EARLY RESUSCITATION WITH POLYMERIZED BOVINE HEMOGLOBIN REVERSES ACIDOSIS, BUT NOT PERIPHERAL TISSUE OXYGENATION, IN A SEVERE HAMSTER SHOCK MODEL

Awake hamsters equipped with the dorsal window chamber preparation were subjected to hemorrhage of 50% of the estimated blood volume. Initial resuscitation (25% of estimated blood volume) with polymerized bovine hemoglobin (PBH) or 10% hydroxyethyl starch (HES) occurred in concert with an equivolumetric bleeding to simulate the early, prehospital setting (exchange transfusion). Resuscitation (25% of estimated blood volume) without bleeding was performed with PBH, HES, or autologous red blood cells (HES-RBCs). Peripheral microcirculation, tissue oxygenation, and systemic hemodynamic and blood gas parameters were assessed. After exchange transfusion, base deficit was −8.6 ± 3.7 mmol/L (PBH) and −5.1 ± 5.3 mmol/L (HES) (not significant). Functional capillary density was 17% ± 6% of baseline (PBH) and 31% ± 11% (HES) (P< 0.05) and arteriolar diameter 73% ± 3% of baseline (PBH) and 90% + 5% (HES) (P< 0.01). At the end, hemoglobin levels were 3.7 ± 0.3 g/dL with HES, 8.2 ± 0.6 g/dL with PBH, and 10.4 ± 0.8 g/dL with HES-RBCs (P< 0.01 HES vs. PBH and HES-RBCs, P< 0.05 PBH vs. HES-RBCs). Base excess was restored to baseline with PBH and HES-RBCs, but not with HES (P< 0.05). Functional capillary density was 46% ± 5% of baseline (PBH), 62% + 20% (HES-RBCs), and 36% ± 19% (HES) (P< 0.01 HES-RBCs vs. HES). Peripheral oxygen delivery and consumption was highest with HES-RBCs, followed by PBH (P< 0.05 HES-RBCs vs. PBH, P< 0.01 HES-RBCs and PBH vs. HES). In conclusion, the PBH led to a correction of base deficit comparable to blood transfusion. However, oxygenation of the peripheral tissue was inferior with PBH. This was attributed to its negative impact on the peripheral microcirculation caused by arteriolar vasoconstriction.