Despite concerns that surgeon fatigue is leading to dangerous complications for patients, and data showing worse outcomes for many patients who undergo surgery at night, new Johns Hopkins research suggests that — in the case of heart and lung transplants — time of day has no affect on patient survival. "We aren't suggesting that fatigue is good," says Ashish S. Shah, an assistant professor of surgery at the Johns Hopkins University School of Medicine, and the study's lead author. "But what is important is that, at least in this specialty, it seems we're able to deal with it without subjecting the patient to risk."

The research, detailed in the Journal of the American Medical Association, covers 10 years and more than 27,000 heart and lung transplants at medical centers across the United States."This is one of the first papers to suggest that fatigue, sleep deprivation and odd hours really don't hurt the patient. It's a surprising finding," Shah says. "While we've felt this, other papers have suggested patients are at risk if they are treated at night. For patients undergoing heart and lung transplants, everything is fine — regardless of the hour, our study shows."

Heart and lung transplants are done whenever scarce organs become available, without regard for the clock or how much work a surgeon has already done that day, Shah noted, likely making results of the Hopkins study especially reassuring to patients and surgical teams. Researchers have long worked to identify factors that contribute to medical errors, and attention has focused especially on medical staff fatigue associated with medical care outside of daytime hours. Several previous studies have linked nighttime care with worse outcomes.

One study found that nighttime cardiac arrests were associated with lower survival and unfavorable neurological outcomes. Another found that urgent orthopedic surgery at night was linked to a higher rate of unplanned re-operation. A third found that nighttime kidney transplantation was associated with higher risk of graft failure and the need for more emergency re-operation.

Shah says it would not have surprised the researchers to find the same issues with heart and lung transplants, especially with the complication of post-operative bleeding not uncommon after complex cardiac surgery. Theoretically, surgeon fatigue could lead to careless technique, resulting in additional bleeding requiring re-operation, or it could increase the tendency to overlook surgical bleeding. Shah and his colleagues found that the rate of re-operation was the same regardless of operative time of the day. The team also found that hospital length of stay was the same no matter what time the surgery took place.

In the new study, Shah and his colleagues reviewed United Network of Organ Sharing (UNOS) data on all adult heart and lung transplants in the United States between January 2000 and June 2010. Of the 16,573 who underwent heart transplants, half were done during the day and half at night. After one year, the survival rate for heart transplants was 88 percent for daytime recipients and 87.7 percent for those who got their new hearts at night. For the 10,545 lung transplants, roughly half were done during the day and half at night. After one year, 83.8 percent of those who got their organs during the day were still alive, compared to 82.6 percent of those who had their surgeries at night.

Shah says he thinks the success in heart and lung transplant outcomes, no matter the time of day, is a testament to experienced transplant teams who have figured out how to effectively perform complex surgeries on very sick patients, despite fatigue and emotional stress. Shah says his new findings are a good example of the need for more outcomes-based research. "It's worth asking these questions rather than extrapolating the conclusions from other specialties," he says.