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

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.

  • Rebecca Smith-Coggins, MD

      Affiliations

    • Stanford University, Palo Alto, CA
    • Corresponding Author InformationAddress for reprints: Rebecca Smith-Coggins, MD, Department of Surgery/Emergency Medicine, Stanford University, 701 Welch Rd, Suite C, Palo Alto, CA 94304-1713; 650-725-5066, fax 650-723-0121
    • ,
  • Steven K. Howard, MD

      Affiliations

    • Stanford University, Palo Alto, CA
    • Department of Anesthesia, VA Palo Alto Health Care System, Palo Alto, CA
    • ,
  • Dat T. Mac, MS

      Affiliations

    • Department of Anesthesia, VA Palo Alto Health Care System, Palo Alto, CA
    • ,
  • Cynthia Wang, MD

      Affiliations

    • Stanford University, Palo Alto, CA
    • ,
  • Sharon Kwan, MD

      Affiliations

    • Stanford University, Palo Alto, CA
    • ,
  • Mark R. Rosekind, PhD

      Affiliations

    • Alertness Solutions, Inc., Cupertino, CA
    • ,
  • Yasser Sowb, PhD

      Affiliations

    • Department of Anesthesia, VA Palo Alto Health Care System, Palo Alto, CA
    • ,
  • Raymond Balise, PhD

      Affiliations

    • Stanford University, Palo Alto, CA
    • ,
  • Joel Levis, MD, PhD

      Affiliations

    • Stanford University, Palo Alto, CA
    • Kaiser Permanente, Santa Clara, CA
    • ,
  • David M. Gaba, MD

      Affiliations

    • Stanford University, Palo Alto, CA
    • Department of Anesthesia, VA Palo Alto Health Care System, Palo Alto, CA

Received 12 September 2005; received in revised form 31 January 2006; accepted 7 February 2006. published online 01 May 2006.

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.

 

 Supervising editor: Debra E. Houry, MD, MPHAuthor 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.

PII: S0196-0644(06)00239-3

doi:10.1016/j.annemergmed.2006.02.005

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