The International Classification of Sleep Disorders manual is being updated to reflect current research and diagnostic advances, including a new classification—complex sleep apnea.
BOSTON—Revisions proposed by the American Academy of Sleep Medicine (AASM) for the third edition of the International Classification of Sleep Disorders (ICSD) manual were outlined at the 26th Annual Meeting of the Associated Professional Sleep Societies, LLC. Richard Berry, MD, of the University of Florida College of Medicine—among other speakers who discussed developments in their areas of expertise—presented proposed criteria for sleep-related breathing disorders. He noted that the task force is still formulating specific wording.
Session Chair Michael Sateia, MD, Professor of Psychiatry (Sleep Medicine) at Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, told Pulmonary Reviews, “We were anticipating the launch of the International Classification of Diseases, Tenth Revision, Clinical Modification [ICD10-CM]next year and felt that updating the ICSD-3 nosology in conjunction with this launch was desirable. The Diagnostic and Statistical Manual of Mental Disorders (DSM), Fifth Edition, is being revised at the same time, which afforded us an opportunity to achieve coherence between the DSM sleep section and the ICSD-3. The academy wishes to ensure that its classification system reflects current science and diagnostics to the greatest extent possible.” Publication of the ICSD-3 will be electronic only and is expected next summer, he added.
Complex Sleep Apnea Emerges as a New Classification
In his presentation, Berry explained that in the ICSD-3, rather than provide definitions for respiratory events, diagnostic criteria will refer to the scoring manual. Home sleep testing will be discussed in the obstructive sleep apnea in adults section, obesity-related hypoventilation syndrome will be included within hypoventilation syndromes, and complex sleep apnea (CompSA), sleep-related hypoventilation, and sleep-related hypoxemia will have distinct diagnostic criteria.
CompSA is a new—and controversial—classification, Berry said. He noted that according to Medicare, central sleep apnea is defined as an apnea/hypopnea index of five or more events per hour, more than 50% of the apneas and hypopneas are central, and symptoms of excessive sleepiness of disrupted sleep are present. Medicare defines CompSA as “a form of central sleep apnea specifically identified by persistence or emergence of central apneas or hypopneas on exposure to continuous positive airway pressure (CPAP) or a device such as bi-level positive airway pressure (BiPAP), without a backup rate when obstructive events have disappeared. These patients have predominantly obstructive or mixed apneas during the diagnostic sleep study occurring five or more times per hour. With the use of CPAP or BiPAP without a backup rate, they meet the criteria of central sleep apnea.”
Berry said that several potential definitions of CompSA are being considered. The major issue is whether or not to incorporate patients with central apneas associated with narcotics or Cheyne-Stokes breathing that appear on PAP treatment after obstructive events are eliminated. In the current definition (still being discussed) CompSA would include only patients whose central apnea could not be diagnosed elsewhere in the central apnea disorders. For example, a patient with predominantly obstructive apnea during a diagnostic study who developed Cheyne-Stokes breathing on positive airway pressure would be diagnosed as having both obstructive sleep apnea and Cheyne-Stokes breathing central apnea rather than CompSA.
Controversy of Complex Sleep Apnea Discussed
At the end of Berry’s talk, conference attendees discussed the challenge of determining whether hypopneas and apneas are central or obstructive and airway narrowing that can occur with central apneas, potentially complicating scoring. Inclusion of Cheyne-Stokes hypopneas was recognized as potentially affecting the percentage of central events. One attendee suggested use of the term treatment emergent central apneas rather than CompSA.
Berry acknowledged these concerns, including possible resolution of CompSA over time in the majority of patients with treatment emergent central apnea. However, he noted that central apneas do persist in a small fraction of patients (1% to 2% in some studies). He also noted that a significant percentage of the Sleep and Breathing Disorders membership section of the AASM requested that a diagnosis of CompSA be included in the new ICSD classification.
It was noted that although Medicare has criteria for a diagnosis of CompSA, the ICD9-CM does not, and an ICD9-CM diagnosis of primary central sleep apnea is used in most locales in order to qualify patients with CompSA for a BiPAP device with a backup rate. Berry admitted that while the diagnosis of CompSA using any criteria will continue to be controversial, there is a need for a diagnostic category for patients with treatment emergent central apneas—especially for those patients in whom the central apnea does not resolve with chronic CPAP treatment.
—Beth Tansey Peller, RN, BS, CWC
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