Fatal errors more likely on 24-hour call

Patients are dying at the hands of tired medical residents, according to Harvard sleep scientists, because the work-hour limits imposed in 2003 are not preventing sleep deprivation.

Their research reveals that first-year medical school graduates who worked five shifts of 24 hours or more during a month were three times more likely to make an error that contributed to a patient's death.

"Academic medicine is failing these doctors and their patients by requiring exhausted doctors to work 30-hour marathon shifts," said Charles Czeisler, MD, PhD, co-author of the study and director of sleep medicine at Harvard Medical School and Brigham and Women's Hospital in Boston. "The human brain doesn't function correctly when working 30 hours straight."

David C. Leach, MD, executive director of the Accreditation Council for Graduate Medical Education, the organization that regulates resident hours, said trimming call hours further would not necessarily improve patient safety.

"[Dr.] Czeisler's study has given us a little truth," Dr. Leach said. "Residents who work 24 hours self-report they are prone to more errors. He has not given us a deeper truth. The problem is more complex than 16- vs. 24-hour shifts."

The study builds on previous research from Harvard that compared interns who worked an average of 80 hours a week with call periods of 24 hours and longer, to interns working 63 hours a week, with call limited to 16 hours. The interns working the longer schedule made 36% more serious medical errors.

The study, in the December 2006 issue of the online journal PloS Medicine, looked specifically at fatigue-related errors that harmed patients. It found that interns who had worked one to four overnight call shifts in a month were three times more likely to report at least one fatigue-related event that hurt a patient.

If they worked five or more shifts in a month, they were seven times more likely to report at least one adverse event. Under ACGME rules, interns can work up to nine 30-hour call periods a month.

"Extended-duration work shifts are hazardous to patients," Dr. Czeisler said. "We need to be concerned about safety and think creatively about alternatives. It's time to rethink [resident hours.]"

Over the course of a year, one out of 20 interns made a serious error that injured a patient. One out of 100 made a mistake that was serious enough to result in a patient's death, Dr. Czeisler said.

"The data suggest tens of thousands of patients are being injured each year, and thousands are dying in relation to fatigue mistakes," he said.

Dr. Leach questioned such reasoning. The data were collected in July 2002 through May 2003, before duty-hour reforms were instituted. Dr. Czeisler said the data were applicable because residents still work call shifts of 24 hours or more. But Dr. Leach said the accumulated sleep debt from longer work weeks may have produced higher error rates than would be found under the current system.