title: Systematic review: association of shift length, protected sleep time, and night float with patient care, residents' health, and education.
abstract: BACKGROUND
  The Accreditation Council for Graduate Medical Education's new duty-hour standards limit interns' shifts to 16 hours and night float to 6 consecutive nights. Protected sleep time (that is, "nap") is strongly encouraged. As duty-hour reforms are implemented, examination of the quality and outcomes of the relevant literature is important.
  
  
  OBJECTIVE
  To systematically review the literature examining shift length, protected sleep time, and night float.
  
  
  METHODS
  MEDLINE, PREMEDLINE, and EMBASE from January 1989 through May 2010.
  
  
  METHODS
  Studies examined the associations of shift length, protected sleep time, or night float with patient care, resident health, and education outcomes among residents in practice settings.
  
  
  METHODS
  Study quality was measured by using the validated Medical Education Research Study Quality Instrument and the U.S. Preventive Services Task Force criteria. Two investigators independently rated study quality, and interrater agreement was calculated.
  
  
  RESULTS
  Sixty-four studies met inclusion criteria. Most studies used single-group cross-sectional (19 studies [29.7%]) or pre-post (41 studies [64.1%]) designs, and 4 (6.3%) were randomized, controlled trials. Five studies (7.8%) were multi-institutional. Twenty-four of 33 (72.7%) studies examining shift length reported that shorter shifts were associated with decreased medical errors, motor vehicle crashes, and percutaneous injuries. Only 2 studies assessed protected sleep time and reported that residents' adherence to naps was poor. Night floats described in 33 studies involved 5 to 7 consecutive nights.
  
  
  CONCLUSIONS
  Most studies used single-institution, observational designs. Publication bias is likely but difficult to assess in this methodologically weak and heterogeneous body of evidence.
  
  
  CONCLUSIONS
  For the limited outcomes measured, most studies supported reducing shift length but did not adequately address the optimal shift duration. Studies had numerous methodological limitations and unclear generalizability for most outcomes. Specific recommendations about shift length, protected sleep time, and night float should acknowledge the limitations of this evidence.
  
  
  BACKGROUND
  Accreditation Council for Graduate Medical Education.
authors.affiliation: Division of Primary Care Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Darcy A
authors.initials: DA
authors.lastname: Reed
authors.forename: Kathlyn E
authors.initials: KE
authors.lastname: Fletcher
authors.forename: Vineet M
authors.initials: VM
authors.lastname: Arora
mesh_terms: D004521:Educational Measurement; D006304:Health Status; D006801:Humans; D007396:Internship and Residency / Q000592:standards*; D005791:Patient Care / Q000592:standards*; D010561:Personnel Staffing and Scheduling / Q000592:standards*; D012890:Sleep; D013997:Time Factors; D014940:Work Schedule Tolerance