Learning how to stop external hemorrhage during a medical simulation using cadavers - a randomized trial

INTRODUCTION: Patients suffering from trauma are at risk of death from uncontrolled external bleeding, therefore witnesses to the incident and emergency medical services should promptly implement appropriate procedures, which requires prior training. The purpose of this study is to comparatively analyze the didactic effectiveness resulting from the use of cadavers – human-based unfixed preparations, and training devices, during practice-based teaching of medical students on how to stop external hemorrhage. MATERIALS AND METHODS: Fifty-four medical students participated in the study. At the initial stage, training was provided including procedures for stopping external hemorrhages using hand maneuvers, tourniquets, and hemostatic dressings. Randomization was performed by selecting a study group (procedures performed on human unfixed specimens) and a control group (procedures performed on a training model). During the practical test, the time to perform the procedure until the hemorrhage was effectively stopped was evaluated. The students were also asked to perform a self-assessment of their skills, as well as to indicate their level of satisfaction with the training. Statistical analysis allowed to obtain correlations of variables, taking age, sex, height, body mass and hand sizes of the subjects into account. RESULTS: The study group consisted of 35 women (64.81%) and 19 men (35.19%). Intergroup comparisons confirmed the absence of significant differences between groups in Mann-Whitney U tests for unrelated variables for the criterion of sex (p=0.403), age (p=0.081), height (p=0.472), body mass (p=0.883), hand width (p=0.653) and hand length (p=0.355). Group A performed the procedures on training models, while Group B performed the procedures on appropriately prepared cadavers. Direct manual compression was performed in an average of 2.85 seconds (group A) and 5.23 seconds (group B), wound packing in an average of 42.48 seconds (group A) and 50.97 seconds (group B), passing a tourniquet fastened into a loop in an average of 27.66 seconds (group A) and 26.01 seconds (group B), and an unfastened tourniquet over bleeding site in an average of 27.70 seconds (group A) and 29.14 seconds (group B). The manual wound compression procedure was performed significantly longer on the cadaver (p=0.005) than on the training model. The level of satisfaction and self-assessment after the training increased comparably in both groups. CONCLUSIONS: Unfixed human-body-based preparations constitute an important part of medical student education. Simulations of external hemorrhage stopping allowed noticing prolonged procedure performance time in the case of cadaver-based exercises, especially regarding the procedure for manual wound compression. The results suggest that selected rescue procedures are more difficult to perform on human specimens, compared to training models, therefore cadaver-based training may prove more effective.