After severe
hemorrhage, low-volume
resuscitation with hypertonic fluids is increasingly preferred to more aggressive
resuscitation strategies.
Oxygen delivery to the tissues may be improved by augmentation with
hemoglobin [Hb]-based
oxygen-carrying compounds (HBOCs); however, previous studies have reported negative outcomes presumably related to extravasation of tetrameric Hb. The purpose of this study was to evaluate a novel large molecular weight
polymer of cross-linked bovine Hb (
OxyVita;
OXYVITA Inc, New Windsor, NY) in a cocktail of hypertonic saline and Hextend (HX; HBOC-C) as an alternative to standard small-volume
resuscitation using Hextend (HX) only. Outcomes were survival to 3 h and duration of MAP support more than 60 mmHg without additional fluid support. Conscious male Long-Evans rats were hemorrhaged to 60% total blood volume over 40 min. There were 4 groups: HBOC-C administered in a pressure-titrated infusion, HX titration, HBOC-C administered as a bolus, and HX bolus. Cardiovascular parameters, arterial
gases,
acid-base status, metabolites,
electrolytes, Hb level, and oxygen saturation were measured at baseline, during each 20%
hemorrhage increment, and 1, 2, and 3 h after the initiation of
hemorrhage. Small-volume
resuscitation with HBOC-C significantly improved survival to 3 h and improved MAP support times regardless of method of administration. However, physiological status at the end of
hemorrhage significantly influenced survival regardless of
resuscitation treatment. These results suggest that HBOC-augmented hypertonic cocktails are of promise in improving survival and providing target MAP support during small-volume
resuscitation. Experimental evaluation of any
resuscitation therapy should account for the degree of preexisting physiological compromise before
therapy is initiated.