Study The Effect Of Oxygen Supply In Hypoxia Dogs With Veno-venous Extracorporeal Membrane Oxygenation

Objective To study the effect of oxygen supply in hypoxia dogs with veno-venous extracorporeal membrane oxygenation(V-V ECMO)Methods Choosed eight healthy dogs whose weight are 20.9±2.8kg. After the bypass of V-V ECMO established which make the right femoral vein as drainage access and the right internal jugular vein as inflow access in anesthesia, spontaneous breath of dog was made to stop with intravenous vecuronium. So the dog was in hypoxia state because it was treated with the inhalation of nitrogen(N2) instead of oxygen(O2) from simple respirator. Then the bypass of V-V ECMO was run. During the time of experiment, the information in the following aspects was observed carefully. The first was the maximum flow rate of the bypass that it could reach in V-V ECMO mode(the flow rate of the bypass was defined as a quotient of extracorporeal circulation volume and cardiac output ). And the second aspect observed carefully was that when the flow rate of the bypass in V-V ECMO mode was a certain value, what was the value of SaO2(the arterial oxygen saturation) at the same time. After the flow rate of the bypass was treated as independent variable X and the SaO2 was treated as dependent variable Y, we could calculate the rank coefficient correlation of them, that is Spearman rank coefficient correlation rs. If the probability was less than 0.05 according to level value table of rs, that showed a significant difference. And if the probability was less than 0.01, that means the differences is very obvious. We could calculate a regression equation of ranks between independent variable X and dependent variable Y according to the method of monotonic regression. The regression equation was Q? =am+bmP. And then we could calculate flow rate of the bypass by SaO2 according to the principle of interpolation.RESULTS The value of Spearman rank coefficient correlation was 0.951 and the probability was less than 0.01(p<0.01).That means the result had a highly significant difference; A regression equation of ranks between flow rate of the bypass and SaO2 was calculated as follow: Q? =1.148+0.949P. And we also calculated that when the value of SaO2 was 90.0%, the value of flow rate of the bypass was 22.5%; The mean maximum flow rate of the bypass that it could reach in V-V ECMO mode was 44.6%,whose confidence interval was between 43.3% and 45.9%.CONCLUSION1. During the bypass of V-V ECMO, the SaO2 has a positive correlation with the flow rate of the bypass. It shows that the SaO2 and the flow rate of the bypass have a high dependability, because whose value of Spearman rank coefficient correlation rs is 0.951. In other words, the flow rate of the bypass was the major factor that influenced the arterial oxygen (SaO2);2. The maximum flow rate of the bypass that it can reach in V-V ECMO mode which make the right femoral vein as drainage access and the right internal jugular vein as inflow access was 44.6%;3. In order to keep the value of SaO2 above and beyond 90%, it should make the flow rate of bypass more than 22.5% during the bypass of V-V ECMO mode which make the right femoral vein as drainage access and the right internal jugular vein as inflow access. That is to say, in order to guarantee the body to be in non-hypoxia during the bypass of V-V ECMO, the flow rate of bypass it must be more than 22.5%.4. The mode of veno-venous extracorporeal membrane oxygenation can bring about a satisfactory effect of oxygen supply in hypoxia dogs.