Postgraduate year 1 (PGY1) residents need to sleep more than 4 hours overnight to function well at work the next day, a new study reports.

Otherwise, they score poorly on psychomotor vigilance tests (PVTs), according to a presentation June 5 at SLEEP 2017, the joint meeting of the American Academy of Sleep Medicine and the Sleep Research Society, in Boston.

"The findings of this study are particularly important given the recent decision by the Accreditation Council for Graduate Medical Education (ACGME) to allow first–year residents to work 24– to 28–hour shifts as of July 1, 2017, which revises their 2011 reform that limited first–year residents to no longer than 16 hours of continuous duty hours," Dr. Melissa A. St. Hilaire of Brigham and Women’s Hospital and Harvard Medical School in Boston, who gave the oral presentation, told Reuters Health in an email.

Dr. St. Hilaire and her colleagues examined data from 11 female and 23 male PGY1 residents. Their average age was 28. The interns were studied over a 3–week period while they were on a Q3 schedule, a 24– to 30–hour on–call extended duration work shift (EDWS) every other shift.

During each EDWS, the residents logged their sleep and work hours and were monitored with ambulatory polysomnography. They also took 10–minute PVTs every 6 hours or so.

The authors examined the correlation between spontaneous sleep amounts (0 hr, > 0 to 1 hr, > 1 to 2 hr, > 2 to 3 hr, > 3 to 4 hr, and > 4 hr) from 11:00 PM to 7:00 AM and PVT attentional failures between 5:00 AM and 7:00 PM the next day.

A total of 296 PVTs were recorded. Compared to no sleep overnight, sleeping less than 4 hours did not significantly improve the doctors' next–day PVT attentional failures (P > 0.05). They needed to have more than 4 hours of actual sleep before they could significantly improve their next–day performance (P=0.0237).

After sleeping longer than 4 hours, their PVT performance was still compromised: they had two or more failures on 68% of the tests and five or more failures on 39% of tests.

“One strength of this study is that we were able to look at spontaneous amounts of sleep that first–year residents obtained during multiple 24–to–30–hour shifts," Dr. St. Hilaire said. But, she noted, "We were not able to look at a direct association between performance on the psychomotor vigilance task and a more patient–oriented outcome, such as the rate of medical errors."

Dr. St. Hilaire added that previous research has found a higher rate of serious medical errors when PGY1 residents were scheduled to work long on–call shifts.

"Members of the research team are currently involved in an NIH–funded multicenter randomized crossover trial to test whether a schedule that limits continuous work shifts in PGY2 and PGY3 residents to no longer than 16 hours will increase sleep and vigilance and decrease preventable injuries to patients and risk of motor vehicle accidents among physicians," she added. The study had no commercial funding.

—Lorraine L. Janeczko