EFFECT OF NIGHT MEDICAL GUARD ON FOLLOWING DAY VIGILANCE - INFLUENCE OF AN HYPNOTIC MEDICATION ON RECOVERY NIGHT AND ON THE VIGILANCE DURING THE FOLLOWING DAY

The consequences of sleep deprivation on vigilance and mood were evaluated in six healthy medical students the day after being on night duty and the following day, after recovering from a full night's sleep. Diurnal vigilance was studied using the Multiple Sleep Latency Test (MSLT) and mood was assessed on an anxiety self-evaluation scale. The study was conducted by means of a double-blind randomized trial to measure the effects of benzodiazepine (lormetazepam, 2 mg) compared to a placebo administered before the night recovery/full night's sleep. Sleep deprivation induced a significant decrease in vigilance the day following the night duty. Sleep latencies were shortened during the morning following the night of recovery/full night's sleep. The Values obtained after administering the lormetazepam did not differ significantly from those obtained after administering the placebo. There were no considerable differences in the anxiety evaluation scores before and after the night of recovery/full night's sleep between the two sequences of the trial. This study suggests that a significant lack of sleep (a 36-hour sleep deficit) modifies diurnal vigilance over two nyctohemeral periods. Administration of benzodiazepine with a short half-life after occasional sleep deprivation does not change the reorganization of the sleep-waking cycle.