997 ## Obstructive Sleep Apnea 998 999 Diagnostic criteria for OSA in adults requires a polysomnogram or home sleep apnea test (HSAT) that demonstrates either (1) 5 or more predominantly obstructive respiratory events (obstructive and/or mixed apneas, hypopneas, or RERAs) per hour of sleep, in association with symptoms or comorbidities, or (2) 15 or more predominately respiratory events per hour of sleep regardless of symptoms or comorbidities. Symptoms related to OSA include excessive daytime somnolence, waking with gasping, choking, or breath holding; or witnessed reports of apneas, loud snoring, or both. Comorbidities include hypertension, a mood disorder, cognitive dysfunction, coronary artery disease, stroke, congestive heart failure, atrial fibrillation, or type 2 diabetes mellitus. Diagnosis may be made on in-lab PSG or by HSAT. Each episode of apnea or hypopnea must last a minimum of 10 seconds, is commonly accompanied by reductions in blood oxygen saturation of at least 3 % to 4 %, and is usually terminated by brief, unconscious arousals from sleep. Thus OSA causes fragmentation and disruption of the normal sleep cycle, resulting in symptoms of EDS and difficulty 1000 1001 *TABLE 15.2 Indexes of Sleep-Disordered Breathing* 1002 1003 1004

Index	Definition
Apnea index	Number of apneas per hour of total sleep time
Hypopnea index	Number of hypopneas per hour of total sleep time
Apnea-hypopnea index	Number of apneas and hypopneas per hour of total sleep time
Respiratory effort–related arousal (RERA) index	Number of RERAs per hour of total sleep time
Respiratory disturbance index	Number of apneas, hypopneas, and RERAs per hour of total sleep time
Central apnea index	Number of central apneas per hour of total sleep time
Mixed apnea index	Number of mixed apneas per hour of total sleep time

1005 1006 1007 1008 1009 ## BOX 15.1 Symptoms of Sleep-Disordered Breathing 1010 1011 Restless sleep 1012 1013 Loud snoring 1014 1015 Observed apnea, choking, or gasping episodes 1016 1017 Excessive daytime sleepiness 1018 1019 Morning fatigue or irritability 1020 1021 Memory loss 1022 1023 Decreased cognitive function 1024 1025 Depression 1026 1027 Personality or mood changes 1028 1029 Decreased libido and impotence 1030 1031 Morning and nocturnal headaches 1032 1033 Nocturnal sweating 1034 1035 Nocturnal enuresis 1036 1037 with concentration and alertness. Snoring between apneas is a frequent complaint of bed partners and is often the symptom that prompts these patients to seek medical attention, although excessive daytime somnolence is a common initial complaint. Many OSA sufferers complain of awakening from sleep with morning headache, sore throat, and fatigue or a feeling of being unrefreshed regardless of the duration of sleep (Box 15.1). OSA is exacerbated by ingestion of alcohol, sedative use, and weight gain. The AASM classifies mild OSA as 5 to 15 events per hour, moderate as 15 to 30 events, and severe as 30 events or more. 1038 1039 1040 ## PATHOPHYSIOLOGY 1041 1042 The obstruction that occurs in OSA [... Output truncated due to length. 6804 tokens/25869 characters removed ...]