Nocturnal oxygen saturation in advanced chronic obstructive pulmonary disease after a moderate dose of ethanol

The effect of a moderate oral dose of ethanol/(0.5 g.kg-1 body weight) on nocturnal arterial oxygen saturation (SaO2) was evaluated in nine male patients with advanced chronic obstructive pulmonary disease (COPD), (median forced expiratory volume in one second (FEV1) 0.9 l, arterial oxygen tension (PaO2) 9.3 kPa, arterial carbon dioxide tension (PaCO2) 5.3 kPa). During the four study nights (two after alcohol and two after placebo intake), the patients were monitored by whole-night computerized recordings of SaO2 (Biox-oximeter), airflow (thermistors) and respiratory as well as body movements (static charge sensitive bed). After alcohol intake, the mean blood ethanol concentration (SEM) in the evening was 42(2.3) mg.100 ml-1. Alcohol intake was associated with a marginal deterioration of nocturnal oxygenation; the mean (SEM) nocturnal SaO2 was 88.4(2.0) % after alcohol ingestion and 89.1(1.6) % after placebo ingestion, respectively. Only during the first 2 h in bed was there a statistically significant difference in SaO2 in favour of placebo (p less than 0.05). It is concluded that moderate alcohol intake in the evening, corresponding to "social" drinking, did not substantially aggravate nocturnal oxygenation in our patients with advanced COPD and mild to moderate daytime hypoxaemia.