Small volume resuscitation: a randomized controlled trial with either norepinephrine or vasopressin during severe...

The present study was designed to evaluate the effects of hypertonic-hyperoncotic hydroxyethyl starch solution (HHS) combined with either norepinephrine (NE) or arginine vasopressin (AVP) on cerebral perfusion pressure (CPP) and brain metabolism after hemorrhagic shock.

Fourteen pigs were subjected to uncontrolled liver bleeding until hemodynamic decompensation followed by resuscitation using HHS (4 mL/kg) combined with either NE (bolus of 1000 microg; 60 microg/kg/hr; n = 7) or AVP (bolus of 10 U; 2 U/kg/hr; n = 7), respectively. Extracellular cerebral concentrations of glucose, glycerol, lactate, and the lactate/pyruvate ratio were assessed by microdialysis. After 30 minutes of therapy, bleeding was controlled by manual compression and all surviving animals were observed for 1 hour.

After hemodynamic decompensation, AVP resulted in a significantly higher increase of CPP (mean +/- SD; 47 +/- 19 versus 28 +/- 9 mm Hg; p < 0.01) and cerebral venous partial pressure of oxygen (66 +/- 8 versus 49 +/- 9 mm Hg; p < 0.05) compared with NE after 10 minutes of therapy. Hemodynamic data and blood gas variables were not different between groups during the remaining study period. Brain metabolism was found comparable in both groups at any time.

AVP was comparable to NE with respect to hemodynamics and blood gases, as well as brain metabolism in surviving animals throughout the study period. Our findings emphasize the importance of early resuscitation, as neuronal cell damage potentially starts immediately after onset of severe hemorrhage.