Hypotensive resuscitation using a polymerized bovine hemoglobin-based oxygen-carrying solution (HBOC-201) leads to reversal of anaerobic metabolism

Background: Traditional resuscitation regimens have been recently challenge d. This study evaluates hypotensive resuscitation with a hemoglobin-based o xygen-carrying (HBOC) solution after severe hemorrhage in a porcine model. We hypothesized that HBOC-201 restores tissue perfusion at a lower mean art erial pressure than standard resuscitation fluids. Methods: Yorkshire swine (55-65 kg, n = 30), were rapidly hemorrhaged to a mean arterial pressure (MAP) of 30 mm Hg, maintained hypotensive for 45 min utes, and randomized into groups. Group I was resuscitated with an HBOC sol ution to a MAP of 60 mm Hg. Groups II and III were resuscitated to a MAP of 80 mm Hg with lactated Ringer's solution (LR) alone or LR (40 mL/kg) follo wed by shed blood, respectively. Group IV was resuscitated with shed blood alone to a MAP of 60 mm Hg, Group V received an HBOC solution to a MAP of 5 0 mm Hg, Hemodynamic variables, Swan-Ganz parameters, blood gas samples, an d lactate levels were followed for 5 hours, Data were analyzed by analysis of variance/Duncan multiple range test. Results: There were no significant differences in mortality between any gro ups. Groups I, IV, and V had lower (p < 0.05) cardiac output, pulmonary art ery wedge pressure, and R IAP than either group II or group III. SVO2 was s ignificantly lower in the HBOC groups. There were no significant difference s in arterial pH or lactate between groups I, III, and IV. Lactate levels, base excess, and arterial pH were significantly worse in the LR-alone and H BOC-50 groups. Conclusion: Hypotensive resuscitation with HBOC-201 at a MAP of 60 mm Hg af ter a controlled hemorrhage in swine provides sufficient tissue perfusion a nd oxygen delivery to reverse anaerobic metabolism on the basis of global p hysiologic markers despite continued hypotension, hypovolemia, and low card iac output.