeral chondrolysis y have been described in ppediatric and adult ppatients followingg intra-articular infusions of local anesthetics with and without eppinephrine p for pperiods of 48 to 72 hours. There is insufficient information to determine whether shorter infusion periods p are not associated with these findings. g The time of onset of symptoms, y p , g y Currently,y, there is no effective treatment such as jjoint ppain,, stiffness and loss of motion can be variable,, but mayy begin g as earlyy as the 2nd month after surgery. for chondrolysis; y ; ppatients who experienced p chondrolysis y have required q additional diagnostic g and therapeutic p pprocedures and some required q arthroplasty p y or shoulder replacement. p It is essential that aspiration for blood, or cerebrospinal fluid (where applicable), be done prior to injecting any local anesthetic, both the original dose and all subsequent doses, to avoid intravascular or subarachnoid injection. However, a negative aspiration does nott ensure against an intravascular or subarachnoid injection. A well-known risk of epidural anesthesia may be an unintentional subarachnoid injection of local anesthetic. Two clinical studies have been performed to verify the safety of Naropin at a volume of 3 mL injected into the subarachnoid space since this dose represents an incremental epidural volume that could be unintentionally injected. The 15 and 22.5 mg doses injected resulted in sensory levels as high as T5 and T4, respectively. Anesthesia to pinprick started in the sacral dermatomes in 2-3 minutes, extended to the T10 level in 10-13 minutes and lasted for approximately 2 hours. The results of these two clinical studies showed that a 3 mL dose did not produce any serious adverse events when spinal anesthesia blockade was achieved. Naropin should be used with caution in patients receiving other local anesthetics or agents structurally related to amide-type local anesthetics, since the toxic effects of these drugs are additive. Patients treated with class III antiarrhythmic drugs (e.g., amiodarone) should be under close surveillance and ECG monitoring considered, since cardiac effects may be additive. PRECAUTIONS: General: The safe and effective use of local anesthetics depends on proper dosage, correct technique, adequate precautions and readiness for emergencies. Resuscitative equipment, oxygen and other resuscitative drugs should be available for immediate use. (See WARNINGS and ADVERSE REACTIONS.) The lowest dosage that results in effective anesthesia should be used to avoid high plasma levels and serious adverse events. Injections should be made slowly and incrementally, with frequent aspirations before and during the injection to avoid intravascular injection. When a continuous catheter technique is used, syringe aspirations should also be performed before and during each supplemental injection. During the administration of epidural anesthesia, it is recommended that a test dose of a local anesthetic with a fast onset be administered initially and that the patient be monitored for central nervous system and cardiovascular toxicity, as well as for signs of unintended intrathecal administration before proceeding. When clinical conditions permit, consideration should be given to employing local anesthetic solutions, which contain epinephrine for the test dose because circulatory changes compatible with epinephrine may also serve as a warning sign of unintended intravascular injection. An intravascular injection is still possible even if aspirations for blood are negative. Administration of higher than recommended doses of Naropin to achieve greater motor blockade or increased duration of sensory blockade may result in cardiovascular depression, particularly in the event of inadvertent intravascular injection. Tolerance to elevated blood levels varies with the physical condition of the patient. Debilitated, elderly patients and acutely ill patients should be given reduced doses commensurate with their age and physical condition. Local anesthetics should also be used with caution in patients with hypotension, hypovolemia or heart block. Careful and constant monitoring of cardiovascular and respiratory vital signs (adequacy of ventilation) and the patient’s state of consciousness should be performed after each local anesthetic injection. It should be kept in mind at such times that restlessness, anxiety, incoherent speech, light-headedness, numbness and tingling of the mouth and lips, metallic taste, tinnitus, dizziness, blurred vision, tremors, twitching, depression, or drowsiness may be early warning signs of central nervous system toxicity. Because amide-type local anesthetics such as ropivacaine are metabolized by the liver, these drugs, especially repeat doses, should be used cautiously in patients with hepatic disease. Patients with severe hepatic disease, because of their inability to metabolize local anesthetics normally, are at a greater risk of developing toxic plasma concentrations. Local anesthetics should also be used with caution in patients with impaired cardiovascular function because they may be less able to compensate for functional changes associated with the prolongation of A-V conduction produced by these drugs. Many drugs used during the conduct of anesthesia are considered potential triggering agents for malignant hyperthermia (MH). Amide-type local anesthetics are not known to trigger this reaction. However, since the need for supplemental general anesthesia cannot be predicted in advance, it is suggested that a standard protocol for MH management should be available. Epidural Anesthesia: During epidural administration, Naropin should be administered in incremental doses of 3 to 5 mL with sufficient time between doses to detect toxic manifestations of unintentional intravascular or intrathecal injection. Syringe aspirations should also be performed before and during each supplemental injection in continuous (intermittent) catheter techniques. An intravascular injection is still possible even if aspirations for blood are negative. During the administration of epidural anesthesia, it is recommended that a test dose be administered initially and the effects monitored before the full dose is given. When clinical conditions permit, the test dose should contain an appropriate dose of epinephrine to serve as a warning of unintentional intravascular injection. If injected into a blood vessel, this amount of epinephrine is likely to produce a transient “epinephrine response” within 45 seconds, consisting of an increase in heart rate and systolic blood pressure, circumoral pallor, palpitations and nervousness in the unsedated patient. The sedated patient may exhibit only a pulse rate increase of 20 or more beats per minute for 15 or more seconds. Therefore, following the test dose, the heart should be continuously monitored for a heart rate increase. Patients on beta-blockers may not manifest changes in heart rate, but blood pressure monitoring can detect a rise in systolic blood pressure. A test dose of a shortacting amide anesthetic such as lidocaine is recommended to detect an unintentional intrathecal administration. This will be manifested within a few minutes by signs of spinal block (e.g., decreased sensation of the buttocks, paresis of the legs, or, in the sedated patient, absent knee jerk). An intravascular or subarachnoid injection is still possible even if results of the test dose are negative. The test dose itself may produce a systemic toxic reaction, high spinal or epinephrine-induced cardiovascular effects. Use in Brachial Plexus Block: Ropivacine plasma concentrations may approach the threshold for central nervous system toxicity after the administration of 300 mg of ropivacaine for brachial plexus block. Caution should be exercised when using the 300 mg dose. (See OVERDOSAGE.) The dose for a major nerve block must be adjusted according to the site of administration and patient status. Supraclavicular brachial plexus blocks may be associated with a higher frequency of serious adverse reactions, regardless of the local anesthetic used. Use in Peripheral Nerve Block: Major peripheral nerve blocks may result in the administration of a large volume of local anesthetic in highly vascularized areas, often close to large vessels where there is an increased risk of intravascular injection and/or rapid systemic absorption, which can lead to high plasma concentrations. Use in Head and Neck Area: Small doses of local anesthetics injected into the head and neck area may produce adverse reactions similar to systemic toxicity seen with unintentional intravascular injections of larger doses. The injection procedures require the utmost care. Confusion, convulsions, respiratory depression, and/or respiratory arrest, and cardiovascular stimulation or depression have been reported. These reactions may be due to intra-arterial injection of the local anesthetic with retrograde flow to the cerebral circulation. Patients receiving these blocks should have their circulation and respiration monitored and be constantly observed. Resuscitative equipment and personnel for treating adverse reactions should be immediately available. Dosage recommendations should not be exceeded. (See DOSAGE AND ADMINISTRATION.) Use in Ophthalmic Surgery: The use of Naropin in retrobulbar blocks for ophthalmic surgery has not been studied. Until appropriate experience is gained, the use of Naropin for such surgery is not recommended. Drug Interactions: Specific trials studying the interaction between ropivacaine and class III antiarrhythmic drugs (e.g., amiodarone) have not been performed, but caution is advised (see WARNINGS). Naropin should be used with caution in patients receiving other local anesthetics or agents structurally related to amide-type local anesthetics, since the toxic effects of these drugs are additive. Cytochrome P4501A2 is involved in the formation of 3-hydroxy ropivacaine, the major metabolite. In vivo, the plasma clearance of ropivacaine was reduced by 70% during coadministration of fluvoxamine (25 mg bid for 2 days), a selective and potent CYP1A2 inhibitor. Thus strong inhibitors of cytochrome P4501A2, such as fluvoxamine, given concomitantly during administration of Naropin, can interact with Naropin leading to increased ropivacaine plasma levels. Caution should be exercised when CYP1A2 inhibitors are coadministered. Possible interactions with drugs known to be metabolized by CYP1A2 via competitive inhibition such as theophylline and imipramine may also occur. Coadministration of a selective and potent inhibitor of CYP3A4, ketoconazole (100 mg bid for 2 days with ropivacaine infusion administered 1 hour after ketoconazole) caused a 15% reduction in in-vivoo plasma clearance of ropivacaine. Pregnancy Category B: There are no adequate or well-controlled studies in pregnant women of the effects of Naropin on the developing fetus. Naropin should only be used during pregnancy if the benefits outweigh the risk. Labor and Delivery: Local anesthetics, including ropivacaine, rapidly cross the placenta, and when used for epidural block can cause varying degrees of maternal, fetal and neonatal toxicity (see CLINICAL PHARMACOLOGY and PHARMACOKINETICS). The incidence and degree of toxicity depend upon the procedure performed, the type and amount of drug used, and the technique of drug administration. Adverse reactions in the parturient, fetus and neonate involve alterations of the central nervous system, peripheral vascular tone and cardiac function. Maternal hypotension has resulted from regional anesthesia with Naropin for obstetrical pain relief. Local anesthetics produce vasodilation by blocking sympathetic nerves. Elevating the patient’s legs and positioning her on her left side will help prevent decreases in blood pressure. The fetal heart rate also should be monitored continuously, and electronic fetal monitoring is highly advisable. Epidural anesthesia has been reported to prolong the second stage of labor by removing the patient’s reflex urge to bear down or by interfering with motor function. Spontaneous vertex delivery occurred more frequently in patients receiving Naropin than in those receiving

might have found a more pronounced effect with a higher threshold.” Despite the weaknesses, the takehome message from both sets of findings is unequivocal: Glucose levels must be controlled. On the other hand, what the ideal intraoperative glucose level should be is less clear, Dr. Clarkk noted. “For a while, tight intraoperative glucose control was recommended, but this was not adopted due to a rise in complications,” she said. “We still do not know the correct range; however

bupivacaine. Nursing Mothers: Some local anesthetic drugs are excreted in human milk and caution should be exercised when they are administered to a nursing woman. The excretion of ropivacaine or its metabolites in human milk has not been studied. Based on the milk/plasma concentration ratio in rats, the estimated daily dose to a pup will be about 4% of the dose given to the mother. Assuming that the milk/plasma concentration in humans is of the same order, the total Naropin dose to which the baby is exposed by breast-feeding is far lower than by exposure in utero in pregnant women at term (see Precautions). Pediatric Use: The safety and efficacy of Naropin in pediatric patients have not been established. Geriatric Use: Of the 2,978 subjects that were administered Naropin Injection in 71 controlled and uncontrolled clinical studies, 803 patients (27%) were 65 years of age or older, which includes 127 patients (4%) 75 years of age and over. Naropin Injection was found to be safe and effective in the patients in these studies. Clinical data in one published article indicate that differences in various pharmacodynamic measures were observed with increasing age. In one study, the upper level of analgesia increased with age, the maximum decrease of mean arterial pressure (MAP) declined with age during the first hour after epidural administration, and the intensity of motor blockade increased with age. This drug and its metabolites are known to be excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Elderly patients are more likely to have decreased hepatic, renal, or cardiac function, as well as concomitant disease. Therefore, care should be taken in dose selection, starting at the low end of the dosage range, and it may be useful to monitor renal function. (See PHARMACOKINETICS, Elimination.) ADVERSE REACTIONS Reactions to ropivacaine are characteristic of those associated with other amidetype local anesthetics. A major cause of adverse reactions to this group of drugs may be associated with excessive plasma levels, which may be due to overdosage, unintentional intravascular injection or slow metabolic degradation. The reported adverse events are derived from clinical studies conducted in the U.S. and other countries. The reference drug was usually bupivacaine. The studies used a variety of premedications, sedatives, and surgical procedures of varying length. A total of 3,988 patients have been exposed to Naropin at concentrations up to 1.0% in clinical trials. Each patient was counted once for each type of adverse event. Incidence ≥5%: For the indications of epidural administration in surgery, cesarean section, postoperative pain management, peripheral nerve block, and local infiltration, the following treatment-emergent adverse events were reported with an incidence of ≥5% in all clinical studies (N=3988): hypotension (37.0%), nausea (24.8%), vomiting (11.6%), bradycardia (9.3%), fever (9.2%), pain (8.0%), postoperative complications (7.1%), anemia (6.1%), paresthesia (5.6%), headache (5.1%), pruritus (5.1%), and back pain (5.0%). Incidence 1-5%: Urinary retention, dizziness, rigors, hypertension, tachycardia, anxiety, oliguria, hypoesthesia, chest pain, hypokalemia, dyspnea, cramps, and urinary tract infection. Incidence in Controlled Clinical Trials: The reported adverse events are derived from controlled clinical studies with Naropin (concentrations ranged from 0.125% to 1.0% for Naropin and 0.25% to 0.75% for bupivacaine) in the U.S. and other countries involving 3,094 patients. Tables 3A and 3B list adverse events (number and percentage) that occurred in at least 1% of Naropin-treated patients in these studies. The majority of patients receiving concentrations higher than 5.0 mg/mL (0.5%) were treated with Naropin. Table 3A Adverse Events Reported in ≥1% of Adult Patients Receiving Regional or Local Anesthesia (Surgery, Labor, Cesarean Section, Post-Operative Pain Management, Peripheral Nerve Block and Local Infiltration)

Adverse Reaction Hypotension Nausea Vomiting Bradycardia Headache Paresthesia Back pain Pain Pruritus Fever Dizziness Rigors (Chills) Postoperative complications Hypoesthesia Urinary retention Progression of labor poor/failed Anxiety Breast disorder, breast-feeding Rhinitis

N 536 283 117 96 84 82 73 71 63 61 42 42 41 27 23 23 21 21 18

Naropin total N=1661 N 1661

(%) (32.3) (17.0) (7.0) (5.8) (5.1) (4.9) (4.4) (4.3) (3.8) (3.7) (2.5) (2.5) (2.5) (1.6) (1.4) (1.4) (1.3) (1.3) (1.1)

N 408 207 88 73 68 57 75 71 40 37 23 24 44 24 20 22 11 12 13

Bupivacaine total N=1433 N 1433

(%) (28.5) (14.4) (6.1) (5.1) (4.7) (4.0) (5.2) (5.0) (2.8) (2.6) (1.6) (1.7) (3.1) (1.7) (1.4) (1.5) (0.8) (0.8) (0.9)

Table 3B Adverse Events Reported in ≥1% of Fetuses or Neonates of Mothers Who Received Regional Anesthesia (Cesarean Section and Labor Studies)

Adverse Reaction Fetal bradycardia Neonatal jaundice Neonatal complication-NOS Apgar score low Neonatal respiratory disorder Neonatal tachypnea Neonatal fever Fetal tachycardia Fetal distress Neonatal infection Neonatal hypoglycemia

N 77 49 42 18 17 14 13 13 11 10 8

Naropin total N=1661 N 1661

(%) (12.1) (7.7) (6.6) (2.8) (2.7) (2.2) (2.0) (2.0) (1.7) (1.6) (1.3)

N 68 47 38 14 18 15 14 12 10 8 16

Bupivacaine total N=1433 N 1433

(%) (11.9) (8.2) (6.6) (2.4) (3.1) (2.6) (2.4) (2.1) (1.7) (1.4) (2.8)

OVERDOSAGE Acute emergencies from local anesthetics are generally related to high plasma levels encountered, or large doses administered, during therapeutic use of local anesthetics or to unintended subarachnoid or intravascular injection of local anesthetic solution. (See ADVERSE REACTIONS, WARNINGS, and PRECAUTIONS.) MANAGEMENT OF LOCAL ANESTHETIC EMERGENCIES: Therapy with Naropin should be discontinued at the first sign of toxicity. No specific information is available for the treatment of toxicity with Naropin; therefore, treatment should be symptomatic and supportive. The first consideration is prevention, best accomplished by incremental injection of Naropin, careful and constant monitoring of cardiovascular and respiratory vital signs and the patient’s state of consciousness after each local anesthetic and during continuous infusion. At the first sign of change in mental status, oxygen should be administered. The first step in the management of systemic toxic reactions, as well as underventilation or apnea due to unintentional subarachnoid injection of drug solution, consists of immediate attention to the establishment and maintenance of a patent airway and effective assisted or controlled ventilation with 100% oxygen with a delivery system capable of permitting immediate positive airway pressure by mask. Circulation should be assisted as necessary. This may prevent convulsions if they have not already occurred. If necessary, use drugs to control convulsions. Intravenous barbiturates, anticonvulsant agents, or muscle relaxants should only be administered by those familiar with their use. Immediately after the institution of these ventilatory measures, the adequacy of the circulation should be evaluated. Supportive treatment of circulatory depression may require administration of intravenous fluids, and, when appropriate, a vasopressor dictated by the clinical situation (such as ephedrine or epinephrine to enhance myocardial contractile force). Should cardiac arrest occur, prolonged resuscitative efforts may be required to improve the probability of a successful outcome. The mean dosages of ropivacaine producing seizures, after intravenous infusion in dogs, nonpregnant and pregnant sheep were 4.9, 6.1 and 5.9 mg/kg, respectively. These doses were associated with peak arterial total plasma concentrations of 11.4, 4.3 and 5.0 μg/mL, respectively. In human volunteers given intravenous Naropin, the mean (min-max) maximum tolerated total and free arterial plasma concentrations were 4.3 (3.4-5.3) and 0.6 (0.3-0.9) μg/mL respectively, at which time moderate CNS symptoms (muscle twitching) were noted. Clinical data from patients experiencing local anesthetic induced convulsions demonstrated rapid development of hypoxia, hypercarbia and acidosis within a minute of the onset of convulsions. These observations suggest that oxygen consumption and carbon dioxide production are greatly increased during local anesthetic convulsions and emphasize the importance of immediate and effective ventilation with oxygen, which may avoid cardiac arrest. If difficulty is encountered in the maintenance of a patent airway or if prolonged ventilatory support (assisted or controlled) is indicated, endotracheal intubation, employing drugs and techniques familiar to the clinician, may be indicated after initial administration of oxygen by mask. The supine position is dangerous in pregnant women at term because of aortocaval compression by the gravid uterus. Therefore, during treatment of systemic toxicity, maternal hypotension or fetal bradycardia following regional block, the parturient should be maintained in the left lateral decubitus position if possible, or manual displacement of the uterus off the great vessels should be accomplished. Resuscitation of obstetrical patients may take longer than resuscitation of nonpregnant patients and closed-chest cardiac compression may be ineffective. Rapid delivery of the fetus may improve the response to resuscitative efforts.

Fresenius Kabi USA, LLC

0155-NAR-05-2/11

Rev. 11/08

studies such as these help define those upper and lower blood glucose limits and are important to emphasize that not just known diabetics are at risk.” —David Wild

Automated Anesthesia Carts A Cost Saver LAS VEGAS—Implementing an automated anesthesia dispensing system enabled a Connecticut hospital system to improve inventory management, medication charge capture and patient safety in surgical suites. “We wanted to make sure that the medications administered to the patients are documented accurately in the medical record for patient safety and the hospital captures appropriate reimbursement,” said Christine Hong, PharmD, medication safety officer at the Yale-New Haven Hospital Saint Raphael’s Campus, in New Haven. Before employing the automated system, a manual billing process was used. An evaluation of manual charge capture for 324 surgical cases (inpatient and outpatient) over five days revealed a charge loss of $6,570 ($1,314 per day). Extrapolation to a full year equated to a loss of more than $427,000—nearly 40% of the pharmacy’s annual anesthesia medication purchases and about 8% of the total pharmacy budget. “We found that approximately 20% of billing forms were completely lost, and the hospital wouldn’t get paid for those,” Dr. Hong said. “We also want to ensure that patients are being charged appropriately.” Thirty-seven automated anesthesia-dispensing systems were installed, covering all operating rooms (ORs) and procedural areas. About 80 surgical procedures are performed daily in the main OR alone. During a four-month period after implementation, the new protocol led to an average daily increase in outpatient gross revenue of $8,700— the annual equivalent of about $696,000. There was also a one-time inventory savings of $11,500 from the reduction of duplicate anesthesia trays. “We are continuing to monitor the utilization to determine the rate of stock-out and refill to optimize inventory control, workflow efficiency and safe anesthesia medication management,” Dr. Hong said. —Steve Frandzel


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CL IN ICA L A N E STH E SIOL OG Y

Desat Events Not Linked to Cardiac Output in One-Lung Trial

C

erebral desaturation events occurring during one-lung ventilation do not appear to be related to decreases in cardiac output or any other hemodynamic parameter, Canadian researchers have found. Interestingly, however, the investigators found that patients who experienced longer periods of desaturation increased stroke volume to maintain cardiac output. Many studies have looked at cerebral desaturation in cardiac surgery, neurosurgery and gastrointestinal surgery, said Ryan Brinkman, MD, a fellow in perioperative medicine at the University of Manitoba, in Winnipeg, who helped conduct the latest trial. One such study (J ( Anesth 2011;25:345-359) showed that patients who had desaturation events did worse in terms of both postoperative pulmonary and nonpulmonary complications.

Each participant underwent a standard anesthetic regimen, with an FiO2 of 1.0 for the duration of the case. Anesthesiologists provided positive end-expiratory pressure and continuous positive airway pressure to the nondependent lung to maintain peripheral oxygen saturations of at least 90%. Serial blood gases were drawn before induction and

then every 15 minutes for two hours. A cerebral desaturation event was defined as a decrease of at least 10% from baseline, which was defined as the highest recorded saturation on two-lungg ventilation with an FiO2 of 1.0. As Dr. Brinkman reported at the 2012 annual meeting of the Canadian Anesthesiologists’ Society (abstract

see desat page 26

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‘If a patient is placed in a lateral decubitus position for a thoracotomy with a lung collapsed, there may be inconsistent and variable changes in brain frontal lobe blood drainage as the lung collapses, the mediastinum shifts and great vessels change position.’ —Bruce Spiess, MD “Nevertheless, it has yet to be determined why these desaturation events occur,” Dr. Brinkman added. “One suggestion is that it may be due to decreases in cardiac output, so we sought to determine its relationship, if any, with cerebral desaturation.” Dr. Brinkman and his colleagues enrolled 23 patients into the trial, each of whom was undergoing surgery with one-lungg ventilation. Cerebral oxygenation was monitored using a cerebral oximeter (Fore-Sight, Casmed) and cardiac indices were measured with the FloTrac system (Edwards Lifesciences).

1310840), data from 18 patients were analyzed; 10 of these patients (55.5%) had significant cerebral desaturation events. “We didn’t find a statistically significant difference between groups in terms of cardiac output, blood pressure or heart rate,” he told Anesthesiology News. Similarly, there was no

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16 I AnesthesiologyNews.com

FEBRUARY 2013

C LIN I C A L A N ES THES IO LO G Y RETHINK

they do but they all know they need each other to make that sound. It doesn’t just happen. These are exactly the teamwork lessons we’re trying to teach.” Even as educators such as Dr. Birnbach attempt to reshape how various specialists interact within the OR, however, Drs. Stiegler and Tung said greater attention needs to be paid to how medical professionals, including anesthesiologists, make decisions preoperatively, perioperatively and postoperatively.

CONTINUED FROM PAGE 1

To address these issues, the experts—David J. Birnbach, MD, MPH, Marjorie Stiegler, MD, Karen B. Domino, MD, MPH, and Avery Tung, MD—recommended that anesthesiologists reconsider operating room (OR) procedures and training approaches, among other steps, as well as “rethink the way [they] think,” as Dr. Stieglerr put it, during clinical decision making. “We need to admit there is a problem,” Dr. Birnbach, professor of anesthesiology and vice provost at the University of Miami, told the audience. “Although the practice of anesthesiology has gotten safer and safer over the past 20 or 30 years, we still are not perfect.” The issue of medical errors, of course, has been widely discussed in all specialties since the release of the Institute of Medicine’s initial report on the subject in 1999, which estimated that as many as 100,000 Americans die each year as a result of mistakes made in diagnosis and treatment. Lessons From Closed Claims To illustrate the effect medical errors have had on the practice of anesthesiology, Dr. Domino, professor of anesthesiology and pain medicine at the University of Washington School of Medicine, in Seattle, summarized data from the American Society of Anesthesiologists (ASA) Closed Claims database. The effort to date has collected data on more than 9,500 patient claims for complications resulting from anesthesiology procedures. (Roughly one-third of the practicing anesthesiologists in the United States submit information to the database.) Although the majority of the claims cover physical injuries, Dr. Domino told the audience at PGA that they also include “persistent” psychological effects, cognitive problems and quality-off life issues (poor job performance, disruption in family relationships). “We need to improve informed consent and patient communication so that patients have a better understanding of how deep sedation may affect them,” Dr. Domino noted. But the need for improved communication does not stop with the patient. Dr. Birnbach emphasized that enhancing focus, communication and teamwork skills within the OR team—including anesthesiologists, nurses and surgeons—is vital in preventing the problems that result in patient claims from occurring in the first place.

Scott Flavin leads the University of Miami’s Mancini Orchestra in a rehersal. David Birnbach, MD, uses the orchestra to help train medical students and residents in the importance of communication and teamwork. OR as Orchestra Pit Dr. Birnbach has used the University of Miami’s student orchestra as a teaching tool in educating medical students and residents on the importance of communication and teamwork skills such as “knowing when to lead and when to follow … when to ask for help … and how to rely” on colleagues during pressure situations in the OR. The orchestra’s rehearsals also serve as a reminder of the importance of practice in improving performance. During his talk at PGA, Dr. Birnbach suggested that institutions should increase their use of simulation in the training, education and continuing education of all OR personnel, including anesthesiologists. Showing the audience a video of the University of Miami’s Mancini Orchestra, under the direction of conductor Scott Flavin, during rehearsal, Dr. Birnbach said, “People are actually talking to each other without verbal expression. The conductor is the leader. He is giving cues and the musicians are following those cues. They are all experts at what

Table. Trends in Guideline Compliance—More Dissonance Than Harmony

a

Rate of Compliancea

Study

Guideline(s)

Calvin et al (Congest Heart Fail 2012;18:73-78)

American College of Cardiology/American Heart Association guidelines for heart failure

63%

Heskestad et al (Scand J Trauma Resusc Emerg Med d 2012;20:32)

Scandinavian Neurotrauma Committee guidelines for management of minimal, mild and moderate headinjured patients

63%

Kosecoff et al (JAMA 1987;258:2708-2713)

National Institutes of Health consensus panel recommendations on surgical management of breast cancer, cesarean delivery and CABG surgery

52%-57%

Leone et al (Crit Care Med 2012;40:3189-3195)

13 clinical guidelines for the treatment of adult patients in the ICU

24%

Avoiding Thought Traps Dr. Stiegler, assistant clinical professor of anesthesiology at the University of North Carolina at Chapel Hill, cited several studies suggesting that medical errors resulting from “cognitive” issues may be more common than those caused by knowledge deficits on the part of clinicians. These cognitive errors— she called them “thought process traps”—are caused, in part, by subconscious processes, including biases, which most physicians may not even recognize much less admit they have. Dr. Stiegler said “feedback bias”—which occurs in medicine when outcomes data are not reported back to the practitioner—is particularly prevalent in anesthesiology. To overcome these cognitive impediments, Dr. Stiegler recommended the use of “metacognition” techniques or, as she defined the concept, “thinking about thinking.” One example is the so-called “Rule of Three,” which, in essence, suggests that clinicians should consider three alternatives before making a final diagnosis (or decision) or reconsider their management of a case if they find themselves taking the same approach three consecutive times (Curr Opin Anaesthesioll 2012;25:724-729). Dr. Tung, associate professor of anesthesia and critical care, and director of the Critical Care Services/ Burn Unit at the University of Chicago School of Medicine, told the audience that anesthesiologists’ thought processes can lead them to make decisions that run counter to current treatment guidelines, thereby increasing the risks facing their patients. He presented several studies that showed that all clinicians, including anesthesiologists, tend to follow treatment guidelines only 50% of the time (Table), and that older clinicians tend to adhere to guidelines less frequently because they “think they have seen it all before.” Although he acknowledged that guidelines are hardly infallible—they often are out of date soon after they are published—Dr. Tungg said these findings should be a cause for alarm. “Ever since there have been guidelines people have been not following [them], and the pattern of guideline noncompliance has been persistent and consistent throughout the entire duration of history of guidelines,” he said. “This may be the result of inadequate training, poor knowledge, or personal beliefs or preferences, which are understudied and influence behaviors that affect decision making. It’s not enough just to care, because when you care all those heuristics start playing in your head and you have to fight against that. Care absolutely, but recognize that when you care, the part of your brain that makes the rational decisions wakes up and starts pushing you to do things you otherwise wouldn’t do.”

Percentage of physicians study subjects who followed prescribed guidelines; see study methodology and eligibility criteria for specific details

CABG, coronaryy arteryy bypass yp graft g

—Brian Dunleavy


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Lesson 302: PreAnesthetic Considerations for a Patient With Hereditary Hemorrhagic Telangiectasia WRITTEN BY:

DISCLOSURES

Eric M. Glenn, MD Fellow, Department of Anesthesiology Tulane University Health Science Center New Orleans, Louisiana

The authors and reviewer have nothing to disclose. No funding was received in preparation of the manuscript.

Charles J. Fox, MD Professor and Vice Chairman, Department of Anesthesiology Tulane University Health Science Center New Orleans, Louisiana

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

CALL FOR WRITERS

NEEDS STATEMENT Hereditary hemorrhagic telangiectasia (HHT) is an uncommon familial multisystem vascular disorder that affects patients of all ages. Patients with HHT develop abnormal blood vessels that are predisposed to hemorrhage and other complications. Often these complications require surgical intervention. Knowledge of the pathophysiology and anesthetic issues specific to the disease allows the anesthesiologist to anticipate challenging management concerns and guide perioperative management, thereby decreasing morbidity and mortality in this patient population.

Alan David Kaye, MD, PhD Professor and Chairman, Department of Anesthesiology Louisiana State University Medical Center New Orleans, Louisiana Professor, Department of Anesthesiology Tulane University Health Science Center New Orleans, Louisiana

CASE HISTORY

REVIEWED BY: James Riopelle, MD Professor, Department of Anesthesiology Louisiana State University Medical Center New Orleans, Louisiana

DATE REVIEWED: September 28, 2011 TARGET AUDIENCE: Anesthesiologists LEARNING OBJECTIVES At the conclusion of this activity, the reader will be able to: 1. Describe the pathophysiology of HHT. 2. List the most common clinical features of HHT. 3. Identify the most frequently involved organ systems. 4. Describe diagnostic criteria. 5. Become aware of treatment options. 6. Summarize screening recommendations. 7. List potential perioperative complications. 8. Specify anesthetic problems associated with managing patients with HHT. 9. Identify important components of the preoperative evaluation. 10. Develop an anesthetic plan for a patient with HHT.

A 68-year-old man presented with recurrent epistaxis for more than 40 years. He had undergone septodermoplasty approximately 18 months before the latest admission. The patient experienced relief of symptoms for 15 months before again developing epistaxis requiring emergency surgery. Intraoperative examination of his nasal cavity revealed newly developed telangiectatic vessels in the superior portion of the nasal vault, as well as ingrowth of new vessels into the septodermoplasty. Laser coagulation therapy and bevacizumab (an anti-angiogenesis chemotherapeutic agent that targets a protein found in many cancer cell types) were used to control acute bleeding, but were ineffective in providing long-term relief. As a result, the patient was scheduled for repeat septodermoplasty. Preoperative assessment identified a long history of anemia that required iron supplementation and multiple transfusions. The patient also reported a history of bilateral plantar bleeding, as well as multiple telangiectases of the nose, eyelids, lips, outer ears, and feet. He had a history of embolization to control bleeding colonic telangiectases and reported a magnetic resonance imaging (MRI) study that revealed no intracranial pathology. Anesthetic records from his most recent treatment, with laser coagulation therapy, were reviewed and revealed an episode of epistaxis occurring during induction of anesthesia. Additional medical conditions identified during the preoperative evaluation included wellcontrolled hypertension and chronic atrial fibrillation. His home medication list was limited to lisinopril (10 mg once daily) and metoprolol (50 mg twice daily). The patient was 73 inches tall and weighed 138 kg. Vital signs were all within normal limits. His oxygen saturation was 98% on room air. Preoperative complete blood count revealed a hematocrit of 32% and a platelet count of 308 k/mcL. Basic metabolic panel and coagulation studies were within normal limits.

H

ereditary hemorrhagic telangiectasia (HHT) is often referred to as Osler-Weber-Rendu syndrome, derived from the names of Sir William Osler, Henri Rendu, and Frederick Weber, who described this familial multisystem vascular disease in the late 19th century.1 Of note, Benjamin Babington, inventor of the laryngoscope, was among the first clinicians to describe the most common features of HHT.2 The estimated prevalence is 1:5,000.3

PREANESTHETIC ASSESSMENT Dr. Elizabeth A.M. Frost, who is the editor of this continuing medical education series, is clinical professor of anesthesiology at the Icahn School of Medicine at Mount Sinai, in New York City. She is the author off 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 Read this article, reflect on the information presented, then go online (www.mssm.procampus.net) and complete the lesson posttest and course evaluation before January 31, 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: February 1, 2013 TERMINATION DATE: January 31, 2014 ACCREDITATION STATEMENT The Icahn School of Medicine at Mount Sinai is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

CREDIT DESIGNATION STATEMENT The Icahn School of Medicine at Mount Sinai designates this enduring material for a maximum of 2.0 AMA PRA Category 1 Creditsâ&#x201E;˘. Physicians should claim only the credit commensurate with the extent of their participation in the activity. It is the policy of the Icahn School of Medicine at Mount Sinai 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.

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HHT is a genetic disorder inherited as an autosomal dominant trait. The majority of cases are associated with an abnormal gene on either chromosome 9 or 12. Both of these genes code for a protein involved in angiogenesis. Inheritance of a single gene mutation results in the formation of abnormal blood vessels in the skin, mucous membranes, and various organs. These vascular malformations lack capillaries and thus contain a direct communication between the high-pressure arterial systems and the thinwalled low-pressure venous system. High pressure causes dilatation of the venules, forming fragile masses of thin convoluted vessels with an increased risk for rupture and hemorrhage.4 Only a small percentage of blood vessels are abnormal in patients with HHT. Furthermore, manifestations of HHT may not develop until later in life. Malformations vary in size and are termed telangiectasia if they involve small blood vessels and arteriovenous malformations (AVMs) when they involve larger blood vessels. The location of these vascular malformations in the body dictates the problems patients encounter.

Clinical Features and Manifestations Telangiectases tend to develop over time in the skin, especially on the face and hands, and mucous membranes that line the naso- and oropharyngeal cavities and the gastrointestinal (GI) and respiratory tracts.4 These vascular anomalies often become more numerous with increasing age.5 They present as small red and purplish blanchable spots on physical exam, laryngoscopy, or endoscopy. Telangiectasia located close to the surface of the skin and mucous membranes tend to rupture easily with bleeding following even slight trauma.4 Spontaneous and recurrent epistaxis is typically the earliest and most common (>90%) manifestation of HHT. An estimated 25% of HHT patients develop symptoms of GI bleeding. Epistaxis and GI bleeding collectively contribute to a high incidence of iron-deficiency anemia.4-6 AVMs often occur in internal organs such as the lungs (≤50%), liver (>30%), and brain (≤20%).4,5 These larger vascular malformations, which typically are congenital and present at birth, can enlarge over time. Bleeding AVMs can create severe, sometimes life-threatening problems. Pulmonary AVM(s) create a right-to-left shunt with a risk

Table 1. International Consensus Diagnostic Criteria for HHT Epistaxis—spontaneous and recurrent Telangiectases—multiple at characteristic sites (face, lips, oral cavity, fingers, nose) Visceral arteriovenous malformations (lung, brain, liver, spinal) or gastrointestinal telangiectases Family history—first-degree relative with HHT according to these criteria HHT diagnosis is definite if 3 criteria are present; suspected if 2 criteria are present; unlikely if less than 2 criteria are present. HHT, hereditary hemorrhagic telangiectasia

for subsequent hypoxemia and paradoxical embolization and/or cerebrovascular accident (CVA).4,7 Rupture of a lung AVM can present with hemoptysis or hemothorax.4,5 The majority of AVMs within the liver remain asymptomatic. However, depending on the size and connections they form between blood vessels, hepatic AVMs can in rare cases produce high-output congestive heart failure, portal hypertension, hepatic encephalopathy, or liver failure. Cerebral AVMs, which also tend to remain clinically silent, can induce headaches, seizures, CVAs, and/or subarachnoid hemorrhage when ruptured. Women with HHT who are pregnant and have untreated pulmonary AVMs are at increased risk for rupture secondary to increased peripartum blood volume, cardiac output, and vascular distensibility.4

Diagnosis Diagnosis of HHT involves criteria summarized more than a decade ago as the International Consensus Diagnostic Criteria for HHT (Table 1).8 The disorder is highly variable in severity. Affected children may not exhibit all the signs and/or symptoms of HHT, thus diagnostic status may change during the life span. Genetic testing is available but is complex and should be preceded by clinical confirmation.

Screening Screening recommendations recently have been developed to help clinicians detect cerebral and pulmonary AVMs (PAVMs) before the development of complications. Patients with definite or suspected HHT should have an MRI with and without gadolinium in childhood, and again as an adult to screen for cerebral AVMs.9 Screening for PAVMs should begin early in childhood with yearly pulse oximetry measurements obtained in both the supine and sitting positions. Most PAVMs are located in the lower lobes; therefore, these patients often have a higher SpO2 when supine than when sitting. At age 10 years, a contrast echocardiogram should be obtained to screen for pulmonary shunting. Appearance of bubble contrast in the left heart after 3 cardiac cycles is consistent with PAVMs.7 The bubble contrast will pass to the left heart much faster with a cardiac shunt. Any patient with a consistent SpO2 less than 97% or a positive contrast echocardiography test requires a chest computed tomography angiogram to confirm the presence of a PAVM and to determine if its size is sufficient to warrant treatment.9

Treatment Treatment for HHT is directed either at relief from symptoms or the prevention of serious complications. No effective therapy currently is available to prevent development of vascular malformations. The recommended treatment options for a telangiectasia and/or AVM depend on both its size and location in the body.

Anesthetic Management The vascular anomalies characteristic of HHT are not only prone to rupture but also may produce severe

FEBRUARY 2013

complications from blood shunting.4 Knowledge of several important anesthetic considerations will help guide perioperative management. Care should be taken to minimize trauma during mask ventilation, laryngoscopy, and endotracheal intubation. Laryngoscopy may induce bleeding; therefore, readily available suction is a key component of induction. Rapid sequence induction may avoid the need for mask ventilation. Instrumentation of the nasal cavity should be avoided if possible, with obvious preference given for placement of an oral endotracheal tube (ETT). Use of a smaller lubricated ETT, with minimally occlusive cuff pressure to decrease mucosal trauma, should be considered. Nasopharyngeal airways also should be avoided due to increased trauma to the mucosa. Use of humidified air during mechanical ventilation may help prevent drying of the respiratory tract mucous membranes that have an increased risk for bleeding. Given the abnormal arterial connection and the absence of normal vessel wall contractile elements, bleeding from telangiectases can be brisk and difficult to control. A preoperative complete blood count often reveals findings consistent with an iron-deficiency anemia. Given the high frequency of preexisting anemia and increased risk for bleeding during airway manipulation, it is important to communicate early with the blood bank to ensure availability of products before surgery. These patients often have a history of red blood cell transfusions and therefore are at increased risk for alloimmunization and transfusion reactions. The presence of alloantibodies complicate testing for red blood cell compatibility. As a result, early antibody screening and cross-matching is preferred. Use of leuko-reduced blood products may reduce the development of alloimmunization. Anticoagulants should be used with caution. Antifibrinolytic therapy such as tranexamic acid and aminocaproic acid may decrease transfusion needs.10,11 The recurrent bleeding that occurs in HHT is caused by vessel wall abnormalities as opposed to a coagulopathy; therefore, patients typically have a normal preoperative platelet count, bleeding time, and prothrombin and partial thromboplastin times. AVMs in the lungs are the most common cause of a serious acute complication in patients with HHT. Complications with PAVMs tend to arise from shunting of blood rather than hemorrhage. Shunting of blood through PAVMs effectively bypasses the capillary bed, which typically acts as a filter for impurities (thrombus, bacteria, air bubbles, etc.), and places these patients at risk for paradoxical embolism. Due to the high frequency of PAVMs in patients with HHT, and their potentially devastating complications, antibiotic prophylaxis in accordance with American Heart Association (AHA) guidelines is recommended before dental and invasive procedures to help prevent brain/systemic abscess formation.9,12 All IV fluids should be bubble-free to avoid air emboli.9 Micropore filters help remove microaggregates during transfusion therapy. PAVMs also can result in hypoxemia depending on the magnitude of the shunt fraction. Positive pressure ventilation can increase alveolar-arterial oxygen gradients. Therefore, maintenance of spontaneous ventilation may optimize oxygenation in the presence of PAVM(s).7 A preoperative contrast echocardiogram is important to screen for PAVMs.9


CONTINUING MEDICAL EDUCATION

FEBRUARY 2013

Table 2. Treatment Options for Common Complications Complication

Treatment Options

Iron-deficiency anemia

Iron supplementation Red blood cell transfusion

Skin telangiectasia (symptomatic or cosmetic)

Laser coagulation therapy

Severe and/or recurrent epistaxis

Keep nasal mucosa moist (humidified air, nasal lubricants) Hormonal therapy (estrogens) External pressure and/or nasal cavity packing Laser coagulation therapy Septodermoplasty Embolization (emergency control)

Severe and/or recurrent GI bleed

Endoscopic ablation

Lung AVM (symptomatic and/or feeding vessel ≥3 mm diameter)

Embolization

Cerebral AVM (≥1 cm diameter)

Embolization Neurovascular surgery Stereotactic radiosurgery

Symptomatic liver AVM (CHF or liver failure)

Varies on case-by-case basis Liver transplantation

AVM, arteriovenous malformation; CHF, congestive heart failure; GI, gastrointestinal

guidelines. The otolaryngologist performed a repeat septodermoplasty in which the offending nasal mucosa was scraped away and a split-thickness skin graft was applied to the nasal cavity. Maintenance of anesthesia was facilitated with sevoflurane. The patient remained hemodynamically stable throughout the case with an estimated blood loss of 600 mL. He received approximately 2 L of crystalloids and 2 units of packed red blood cells administered using micropore filters. The patient’s trachea was extubated at the conclusion of the case and he was transported to the postanesthesia care unit in stable condition. He was monitored overnight as an inpatient and discharged home the following day without incident.

Summary Approximately 1.2 million people worldwide have HHT, making the condition uncommon but not rare. These patients develop abnormal blood vessels that often involve multiple organ systems. Complications are common and often require surgical management. Patients with HHT therefore are likely to undergo multiple operations throughout their lifetimes. Perioperative care of patients with HHT can be especially challenging for the anesthesiologist. Anticipation and preparation for all potential perioperative problems is essential in avoiding life-threatening complications in these patients.

References Cerebral AVM(s) affect an estimated 10% of patients with HHT and usually are asymptomatic. Rupture can result in intracerebral hemorrhage and/or subarachnoid hemorrhage and possibly a hemorrhagic CVA. These vascular malformations generally represent high-flow, lowresistance shunts when vascular intramural pressure is less than systemic arterial pressure, and rupture does not appear to be clinically associated with acute or chronic hypertensive episodes. However, high-pressure arterial flow in cerebral AVMs results in dilatation of the venous component of these malformations with subsequent increased risk for developing aneurysms. Hypertension is a widely accepted risk factor for aneurysm rupture. It seems reasonable to implement measures to avoid sudden increases in systemic arterial blood pressure that can increase aneurysm transmural pressure and potentially cause rupture. Often this aim includes achieving an adequate depth of anesthesia before endotracheal intubation, as well as use of adjunctive agents such as opioids and/or lidocaine, to further attenuate the sympathetic response to laryngoscopy, tracheal intubation, and tracheal extubation. Furthermore, the low-resistance characteristic of cerebral AVMs can divert blood flow away from adjacent brain tissue (“steal phenomenon”) and can lead to ischemia. Avoidance of hypotension and maintenance of normal or even increased systemic arterial blood pressure may optimize perfusion of adjacent tissues. Hyperventilation can potentially shunt additional blood flow to the low-resistance malformation, and therefore, maintenance of normocarbia is ideal for these patients.13 Spinal AVMs develop in 1% to 2% of patients with HHT and almost always cause neurologic symptoms.4 Common

symptoms suggesting a possible spinal AVM include back pain, sensory loss, and weakness in the lower extremities. If the preoperative assessment reveals the presence of any concerning neurologic symptoms, it is reasonable to obtain an MRI scan to exclude a spinal AVM before neuraxial anesthesia.

Management of the Case Presented The patient had a recent negative MRI for intracranial pathology. A previous contrast echocardiogram was reviewed with no evidence of PAVMs. Basic metabolic panel and coagulation studies were within normal limits. Red blood cell compatibility testing revealed a positive antibody screen. A formal crossmatch identified 2 compatible units of packed red blood cells before surgery. A large-bore peripheral IV catheter was inserted and a lactated Ringer’s infusion was started. Care was taken to ensure all IV fluids were free of bubbles. The patient was premedicated in the holding area with 2 mg of IV midazolam. The patient was transferred to the operating room and standard monitors were attached in accordance with guidelines from the American Society of Anesthesiologists. He was preoxygenated with care taken to minimize pressure over the nasal bridge. A mild bleed was noted from his nasal pharynx. Rapid sequence induction was performed with atraumatic placement of a lubricated 7.0-mm ETT. The endotracheal cuff was inflated with minimal occlusive pressure. Another large-bore peripheral IV catheter was obtained for additional access. He received antibiotic prophylaxis before incision, according to AHA

1.

Fuchizaki U, Miyamori H, Kitagawa S, Kaneko S, Kobayashi K. Hereditary haemorrhagic telangiectasia. Lancet. 2003;362(9394):1490-1494.

2.

Babington BG. Hereditary epistaxis. Lancet. 1865;2:362-363.

3.

Kjeldsen AD, Vase P, Green A. Hereditary haemorrhagic telangiectasia: a population-based study of prevalence and mortality in Danish patients. J Intern Med. 1999;245(1):31-39.

4.

Govani FS, Shovlin CL. Hereditary haemorrhagic telangiectasia: A clinical and scientific review. Eur J Hum Genet. 2009;17(7):860-871.

5.

Dupuis-Girod S, Bailly S, Plauchu H. Hereditary hemorrhagic telangiectasia (HHT): from molecular biology to patient care. J Thromb Haemost. 2010;8(7):1447-1456.

6.

Shah RK, Dhingra JK, Shapshay SM. Hereditary hemorrhagic telangiectasia: a review of 76 cases. Laryngoscope. 2002;112(5):767-773.

7.

Gossage RJ, Ghassan K. Pulmonary arteriovenous malformations. A state of the art review. Am J Respir Crit Care Med. 1998;158(2):643-661.

8.

Shovlin CL, Guttmacher AE, Buscarini E, et al. Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome). Am J Med Genet. 2000;91(1):66-67.

9.

Faughnan ME, Palda VA, Garcia-Tsao G, et al. International guidelines for the diagnosis and management of hereditary hemorrhagic telangiectasia. J Med Genet. 2009;48(2):73-87.

10. Sabbà C, Gallitelli M, Palasciano G. Efficacy of unusually high doses of tranexamic acid for the treatment of epistaxis in hereditary hemorrhagic telangiectasia. N Engl J Med. 2001;20;345(12):926. 11. Korzenik JR, Topazian MD, White R. Treatment of bleeding in hereditary hemorrhagic telangiectasia with aminocaproic acid. N Engl J Med. 1994;331(18):1236. 12. Shovlin CL, Bamford K, Wray D. Post NICE 2008: antibiotic prophylaxis prior to dental procedures for patients with pulmonary arteriovenous malformations (PAVMs) and hereditary haemorrhagic telangiectasia. Br Dental J. 2008;205(10):531-533. 13. Ogilvy CS, Stieg PE, Awad I, et al. Recommendations for the management of intracranial arteriovenous malformations. Stroke. 2001;32(6):1458-1471.

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

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.

FEBRUARY 2013

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.

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disease associated with an abnormal gene involved in _____. a. cellular differentiation b. factor V synthesis c. angiogenesis d. collagen synthesis

6.

Match the common complication with its recommended treatment option a. Recurrent GI bleed→hormonal therapy b. Iron-deficiency anemia→iron supplementation c. Cerebral AVM (<1cm in diameter)→neurovascular surgery d. Lung AVM→estrogen

2.

Vascular anomalies can develop in which of the following organ systems of patients with HHT? a. Skin b. Pulmonary c. Central nervous system d. All of the above

7.

Screening recommendations for patients with definite or suspected HHT include _____. a. MRI with/without gadolinium in childhood and again as adult b. yearly pulse oximetry measurements obtained in both supine and sitting positions c. contrast echocardiogram at 10 years of age d. all of the above

3.

The most common manifestation of HHT is _____. a. anemia b. gastrointestinal (GI) bleeding c. hemoptysis d. epistaxis

8.

The preoperative test most often abnormal in patients with HHT is _____. a. coagulation study b. hematocrit c. platelet count d. CXR

4.

According to the International Consensus Diagnostic Criteria for HHT, _____ is consistent with a definite diagnosis of HHT. a. family history of first-degree relative with HHT and recurrent epistaxis b. history of multiple colonic telangiectases and several telangiectases over the face c. history of recurrent epistaxis, telangiectases on the fingers, and a cerebral arteriovenous malformation (AVM) d. multiple facial telangiectases and family history of first-degree relative with HHT

9.

All of the following are airway management recommendations in patients with HHT except _____. a. minimize pressure over nasal bridge during preoxygenation b. use a larger lubricated ETT with minimally occlusive cuff pressure c. use humidified air during mechanical ventilation d. spontaneous ventilation is preferred to positive pressure ventilation

5.

Potential problems encountered during the anesthetic management of a patient with HHT include _____. a. airway bleeding during mask ventilation and endotracheal intubation b. epistaxis refractory to treatment with nasal phenylephrine c. hypoxemia from pulmonary shunting d. all of the above

10. All of the following are intraoperative anesthetic recommendations in patients with HHT except _____. a. maintenance of normocarbia b. avoid hypertension/hypotension c. ensure all intravenous fluids are bubble-free d. antibiotic prophylaxis only for invasive procedures


FEBRUARY 2013

AnesthesiologyNews.com I 23

CL IN ICA L A N E STH E SIOL OG Y COMPLICATIONS

CONTINUED FROM PAGE 1

J. Barrington, MD, discussed the etiology of adverse events associated with peripheral nerve blockade and neuraxial anesthesia, along with possible ways such events can be avoided. “Postoperative neurological sequelae are not uncommon following peripheral regional anesthesia, but these are usually benign and resolve fairly quickly,” said Dr. Barrington, staff anesthetist at St. Vincent’s Hospital in Melbourne, Australia. “On the other hand, the incidence of serious complications related to the practice is infrequent or rare, but distinguishing between anesthetic and surgical factors contributing to these injuries is challenging.” Neuraxial Anesthesia Dr. Barrington began his presentation by discussing the safety of neuraxial anesthesia, which has been the subject of considerable research. One of the most comprehensive studies in this area was that by Moen et al ((Anesthesiology 2004;101:950-959), which examined severe neurologic complications after central neuraxial blockades in Sweden between 1990 and 1999. Using a national database, the researchers studied roughly 1.26 million spinal blocks and 450,000 epidural blocks that had resulted in 127 complications. Among these were spinal hematoma (33), cauda equina syndrome (32), meningitis (29) and epidural abscess (13). Eighty-five patients experienced permanent neurologic damage. The study yielded an overall incidence of one complication per 20,000 to 30,000 blocks. Neuraxial anesthesia also is linked to several infectious complications, the most common of which are epidural abscesses. Danish researchers in 1999 published a report in Anesthesiology reporting an incidence of epidural abscesses of one in 1,900 (91:1928-1936) catheters placed. “I think prior to that we really thought that these major complications were far more rare than that,” Dr. Barrington said. “So it really made us look at some of the associated factors. And in that study, they pointed out that prolonged duration of epidural catheterization was a risk. And also in many patients in that study there was a delayed diagnosis, and that as we know is associated with poor prognosis.” Meningitis is commonly associated with puncture of the dura and appears to occur in clusters of events associated with poor hygiene. The offending organism is typically a hemolytic

streptococcus, which originates in the nasopharynx of the clinician. “These are catastrophic complications,” Dr. Barrington said. “But it doesn’t mean the patient is always going to end up with permanent neurological deficit. Either way, it’s quite clear that most neuraxial catastrophes are associated with organizational or professional failures. I think one of the factors that contributes to good outcome in these patients is standardized methods of follow-up, and very good neurological

surveillance in the postoperative period.”

anesthesia, as well as the number and type of regional anesthesia procedures Peripheral Blocks performed. The use of peripheral block has A total of 487 participants reported grown considerably over the past 56 major complications in 158,083 decade, as has the amount of research regional procedures (3.5 per 10,000), into the technique. A study by including four deaths. “They had large Auroy and colleagues ((Anesthesiology enough numbers that they were able 2003;98:595) examined major compli- to document the risk associated with cations of regional anesthesia in France individual blocks,” Dr. Barrington over a 10-month period. Participating explained. “Overall, they had 50,000 anesthesiologists voluntarily reported blocks and 12 complications. Of those major complications related to regional see complications page 24

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24 I AnesthesiologyNews.com

FEBRUARY 2013

C LIN I C A L A N ES THES IO LO G Y COMPLICATIONS

CONTINUED FROM PAGE 23

12 neuropathies, seven were still evident at six months. So it made for a very low incidence of major neuropathy associated with peripheral nerve blockade.” Nine of the 12 neuropathic injuries occurred in patients in whom a nerve stimulator had been used. As in any complication, patient factors—particularly those that can affect the health of the peripheral nervous system—certainly play a role in the development of adverse events after neurological blockade. “In local data that we collected, 78% of our patients have diabetes mellitus,” Dr. Barrington said. “Ulnar neuropathy is common in our population. Carpal tunnel syndrome, peripheral neuropathy, chemotherapy and vascular disease are all factors that can impact on the health of the nerves.” A large proportion of patients at Dr. Barrington’s institution have nerve root compression and spinal canal

stenosis that goes unidentified, he added. “What this really means is that many of our patients have potential preoperative neural compromise that puts them at the increased risk of nerve injury in the perioperative and postoperative period.” Surgical factors also influence the possibility of perioperative and postoperative nerve injury, of which Dr. Barrington first mentioned tourniquets, which are frequently used in orthopedic surgery. Tourniquets are known to damage alpha motor neurons, particularly in the area closest to the tourniquet itself; such damage is largely dependent on the amount and duration of pressure. “Of course we position our patients in unusual ways, and the nerves are subject to compression, contusion, stretching, and in worst-case scenarios, transection,” he continued. Patients sometimes leave the hospital with ill-fittingg casts and compression dressings, which can mask the symptoms of neural compromise.

CLA SSI FI EDS

Clinical or Basic Science Faculty Position, Research Anesthesiologist The Department of Anesthesiology at Penn State Hershey College of Medicine is seeking an experienced, Anesthesiology Board Certified, Clinical or Basic Science Research Faculty member to join a growing Anesthesiology Research Department. The applicant will be a clinical anesthesiologist, preferably at the Associate or Full Professor level, who has demonstrable ongoing research productivity. The candidate will receive suitable seed funding, commensurate academic time as well as the necessary facilities to pursue research interests. The successful candidate will be assigned a named Professorial Endowment for the first three years as a Faculty member in the Department. Interested applicants should submit their CV and cover letter outlining their research interests to: Dr. Berend Mets, MB, ChB, PhD, FRCA, FFA (SA) Eric A. Walker Professor and Chair, Department of Anesthesiology Penn State Milton S. Hershey Medical Center/ Penn State College of Medicine P.O. Box 850, M.C. H187 500 University Drive Hershey, PA 17033-0850 bmets@hmc.psu.edu Applicants can visit: www.pennstatehershey.org/anesthesia to learn more about the Department. Penn State is committed to affirmative action, equal opportunity, and the diversity of its workforce. AN-0113-001

Physical factors play an important role in orthopedic surgery, as significant forces are used, forces that are transmitted through the body. The role of anesthetic factors in nerve injury is more challenging to ascertain, although certainly possible, and through a variety of means, including mechanical trauma from needles or catheters, nerve perforation and damage to fascicles. “All the things we do impair neuronal blood flow,” Dr. Barrington added. “We also know most of our local anesthetics have the potential to cause toxicity.” Determining the etiology of a nerve injury—particularly distinguishing between anesthesia and non–anesthesia-related causes—is a challenging undertaking even in the best cases. To help clarify these otherwise muddy waters, Dr. Barrington and his colleagues recently performed a prospective audit of more than 6,000 patients (7,156 blocks) undergoing peripheral nerve and plexus blocks (Reg Anesth Pain Medd 2009;34:534-541). The researchers found that 30 patients (0.5%) had clinical features requiring referral for neurologic assessment, three of whom had blockrelated nerve  injuries (incidence of 0.4 per 1,000 blocks). “Clearly there’s going to be reasonably wide confidence intervals with such a low number of events,” Dr. Barrington explained, “so the figure I use with my patients is one in 1,000, and even then it’s most likely going to be a sensory complication that will resolve with time. “My experience,” he added, “has told me that it’s the complex patients—the ones with the comorbidities—who are most likely to do poorly. So perhaps we should pay more attention to those

patients with increased risk factors and think about changing the way we administer anesthetic to them.” Jeff Gadsden, MD, director of regional anesthesia at St. Luke’sRoosevelt Hospital in New York City, said any analysis of neurologic complications following regional anesthesia is made challenging by the rarity of the events. “Dr. Barrington’s efforts to spearhead a collaborative standardized registry have resulted in a vast amount of prospectively collected information, and will no doubt lead to a better understanding of the nature of injuries during regional anesthesia as time goes on,” Dr. Gadsden said.

‘I think prior to [this study] we really thought that these major complications were far more rare.’ —Michael J. Barrington, MD “As patterns emerge for patient or surgical characteristics that increase risk for neurologic injury, the more difficult question will be how to adapt our practice,” he continued. “For example, will a reduction in the concentration of local anesthetics for ‘at-risk’ patients prevent injury? How about reduced tourniquet times? Or injection pressure monitoring? “This is an exciting topic for regional anesthesiologists and large, global registries such as these will be invaluable in aiding our understanding of these potentially catastrophic complications.” —Michael Vlessides

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C LIN I C A L A N ES THES IO LO G Y DOUBLE

CONTINUED FROM PAGE 1

pressure—or extremes of blood pressure—and anesthetic depth have been shown to predict worse outcomes.” Using data from the institution’s electronic anesthesia record and cardiothoracic anesthesia registry, Dr. Maheshwari and his colleagues grouped 3,445 patients into categories based on time-weighted BIS and MAP scores. For technical reasons, MAC fraction was not available in this patient population, Dr. Maheshwari said. Patients were included in the reference group if their time-weighted MAP and BIS scores were within 1 standard deviation of the mean. “In the double-low w group, the BIS was 27 and the MAP was around 69, compared with the doublehigh group, where the BIS was around 46 and MAP around 80,” Dr. Maheshwari said. “So there’s a clear difference between the groups” (Figure). Multivariable logistic regression was used to assess the relationship between each of the exposure groups and the reference group on both 30-dayy mortality and in-hospital mortality and morbidity outcomes. As Dr. Maheshwari reported at the 2012 Annual Meeting of the American Society of Anesthesiologists (abstract 014), he and his colleagues adjusted for 54 confounding variables, including demographics, medical history and perioperative data. The observed mean time-weighted BIS and MAP averages for the entire patient cohort were 35±9 and 75±5 mm Hg, respectively. The researchers found no significant associations between the four BIS-MAP exposure groups and the reference group with respect to either 30-dayy mortality or in-hospital morbidity and mortality (Table).

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Table. Multivariable Associations With BIS-MAP Category (N=3,445) 30-Day Mortality

In-Hospital Mortality/Morbidity

BIS-MAP Category N

Incidence, n (%)

OR (99.4% CI) vs. Reference

P value

Incidence, n (%)

OR (99.4% CI) vs. Reference

P value

Reference

1,608

21 (1.3)

1.00

98 (6.1)

1.00

Double low

492

12 (2.4)

0.62 (0.18-2.16)

0.30

53 (10.8)

0.92 (0.53-1.62)

0.70

Low BIS/high MAP

445

4 (0.9)

0.56 (0.10-3.28)

0.37

32 (7.2)

0.93 (0.51-1.70)

0.74

High BIS/low MAP

417

15 (3.5)

2.28 (0.77-6.76)

0.04

40 (9.6)

1.07 (0.59-1.93)

0.77

Double high

480

11 (2.3)

2.57 (0.58-8.42)

0.03

23 (4.8)

0.87 (0.44-1.3)

0.59

BIS, bispectral p index; CI, confidence interval; MAP, MAP, mean arterial pre pressure; p essure;; OR, odds ratio

Figure. Time-weighted averages (TWA) show a difference between patients with doublehigh and double-low scores on BIS and mean arterial pressure (MAP).

DESAT

Dr. Maheshwari said the inability to include MAC fraction in the analysis means the researchers could not identify patients who had low BIS and low MAC—a group that is sensitive to volatile anesthesia and appears to have especially poor outcomes. Jesse M. Ehrenfeld, MD, MPH, assistant professor of anesthesiology and biomedical informatics at Vanderbilt University School of Medicine, in Nashville, Tenn., said, “In spite of this particular study’s negative findings, I believe that there is enough literature to suggest that what happens in the operating room really does impact long-term outcomes. However, there have not been any large prospective randomized evaluations of these ‘low’ states and it might turn out that there is no effect at all, just unaccounted comorbidities or other confounders.” —Michael Vlessides

CONTINUED FROM PAGE 15

correlation between cardiac output, mean arterial pressure, stroke volume, or cardiac index and cerebral desaturation events. “We also calculated the area under the curve for the amount of time patients were desaturated,” Dr. Brinkman added. “And we showed that heart rate would go down in patients with longer desaturation time, but stroke volume would increase significantly to maintain cardiac output. It was something we didn’t expect to find, but it’s an interesting reflex that hasn’t been shown before, as far as I can tell.” No correlation was found between peripheral arterial saturation and cerebral oxygen saturation. Dr. Brinkman suggested that future research should focus on outcomes of patients who sustain cerebral desaturation. “And if down the road we show that there is potential for harm in these individuals, then maybe a device like the Fore-Sight needs to be a more standard monitor, even if it’s just in selected high-risk groups.” Bruce D. Spiess, MD, professor of anesthesiology at Virginia Commonwealth University, in Richmond, said physiologic effects of one-lungg ventilation are farther reaching than merely a reduction

in blood flow to the nonventilated lung. “The fact that cerebral oximetry readings decreased in approximately 50% of these patients is intriguing, although perhaps not surprising,” Dr. Spiess said. Cardiac changes do not appear to fully explain the findings, he noted. Cerebral oximetry is a localized measure of hemoglobin saturation. “If a patient is placed in a lateral decubitus position for a thoracotomy with a lung collapsed, there may be inconsistent and variable changes in brain frontal lobe blood drainage as the lung collapses, the mediastinum shifts and great vessels change position,” Dr. Spiess said. “It would be interesting to see if the changes occurred in thoracoscopic versus open thoracotomy changes, as well as whether it was more prevalent on the right or left side.” If this phenomenon is found in more patients and if the levels of desaturation reach critical levels, he continued, “it will be very interesting to see if there are longer-term clinical outcome correlates. We do not know the reasons for the observations; they are new and warrant further investigation.” —Michael Vlessides


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The February 2013 Digital Edition of Anesthesiology News  

The February 2013 Digital Edition of Anesthesiology News

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