Sleep

Obstructive Sleep Apnea (OSA)

Added by Dr. Andrew · Last updated 2024-01-15

Overview

OSA is the most common sleep-disordered breathing disorder, characterized by repetitive upper airway obstruction during sleep causing hypoxemia, hypercapnia, and sleep fragmentation. It is strongly associated with cardiovascular disease, metabolic syndrome, and neurocognitive impairment.

Key Points

1Diagnosis: polysomnography (PSG) gold standard; home sleep apnea testing (HSAT) for uncomplicated OSA
2AHI severity: mild 5–14, moderate 15–29, severe ≥30 events/hour
3CPAP: first-line treatment — reduces AHI, improves symptoms, reduces BP
4Alternatives: oral appliance (mild-moderate), positional therapy, weight loss, surgery (UPPP, hypoglossal nerve stimulator)
5Hypoglossal nerve stimulator (Inspire): for CPAP-intolerant patients with AHI 15–65, BMI <32, no complete concentric collapse
6OSA + obesity hypoventilation: BiPAP preferred over CPAP

Clinical Pearls

CPAP does NOT reduce CV events in established cardiovascular disease (SAVE, ISAACC trials)
Residual sleepiness on CPAP: check compliance, mask leak, residual AHI; consider modafinil/solriamfetol
Complex sleep apnea: central apneas emerge after CPAP initiation — treat with ASV (if EF >45%)
Perioperative OSA: increased risk of respiratory complications — CPAP perioperatively

Board High-Yield

Exam Focus

SAVE trial: CPAP did not reduce CV events in OSA with established CVD
Hypoglossal nerve stimulator criteria: AHI 15–65, BMI <32, no complete concentric collapse on DISE
OHS diagnosis: BMI >30 + daytime hypercapnia (PaCO₂ >45) + sleep-disordered breathing + no other cause
Central sleep apnea with Cheyne-Stokes: associated with HF — ASV contraindicated if EF <45% (SERVE-HF)
CPAP adherence: ≥4 hours/night on ≥70% of nights = adequate adherence

ABIM Exam Weight

10%

Sleep Medicine represents approximately 10% of the PCCM certification exam.