Elsevier

Annals of Emergency Medicine

Volume 48, Issue 5, November 2006, Pages 596-604.e3
Annals of Emergency Medicine

Physician wellness/original research
Improving Alertness and Performance in Emergency Department Physicians and Nurses: The Use of Planned Naps

Presented at the Society for Academic Emergency Medicine 2002 annual meeting, October 2002, St. Louis, MO; and the Association for Professional Sleep Societies 16th annual meeting, June 2002, Seattle, WA.
https://doi.org/10.1016/j.annemergmed.2006.02.005Get rights and content

Study objective

We examine whether a 40-minute nap opportunity at 3 am can improve cognitive and psychomotor performance in physicians and nurses working 12-hour night shifts.

Methods

This is a randomized controlled trial of 49 physicians and nurses working 3 consecutive night shifts in an academic emergency department. Subjects were randomized to a control group (no-nap condition=NONE) or nap intervention group (40-minute nap opportunity at 3 am=NAP). The main outcome measures were Psychomotor Vigilance Task, Probe Recall Memory Task, CathSim intravenous insertion virtual reality simulation, and Profile of Mood States, which were administered before (6:30 pm), during (4 am), and after (7:30 am) night shifts. A 40-minute driving simulation was administered at 8 am and videotaped for behavioral signs of sleepiness and driving accuracy. During the nap period, standard polysomnographic data were recorded.

Results

Polysomnographic data revealed that 90% of nap subjects were able to sleep for an average of 24.8 minutes (SD 11.1). At 7:30 am, the nap group had fewer performance lapses (NAP 3.13, NONE 4.12; p<0.03; mean difference 0.99; 95% CI: −0.1-2.08), reported more vigor (NAP 4.44, NONE 2.39; p<0.03; mean difference 2.05; 95% CI: 0.63-3.47), less fatigue (NAP 7.4, NONE 10.43; p<0.05; mean difference 3.03; 95% CI: 1.11-4.95), and less sleepiness (NAP 5.36, NONE 6.48; p<0.03; mean difference 1.12; 95% CI: 0.41-1.83). They tended to more quickly complete the intravenous insertion (NAP 66.40 sec, NONE 86.48 sec; p=0.10; mean difference 20.08; 95% CI: 4.64-35.52), exhibit less dangerous driving and display fewer behavioral signs of sleepiness during the driving simulation. Immediately after the nap (4 am), the subjects scored more poorly on Probed Recall Memory (NAP 2.76, NONE 3.7; p<0.05; mean difference 0.94; 95% CI: 0.20-1.68).

Conclusion

A nap at 3 am improved performance and subjective report in physicians and nurses at 7:30 am compared to a no-nap condition. Immediately after the nap, memory temporarily worsened. The nap group did not perform any better than the no-nap group during a simulated drive home after the night shift.

Introduction

Health care professionals perform rotating shift work to provide patient care 24 hours a day. Not only does this present a serious concern for patient safety but also it places the workers themselves at risk for problems associated with circadian disruption and sleep deprivation.1, 2, 3, 4, 5, 6 It has been well documented that shift workers sleep less, perform less effectively on psychomotor and cognitive tests, make more errors during night shifts, and are at higher risk for driving crashes because of postnight shift drowsiness.7, 8, 9, 10, 11, 12

Adequate sleep before a night shift addresses a core physiological mechanism that underlies performance and alertness, though circadian factors typically reduce the quantity and quality of this day sleep.13 Therefore, planned naps in the workplace might be effective for health care professionals to promote a high level of alertness, attention to detail, and decisionmaking proficiency. Studies have demonstrated that under conditions of prolonged wakefulness, naps can improve performance and alertness.14, 15, 16, 17 Field studies in pilots and truckers have shown that naps mitigate drowsiness and improve performance and alertness.18, 19, 20 In a randomized, prospective study of planned naps as an operational countermeasure in a high-risk industry, long-haul flight crew members who napped had significantly improved performance and alertness, including fewer microsleeps in the last 90 minutes of flight.21 Based on these findings, a proposed Federal Aviation Administration advisory circular outlined the use of planned naps for flight crews. Several international airlines, including British Airways, Air New Zealand, Lufthansa, Quantas, Swissair, and Finnair, have implemented planned cockpit nap procedures, whereas the Federal Aviation Administration continues its consideration for use in the United States.22 However, planned naps have not been adequately tested as a fatigue countermeasure for physicians and nurses.

The goal of this study was to conduct a randomized controlled trial of napping as an intervention in the middle of a night shift for a physician and nurse population to see if there is improvement in their cognitive and psychomotor performance, ability to drive home, and subjective report.

Section snippets

Study Design and Setting

The study design was a randomized, controlled intervention trial conducted at a university emergency department (ED). The ED had 38,802 patient visits during the recruitment period, with 38.2% of visits occurring between 7:30 pm and 7:30 am. The study was approved by the university’s human subjects committee, and written informed consent was obtained for all subjects.

Selection of Participants

Inclusion criteria were resident physicians and nurses working at least 3 consecutive 12-hour night shifts in the ED. Attending

Results

Table 1 shows demographic characteristics of the 2 groups of subjects. There were no differences between NAP and NONE.

There were no differences between the 2 groups with reference to the Sleep Disorders Questionnaire, Shift-work Experiences Questionnaire, or Owl and Lark Questionnaire. All subjects scored within normal limits on the Sleep Disorders Questionnaire and reported no evidence of clinical sleep disorders. As a whole, the groups reported that their optimal sleep would be mean 9.0 (SD

Limitations

The driving simulator was limited as it lacked the usual noises, vibration, and lights of a real environment. Moreover, subjects knew there was no real risk associated with falling asleep. Any potential alertness-enhancing effects of the nap may have been overpowered by the simulator’s relatively soporific nature. As a result, the driving performance may have been reduced to a common poor quality in both groups.

There was no baseline measure of driving performance obtained when the subjects were

Discussion

This study reports the first randomized trial of a nap intervention during the night shift for physicians and nurses. It was accomplished as a field study in the ED of a Level I trauma center. Results showed that a 40-minute nap opportunity allowed health care professionals to maintain their performance, self-reported alertness, and mood through the end of their night shift. However, these improvements did not extend beyond the night shift to ensure the safety of subjects’ simulated drive home.

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    Supervising editor: Debra E. Houry, MD, MPH

    Author contributions: RS-C, SKH, MRR, and DMG conceived the study and designed the trial. RS-C, SKH, DTM, CW, SK, and JL supervised the conduct of the trial and data collection. RS-C, SKH, DTM, CW, SK, and JL undertook recruitment of participating subjects and managed the data, including quality control. YS, RB, and DMG provided statistical advice on study design and analyzed the data. RSC drafted the manuscript, and all authors contributed substantially to its revision. RSC takes responsibility for the paper as a whole.

    Funding and support: The authors report this study did not receive any outside funding or support.

    Publication dates: Available online May 2, 2006.

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