Purpose: The correlation between simulator-based medical performance and real-world behavior remains unclear. This study explored whether the effects of extended work hours on clinical performance, as reported in prior hospital-based studies, could be observed in a simulator-based testing environment.
Method: Intern volunteers reported to the simulator laboratory in a rested state and again in a sleep-deprived state (after a traditional 24- to 30-hour overnight shift [n=17]). A subset also presented after a shortened overnight shift (16 scheduled hours [n=8]). During each laboratory visit, participants managed two critically ill patients. An on-site physician scored each case, as did a blinded rater later watching videotapes of the performances (score=1 [worst] to 8 [best]; average of both cases=session score).
Results: Among all participants, the average simulator session score was 6.0 (95% CI: 5.6-6.4) in the rested state and declined to 5.0 (95% CI: 4.6-5.4) after the traditional overnight shift (P<.001). Among those who completed the shortened overnight shift, the average postshift simulator session score was 5.8 (95% CI: 5.0-6.6) compared with 4.3 (95% CI: 3.8-4.9) after a traditional extended shift (P<.001).
Conclusions: In a clinical simulation test, medical interns performed significantly better after working a shortened overnight shift compared with a traditional extended shift. These findings are consistent with real-time hospital studies using the same shift schedule. Such an independent correlation not only confirms the detrimental impact of extended work hours on medical performance but also supports the validity of simulation as a clinical performance assessment tool.