Volume expansion with modified hemoglobin solution, colloids, or crystalloid after hemorrhagic shock in rabbits: Effects in skeletal muscle oxygen pressure and use versus arterial blood velocity and resistance

Therapeutic goals for hemorrhagic shock resuscitation are the increase of cardiac output and oxygen delivery. The possibility exists that because of microcirculatory effects, different volume expanders result in different tissue oxygen delivery and oxygen use. In a rabbit model of resuscitation from hemorrhagic shock (500% blood loss), we compared the effects of an hemoglobin-based O-2-carrying solution (HbOC) with those elicited by albumin, hydroxyethyl starch (HES), or saline on systemic hemodynamics, skeletal muscle O-2 pressure (PtiO(2)), and interstitial concentration of lactate (LACi) through the combined implantation of a microdialysis probe and a sensitive O-2 electrode into the hind limb. Hemorrhagic shock induced a 500%. decrease in mean arterial pressure (MAP), femoral artery blood flow (BF), and PtiO(2). After resuscitation, there were statistically significant differences among the volume expanders. The increase in MAP was faster with HbOC and colloids, and slower with saline, mainly obtained by vasoconstriction for HbOC and by increased BF with albumin and HES. The maximum MAP values were significantly higher for HbOC compared with the other volume expanders. HbOC; and colloids induced a faster increase in PtiO(2) as compared with saline, but maximum PtiO(2) values were not different among the volume expanders. Tissue oxygen use as estimated by LACi increased transiently at the beginning of volume expansion with similar maximum values. Animals resuscitated with saline had significantly higher LACi concentrations after the onset of volume expansion as compared with HbOC but not with colloids. Our mutts demonstrate that there are measurable differences in MAP and BF upon resuscitation with the four different solutions and there is a slower increase in tissue PtiO(2) with saline than With colloids associated with significantly increased LACi consistent with delayed reoxygenation upon resuscitation with saline.