Polysomnography Unmasks Sleep Apnea

Results of this sleep study help diagnose the specific type of sleep apnea. Evidence of 5 or more predominantly obstructive respiratory events per hour of sleep suggests obstructive disease.

Results of an annual physical examination of a 54-year-old man have led you to suspect he may have-or be at high risk for-sleep apnea syndrome. His BMI is 37 and his blood pressure is 126/82 mm Hg. He has hypertension and hyperlipidemia. He reports restful sleep and no daytime sleepiness.  

The  clinical characteristics that raise your suspicion are: BMI greater than 35, a history of hypertension, and male sex. These are 3 of 8 risk factors for sleep apnea identified by the STOP-BANG screening tool. The presence of 3 or more factors is sufficient  to confer a high risk of the disorder.

You refer him for polysomnography (sleep laboratory testing) and receive the following test results:

- Apnea-hypopnea index of 22
- 20 obstructive apneas
- 10 mixed apneas
- 22 central apneas
- 80 hypopneas
- Lowest oxygen saturation 82%
- 12 awakenings and 32 arousals

Based on these data, the most appropriate diagnosis is: