UC San Diego

Study aimed to examine the limitation of cardiac function (CF) by oxygenation and strategies to improve CF in two cases of reduced oxygen supply : 1) hemodilution by hemorrhagic shock (HS) 2) hypoxia. CF indices where obtained by changes in pressure and volume (PV) through the insertion of a miniaturized conductance catheter into the left ventricle (LV) in a Golden Syrian hamster model. 1) HS was simulated by extracting 30% of blood volume and equal volume reinfusion with either Dextran 70 (Dxt70) or polymerized hemoglobin (PolyHb), the latter is a Hemoglobin (Hb)-based oxygen carrier(HBOC). HS resulted in the fall of CF, decrease cardiac output (CO), stroke volume (SV) and stroke work (SW), with slow recovery to baseline after reinfusion. PolyHb did not show beneficial effects in the CF and resulted in vasoconstriction, with a 116% and 46% increase in systemic vascular resistance (SVR) for 11.5g/dL and 8.5g/dL PolyHb respectively. 2) Effects of hypoxia in the heart were investigated by subjecting animals to 30 min stepwise changes of 15%, 10% and 5% O2. Before hypoxia, hamster was given a vehicle or 100mg/kg of 5-hydroxymethyl-2-furfural (5-HMF). 5-HMF produced no significant differences on moderate hypoxia. At 5\% O2, 5-HMF resulted in increased SW, SV, CO and ejection fraction (EF) of 38%, 53%, 30% and 37% from normoxia; vehicle group resulted in a slight decrease from normoxia. Tissue hypoxia was examined by pimonidazole staining, 5-HMF reduced tissue hypoxia by 64%. Overall 5- HMF reduced the amount of hypoxic tissue and improved CF during acute hypoxia