The Effects of On-Duty Napping on Intern Sleep Time and Fatigue

6 June 2006 | Volume 144 Issue 11 | Pages 792-798

Background: Naps during extended work shifts are effective in reducing fatigue in other industries, but the use of a nap as a countermeasure to prevent fatigue in residents is uncertain.

Objective: To assess the effects of a call-night nap on resident sleep and fatigue.

Design: 1-year, within-participant, paired trial with crossover at midmonth.

Setting: Academic teaching hospital.

Participants: 38 of 40 internal medicine interns.

Measurements: Sleep was measured by using wristwatch actigraphy. By using the experience sampling method on a personal digital assistant, random alerts prompted interns to rate fatigue on the 7-point Stanford Sleepiness Scale (7 is most tired). Hospital paging logs and structured interviews provided information on use of coverage.

Intervention: For 2 weeks of every month, interns were assigned to the nap schedule, which provided coverage to on-duty interns from midnight to 7:00 a.m. so that they could finish their work and take a nap. The other 2 weeks of the month constituted a standard schedule.

Results: Interns received 41 more minutes of sleep while on call with the nap schedule (185 minutes vs. 144 minutes; P < 0.001). When interns with the nap schedule used coverage, they received 68 more minutes of sleep (210 minutes vs. 142 minutes; P < 0.001). Despite these small increases in sleep, interns reported less overall fatigue while on the nap schedule than while on the standard schedule (1.74 vs. 2.26; P = 0.017). Postcall fatigue with the nap schedule was lower by nearly 1 point (2.23 vs 3.16; P = 0.036), which is almost equivalent to the difference between on-call and postcall fatigue with the standard schedule (2.06 vs. 3.16). However, use of coverage by interns on the nap schedule was impaired by their desire to care for their patients and concerns about discontinuity of care.

Limitations: This was a single-institution study that did not have the power to examine outcomes related to intern or patient well-being.

Conclusions: Coverage to allow a nap during an extended duty-hour shift can increase sleep and decrease fatigue for residents.

Editors' Notes Context Short naps improve performance during long work shifts. Their effect on residents-in-training is unknown. Contribution For 2 weeks in a month-long rotation, a resident physician provided on-demand nap coverage for on-call interns. During the entire month, interns wore an activity monitor to measure sleep time, record on-call and postcall fatigue, and assess evidence that they used the nap coverage. Compared with the standard schedule, interns slept 41 minutes more, reported less fatigue, and slept more efficiently with the nap schedule. Cautions Adherence was poor. Implications Short naps were associated with less fatigue during extended duty hours. —The Editors

 

Author and Article Information

From the University of Chicago, Chicago, Illinois, and University of Arkansas for Medical Sciences, Little Rock, Arkansas.

Acknowledgments: The authors thank Dr. Eve Van Cauter, Dr. Kristen Knutson, and Mr. Armand Ryden of the University of Chicago Sleep Laboratory for their financial support and assistance during the study; Ms. Jennifer Higa for her assistance in manuscript preparation; and Ms. Joyce Keldsen in Paging Services at University of Chicago Hospitals for her support and assistance in obtaining paging logs. They also thank Julie Johnson, PhD; Juned Siddique, DrPH; and Paul Rathouz, PhD for their helpful commentary on analytic issues. Finally, the authors thank Dr. Harvey Golomb from the Department of Medicine for his financial support and encouragement and Dr. James Woodruff, Internal Medicine Residency Program Director, for the enthusiastic support and participation of the interns, residents, and chief residents of the 2003–2004 University of Chicago Internal Medicine Residency Program.

Grant Support: By the University of Chicago Department of Medicine and the Pritzker School of Medicine. Drs. Arora and Meltzer are supported by the National Institute for General Medical Sciences (1 R01 GM075292-01 [Effectiveness of TEACH Research]). Dr. Meltzer and Mr. Ahmad were supported by the Agency for Healthcare Research and Quality (R01 10597 [A Multicenter Trial of Academic Hospitalists]) while most of the work was performed. Ms. Dunphy was supported by the Pritzker School of Medicine Summer Research Program; Ms. Chang was supported by a short-term training grant (5 T35DK062719-16).

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Vineet Arora, MD, MA, University of Chicago, 5841 South Maryland Avenue, MC 2007, AMB W216, Chicago, IL 60637; e-mail, varora{at}medicine.bsd.uchicago.edu.

Current Author Addresses: Drs. Arora and Meltzer: University of Chicago, 5841 South Maryland Avenue, MC 2007, AMB B200, Chicago, IL 60637.

Ms. Dunphy, Ms. Chang, and Dr. Humphrey: University of Chicago Pritzker School of Medicine, 924 East 57th Street, Chicago, IL 60637.

Mr. Ahmad: University of Arkansas for Medical Sciences College of Medicine, 4301 West Markham, Little Rock, AR 72205.

Author Contributions: Conception and design: V. Arora, F. Ahmad, H.J. Humphrey, D. Meltzer.

Analysis and interpretation of the data: V. Arora, C. Dunphy, V.Y. Chang, F. Ahmad, H.J. Humphrey, D. Meltzer.

Drafting of the article: V. Arora, C. Dunphy, V.Y. Chang, H.J. Humphrey, D. Meltzer.

Critical revision of the article for important intellectual content: V. Arora, C. Dunphy, V.Y. Chang, H.J. Humphrey, D. Meltzer.

Final approval of the article: V. Arora, C. Dunphy, F. Ahmad, H.J. Humphrey, D. Meltzer.

Provision of study materials or patients: V. Arora, F. Ahmad, H.J. Humphrey, D. Meltzer.

Statistical expertise: V. Arora, C. Dunphy, D. Meltzer.

Obtaining of funding: V. Arora, V.Y. Chang, H.J. Humphrey, D. Meltzer.

Administrative, technical, or logistic support: V. Arora, C. Dunphy, V.Y. Chang, F. Ahmad, H.J. Humphrey, D. Meltzer.

Collection and assembly of data: V. Arora, C. Dunphy, V.Y. Chang, F. Ahmad, D. Meltzer.