Effects Of Different Degree Acute Normovolemic Hemodilution On Oxygenation And Breathing Mechanics In Rabbits

Objective To observe the effect of different degree acute normovolemic hemodilution (ANH) on lung and systemic oxygen metabolism in rabbits.Methods Twenty-four healthy rabbits were randomly divided into 4 equal groups with 6 animals in each group: control groupâ… was without hemodilution; groupâ…¡which Hct was 24%; groupâ…¢which Hct was 18%; groupâ…£which Hct was 12%. Blood sample were taken before hemodilution(T0), and at 2 hours(T1),4 hours (T2)and 8 hours (T3)after hemodilution for determination of plasma level of MDA,SOD,ERO2 and respiratory mechanics. At the end of the experiment, the lungs were obtained for microscopic examination and determination of wet/dry lung weight ratio (W/D).Results There was no significant difference in ERO2,MDA content, SOD activity and respiratory mechanics between groupâ… andâ…¡; ERO2 ,MDA content, SOD activity raised up and changes of respiratory mechanics appeared at 8 hours after hemodilution in groupsâ…¢(P<0.05); In groupâ…£, ERO2 ,MDA content SOD activity and changes of breathing mechanics stepped up from 2 hours to 8 hours after hemodilution and were different to that points of groupâ… (P<0.05).Conclusion Lung injury was not observed in rabbits when target Hct was 24%; lungs injury appeared with the changes of respiratory mechanics and pathology in rabbits of groupâ…¢which Hct was 18%; lungs injury aggravated in rabbits of group â…£which Hct was 12%.ANH in the range of Hct 18%-20% is safe in terms of systemic and lung O2 supply.