BOVINE HEMOGLOBIN INCREASES SKELETAL-MUSCLE OXYGENATION DURING 95-PERCENT ARTIFICIAL ARTERIAL-STENOSIS

Background. This study investigates the effect of a stroma-free ultrap urified bovine hemoglobin solution (HBOC) on skeletal muscle tissue ox ygenation in comparison with hetastarch during nearly complete arteria l stenosis. Methods. Fourteen foxhounds were intravenously anesthetize d and mechanically ventilated with 30% oxygen in air. Catheters were i nserted into the right femoral artery and vein for measurements of hem odynamic parameters and blood gas sampling. Arterial bloodflow of the left popliteal artery was measured by means of an electromagnetic flow probe. Skeletal muscle tissue oxygen tension (tpO(2)) was measured in the left gastrocnemius muscle by using a stepwise driven polarographi c needle probe creating histograms from 200 single tpO(2) measurements . After isovolemic hemodilution with Ringer's lactate solution to a he matocrit of 25%, a 95% artificial stenosis of the popliteal artery was established. The animals then randomly received two applications of e ither 50 ml HBOC (molecular weight, 32,000 to 500,000; hemoglobin 13 /- 1 gm/dl(-1)) or 200 ml 6% hetastarch 200,000/0.5. Variables were me asured at baseline, after hemodilution, 30 minutes after stenosis, and 15 minutes after two applications of the respective compound. Results . Demographic data, muscle temperature, and arterial blood gases did n ot differ between groups. With the exception of higher mean arterial a nd mean pulmonary artery pressures in HBOC-treated animals, hemodynami cs did not differ between groups. In both groups oxygen delivery and o xygen consumption of the muscle decreased in parallel to the decreasin g blood flow during arterial stenosis. In contrast, oxygen extraction ratio increased after infusion of HBOC and was higher after the second application when compared with hetastarch-treated animals (p < 0.05). During stenosis tpO(2) was decreased in both groups when compared wit h baseline (p < 0.001). Mean tpO(2) remained at decreased levels after administration of hetastarch but increased to nearly baseline values after HBOC treatment (p < 0.001). Conclusions. The data suggest that i ncreased oxygen extraction in the HBOC group is associated with improv ed skeletal muscle tissue oxygenation during severe arterial stenosis.