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PULMONARYQ

OBSTRUCTIVE SLEEP APNEA (OSA)

Definition and pathophysiology

•  Repetitive pharyngeal collapse during sleep causing apnea (≥10 s) or hypopnea (airflow reduction) ± desaturation, arousals from sleep → daytime sleepiness

•  Apnea-hypopnea index = avg # apneas and hypopneas per hr of sleep

•  Sleep-induced loss of activity of pharyngeal dilator muscles → pharyngeal collapse → arousal → activation of sympathetic nervous system; phenotypes vary across OSA Pts

•  Apnea → negative intrathoracic pressure → ↑ preload, ↑ afterload → HTN, CV sequelae

•  Risk factors: obesity (present in 70%), male, age, alcohol, smoking, black race

Clinical manifestations (Lancet 2002;360:237; Lancet Resp Med 2013;1:61)

•  Snoring, witnessed apneas/gasping, daytime sleepiness

•  Cardiovascular: HTN (  JAMA 2012;307:2169); a/w ↑ risk of stroke and death (NEJM 2005;353:2034) & possibly CAD & endothelial dysfxn (AJRCCM 2001;163:19; Circ 2008;117:2270)

•  Neurocognitive: ↓ cognitive performance, ↓ QoL, ↑ motor vehicle and work accidents (NEJM 1999;340:847; AJRCCM 2001;164:2031)

Diagnosis and treatment

•  Polysomnography (sleep study); can do home-testing. If , trial of CPAP.

•  CPAP: ↓↓ apnea/hypopnea, ↓ BP (Lancet 2002;359:204), ↓ sleepiness, ↑ performance (AJRCCM 2012;186:677), ↑ EF in Pts with CHF (NEJM 2003;348:1233), ↓ metab syndrome (NEJM2011;365:2277), ↓ mortality after stroke (AJRCCM 2009;180:36)

•  Oral appliances can prevent retroglossal collapse. Offer if refusing CPAP.

•  Avoid alcohol and sedatives

•  Surgery (eg, uvulopalatopharyngoplasty, UPPP) of limited benefit (Chest 1997;111:265)