In 2013, researchers at Boston Children’s Hospital and Brigham and Women’s Hospital launched a multi-center study comparing a work schedule that included traditional, extended work shifts for resident physicians (24 hours or more) with a schedule that eliminated extended shifts and cycled resident physicians through day and night shifts (maximum, 16 hours). They expected the new schedule with shorter shifts would reduce serious medical errors by allowing residents to get more sleep. But as they report today in The New England Journal of Medicine, they found something different: patient safety worsened at some of the sites. On further analysis, a key factor that appeared to drive medical errors was how many patients each resident cared for.

“Our first finding was that the new scheduling didn’t work — it actually appeared to make outcomes worse overall,” says Christopher Landrigan, MD, MPH, chief of General Pediatrics at Boston Children’s Hospital and the study’s first author. “When we tried to understand why, it became clear that workload was a major component of medical errors. We didn’t set out to look at workload, so this was an unexpected finding.”

Comparing work schedules

The randomized study, called ROSTERS, was conducted in six pediatric intensive care units in different parts of the U.S. In a “crossover” design, the hospitals followed each work schedule for eight months, in random order. Total work hours for the traditional schedule and the new schedule were the same. The researchers collected data on adverse events, work rosters, work hours, sleep hours, residents’ reports of sleepiness, and residents’ performance on vigilance tasks.

To the researchers’ surprise, serious medical errors increased by about 50 percent overall when ICUs followed the new schedule. But there were differences among the hospitals: One logged many fewer serious medical errors, three reported more errors, and two saw no change.

“The Data Safety Monitoring Board charged us with investigating why one center had a 75 percent reduction in serious errors, while another had a tripled error rate,” says senior author Charles Czeisler, MD, PhD, Chief of the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital. “We spent a year going through the data trying to understand what was happening. We thought there was a problem with the intervention.”

The additional analyses showed that residents got more sleep with the new schedule, and did better on performance tests, as expected. Though the number of patient “handoffs” between shifts increased by about 25 percent, this was consistent across sites, and didn’t appear to account for why some sites did better and others did worse. So the team began looking at workload.

U.S. Healthcare Homepage