Daytime Surgery Not Affected by Nighttime Work

Laird Harrison

August 27, 2015

Whether a surgeon works the night before performing surgery does not change the risk for adverse outcomes, a new study shows.

"These data suggest that calls for broad-based policy shifts in duty hours and practices of attending surgeons may not be necessary at this time," write Anand Govindarajan, MD, from the Institute for Clinical Evaluative Sciences and the Department of Surgery, Mount Sinai Hospital, Toronto, Ontario, Canada, and colleagues.

The researchers published their findings in the August 26 issue of the New England Journal of Medicine.

The effects of sleep deprivation on physician performance has stimulated hot debate for years. Previous research has shown that acute sleep deprivation can affect mood and impair cognition in general, but how much it affects clinical performance is not clear.

Much of the previous research on this topic has focused on medical trainees and has helped spur duty-hour restrictions mandated on all North American residency training programs. Few studies have looked at the effects of sleep deprivation on the performance of attending physicians, however, and they have produced mixed findings. In addition, the previous studies on attending physicians have mostly taken place in academic centers, which is not where the majority of physicians practice.

To fill this gap, Dr Govindarajan and colleagues retrospectively analyzed the records of everyone in the province of Ontario who underwent one of 12 procedures (cholecystectomy, gastric bypass, colon resection, coronary-artery bypass grafting, coronary angioplasty, knee replacement, hip replacement, repair of a hip fracture, hysterectomy, spinal surgery, craniotomy, and lung resection) between January 1, 2007, and December 31, 2011.

The researchers used fee codes to identify physicians who conducted one of these procedures during the day after treating patients in the preceding overnight hours (midnight - 7 a.m.).

The researchers compared outcomes in 38,978 patients evenly split in pairs. In each pair, one patient was treated after the physician had performed medical service during the previous night and the other patient was treated after the same physician had not performed a medical service the night before.

The researchers found no statistically significant differences in the outcomes in the two groups.

Table. Outcomes in Patients Whose Surgeons Either Worked Nights or Did Not

Variable Control Group, N = 19,489 Post-Midnight Group, N = 19,489 P Value
Death within 30 days 1.1% 1.1% .92
Readmission within 30 days 7.1% 6.6% .05
Complications within 30 days 18.2% 18.1% .83
Median number of days in the hospital 3 3 .84

Differences between the groups were not significant even when the results were stratified by hospital type or physician's age.

However, a small but significant increase in complications was observed in patients whose physicians had performed two or more procedures the night before.

The authors speculate about why their results differed from findings in medical trainees: In addition to having more experience, attending physicians may "self-regulate" their practice by canceling surgeries or arranging coverage by colleagues if they feel too fatigued to perform surgery safely, they write. In addition, physicians might change their surgical caseload in anticipation of being sleep-deprived the day after being on call during the night.

"In conclusion, we found that sleep loss resulting from the provision of overnight medical care did not measurably affect the short-term outcomes of elective procedures performed the next day by attending surgeons in Ontario, Canada," the researchers write.

The study was supported by the University of Toronto, the Canadian Institutes of Health Research, and the Institute for Clinical Evaluative Sciences. The authors have disclosed no relevant financial relationships.

N Engl J Med. 2015;373:845-853. Abstract


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