Abstract 37: Release of Protein S100B in Hemorrhagic Shock: Effects of Small Volume Resuscitation Combined with Arginine Vasopressin
Background: With respect to resuscitation of uncontrolled hemorrhagic shock there is growing evidence that conventionally aggressive fluid resuscitation does not increase the chance of survival. Accordingly, alternative strategies such as small volume resuscitation (SVR) and drug therapy merit further evaluation. The purpose of this prospective, controlled, blinded experimental study was to compare the effect of SVR alone, or combined with arginine vasopressin (AVP) on cerebral perfusion pressure (CPP) and the release of serum protein S100B during severe hemorrhage with near fatal hypotension.
Materials and Methods: Following approval of the Animal Investigational Committee, twenty anesthetized and mechanically ventilated pigs (12 to 16 weeks, 42 to 46 kg) underwent a penetrating liver trauma. Following hemodynamic decompensation, pigs were randomly assigned to receive hypertonic-hyperoncotic solution (HHS; 4 mL/kg) combined with either normal saline placebo (HHS + NS; n = 10) or AVP (.2 U/kg) followed by a continuous infusion (2 U/kg/hr; HHS + AVP; n = 10). Cardiovascular hemodynamics, CPP, blood gases and serum protein S100B were evaluated.
Results and Discussion: Compared to baseline, CPP dropped and S100B levels increased at hemodynamic decompensation (CPP: HHS + NS 10 ± 2 versus 82 ± 17 mm Hg, HHS + AVP 14 ± 3 versus 69 ± 14 mm Hg, p < .001; S100B: HHS + NS .90 ± .1 versus .47 ±.06 μg/L, p< .05; HHS + AVP .85 ±.13 versus .58 ± .06 μg/L, p< .01). After pharmacological intervention and control of bleeding, CPP increased and S100B levels decreased close to baseline values (p < .001). Both groups did not differ significantly at any time. All animals of the HHS + AVP group survived compared to 70% of the HHS+ NS group. S100B and CPP were inversely correlated (HHS + NS r = −.67; HHS + AVP r = −.55; p < .001).
Conclusions: Hemorrhage-induced hypotension resulted in increased S100B levels. AVP was comparable to placebo with respect to CPP and S100B release. S100B and CPP were inversely correlated in both groups, suggesting that increased S100B may indicate blood-brain barrier dysfunction due to an inadequate CPP during hemorrhagic shock.