Bedtime ethanol increases resistance of upper airways and produces sleep apneas in asymptomatic snorers

Abstract

Nasal continuous positive airway pressure (nasal CPAP) and polysomnography were used to analyze the time course of the effect of bedtime ethanol on resistance of upper airways and on the number of respiratory pauses during sleep. On one night, six asymptomatic nonalcoholic male snorers drank 2 ml/kg of 100 proof vodka mixed in orange juice (ethanol dose, 0.79 gm/kg, giving a peak blood alcohol level of 71.8 +/- 33.3 mg/dl). On a second night they received a placebo (1-2 drops of vodka floated on top of the orange juice). We measured (a) the minimum nasal (CPAP) required to eliminate snoring, (b) the number of hypopneas and apneas during each hour of sleep and (c) the arterial oxygen saturation (SaO2) by ear oximetry. On the alcohol night there was a significant increase in the CPAP pressure required to eliminate snoring (placebo 4.8 +/- 1.7 cm H2O, alcohol 6.2 +/- 1.5 cm H2O). The number of respiratory events per hour of sleep (apnea index) was 7.5 +/- 2.1 for ethanol nights versus 3.8 +/- 2.7 for placebo nights (p less than 0.0125). An apnea index of greater than 5 is generally considered abnormal. There was no significant difference in the number of desaturation events (declines of 4% or more in the SaO2) or in the mean SaO2, but the minimum SaO2 was significantly lower on the ethanol night (placebo 89.8% +/- 1.6, alcohol 86.8% +/- 2.7, p less than 0.05). The effect of this dose of alcohol on airway resistance was most pronounced during the first 2 hr after ingestion.

Fig 1

Mean (±SEM) blood ethanol levels in mg/dl at baseline and 25, 60, and 180 min after ingestion of 100 proof vodka in orange juice at a dose of 2 cc per kg of body weight (ethanol: 0.79 gm/kg).

Fig. 2

Nasal CPAP pressures required to stop snoring during NREM sleep as a function of time after either ethanol (0.79 gm/kg) in the form of 100 proof vodka mixed with orange juice or a “placebo” drink. Analysis of variance disclosed a significant condition × hours interaction (p < 0.05) with pressures during hours 1 and 2 elevated on ethanol nights.