But simply looking at whether a doctor did any work overnight doesn’t tell you if the physician was actually sleep deprived, he said. For example, an hour-long procedure might be done at midnight and the doctor may not have to be back at work until late the next morning.
So in their JAMA study, the Czeisler team went further. They calculated the actual time between the overnight procedure and the morning procedure.
When the doctor had only six hours or less to sleep, the complication rate was 170% higher than when the doctor had the opportunity to sleep more than six hours.
He said the Baxter study didn’t go far enough because, “If you don’t know if the person is sleep deprived, you can’t evaluate it.”
He also faulted the study for assuming that doctors who worked anytime from midnight to 7 a.m. hadn’t received a full night’s sleep. Surgeons often start their day before seven.
“Physicians who have started their procedure at 6:30 in the morning would be placed in that sleep-deprived group” when they probably don’t belong there, Dr. Czeisler said.
Baxter, in a follow-up email, acknowledged that “we do not know how much sleep was lost. However we looked at the subgroup of individuals who performed at least two procedures overnight, assuming they were up for most of the night, and still did not see a consistent signal – certainly nothing like the effect found by the JAMA study.”
“The JAMA study was in a single institution and included only a small number of patients and providers. It is possible that the findings were due to chance alone,” she said. Alternatively, the doctors in the JAMA study might not have had the flexibility to changes their schedules to avoid sleep deprivation.
Baxter, who is chief of the division of general surgery at St. Michael’s Hospital in Toronto, said lack of sleep may not have had an effect because experienced surgeons know how to pace themselves, their experience lets them do an adequate job even when they’re tired, and “surgeons tend to be people who deal better with lack of sleep than other physicians” thanks to self-selection.
But the findings should not be considered by doctors to be a license to work without proper rest, she said. “I don’t want people to take from this the idea that this is open season on being on call and operating the next day without self-regulation being in place, without understanding your abilities, and potentially canceling cases if you’re that tired,” she said.
