Development of a Swine Polytrauma Model in the Absence of Fluid Resuscitation

Background: In locations in which access to resuscitative therapy may be limited, treating polytraumatized patients present a challenge. There is a pressing need for adjuncts that can be delivered in these settings. To assess these adjuncts, a model representative of this clinical scenario is necessary. We aimed to develop a hemorrhage and polytrauma model in the absence of fluid resuscitation. Materials and Methods: This study consisted of two parts: pulmonary contusion dose-finding (n = 6) and polytrauma with evaluation of varying hemorrhage volumes (n = 6). We applied three, six, or nine nonpenetrating captive bolt-gun discharges to the dose-finding group and obtained computed tomography (CT) images. We segmented images to assess contusion volumes. We subjected the second group to tibial fracture, pulmonary contusion, and controlled hemorrhage of 20%, 30%, or 40% and observed for 3 hours or until death. We used Kaplan-Meier analysis to assess survival. We also assessed hemodynamic and metabolic parameters. Results: Contusion volumes for three, six, and nine nonpenetrating captive bolt-gun discharges were 24 ± 28, 50 ± 31, and 63 ± 77 cm³, respectively (p =.679). Animals receiving at least six discharges suffered concomitant parenchymal laceration, whereas one of two swine subjected to three discharges had lacerations. Mortality was 100% at 12 and 115 minutes in the 40% and 30% hemorrhage groups, respectively, and 50% at 3 hours in the 20% group. Conclusion: This study characterizes a titratable hemorrhage and polytrauma model in the absence of fluid resuscitation. This model can be useful in evaluating resuscitative adjuncts that can be delivered in areas remote to healthcare access.