Evaluation of indicators of tissue hypoxia during progressive hemorrhage and blood retransfusion

To establish whether the indicators of oxygen metabolism reflects the improvement in tissue oxygenation during therapy, twelve rabbits subjected to progressive hemorrhage followed by retransfusion were studied. The changes in oxygen delivery (Do(2)), oxygen consumption (Qo(2)), oxygen extraction ratio (O(2)ER), arterial lactate concentration, venous-arterial difference in Pco(2) (v-aDPco(2)) and arterio-venous difference in pH (a-vDpH) were analyzed during two phases (above and below) the critical Do(2) with the regression coefficient (slope). The main findings during the transfusion were: a) the slope, when compared during the two phases was not significantly different for O(2)ER, V-aDPco(2) or a-vDpH, while during hemorrhage each variable showed a significantly different slope, b) in the phase below the critical Do(2), the slope was significantly less sleep than that during hemorrhage for lactate and v-aDPco(2), c) in the phase above the critical Do(2), lactate alone had significantly steeper slope than that during hemorrhage. In conclusion, it is suggested that the changes in Qo(2) best reflect the recovery from tissue hypoxia.