Association of workload of on-call medical interns with on-call sleep duration, shift duration, and participation in educational activities

Context Further restrictions in resident duty hours are being considered, and it is important to understand the association between workload, sleep loss, shift duration, and the educational time of on-call medical interns. Objective To assess whether increased on- call intern workload, as measured by the number of new admissions on- call and the number of previously admitted patients remaining on the service, was associated with reductions in on- call sleep, increased total shift duration, and lower likelihood of participation in educational activities. Design, Setting, and Participants Prospective cohort study of medical interns at a single US academic medical center from July 1, 2003, through June 24, 2005. Of the 81 interns, 56 participated ( 69%), for a total of 165 general medicine inpatient months resulting in 1100 call nights. Main Outcome Measures On- call sleep duration, estimated by wrist watch actigraphy; total shift duration, measured from paging logs; and participation in educational activities ( didactic lectures or bedside teaching), measured by experience sampling method via a personal digital assistant. Results Mean ( SD) sleep duration on- call was 2.8 ( 1.5) hours and mean ( SD) shift duration was 29.9 ( 1.7) hours. Interns reported spending 11% of their time in educational activities. Early in the academic year ( July to October), each new on- call admission was associated with less sleep (- 10.5 minutes [ 95% confidence interval {CI}, - 16.8 to - 4.2 minutes]; P <. 001) and a longer shift duration ( 13.2 minutes [ 95% CI, 3.2- 23.3 minutes]; P=. 01). A higher number of previously admitted patients remaining on the service was associated with a lower odds of participation in educational activities ( odds ratio, 0.82 [ 95% CI, 0.70- 0.96]; P=. 01]. Call nights during the week and early in the academic year were associated with the most sleep loss and longest shift durations. Conclusion In this study population, increased on- call workload was associated with more sleep loss, longer shift duration, and a lower likelihood of participation in educational activities.