Clinical features of obstructive sleep apnea:
(1) usually occurs in obese males
(2) repetitive apneic episodes occur during sleep
(3) apneic episodes are associated with bradycardia, hypoxemia, and arousals with fragmented sleep
Classification of apneic episodes:
(1) central: cessation of nasal and oral airflow with cessation of respiratory effort
(2) obstructive: absence of nasal and oral airflow despite continuing respiratory effort
(3) mixed: both central and obstructive patterns, usually with the central apnea being followed by the obstructive component
apnea index =
= (sum of all apneic episodes during study period) / (number of hours in study period)
Interpretation
• Patients with apnea index >=20 associated with higher mortality rate than patients with apnea index < 20
• 8-year survival in patients with apnea index >=20 is 63 +/- 17%
• 8-year survival in patients with apnea index <20 is 96 +/- 2%
If patients with a high apnea index do not respond to surgical therapy (uvulopalatopharyngoplasty), then they should be treated with either nasal CPAP or tracheostomy.
