Resuscitation from hemorrhagic shock using polymerized hemoglobin compared to blood

Area of Science:

• Biomedical Engineering
• Emergency Medicine
• Hematology

Background:

• Severe hemorrhage presents a significant challenge, particularly in remote settings lacking blood availability.
• Hemoglobin-based oxygen carriers (HBOCs) were developed as potential alternatives to blood transfusions.
• Hemopure (HBOC-201) is an approved HBOC, yet its functional understanding requires further investigation.

Purpose of the Study:

• To investigate the microcirculatory hemodynamics and oxygenation effects of Hemopure compared to blood transfusion during hemorrhagic shock resuscitation.
• To evaluate Hemopure's efficacy at varying hemoglobin concentrations (4, 8, and 12 gHb/dL).

Main Methods:

• Intravital microscopy was employed in unanesthetized hamsters with a skinfold window chamber.
• Hemorrhagic shock was induced (50% blood volume loss), followed by hypovolemic shock and fluid resuscitation (50% shed volume).
• Microcirculation parameters including diameters, blood flow, and functional capillary density (FCD) were analyzed.

Main Results:

• Both Hemopure and blood transfusion restored systemic and microvascular parameters post-resuscitation.
• Microcirculatory oxygen delivery correlated with Hemopure concentration, alongside increased vasoconstriction.
• Functional capillary density decreased at 12 gHb/dL of Hemopure and blood, indicating a balance between oxygen transport and blood flow.

Conclusions:

• Fluid resuscitation with Hemopure or blood effectively normalized microcirculatory function.
• Optimal resuscitation from hemorrhagic shock may be achieved with lower HBOC concentrations compared to blood transfusion, by balancing oxygen delivery and tissue perfusion.