Resuscitation of uncontrolled liver hemorrhage: effects on bleeding, oxygen delivery, and oxygen consumption

Using a standardized liver injury model of uncontrolled hemorrhage, we tested the effect of different fluid resuscitation regimens on hemodynamics, oxygen delivery, oxygen consumption, bleeding volume, and fluid resuscitation requirements. Rats were randomized into three bolus resuscitation groups 15 minutes after liver injury: lactated Ringer's solution (LR, n = 10), hypertonic saline (HS, n = 10), and hypertonic sodium acetate (HA, n = 10). In all resuscitation groups, a 4 mL/kg bolus was first infused at a rate of 0.4 mL/min. Continuous supplemental LR infusion was then given for 90 minutes to maintain a mean arterial pressure of 80 mm Hg. An initial bolus of LR led to minimal changes in hemodynamics. Initial resuscitation with HS markedly increased blood pressure and cardiac index. The bolus of HA increased cardiac index but did not increase blood pressure; systemic vascular resistance was significantly decreased and bleeding significantly increased. Resuscitation with HS did not increase bleeding compared with LR and resulted in the smallest total resuscitation volume requirement. Resuscitation with HS and HA both resulted in a rapid increase in oxygen consumption; LR did not increase oxygen consumption. Animals in the HS group had significantly higher oxygen extraction ratios at the conclusion of the experiment. The use of different bolus fluids for the resuscitation of uncontrolled hemorrhage resulted in significant differences in hemodynamics, oxygen metabolism, and blood loss even when subsequent resuscitation was the same in all groups. Results from large vessel injury animal models and clinical studies of patients with penetrating trauma may not apply to solid parenchymal injuries.