Effect of alcohol on minimal effective nCPAP pressure

Alcohol may have an aggravating effect on sleep disordered breathing. Aim of our study was to test the effect of alcohol on the required nCPAP pressure as determined by the self-adjusting nCPAP-system AutoSet. Ten male subjects (age 54 +/- 9 yrs, body mass index 37 +/- 5 kg/m2) with moderate to severe obstructive sleep apnoea (OSA) were investigated. Full polysomnography was performed on four consecutive days (control night with and without alcohol, nCPAP pressure determination by AutoSet with and without alcohol, in randomised order). Alcohol was given in a single dose of 80 proof vodka (1.5 ml per kg of body weight) one hour prior to bedtime. Alcohol to a deterioration of the respiratory disturbance index (RDI, 56 +/- 23 without vs. 66 +/- 19 with alcohol, p = 0.02), but no significant change was observed in mean or minimal oxygen desaturation, mean or maximal event duration. The 95th percentile of the AutoSet-pressure was not different with or without alcohol (10.7 +/- 2.5 vs. 10.6 +/- 2.5 cm H2O). Moderate alcohol intake in the evening need not be taken into account for CPAP pressure determination in moderate to severe OSA.