Effects of intravenous catheter on sleep in healthy men and in depressed patients.

The effects of intravenous catheter and nocturnal blood samplings at frequent intervals on sleep electroencephalogram (EEG) variables were investigated in 8 male healthy controls and 12 depressed patients, who were studied in the same experimental conditions. After one night of habituation, sleep was recorded during 4 consecutive nights in the sleep laboratory. A catheter was inserted around noon the day before the fourth night, and blood was sampled every 15 min for 25 h. The night-to-night comparison of sleep EEG variables did not show significant sleep continuity modifications in the control subjects, other than a weak trend toward an increase in nocturnal awakenings during the night with the catheter. A lengthening of sleep onset latency during the fourth night was found in the depressed patients. No significant changes were detected in percentage of rapid eye movement (REM) sleep in the two groups. However, a gradual increase in Stage 3 was observed across the 4 nights in the control subjects. These results indicate that intravenous blood sampling via a catheter can be performed without inducing significant disruption of sleep length and structure.