© Heide Benser/Corbis

The debate over the lengthy hours and the sleepless overnight shifts that characterize medical training programs continues to rage, both in the U.S. and abroad. But new research published in the October 14 issue of the Journal of the American Medical Association underscores that getting enough sleep isn’t only crucial for medical residents. In an analysis of nearly 1900 surgical and obstetrical procedures performed by attending physicians—that is, senior doctors who have completed training—the day after completing overnight shifts, researchers found that, in surgeries, mistakes were made nearly twice as often when the doctor had slept fewer than 6 hours, compared with those performed by surgeons who had gotten more sleep.

The study, led by Dr. Jeffrey M. Rothschild of Brigham and Women’s Hospital in Boston, set out to determine whether working late night or overnight shifts (between 12AM and 6AM) negatively impacted doctor’s performance the day after. Rothschild and colleagues analyzed data for procedures performed between January 2000 and December 2007 by 86 surgeons and 134 obstetricians and gynecologists who had just worked a late night or overnight shift. Those were then compared with some 8,500 procedures performed by doctors who hadn’t just pulled all-nighters.

They found that, proportionately, the rates of errors were comparable, and statistically insignificant, between control and “post nighttime” surgeries—4.9% compared with 5.4%, respectively. (The most frequent complications—errors—during surgeries were injured organs and bleeding.) Longer shift length too was associated with slightly higher, but statistically negligible differences in rates of complications—physicians who worked 12 or more hours in a shift had complications in 6.5% of procedures, compared with 4.3% for those who worked fewer than 12 hours.

Yet what was statistically significant, the researchers point out, was the difference in errors made by surgeons who had less rest. “Surgeons who had limited opportunity for sleep had significantly higher rates of complications than those who had a longer sleep opportunity,” they write. In fact, among surgeons who had slept fewer than 6 hours the night before, mistakes were made in 6.2% of surgeries, compared to just 3.4% in those who’d gotten at least 6 hours of rest.

Interestingly, the researchers didn’t find this same increase in complications among obstetrical and gynecological procedures performed by doctors who’d gotten less sleep. They suggest this might reflect the lower number of complications generally found in deliveries compared with surgeries, but recommend further studies to analyze the impact of exhaustion on attending physicians in obstetrics and gynecology, and across a broad range of specialties.

Future studies are essential to determining how safe it is for doctors to perform procedures after working into the wee hours, the researchers suggest. And in the meantime, they write, “[f]or situations in which it is necessary for attending physicians to conduct life-saving procedures following overnight work, effective strategies to minimize the effects of fatigue should be adopted into practice.”