Diaspirin cross-linked hemoglobin improves oxygen extraction capabilities in endotoxic shock

We studied the effects of diaspirin cross-linked hemoglobin (DCLHb), a cell -free hemoglobin derived from human erythrocytes, on blood flow distributio n and tissue oxygen extraction capabilities in endotoxic shock. Eighteen pe ntobarbital sodium-anesthetized, mechanically ventilated dogs received 2 mg /kg off. coli endotoxin, followed by saline resuscitation to restore cardia c filling pressures to baseline levels. The animals were randomly divided i nto three groups: six served as control, six received DCLHb at a dose of 50 0 mg/kg (group I) and six DCLHb at a dose of 1,000 mg/kg (group 2). Cardiac tamponade was then induced by saline injection in the pericardial sac to p rogressively reduce cardiac index and thereby allow study of tissue oxygen extraction capabilities. DCLHb had a dose-dependent vasopressor effect but did not significantly alter cardiac index or regional blood flow. During ca rdiac tamponade, critical oxygen delivery was 12.8 +/- 0.7 ml kg(-1) min(-1 ) in the control group, but 8.6 +/- 0.9 and 8.2 +/- 0.7 ml kg(-1) min(-1) i n groups I and 2, respectively (both P < 0.05 vs. control group). The criti cal oxygen extraction ratio was 39.1 +/- 3.1% in the control group but 58.7 +/- 12.8% and 60.2 +/- 9.0% in groups I and 2, respectively. We conclude t hat DCLHb can improve whole body oxygen extraction capabilities during endo toxic shock in dogs.