Shorter shifts for medical residents don't appear to be making any big improvements in doctors' fatigue levels or in patient care, new research shows.
The study found that although doctors weren't less tired during their shortest shifts, an adverse patient event was more likely to occur during a short shift.
The results "question the rationale for shortening the exposure of the residents to the patients," said study leader Dr. Christopher Parshuram, an associate professor of pediatrics, critical care and health policy management and evaluation at the University of Toronto.
The study is published in the Feb. 9 online edition of CMAJ (Canadian Medical Association Journal).
The optimal length of medical residents' work hours has been an ongoing topic of debate and discussion for years. In 2003, the Accreditation Council for Graduate Medical Education lowered work hours for residents and interns (first-year residents) to no more than 80 hours a week.
In 2011, the council rule was changed, from a maximum of no more than 30 consecutive hours for interns to no more than 16 and no more than 24 for other residents. In addition, they could have four hours for transferring care of patients and participating in educational activities.
The focus of the changes was based on the idea that doctor fatigue might lead to more mistakes.
The new study findings do not support the advantage of shorter shifts, the researchers found. They looked at overnight schedules of 12-, 16- or 24-hour shifts. The investigators evaluated 47 residents in two adult teaching hospitals assigned randomly to each of the shifts for two months.
Residents assigned to the shorter schedule did not report feeling less tired. "We found that the doctors were most tired at 4 o'clock in the morning and that [the length of the] schedule made no difference on how tired the doctors were," Parshuram said.
There was no significant difference between shifts in levels of doctor burnout either, the study found.
The doctors did report more complaints such as nausea, headache and eye pain while on the longest shift.
Just over 800 patients were admitted to intensive care units (ICUs) during the study period. The number of adverse events did not differ among the three shifts, the researchers found. But, of the eight adverse events classified as preventable, seven of them happened during the shortest shift (12 hours).
Patients were no more likely to die during a long shift than a shorter one, the study found.
How to explain the findings? One possibility, Parshuram said, is that a doctor who stays a longer time with a patient might be more tuned in to that patient's needs.
In an editorial accompanying the study, Dr. Thomas Maniatis of McGill University in Montreal said one limitation of the study is that the researchers did not document the exchange of information when one shift takes over for another. The loss of information during that time may greatly affect patient safety, according to Maniatis.
That is possible, Parshuram said. "The handover and information loss is a contributor, but also the loss of information that comes from not being there," he said, referring to the shorter shifts.
Maniatis also noted that because the study lasted only two months, any long-term effects from shorter shifts wouldn't be evident.
The findings in the new study are similar to those found by Dr. Mitesh Patel, an assistant professor at the University of Pennsylvania, published in the Journal of the American Medical Association in December 2014.
That study found that shorter shifts for interns that became effective after 2011 "were not associated with changes in patient outcomes in the first year after reforms," Patel said.
"Patient outcomes are affected by many other factors in addition to resident fatigue," Patel said, including the "handoffs" from one shift to another. It's too soon to give any advice to patients, though, he said, adding more study is needed.