In 2011 it was mandated that resident physicians work shorter hours: shifts no longer than 16 hours for first-year residents and no longer than 24 hours for other residents. The logical premise was that doctor fatigue leads to more mistakes. In 2013 Dr. Steven Lockley of Harvard University was quoted in The Wall Street Journal: “When hours are reduced, medical error rates fall enormously. No other simple solution comes as close as a way of cutting errors.”

Along comes a new study in 2015 that shows “shorter shifts for medical residents don’t appear to be making big improvements in doctors’ fatigue levels or in patient care” (HealthDay News, February 9, 2015). Researchers at the University of Toronto evaluated overnight shifts of 12, 16, and 24 hours involving 47 residents and over 800 ICU admissions at two teaching hospitals. Their findings,

published in the February 9 online edition of the Canadian Medical Association Journal, questions the rationale for shortening the consecutive hours that residents can devote to patient care. Study leader Dr. Christopher Parshuram says that adverse events and patient deaths were no more likely to occur during a long shift than a shorter one. It’s possible, says Parshuram, that “a doctor who stays a longer time with a patient might be more tuned into that patient’s needs.”

These findings are consistent with those of Dr. Mitesh Patel at the University of Pennsylvania (Journal of the American Medical Association, December 2014). Patel found that during the first year after the shorter shift rules were put in place there was no evidence that patient care improved. His conclusion: “Patient outcomes are affected by many factors in addition to resident fatigue, including the handoffs from one shift to another.”