Nocturnal Middle Ear Pressure and the Effects of Continuous Positive Airway Pressure

Abstract

Objectives:

1) Quantify normal middle ear pressure during sleep; 2) Quantify middle ear pressure during sleep in the presence of continuous positive airway pressure (CPAP).

Methods:

A prospective cohort study was conducted on adults without middle ear disease undergoing polysomnography at a tertiary referral sleep medicine center during 2012. Tympanometry was performed on sleeping patients, and middle ear pressure was recorded at 1-hour intervals during diagnostic polysomnography and at all CPAP levels during CPAP titration. Mean middle ear pressures were calculated. Pearson correlation coefficients (r) were used for analysis.

Results:

Ten adults with type A tympanograms and normal otoscopic examinations were included (4 females; 6 males; mean age 58 years). The mean awake middle ear pressure was 3.2 decapascals (daPa). The mean middle ear pressure during sleep without CPAP rose steadily from 14.3 daPa at 1 hour to 41.4 daPa at 4 hours, r = 0.53 (P < 0.001). The mean middle ear pressure did not change with sleep stages (P = 0.99). At a CPAP of 5 cm of water, the mean middle ear pressure was 53.7 daPa. The mean middle ear pressure rose with increasing CPAP levels and was 104 daPa at 10 cm of water, r = 0.86 (P < 0.001).

Conclusions:

In normal ears, middle ear pressure rises with time asleep. CPAP causes a greater than physiologic elevation in middle ear pressure that rises with increasing CPAP levels. These findings may help guide future studies examining the safety of CPAP following ear surgery and potential therapeutic roles for CPAP in patients with middle ear disease.