Knowledge retention after simulated crisis: importance of independent practice and simulated mortality

Background: Simulation is an important component of postgraduate medical education, but optimal parameters for simulation are not known. Managing simulations independently and allowing simulated morbidity and mortality have been shown to improve follow-up performance in simulation. We hypothesised that allowing simulated mortality improves performance in follow-up simulations more than independent practice. Methods: Using a randomised, controlled, observer-blinded design, 48 first-year residents in anaesthesia were exposed to a hyperkalaemia scenario. Subjects were divided into two groups (n=24) that allowed for independent practice or support from an attending physician. Each of these groups was then subdivided into two groups (n=12) that allowed for simulated mortality or did not. All groups received a standardised debriefing. Six months later, the subjects returned to manage a different hyperkalaemia scenario independently with potential simulated mortality. The primary outcome was total treatment score; secondary outcomes included subjects' time to request diagnostic information, time to treatment, and simulator mortality rate. Results: Subject characteristics were not statistically different. The independent practice–mortality possible group had the highest total treatment score (P=0.004), fastest time to treatment (P=0.009), and lowest mortality rate (P=0.002) compared with all groups. Two-way analysis of variance and least-squares means were calculated for each combination of variables. The overall practice effect was contrasted to the potential for mortality and was insignificant; however, their interaction effect (P=0.003) was significant and produced the best results. Conclusions: Independence and the potential for simulated mortality have a greater impact on performance in follow-up simulations when combined than either factor alone.