Abstract
Animal models of combined traumatic brain injury (TBI) and hemorrhagic shock (HS) suggest a benefit of hemoglobin-based oxygen carrier (HBOC)-based resuscitation, but their use remains controversial, and little is known of the specific effects of TBI and high-pressure (large arterial injury) bleeding on resuscitation. We examine the effect of TBI and aortic tear injury on low-volume HBOC resuscitation in a swine polytrauma model and hypothesize that HBOC-based resuscitation will improve survival in the setting of aortic tear regardless of the presence of TBI. Anesthetized swine subjected to HS with aortic tear with or without fluid percussion TBI underwent equivalent limited resuscitation with HBOC, lactated Ringer's solution, or HBOC + nitroglycerine (vasoattenuated HBOC) and were observed for 6 h. There was no independent effect of TBI on survival time after adjustment for fluid type, and there was no interaction between TBI and resuscitation fluid type. However, total catheter hemorrhage volume required to reach target shock blood pressure was less with TBI (14.0 mL · kg(-1) [confidence interval, 12.4-15.6 mL · kg(-1)]) versus HS only (21.0 mL · kg(-1) [confidence interval, 19.5-22.5 mL · kg(-1)]), with equivalent lactate accumulation. Traumatic brain injury did not affect survival in this polytrauma model, but less hemorrhage was required in the presence of TBI to achieve an equivalent degree of shock suggesting globally impaired cardiovascular response to hemorrhage in the presence of TBI. There was also no benefit of HBOC-based fluid resuscitation over lactated Ringer's solution, contrary to models using liver injury as the source of hemorrhage, considering wound location is of paramount importance when choosing resuscitation strategy.