Applying mathematical models to predict resident physician performance and alertness on traditional and novel work schedules.
BACKGROUND
In 2011 the U.S. Accreditation Council for Graduate Medical Education began limiting first year resident physicians (interns) to shifts of ≤16 consecutive hours. Controversy persists regarding the effectiveness of this policy for reducing errors and accidents while promoting education and patient care. Using a mathematical model of the effects of circadian rhythms and length of time awake on objective performance and subjective alertness, we quantitatively compared predictions for traditional intern schedules to those that limit work to ≤ 16 consecutive hours.


METHODS
We simulated two traditional schedules and three novel schedules using the mathematical model. The traditional schedules had extended duration work shifts (≥24 h) with overnight work shifts every second shift (including every third night, Q3) or every third shift (including every fourth night, Q4) night; the novel schedules had two different cross-cover (XC) night team schedules (XC-V1 and XC-V2) and a Rapid Cycle Rotation (RCR) schedule. Predicted objective performance and subjective alertness for each work shift were computed for each individual's schedule within a team and then combined for the team as a whole. Our primary outcome was the amount of time within a work shift during which a team's model-predicted objective performance and subjective alertness were lower than that expected after 16 or 24 h of continuous wake in an otherwise rested individual.


RESULTS
The model predicted fewer hours with poor performance and alertness, especially during night-time work hours, for all three novel schedules than for either the traditional Q3 or Q4 schedules.


CONCLUSIONS
Three proposed schedules that eliminate extended shifts may improve performance and alertness compared with traditional Q3 or Q4 schedules. Predicted times of worse performance and alertness were at night, which is also a time when supervision of trainees is lower. Mathematical modeling provides a quantitative comparison approach with potential to aid residency programs in schedule analysis and redesign.
Division of Sleep and Circadian Disorders, Departments of Neurology and Medicine, Brigham and Women's Hospital, Boston, MA, 02115, USA. ebklerman@hms.harvard.edu.|Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA. ebklerman@hms.harvard.edu.
Elizabeth B
http://orcid.org/0000-0002-7402-3171
EB
Klerman
Division of Sleep and Circadian Disorders, Departments of Neurology and Medicine, Brigham and Women's Hospital, Boston, MA, 02115, USA.
Scott A
SA
Beckett
Division of Sleep and Circadian Disorders, Departments of Neurology and Medicine, Brigham and Women's Hospital, Boston, MA, 02115, USA.|Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.|Division of General Pediatrics, Department of Medicine, Boston Children's Hospital, Boston, MA, 02115, USA.
Christopher P
CP
Landrigan
D002940:Circadian Rhythm; D002983:Clinical Competence; D005221:Fatigue; D006801:Humans; D007396:Internship and Residency; D015233:Models, Statistical; D010561:Personnel Staffing and Scheduling; D012892:Sleep Deprivation; D014481:United States; D014851:Wakefulness; D014940:Work Schedule Tolerance
Circadian misalignment; Intern; Modeling; Physician-in-training; Resident; Sleep deprivation