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SUPPLEMENT ARTICLES: Sherri L. Katz Assessment of Sleep-Disordered Breathing in Pediatric Neuromuscular Diseases Pediatrics 2009; 123: S222-S225 [Abstract] [Full text] [PDF]

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Sleep disordered breathing or inspiratory muscle weakness?

Joyce Cheng, John R. Bach, MD   (17 July 2009)

Sleep disordered breathing or inspiratory muscle weakness? 17 July 2009
Joyce Cheng, Medical student Drexel University College of Medicine, John R. Bach, MD Send letter to journal: Re: Sleep disordered breathing or inspiratory muscle weakness? jcc92{at}drexel.edu Joyce Cheng, et al.	We read with interest “Assessment of sleep-disordered breathing in pediatric neuromuscular disease.”(1) The author wrote that “the presence of OSA often precedes the development of nocturnal hypoventilation” in Duchenne muscular dystrophy (DMD). However, since polysomnograms are programmed to interpret paradoxical chest-abdominal movements as obstructive in nature, whereas the same pattern is seen with weak or poorly recruited accessory respiratory muscles, and CO2 is rarely monitored during polysomnography, how can one be certain that the problem is central or obstructive apneas rather than inspiratory muscle dysfunction? Maybe the treatment should be volume or pressure cycled ventilation without EPAP rather than continuous positive airway pressure (CPAP) or low span bi-level PAP. The authors wrote that, “12% of subjects with a low apnea-hypopnea index had abnormally high CO2 levels, which were clinically significant. The role of capnography, therefore, is not entirely clear but may be a helpful…” However, rather than “titrate away” apneas/hypopneas and have to repeat the titration every six months as patients deteriorate, why not treat symptomatic hypercapnia (inspiratory dysfunction) with full-setting noninvasive ventilation (NIV) to more completely rest inspiratory muscles overnight so that the patient can better maintain diurnal alveolar ventilation? This has been our approach for over 1000 neuromuscular disease NIV users (2) including several hundred who eventually developed continuous NIV dependence.(3) What evidence is there that EPAP is needed at all when apneas/hypopneas are avoided by NIV inspiratory pressures of 18 to 20 cm H2O? References: 1. Katz SL. Assessment of sleep-disordered breathing in pediatric neuromuscular disease. Pediatrics 2009;123:S222-S225. 2. Bach JR. The Management of Patients with Neuromuscular Disease. Philadelphia: Elsevier 2004, 414 pages. 3. Bach JR, Alba AS, Saporito LR. Intermittent positive pressure ventilation via the mouth as an alternative to tracheostomy for 257 ventilator users. Chest 1993;103:174-182. Conflict of Interest: None declared