dose-dependent hemodynamic, biochemical, and tissue oxygen effects of oc99 following severe oxygen debt produced by hemorrhagic shock in dogs

We determined the dose-dependent effects of OC99, a novel, stabilized hemoglobin-based oxygen-carrier, on hemodynamics, systemic and pulmonary artery pressures, surrogates of tissue oxygen debt (arterial lactate 7.2±0.1 mM/L and arterial base excess −17.9 ± 0.5 mM/L), and tissue oxygen tension (tPO2) in a dog model of controlled severe oxygen-debt from hemorrhagic shock. The dose/rate for OC99 was established from a pilot study conducted in six bled dogs. Subsequently twenty-four dogs were randomly assigned to one of four groups (n=6 per group) and administered: 0.0, 0.065, 0.325, or 0.65 g/kg of OC99 combined with 10 mL/kg lactated Ringers solution administered in conjunction with 20 mL/kg Hextend IV over 60 minutes. The administration of 0.325 g/kg and 0.65 g/kg OC99 produced plasma hemoglobin concentrations of 0.63±0.01 and 1.11±0.02 g/dL, respectively, improved systemic hemodynamics, enhanced tPO2, and restored lactate and base excess values compared to 0.0 and 0.065 g/kg OC99. The administration of 0.65 g/kg OC99 significantly elevated pulmonary artery pressure. Plasma hemoglobin concentrations of OC99 ranging from 0.3 to 1.1 g/dL, in conjunction with colloid based fluid resuscitation, normalized clinical surrogates of tissue oxygen debt, improved tPO2, and avoided clinically relevant increases in pulmonary artery pressure.