Purpose: Protected sleep periods for internal medicine interns have previously resulted in increased amount slept and improved cognitive alertness but required supplemental personnel. The authors evaluated intern and patient outcomes associated with protected nocturnal nap periods of three hours that are personnel neutral.
Method: Randomized trial at Philadelphia Veterans Affairs Medical Center (PVAMC) Medical Service and Hospital of the University of Pennsylvania (HUP) Oncology Unit. During 2010–2011, four-week blocks were randomly assigned to a standard intern schedule (extended duty overnight shifts of up to 30 hours), or sequential protected sleep periods (phone sign-out midnight to 3:00 AM [early shift] intern 1; 3:00 to 6:00 AM [late shift] intern 2). Participants wore wrist Actiwatches, completed sleep diaries, and performed daily assessments of behavioral alertness. Between-group comparisons of means and proportions controlled for within-person correlations.
Results: HUP interns had significantly longer sleep durations during both early (2.40 hours) and late (2.44 hours) protected periods compared with controls (1.55 hours, P < .0001). At PVAMC sleep duration was longer only for the late shift group (2.40 versus 1.90 hours, P < .036). Interns assigned to either protected period were significantly less likely to have call nights with no sleep and had fewer attentional lapses on the Psychomotor Vigilance Test. Differences in patient outcomes between standard schedule months versus intervention months were not observed.
Conclusions: Protected sleep periods of three hours resulted in more sleep during call and reductions in periods of prolonged wakefulness, providing a plausible alternative to 16-hour shifts.