No Evidence Longer Resident Hours Compromise Patient Safety

Ricki Lewis, PhD

February 10, 2015

Benefit in continuity of care may outweigh risk for adverse events associated with residents' longer shifts, according to results from a randomized prospective study.

The Accreditation Council for Graduate Medical Education began recommending duty hour requirements for residents in 2003 (24 hours) and revised them in 2011 (16 hours for junior trainees and 24 hours for senior trainees), following preliminary evidence that restricting shifts improved patient safety and resident well-being.

However, the association of long resident hours with medical errors is largely observational. To more rigorously assess the relationship, Christopher Parshuram, MD, PhD, staff physician in critical care medicine at the Hospital for Sick Children in Toronto, Ontario, Canada, and colleagues randomly assigned 49 medical residents to 2-month rotation blocks of 12, 16, or 24 consecutive hours in intensive care units (ICUs) during the first half of 2009. They report their results in an article published online February 9 in the Canadian Medical Association Journal.

Primary patient outcome was adverse events (injuries arising from care in the ICU associated with morbidity necessitating treatment, prolonging hospital stay, or causing disability at discharge). Secondary patient outcomes were preventable adverse events, death in the ICU, and severity of adverse events.

The primary resident outcome was sleepiness, assessed on the Stanford Sleepiness Scale at 4-hour intervals on 4 randomly selected days per week. Secondary resident outcomes were burnout (using the Maslach Burnout Inventory) and physical symptoms.

A survey estimated continuity of care as the number of days individual residents and nurses had cared for an index patient; two patients were randomly selected weekly from each ICU for surveys. Staff in the ICU other than the residents (302 nurses, 58 respiratory therapists, and 37 physicians) completed a survey after each rotation to assess residents' knowledge, evidence of fatigue, clinical results, and relationships of residents with other staff. Physicians who reviewed the medical records of the patients did not know to which shifts residents had been assigned.

Residents came from internal medicine, anesthesia, surgery, and emergency medicine. All patients admitted to the ICU during the period examined were eligible.

Of 49 residents asked to participate, 47 (96%) followed through. They cared for 807 patients who had 971 ICU admissions over the course of 5894 total days in the ICU. The patients spent a median of 3 days in the ICU.

Shift length (12-, 16-, or 24-hour shifts) had no effect on adverse events (78.2, 76.3, and 81.3 events per 1000 patient-days, respectively; P = .7) or on daytime fatigue of residents (mean rating, 2.30, 2.61, and 2.33, respectively; P = .3) or at night (mean rating, 2.42, 2.73, and 3.06, respectively; P = .2).

Eight preventable adverse events affected seven patients. Seven events happened over the course of 12-hour shifts (P = .1). Four of the eight preventable adverse events, all during 12-hour shifts, were in patients with prolonged hospital stays.

Mortality rates in the ICU were 14.4% (53/367) with the 12-hour shift, 17.1% (50/293) with the 16-hour schedule, and 18.3% (57/311) with the 24-hour schedule (unadjusted, P = .2; adjusted, P = .6).

Burnout among residents was similar in the three groups, but symptoms associated with fatigue were more frequent and severe with the 24-hour shift. Peak sleepiness was at 4 AM for all, suggesting that "time of day may be a more important determinant of fatigue than duration of duty," the researchers write.

According to the ICU staff, residents on the 16-hour schedule made poorer decisions and seemed less familiar with patient details. The staff judged the residents on 12-hour shifts as most alert. How frequently residents saw each patient did not differ among the three schedules.

The investigators conclude that the "findings do not support the purported advantages of shorter duty and highlight trade-offs between residents' symptoms and multiple secondary measures of patient safety." They call for a larger study to better estimate likelihood of adverse events and to reveal smaller effects.

In a commentary, Thomas Maniatis, MD, from the Department of Medicine, McGill University, Montreal, Quebec, Canada, suggests monitoring residents for longer than 2 months, as well as in different rotation settings.

A limitation of the study is that the evaluators in the ICU knew which residents were on which schedule. Dr Maniatis points out that the investigation did not consider details of hand-off (patient sign-over), which is the prime time for losing information.

James Wilson, MD, PhD, professor of pathology and laboratory medicine at Penn Medicine, Philadelphia, Pennsylvania, recalled the days of longer shifts as a resident at Massachusetts General Hospital in Boston. "In acute care medicine, you can be in the hospital for 36 hours following the progression of a disease. If that had been interrupted, you wouldn't have that direct experience of following how a myocardial infarction or stroke or seizure disorder evolves. From an educational standpoint, it's much more rewarding, well worth the downside of being awake a long time." He participated in three-person teams with staggered shifts so complete hand-offs from one team to another never happened.

Dr Wilson said the results of the current study are not surprising. "In terms of quality of care, the risk that someone could make a bad decision because of fatigue would be significantly offset by really knowing the patients."

The researchers, Dr Maniatis, and Dr Wilson have disclosed no relevant financial relationships.

CMAJ. Published online February 9, 2015. Article full text


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