Effect of oxygen affinity on systemic perfusion and brain tissue oxygen tension after extreme hemodilution with hemoglobin-starch conjugates in rats

Abstract

Purpose: To determine the oxygen affinity for optimal tissue oxygen delivery with a hemoglobin-hydroxyethyl starch conjugate (HRC 101). Methods: Anesthetized rats were hemodiluted (180 ml kg -1) with low (P 50 ∼ 70 mmHg) or high affinity (P 50 ∼ 14 mmHg) HRC 101 at hemoglobin (Hb) concentrations near 100 or 70 g l -1 (n = 6-8). Hippocampal tissue oxygen tension (P BrO 2), blood flow, arterial blood gases, Hb, hematocrit (Hct) and lactate were measured. Data (mean ± SD) were analyzed by two-way ANOVA. Results: Hemodilution reduced the hematocrit to 1 ± 1% in all groups. PB rO 2 was best maintained after hemodilution with low affinity HRC 101 at Hb 100 and 70 g l -1(25.2 ± 7.6 and 16.6 ± 8.3 torr, respectively). P BrO 2 decreased (9.5 ± 9.3 torr, P < 0.05) and serum lactate levels increased (5.0 ±1.7 mmol l -1, P < 0.05) following hemodilution with the high affinity HRC 101 (Hb 100 g l -1). Conclusions: HRC 101 with a lower oxygen affinity favored tissue perfusion and maintained P BrO 2 after near complete blood volume exchange in rats. © Springer-Verlag 2009.