Dr. Christopher P. Landrigan, the Primary Author, is the Research Director of Children's Hospital Boston Inpatient Service, an Associate Physician at Brigham and Women's Hospital Division of Sleep Medicine, and an Assistant Professor of Pediatrics at Harvard Medical School. Dr. Charles A. Czeisler, the Senior Author, is the Co-Director of the Division of Sleep Medicine at Brigham and Women's Hospital and a Professor of Medicine at Harvard Medical School.

1. Drs. Czeisler and Landrigan, what motivated you and your colleagues to pursue this line of research on the relationship between extended work shifts for interns and errors in medical care?

"Over the past few decades, extensive research has been conducted on the relationship between sleep deprivation, night work, and performance. Laboratory experiments have demonstrated that sleep deprivation and circadian misalignment (i.e. working at a time of day when the biological clock is promoting sleeping) lead to marked decrements in performance (1-3). Data from trucking, aviation, and other industries have established that sleep deprivation and work at night greatly increase the risk of errors and accidents (4-6). Consecutive sleep deprivation for 24 hours has been found to induce decrements in performance comparable to those induced by a blood-alcohol level of 0.10% (7), a concentration in excess of the legal limit in many states.

"The Institute of Medicine estimates that medical errors result in more than a million injuries and between 44,000-98,000 deaths each year, making medical errors one of the leading causes of death in the United States (8). The role of physician sleep deprivation in the genesis of medical error in clinical settings has been unclear, however. Although a number of studies have found that physicians working extended hours without sleep are more likely to make errors in the performance of diverse tasks, from electrocardiogram interpretation (9), to simulated surgery (10), to history-taking (11), systematic data collected in clinical settings have been lacking (12,13), In addition, there has been a concern that decreasing physicians' work hours might actually increase the risk of medical errors, due to increased numbers of patient care "hand-offs" between physicians working shorter shifts (14).

"In the mid-1980s, we were studying the relationship between sleep and hormone release, which required us to keep subjects awake all night. We saw tremendous decrements in alertness and performance when subjects stayed awake for the equivalent of a 30-hour 'on-call' shift. When we did two small pilot surveys of housestaff, they reported profound fatigue, which caused them to fall asleep while on the telephone and while driving, and make medical errors. This led to our concern about the safety of working such long shifts. However, it was held that these shifts were necessary for optimal patient care. The purpose of the present study was to evaluate whether or not the care of patients is well served when interns work 30 consecutive hours.

"In our study, we tested the hypotheses that an intervention schedule that eliminated interns' traditional 30-hour-in-a-row extended work shifts would improve their sleep, decrease failures of attention, and decrease serious medical errors in intensive care settings. We found that interns on the intervention schedule worked approximately 20 hours per week less, slept nearly an hour per night more, and had fewer attentional failures while working at night. In addition, compared with interns working on our intervention schedule, interns working the traditional schedule made 36% more serious medical errors, and more than five times as many serious diagnostic errors."

2. What do you hope will follow this research? Do you expect to see local, regional, or national changes in work schedules for interns?

"Our research demonstrates that interns' traditional 30-consecutive-hour work shifts pose a risk to the safety of ICU patients. The Accreditation Council for Graduate Medical Education (ACGME) recently implemented duty hour standards for physicians in training, but these duty hour standards continue to allow 30-hour long consecutive work episodes, and 80 hour long work weeks (15). Our data suggest that the safety of patients, particularly in intensive care settings, could be improved by further limitation of interns' consecutive work hours. Such limits must be complemented, however, by improvements in patient care hand-offs, and careful schedule re-design.

"Schedule design is a critical element in the success of re-scheduling interventions. Effective designs must be tailored to the constraints of individual work settings, with an eye toward minimizing decrements in performance due to sleep deprivation and circadian factors. Re-designed schedules must also address the risks inherent in hand-offs of patient care. Teamwork and sign-out skills have not been a traditional focus of medical education, and most hospitals do not explicitly structure hand-offs of care between physicians. These must be optimized to insure that scheduling interventions do not introduce unnecessary patient safety risks.

"While it is unlikely that interns in ICU settings are uniquely susceptible to the detrimental effects of prolonged sleep deprivation, further studies are required to determine the effect on patient safety of limiting work hours in other settings, and for physicians other than interns. We hope to study the impact of extended work shifts on surgical performance in the operating room. We also hope to study residents and physicians after they have finished their training.

"We also hope that at a local and national level, hospitals and policy makers begin to redesign the work schedules of physicians in training, particularly in ICU settings, to minimize serious errors due to sleep deprivation."

3. Lastly, what message would you like current premed and medical students to learn from the methods and results of your research?

"Our studies demonstrate that doctors who are sleep deprived are more likely to make mistakes. Much of hospital work will always occur at night, but physicians and students working under such circumstances can minimize the detrimental effects of night work on performance by napping before overnight duty, when possible, and by sleeping as much as they can when not on duty.

"Our study also exemplifies how the scientific method can be applied to studying systems of care as well as specific therapies such as medications. Well-designed controlled clinical trials can and should be used to study how care delivery can be improved, rather than relying on tradition to dictate how medicine is practiced."

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13. Buysse DJ, Barzansky B, Dinges D, Hogan E, Hunt CE, Owens J et al. Sleep, fatigue, and medical training: setting an agenda for optimal learning and patient care. Sleep 2003; 26: 218-225.

14. Petersen LA, Brennan TA, O'Neil AC, Cook EF, Lee TH. Does housestaff discontinuity of care increase the risk for preventable adverse events? Ann Intern Med 1994; 121: 866-872.

15. Accreditation Council for Graduate Medical Education. Number of programs and filled positions by specialty for the current academic year (Ending June 30th, 2004). Accreditation Council for Graduate Medical Education. www.acgme.org. Accessed April 12, 2004

Lester Y. Leung is the Editor-in-Chief of the Next Generation and a member of the Harvard College Class of 2006.