Effects of Top-Loading a Zero-Link Bovine Hemoglobin, OxyVita, on Systemic and Microcirculatory Variables

Abstract

This study was designed to test the effect of top-load infusions of increasing doses of two versions of the novel, high molecular weight hemoglobin-based oxygen carrier, OxyVita and OxyVita C solution ([Hb] = 6 g/dL), on mean arterial pressure (MAP), arteriolar diameter, and tissue oxygenation. Experiments were carried out on 18 anesthetized male Sprague-Dawley rats in which microcirculatory observations were made on the spinotrapezius muscle. Intravenous infusions of four increasing doses of the OxyVita solutions (2, 22, 230, and 780 mg/kg) were made for each group, and a separate group of animals was used for volume control. Tissue oxygenation was measured as interstitial fluid (ISF) PO2 using phosphorescence quenching microscopy. Increasing doses of either OxyVita solution or Lactated Ringer's solution (LRS, volume control) were associated with increasing MAP. For LRS infusions, MAP returned to baseline between each incremental dose injected, whereas there was an incomplete return for either of the OxyVita solutions. ISF PO2 for OxyVita was significantly lower than that for either LRS or OxyVita C, whereas ISF PO2 for OxyVita C was never statistically different from LRS. There were no significant changes in arteriolar diameters for LRS and either of the OxyVita solutions.