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Physicians' extended work shifts are associated with increased risks of medical errors that harm patients

First-year doctors-in-training reported that working five extra-long shifts—of 24 hours or more at a time without rest—per month led to a 300 percent increase in their chances of causing a fatigue-related preventable adverse event that contributed to the death of a patient, according to a new study. Preventable adverse events are defined as medical errors that cause harm to a patient.

The study, which was funded by the Agency for Healthcare Research and Quality (HS12032 and HS14130) and the Centers for Disease Control and Prevention's National Institute for Occupational Safety and Health, has a sample size large enough to demonstrate that the rate of preventable adverse events grows when interns work shifts of 24 hours or more. Interns were three times more likely to report at least one fatigue-related preventable adverse event during months in which they worked between one and four extended-duration shifts. In months in which they worked more than five extended-duration shifts, interns were seven times more likely to report at least one fatigue-related preventable adverse event and were also more likely to fall asleep during lectures, rounds, and clinical activities, including surgery.

The researchers analyzed the results of a national, Web-based survey in which 2,737 interns completed 17,003 monthly reports and assessed the association between the number of extended-duration shifts worked in the month and the reporting of significant medical errors, preventable adverse events, and attentional failures. The findings are significant because interns routinely work extended shifts in teaching hospitals. Guidelines for graduate medical education in the United States still allow up to nine "marathon" shifts (30 hours at a stretch) per month, even though the total number of hours worked is capped.

For more details, see "Impact of extended-duration shifts on medical errors, adverse events, and attentional failures," by Laura K. Barger, Ph.D., Najib T. Ayas, M.D., M.P.H., Brian E. Cade, M.S., and others, in the December 2006 PLoS Medicine 3(12), online at

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