Study Shows Difficulty Of Pegging Doctor, Hospital Errors To Physician Sleep Deprivation

A new multi-hospital study assessing the effect of sleeplessness on medical errors found that house staff forced to work 24-hour shifts made fewer serious medical mistakes than their counterparts assigned to schedules without extended shifts.

Doctors on the less-exhausting shift made 53% more serious errors than their colleagues saddled with the more grueling hours.

But the results of the ROSTERS trial are complicated by the fact that doctors working fewer consecutive hours found themselves responsible for 31% more pediatric intensive care unit patients than those in the extended-shift group.

In addition, the error rate varied by institution, with shorter hours producing fewer mistakes at one hospital, more mistakes at three hospitals, and no significant difference at two hospitals, the study team reports inThe New England Journal of Medicine.

"This is a very important finding because it showed that you can't simply focus on work hours. You also have to look at workload," coauthor Dr. Charles Czeisler, director of the division of sleep and circadian disorders at Brigham and Women's Hospital in Boston, told Reuters Health in a telephone interview.

But Dr. David Asch, a professor of medicine at the University of Pennsylvania who has also studied how sleep deprivation affects physician performance, said the findings suggest that the source of serious medical errors may be even more complex.

"I think the shift length stuff is important and is interconnected with so many things like the number of handoffs you have. It's hard to disentangle the isolated facets of care. It isn't just a story of sleep," Dr. Asch, who wasn't involved in the study, told Reuters Health by phone.

The ROSTERS trial is only the latest to look at sleep deprivation among doctors in training. The same team reported in 2004 that physicians working frequent shifts of 24 hours or more made 36% more serious medical errors. But a subsequent study found no decline in death or serious surgical complications when first-year surgical residents were given shorter shifts.

ROSTERS, conducted from 2013 to 2017, was the latest attempt to unravel the question of the best shift for doctors and their patients. It included doctors who were second-year residents and above. Each site served as its own control, matched for time of year.

Doctors who had to work a shift as long as 28 hours every four or five days ended up being responsible for an average of 6.7 pediatric ICU patients at a time. Doctors whose shifts were no longer than 16 hours every four or five days were responsible for an average of 8.8 patients.

But the rate of serious errors per 1,000 patient days was 97 when there were no 24-hour shifts on the schedule and 79 when there were (relative risk 1.53; P<0.001).

Yet the magnitude of the error rate varied widely by hospital. At three hospitals, that risk of serious error jumped 51%, 138% and 490% for residents working fewer consecutive hours. The error rate was 76% lower in a fourth hospital, and not significantly different in the other two sites.

Dr. Czeisler said the key seemed to be workload, which also varied widely.

At two hospitals, doctors who faced 24-hour shifts were, on average, responsible for only about 4 patients at time. In another hospital, it was nearly 10 and jumped to about 13 when the doctors were allowed to have more sleep and were better rested.

"We did not expect to see this tremendous variation" in workload at the start of the trial and "that in and of itself is potentially hazardous," Dr. Czeisler said. "And that's just the average. That means on some days it may have been 18 patients and probably higher, maybe 20."

"And these are all gravely ill patients," he said. "If one is having an issue that requires your full attention for an hour or half hour, you can't see any of the others."

"As soon as you increase the workload beyond a certain point, it's just not possible to prevent errors," Dr. Czeisler said. "This study would need to be repeated to control for workload."

But Dr. Asch said he thinks there's more going on because a similar pattern of errors was seen within the whole ICU at the hospitals, with a 56% increase in serious errors when shorter-shift invention schedules were in place, even though other non-sleep-deprived health professionals were independently involved in care.

"How should it be that the shifts that the residents are on are determining the errors the units themselves make?" he said.

Using the ROSTERS data, and comparing rates of serious medical errors to patient days, he calculated that the rates of serious medical errors attributable to doctors on 24-hour shifts ranged from 0.5% to 14.5%. With more sleep for the residents, the per-patient-day rates at the same two hospitals ranged from 2.9% to 24.4%.

The enormous variation "completely dwarfs the effects of shift," said Dr. Asch, and "suggests shifts are not the big deal here. Something else is."

—Gene Emery

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