Emergency chest reopen of the post cardiac surgical patient in the intensive care unit is a high-stakes but infrequent procedure which requires a high-level team response and a unique skill set. We evaluated the impact on knowledge and confidence of team-based chest reopen training using a patient simulator compared with standard video-based training. We evaluated 49 medical and nursing participants before and after training using a multiple choice questions test and a questionnaire of self-reported confidence in performing or assisting with emergency reopen. Both video- and simulation-based training significantly improved results in objective and subjective domains. Although the post-test scores did not differ between the groups for either the objective (P = 0.28) or the subjective measures (P = 0.92), the simulation-based training produced a numerically larger improvement in both domains. In a multiple choice question out of 10, participants improved by a mean of 1.9 marks with manikin-based training compared to 0.9 with video training (P = 0.03). On a questionnaire out of 20 assessing subjective levels of confidence, scores improved by 3.9 with manikin training compared to 1.2 with video training (P = 0.002). Simulation-based training appeared to be at least as effective as video-based training in improving both knowledge and confidence in post cardiac surgical emergency resternotomy.