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Objective: Sleep deprivation increases the risk that residents will make medical errors. Consequently, IOM and the ACGME have called for new limits on resident work hours. However, the incidence and severity of resident fatigue remains unclear.The study purpose was to determine the incidence and severity of resident fatigue and its propensity for error.
Design: A prospective cohort study for two or more weeks.
Setting: Two large academic tertiary care centers.
Patients or Other Participants: Orthopaedic surgery residents (PGY1-5).
Intervention(s): Subjects' sleep and wake periods were continuously recorded via actigraphy and a daily questionnaire to allow for individual mental fatigue analysis. Data on sleep and wake periods were processed through the Sleep, Actigraphy, Fatigue, and Task Effectiveness (SAFTE) model, a previously validated accident prediction tool.
Main Outcome Measure(s): Average daily sleep, % time spent with a SAFTE effectiveness score <80 and <70; and predicted error propensity. SAFTE effectiveness scores <80 predict increased error risk; scores <70 predict critical impairment, equivalent to a blood alcohol level of 0.08.
Results: 20 of 23 (87%) subjects completed the study. Mean daily sleep was 5.2 hours (individual mean: 2.8 to 6.4 hours). Subjects functioned at <80% effectiveness 49% of their time awake, and at <70% effectiveness 28% of their time awake. Overall, subjects' fatigue levels were predicted to increase their error risk by 23% compared with rested controls (individual range 11 to 49%). Night float residents functioned at <70% effectiveness 31% of their time awake compared with 15% for daytime residents (p = 0.033).
Conclusions: Resident fatigue is prevalent, pervasive and variable. Fatigue modeling can be conducted non-invasively, and may help to identify time-periods, rotations, and individuals at risk of error and guide targeted interventions.