Preventing Respiratory Complications in Patients with Neuromuscular Disease Jonathan D. Finder, MD Professor of Pediatrics University of Pittsburgh School of Medicine ————Clinical Director Pediatric Pulmonary Medicine Children’s Hospital of Pittsburgh
Introduction • Much of morbidity/mortality in severe neurologic and neuromuscular disease is respiratory • Cause of death NMD is “pneumonia” • The course is worsening respiratory insufficiency until death • Cost of complications >> cost of prevention
New paradigms • No longer is “therapeutic nihilism” appropriate • New technologies, new therapies have changed the natural history of these disease • A new activism on the part of parents has also pushed care forward
Guillaume Benjamin Amand Duchenne de Boulogne (1806-1875)
Duchenneâ€™s drawing of pt with muscular
Duchenne with patient
Duchenne MD • The best studied and most common pediatric NMD • Incidence 1:3,500 males (similar to CF) • Easily predictable course • Majority of morbidity is respiratory • Cause of death 80% respiratory causes – (Entirely preventable)
Survival in DMD: Room for Improvement.
The following data from 1983-1997 are from a poster presentation from the CDC: Kenneson A, Yang Q, Olney R, Rasmussen S, Friedman JM. Mortality in Duchenne Muscular Dystrophy: An Analysis of Multiple Cause Mortality Data, 1983-1997 (Poster presentation). American College of Medical Genetics Annual Clinical Genetics Meeting. March 2004.
Evidence-based medicine? • Most literature is anecdotal and retrospective • Most RTC studies have involved steroids • As a result there has been a delay in approval of many life-saving therapies • Clinical equipose does not exist today: – Unethical to withhold effective therapies to study them
Many issues: therapeutic nihilism, lack of training… • Crosses all borders (US1, Canada2, Switzerland3) • Few physicians prepared to care for adults with DMD4 • QOL studies reflect overall satisfaction (except for “love life”)4, 5 1Bach,
Arch Physical Med Rehabil 73(2):179-83, 1992. 2Gibson, Chest. 119(3):940-6, 2001. 3Ramelli, Swiss Med Weekly. 135(39-40):599-604, 2005 4Jeppesen J. Pediatr Rehab. 8(1):17-28, 2005 5Raphael JC, Revue Neurologique. 158(4):453-60, 2002 Apr
Stages of respiratory function in Duchenne MD 1. Normal (age 0-10) â€˘
2. Inadequate cough (age 10-15) 3. Inadequate night time ventilation (age 1520) 4. Inadequate daytime ventilation (>age 17) â€˘
These ages vary greatly!
Stage 1: Normal Resp Function • Rule of thumb: ambulatory pt does not require assistance with cough or breathing • Aside from usual risks of anesthesia no special risks • Pulmonary function testing in pts over age 6 • Immunization (influenza & s. pneumo.)
Airway Clearance 2 linked portions of airway clearance: â€“ Mucociliary escalator (impaired in CF, PCD, smokers, etc) â€“ Cough clearance (impaired in NMD but also by tracheostomy
Stage 2: Inadequate cough • Often asymptomatic until a respiratory tract infection • Easily predicted with PFT’s and/or measurement of “peak cough flow” • Peak cough flow <160 L/min associated with failure to extubate • PEFR/PCF <270 L/m is indication for assisting cough Bach, J. R., Y. Ishikawa, and H. Kim. 1997. Prevention of pulmonary morbidity for patients with Duchenne muscular dystrophy. Chest 112(4):1024-8. Gomez-Merino E, Bach JR. Duchenne muscular dystrophy: prolongation of life b noninvasive respiratory muscle aids. Am J Phys Med Rehabil 2002;81:411-415
Assisting cough: Manual Assisted Cough • Abdominal thrust or thoracic squeeze after a maximal insufflation with AMBU bag or vent breath – Do this on an empty stomach – Scoliosis and contractures of thoracic wall limits effectiveness of this technique
Manually assisting cough
Mechanically assisted cough
• Preferred to direct suctioning in pts w/ trach (more effective, too) • Can be used via mask, mouthpiece, or tracheostomy • Achieves effective cough flows even in severely weak patients • Prophylactic use prevents atelectasis, supports chest wall compliance
Barach, AJP, 1952 • Used tank respirator adapted to provide insufflation and exsufflation • Polio patients
The first mechanical exsufflator, 1952
Bickerman, 1952 • Canine study • AJP 1952
Bickerman, 1952 â€˘ Showed exsufflation effective for clearing airways in canine model
Mechanically Assisting cough: • Mechanical InsufflationExsufflation (MI-E) • Respironics “CoughAssist” device • Very effective in clearing The original “Cofflator” secretions • Takes getting used to! • Adult range -30 to -45 cm H2O expiratory
MI-E -- Indications • Neuromuscular weakness • Peak cough flow <270 L/min • Maximum expiratory pressure <60 cm H2O • History of difficulty clearing secretions • NOT indicated for CF
Special warning: O2 can be hazardous to your health… • Treatment of low hemoglobin sat with oxygen can be dangerous! • Further suppresses drive • Can lead to respiratory failure and death • Low saturation means increased airway clearance, need for increased ventilation • Pulse oximeter very helpful
Pulse oximetry and O2 • Development of mucus plugs can be silent • Patients with NMD should have pulse oximeters in the home • SaO2 < 95% is indication for aggressive use of MI-E • Oxygen is NOT the answer!
Stage 3: Nocturnal Hypoventilation • • • • •
FVC < 30-40% Morning headache Increasing # of nocturnal awakenings Nightmares of smothering or drowning Daytime sleepiness, poor school performance, etc • Nocturnal hypoxemia noted on O/N oximetry or on polysomngraphy
Note that FVC<30% in DMD correlates to ventilatory failure (but not in SMA) Selected cohort FVC% and funct score pred of need for MV in DMD not SMA II (youngest pt 9
Management of nocturnal hypoventilation • Avoid tracheostomy, avoid suppl. O2 • BiPAP or other positive pressure ventilator • Avoid CPAP – Increases WOB w/o increasing ventilation
• Getting a comfortable mask fit is essential. • Titrate to normal pCO2 in sleep • Patient should awaken feeling refreshed
Effect of NIV on diurnal arterial blood gas tensions: improved!
Simonds, A K. Ward, S. Heather, S. Bush, A. Muntoni, F Outcome of paediatric domiciliary mask ventilation in neuromuscular and skeletal disease. Eur Respir J 2000;16: 476-81
Bear in mind: Many noses -- many interfaces
Various interfaces used for noninvasive positive pressure ventilation. Standard nasal masks in different sizes (Respironics, Inc.) (upper left), oronasal mask with very soft silicone seal (Resmed, Inc.) (upper right), nasal "pillows" (ADAM Circuit, Puritan Bennett, Inc.) (lower left) and mouthpiece attached to lipseal (lower right).
Stage 4: 24 hour ventilation dependence • In years past, this was indication for trach • No longer has to be the case! • Most patients can be managed noninvasively with mouthpiece ventilation • Newer, lightweight ventilators facilitate portability and remaining in school or at work
1950’s: Early respiratory care experience in Polio shapes later care in MD
1952 Emerson infant “iron lung:” the first non-invasive ventilator
Non-invasive Positive Pressure Ventilation (NIPPV)
• First described by Alexander in 1979 – Alexander, M. A., E. W. Johnson, J. Petty, and D. Stauch. 1979. Mechanical ventilation of patients with late stage Duchenne muscular dystrophy: management in the home. Arch Phys Med Rehabil 60(7):289-92.
• Non-invasive use of PPV best described by Bach – Gomez-Merino, E., and J. R. Bach. 2002. Duchenne muscular dystrophy: prolongation of life by noninvasive ventilation and mechanically assisted coughing. American Journal of Physical Medicine & Rehabilitation 81(6):411-5 – Tzeng, A. C., and J. R. Bach. 2000. Prevention of pulmonary morbidity for patients with neuromuscular disease. Chest 118(5):1390-6.
John Bach’s protocol • Assisted cough • Non-invasive ventilation • Use of pulse oximetry to determine need for increased MI-E • Change to 24 hour ventilatory assistance at times of URI – Tzeng, A. C., and J. R. Bach. 2000. Prevention of pulmonary morbidity for patients with neuromuscular disease. Chest 118(5):1390-6
AJRCCM, August 15, 2004
• Stress is on anticipation of respiratory care • NON-INVASIVE management also emphasized • Access to subspecialty care important: – – – – –
Pulmonologist Nutritionist Cardiologist Orthopedist Physical, speech, and occupational therapists; psychiatry, pastoral care as needed
Gaining World-wide Acceptanceâ€Ś
Italian translation courtesy of PPMD Italy
To wrap it upâ€Ś
Kevin, age 17, in ventilatory failure, 24 hour vent-dependent..
Patrick, age 26, graduating from Pitt Law
Preventing Respiratory Complications in Patients with Neuromuscular Disease Jonathan D. Finder, MD Professor of Pediatrics University of Pit...