Lesson 11

Obstructive Sleep Apnea: Diagnosis Overview

  • Prevalence: Up to 60-70% remain undiagnosed; screening is imperative due to perioperative morbidity risk.

Diagnosis Tools

  • Polysomnography:
    • Definitive test for OSA.
    • Calculates apnea-hypopnea index (AHI).
    • AHI Formula: AHI=Number of episodes of apnea and hypopneaHours of sleep\text{AHI} = \frac{\text{Number of episodes of apnea and hypopnea}}{\text{Hours of sleep}}

AHI Severity Classifications

  • Mild: 5-15 episodes/hr
  • Moderate: 15-30 episodes/hr
  • Severe: ≥ 30 episodes/hr

Risks Associated with Severity

  • Severe OSA increases risk for difficult mask ventilation and intubation.

Classic Triad of Dysfunctional Sleep

  1. Apnea or snoring with hypopnea
  2. Arousal from sleep
  3. Daytime somnolence

STOP-BANG Score

  • A bedside tool predicting undiagnosed OSA likelihood.
  • Risk Classifications:
    • High risk: ≥ 3 yes answers
    • Low risk: < 3 yes answers
  • Questions:
    • S: Do you snore loudly?
    • T: Do you often feel tired throughout the day?
    • O: Has anyone observed you stop breathing during sleep?
    • P: Do you have or are you treated for high blood pressure?
    • B: Is your BMI > 35 kg/m²?
    • A: Are you older than 50?
    • N: Is your neck circumference > 40 cm?
    • G: Are you male?