Does HBOC-201 (Hemopure) affect platelet function in orthopedic surgery: a single-site analysis from a multicenter study.

HBOC-201, Hemoglobin glutamer-250 (bovine), (Biopure Corp., Cambridge, MA) has been studied in an international, multicenter, pivotal Phase III trial. A subset analysis of use of blood products indicated that the HBOC-201 group required no more than the packed red blood cell (PRBC) group and was limited to less than 6% in both treatment groups. In a subset analysis from one site, platelet function using PFA-100 was assessed before and after transfusion, and compared those receiving HBOC-201 versus PRBC. After initial IRB approval, patient consent for the Phase III trial and blood draws for PFA-100, an additional IRB exemption for retrospective chart review was obtained. cEPI and cADP means were compared at seven time periods: true baseline(before starting surgery and anesthesia), before transfusion, after transfusion, 1 day, 2 days, 3 to 9 days and 21 or more days after transfusion. Twenty-seven (HBOC: n = 12, PRBC: n = 15) subjects were studied. Comparing data from before transfusion and baseline did not show statistically significant differences in any of cEPI or cADP measurements. cEPI means for the HBOC-201 group increased after transfusion compared to the true baseline (P = 0.01), before transfusion (P = 0.0004) and day 1 after transfusion (P = 0.002). cADP means for the HBOC-201 group were greater after transfusion compared to the true baseline (P = 0.05) and before transfusion (P = 0.005). In the PRBC group there were no significant difference in cEPI and cADP means between all of the time periods. Our study shows that HBOC-201 causes mild platelet dysfunction. Although there were significant changes after HBOC infusion and cEPI and cADP mean values were above the upper normal limit, they did not reach the non-closure time. Further controlled studies are needed to establish definitively the effects that HBOC-201 has on platelet function in patients.

Methemoglobin effects on coagulation: a dose-response study with HBOC-200 (Oxyglobin) in a thrombelastogram model.

OBJECTIVES: Because oxidation affects platelet and coagulation factors, hemoglobin auto-oxidation in HBOCs results in the transformation to methemoglobin, which may have additive adverse effects on coagulation. The risk of coagulopathy after different dilutions of HBOC-200 with low and high methemoglobin concentrations was studied. DESIGN: A laboratory study on donor blood using thromboelastography (TEG; Haemoscope, Niles, IL). SETTING: A university laboratory. PARTICIPANTS: Volunteer donor blood. INTERVENTIONS: Blood samples simulated hemodilution during clinical resuscitation of hemorrhagic shock with varying doses of HBOC-200 (Oxyglobin; Biopure Corp, Cambridge, MA). Coagulopathy related to 1:11, 1:5, 1:2, and 1:1 dilution of whole blood with HBOC-200 high methemoglobin concentrations (65%) and HBOC-200 low methemoglobin concentrations (1%) were analyzed. MEASUREMENTS AND MAIN RESULTS: Analysis of fixed effects of dilution on coagulation showed that the progressive dilution of HBOC-200 (low methemoglobin) and HBOC-200 (high methemoglobin) produced significant prolongation in reaction time (R) and clot propagation (K) and significant decreases in clot kinetics (alpha) and clot strength (MA and G). Analysis of fixed effects of treatment group on coagulation showed that clot propagation (K, alpha) and clot strength (MA and G) are significantly different in HBOC-200 (high methemoglobin) compared with HBOC-200 (low methemoglobin). CONCLUSIONS: High methemoglobin concentrations in HBOC-200 cause additive coagulation impairment that likely results from the effects of oxidative substances on platelet function and coagulation proteins. Oxidative products adversely react with coagulation factors and modify redox-sensitive sites in the platelets. Therefore, if methemoglobinemia occurs as a result of HBOC administration and if the levels are significantly elevated (greater than 10%), impairment of coagulation is possible.

HBOC-201, hemoglobin glutamer-250 (bovine), Hemopure (Biopure Corporation).

BACKGROUND: Producing an alternative to human erythrocytes has been one the most exciting dreams of medicine. Hemoglobin-based oxygen carriers (HBOCs) derived from purified human or bovine hemoglobin have been studied for clinical use and one product is currently available in the United States and European Union for veterinary use, and another in South Africa for human use. OBJECTIVE: HBOC-201, bovine purified hemoglobin crosslinked and polymerized with glutaraldehyde, has been studied extensively in patients. We describe HBOC-201's potential market share, the history of HBOCs in general and of this compound, its pharmacology, published studies in patients and HBOCs that are currently being studied. METHODS: A literature review using PubMed listed publications and official product websites. CONCLUSIONS: While HBOC-201 may not replace allogenic blood transfusions, it may serve to allow critically ill patients to be resuscitated in the field or hospital setting until either regeneration of red cell occurs or a transfusion is available.