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)