Restricting resident duty hours- Where is the evidence

January 1, 2013

Resident duty hour restrictions became the way of life after the Libby Zion case in 1984, but have these restrictions actually done anything for patient safety?

Dr. Lockwood, editor in chief, is Dean of the College of Medicine and Vice President for Health Sciences at The Ohio State University, Columbus, Ohio. Send your feedback to


Those of us who trained in the 1980s or earlier have less-than-fond memories of being on call as residents. I remember a particularly grueling series of every-other-night calls while covering a busy internal medicine intensive care step-down unit early in my internship.

One morning, I was summoned to the office of the program director, who told me the nurses on the unit had complained that I used foul language. I was honestly shocked and indignantly denied the charge. When I spoke with the unit’s head nurse, he stunned me by saying it was true; the night nurses noticed that when they phoned my on-call room (ie, closet) after I had been asleep for an hour or 2, I would sometimes curse and, worse, not come out. They then had to knock on the door to rouse me. Apparently, I was so exhausted that I never fully awoke until they actually knocked on my door.

That was the last time I ever had REM sleep while on call-or heard any complaints about my language. However, as tired as I might have been, I can’t recall making an error of commission or omission because of sleep deprivation, although I may have been too tired to notice. On the other hand I am confident that I delivered far more babies, applied far more forceps, managed more vaginal breech deliveries, and performed more gynecological surgeries than the average graduating ob/gyn resident does today based on published norms. So as we approach the 10th anniversary of resident duty hour restrictions, it is a good time to ask whether these regulations have improved either patient safety or residency training as intended.

The history of duty hour regulations

The genesis of resident duty hour restrictions began in 1989, when the State of New York mandated an 80-hour resident workweek in reaction to the now notorious 1984 Libby Zion case. The allegation by Ms. Zion’s family was that exhaustion contributed to residents missing a fatal drug interaction. In retrospect, knowledge deficits, lack of current electronic prescribing software, and a failure by the patient to fully disclose clinically relevant facts were far more relevant to the tragic outcome. Interestingly, while implementation of these requirements added more than $350 million in staffing costs to New York hospitals, the regulations did not improve patient safety.1-3

Despite the cost of duty hour restrictions and their failure to measurably enhance patient safety, consumer and congressional pressure for national regulations mounted, and in 2003 the Accreditation Council for Graduate Medical Education (ACGME) adopted a national standard limiting duty hours.4 Elements included the limitation of duty hours to 80 hours per week averaged over a 4-week period; 1 day off in 7; and a maximum shift of 24 hours with 6 additional hours for education and handoffs. The ACGME decision was prompted by 3 factors: 1) a perception that healthcare delivery was becoming more complex and acute; 2) research that sleep deprivation adversely impacted job performance; and 3) public attention to resident work hours.5 Of course it is hard to say which factor had the greatest impact on the ACGME’s decision.

In 2008 the Institute of Medicine (IOM) released a report on resident duty hours recommending even stricter standards, including limiting intern shifts to 16 hours and counting moonlighting.6 In 2011 the ACGME implemented these changes as well.4 However, even as it implemented these more stringent standards, the ACGME admitted “both the IOM report and the Task Force found a relative dearth of scientific evidence in many areas important for setting standards to promote sound education and safe and effective patient care.”
For an organization that prides itself on using evidence to dictate management, the basis for the ACGME’s decision to limit duty hours was remarkably bereft of empirical evidence that it would either improve patient safety  or benefit training. Indeed, evidence suggests it did neither.



Is there evidence that care is now safer?

While there is evidence that sleep deprivation impairs residents’ performance in controlled experiments,7 in today’s “real world” a host of factors likely mitigates the adverse impact of fatigue.
First, most residents work in environments in which team care predominates, including the assistance of well-rested nurse practitioners and physician assistants. Second, most residents now use electronic medical records with embedded decision support that likely would prevent medication errors such as those that occurred in the Libby Zion case. Third, the use of crew resource management and checklists may help prevent fatigue-induced errors. Conversely, errors resulting from the increased use of shifts and handoffs may exceed or at least equal those committed by fatigued residents providing continuous care.

Thus, it is not surprising that studies of the impact of duty hour restrictions in New York have shown higher rates of complications, likely due to fragmented care.2,3,8 Indeed the 2 years following implementation of the original ACGME standards saw little change in mortality.9 Thus, at best, duty hour restrictions may not have adversely impacted patient safety, but they also have not improved it.

Has resident training improved or suffered?

To be fair, it is unclear if there has been a major decrement in the skills of trainees subject to duty hour restrictions in the so-called cognitive fields (eg, internal medicine, psychiatry, pediatrics, and neurology). In these fields residents can use the added time for reading and literature reviews, although it is unclear if they are actually doing so.4 Of greater concern has been the impact of duty hour restrictions in the procedural fields (eg, surgery, orthopedics, and ob/gyn). There is fairly extensive and contradictory literature examining this question that suggests a modest but measurable negative effect on the surgical volume available to trainees,10,11 but there are no studies that address whether graduating residents are better trained today than they were a decade ago.

A need for real evidence

Recently, Rosenbaum and Lamas called for the ACGME to grant residency programs a research exemption to study the impact of duty hour restrictions.12 That research, they argue, can address questions such as, “When assessing work hours, do we look at safety within the confines of a 16-hour shift, or can we examine the effects of a bad handoff 6 months after the fact?” and “How do we understand what will happen 5 years down the road, when today’s trainee is suddenly facing 100-hour workweeks because that’s what it takes to get the work done?”

The notion that all residency disciplines should be subject to identical work hour limitations strains credulity. Moreover, the basis for the work hour thresholds chosen needs to be rigorously examined. Studies should be performed to assess the impact of duty hour restrictions on the proficiency of graduates of ob/gyn and other surgical discipline residency programs.
What duty hour threshold optimizes acquisition of surgical skills? Similarly, what duty hour threshold minimizes errors resulting from fatigue without increasing those arising from more frequent handoffs? I, like most old codgers, think we have gone too far with duty hour limits, but I have learned not to base my management on hunches-I would like to see the evidence!



1. Thorpe KE. House staff supervision and working hours. Implications of regulatory change in New York State. JAMA. 1990;263(23):3177-3181.

2. Howard DL, Silber JH, Jobes DR. Do regulations limiting residents’ work hours affect patient mortality? J Gen Intern Med. 2004;19(1):1-7.

3. Laine C, Goldman L, Soukup JR, Hayes JG. The impact of a regulation restricting medical house staff working hours on the quality of patient care. JAMA. 1993;269(3):374-378.

4. Accreditation Council for Graduate Medical Education (ACGME) Task Force on Quality Care and Professionalism. The ACGME 2011 Duty Hour Standards: Enhancing Quality of Care, Supervision, and Resident Professional Development.

5. Philibert I, Friedmann P, Williams WT; ACGME Work Group on Resident Duty Hours. Accreditation Council for Graduate Medical Education. New requirements for resident duty hours. JAMA. 2002;288(9):1112-1114.

6. Institute of Medicine (IOM). Resident Duty Hours: Enhancing Sleep, Supervision, and Safety. Washington, DC: National Academies Press; 2009.

7. Weinger MB, Ancoli-Israel S. Sleep deprivation and clinical performance. JAMA. 2002;287(8):955-957.

8. Conigliaro J, Frishman WH, Lazar EJ, Croen L. Internal medicine housestaff and attending physician perceptions of the impact of the New York State Section 405 regulations on working conditions and supervision of residents in two training programs. J Gen Intern Med. 1993;8(9):502-507.

9. Shetty KD, Bhattacharya J. Changes in hospital mortality associated with residency work-hour regulations. Ann Intern Med. 2007;147(2):73-80.

10. Kairys JC, McGuire K, Crawford AG, Yeo CJ. Cumulative operative experience is decreasing during general surgery residency: a worrisome trend for surgical trainees? J Am Coll Surg. 2008;206(5):804-811.

11. Simien C, Holt KD, Richter TH, et al. Resident operative experience in general surgery, plastic surgery, and urology 5 years after implementation of the ACGME duty hour policy. Ann Surg. 2010;252(2):383-389.

12. Rosenbaum L, Lamas D. Residents’ duty hours-toward an empirical narrative. N Engl J Med. 2012;367(21):2044-2049.