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A Randomized Trial of a Three-Hour Protected Nap Period in a Medicine Training Program: Sleep, Alertness, and Patient Outcomes

Shea, Judy A. PhD; Dinges, David F. PhD; Small, Dylan S. PhD; Basner, Mathias MD, PhD; Zhu, Jingsan MBA, MA; Norton, Laurie MA; Ecker, Adrian J.; Novak, Cristina MA; Bellini, Lisa M. MD; Dine, C. Jessica MD, MS; Mollicone, Daniel J. PhD; Volpp, Kevin G. MD, PhD

doi: 10.1097/ACM.0000000000000144
Research Reports

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.

Dr. Shea is professor of medicine-clinician educator and associate dean of medical education research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Dr. Dinges is professor of psychology in psychiatry and chief of the division of sleep and chronobiology, department of psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Dr. Small is associate professor, department of statistics, The Wharton School, University of Pennsylvania, Philadelphia, Pennsylvania.

Dr. Basner is assistant professor of sleep and chronobiology in psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Mr. Zhu is assistant director of data analytics, LDI Center for Health Incentives and Behavioral Economics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Ms. Norton is research project manager, CHERP, Philadelphia VA Medical Center, and CHIBE, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Mr. Ecker is a senior information technology project leader, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Ms. Novak was research coordinator, CHERP, Philadelphia VA Medical Center, and CHIBE, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, at the time this study was conducted. Currently she is a second-year medical student, Temple University School of Medicine, Philadelphia, Pennsylvania.

Dr. Bellini is professor of medicine, and vice chair for education, department of medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Dr. Dine is assistant professor of medicine, division of pulmonary and critical care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Dr. Mollicone is president and CEO of Pulsar Informatics, Inc., Philadelphia, Pennsylvania.

Dr. Volpp is staff physician, CHERP, Philadelphia VA Medical Center, and professor, Perelman School of Medicine and the Wharton School, University of Pennsylvania, Philadelphia, Pennsylvania.

Funding/Support: This work was funded by grant VA HSR&D EDU 08-429, to Dr. Volpp.

Other disclosures: Dr. Dinges served as a committee member on the Institute of Medicine report that was later published as Ulmer C, Wolman DH, Johns MMH, eds. Resident Duty Hours: Enhancing Sleep, Supervision and Safety. Washington, DC: National Academies Press; 2009. Dr. Volpp served as an unpaid member of the Accreditation Council for Graduate Medical Education Committee on Innovations from 2005 to 2009.

Ethical approval: Institutional review board approval was obtained from the Philadelphia VA Medical Center and the University of Pennsylvania, and all interns gave informed consent prior to participation.

Previous presentations: The abstract of an earlier version of this article was submitted to the SLEEP 27th Annual Meeting of the Associated Professional Sleep Societies, Baltimore, Maryland, June 1–5, 2013.

Correspondence should be addressed to Dr. Shea, 1232 Blockley Hall, 423 Guardian Dr., Philadelphia, PA 19104-6021; telephone: (215) 573-5111; fax: (215) 573-8778; e-mail: sheaja@mail.med.upenn.edu.

© 2014 by the Association of American Medical Colleges