| Objective To observe the effects of acute hypervolemic hemodilution(AHHD) on intestinal oxygen metabolism in anesthetized rabbits ,and investigate the limits of AHHD that result in intestinal anaerobic metabolism. To study the tendence of intestinal and systemic oxygen metabolism after AHHD.Methods 12 rabbits, weighting 2.4-2.9kg, were anesthetized with ketamine and diazepam . Endotracheal intubation was facilitated with pancuronium and mechanically ventilated with 60% oxygen. The different degrees of AHHD(Hct25% Hl,Hct20% H2,Hctl5% H3,Hctl0% H4)were accomplished by progressively infusion of 4% Gelofusion. Superior mesenteric arterial and superior mesenteric venous blood gas, femoral arterial and internal jugular venous blood gas, femoral arterial blood lactate value(ABL), superior mesenteric venous and internal jugular venous blood lactate value(VBL), were measured prior to hemodilution and 1 hour after hemodilution. Difference of oxygen content, oxygen extraction ratio(ERO2) and venous-arterial difference of lactate(VADL) were calculated.Results Hct dropped to 25.24%± 0.55%, 19.86%± 1.25%, 15.09% ± 0.38% and 10.64%±0.77% in H1 , H2, H3andH4 respectivly after AHHD. There were no significant changes in MAP until Hct dropped to 15%, while heart rate(HR)increased after AHHD in H3 and H4 groups. After AHHD, both intestinal and systemic CaO2, CvO2 decreased gradually. There was a significant increase in ERO2 after AHHD in H3 and H4 groups. ABL, VBL and VADL increased significantly after AHHD in H4 groups. No significant difference was found between intestinal and systemic oxygen metabolism after AHHD.Conclusions The study suggests that has no significant change in moderate(Hct25%) AHHD on intestinal oxygen metabolism and little change in severe(Hct20%)AHHD but can be compensated; intestinal anaerobic metabolism out ofcompensation results in extreme(Hct15%) AHHD. Systemic and intestinal oxygenmetabolism are same changed at the same AHHD degree. |
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