Young doctors make far fewer mistakes when their hours are restricted to let them get enough sleep, according to the first study to directly examine the issue.
The study of 24 student doctors caring for seriously ill patients in a hospital found that those who were restricted to working no more than 16 hours without a break made about one-third fewer serious errors that could harm patients.
Since doctors-in-training provide much of the medical care in American hospitals, the findings suggest that current guidelines that allow interns and residents to work long hours without a break are endangering patient safety, the researchers concluded in research published in today's New England Journal of Medicine.
"The tradition of working 30 hours in a row may be the Achilles' heel of the medical education system," said Charles A. Czeisler of Brigham and Women's Hospital in Boston, who helped conduct the research. "Our study challenges the notion that it's safe to deliver patient care under those circumstances."
Czeisler and his colleagues first studied 20 student doctors during their first year after medical school while they worked two three-week rotations in an intensive care unit and a cardiac care unit at Brigham and Women's Hospital in Boston. The researchers compared the impact of a traditional schedule of more than 80 hours per week, including some shifts of 24 hours, with a restricted schedule of less than 80 hours per week with no shifts exceeding 16 hours.
During the restricted schedule, the interns worked 19.5 fewer hours and slept 5.8 more hours each week, and they slept more in the 24 hours preceding each working hour. They were also more alert, nodding off about half as often while on duty.
The researchers then compared the number of mistakes 24 interns made over a year when they rotated between the two schedules for three weeks at a time.
During the traditional schedule, the interns made 35.9 percent more serious errors, including misdiagnosing patients, ordering the wrong medication or dose, interpreting test results incorrectly, or making a mistake during a procedure, the researchers found.
There was no significant difference in the number of patients who died, but that may have been largely because a special panel of doctors was monitoring the interns and caught many of the errors.
Patient-safety advocates hailed the research as a milestone in the long debate over student doctors' hours.