The Effect Of Different Degree Acute Normovolemic Hemodilution On Small Intestinal Oxygen Metabolism And Mucosal Injury Of Rabbit

Objective To observe the effect of different degree acute normovolemic hemodilution on small intestinal oxygen metabolism and mucosal injury of rabbit.Methods Thirty-two cases of rabbit were divided into four groups randomly: control group(H0 group),Hct24%(H1 group),Hct18%(H2 group)and Hct12%(H3 group)。Superior mesenteric arterial and superior mesenteric venous blood gas were measured prior to hemodilution(T0),and also evaluated 2(T1),4(T2),8(T3)hours after hemodilution in each group. Superior mesenteric arterial oxygen content,superior mesenteric venous oxygen content and oxygen extraction ratio of intestine were calculated. Plasmic contents of TNF-a in superior mesenteric vein were measured at T₀,T₁,T₂ and T₃ in each group.The contents of MDA and SOD in mucous membrane of small intestine were measured 8 hours after hemodilution in each group.And mucosal structure of small intestine was observed 8 hours after hemodilution under the light and electron microscopy in each group.Results There was no obvious difference in each index between diluted groups and H0 group. Intestinal ERO2 increased significantly(P<0.05) after ANH in H1 groups at T₁ and T₂.There was a significant(P<0.01) increase in ERO2 after ANH in H1group at T₃ and there was a significant(P<0.01) increase in ERO2 at each time in H₂,H₃ group.The value of TNF-a in superior mesenteric venous was increased significantly(P<0.01) after ANH in H₂ group at T₃ ,and it also increased significantly(P<0.01) in H3 group at each time. There was a significant(P<0.01) increase in MDA and decrease in SOD in H2,H3 groups 8 hours after hemodilution.Minor injury was found in mucous membrane of small intestine in H2 group 8 hours after hemodilution under the light and electron microscopy. Major injury occurs in H3 group.Conclusions When targeted Hct is 24%, ANH does not disturb intestinal oxygen metabolism and there is no injury in mucous membrane of small intestine. If the targeted Hct is 18%, we may observe that intestinal oxygen metabolism is changed,and there is minor injury in mucous membrane of small intestine at 8 hours after hemodilution.When targeted Hct is 12%,intestinal oxygen metabolism is changed and there is injury in mucous membrane of small intestine only at 2 hours after hemodilution.and more longer,there is more aggravation in small intestinal injury. We should mention that the above situations occurred when rabbits are in the situation of general anaesthesia, and they happened when the temperature of rabbit is normal.