Effects Of Lipid Emulsion With Various Concentrations On The Therapeutic Effect Of A Rabbit Model With Bupivacaine-Induced Cardiac Depression

Objective:To investigate the effects of lipid emulsion with various concentrations on the therapeutic effect of a rabbit model with bupivacaine-induced cardiac depression .Method: New Zealand rabbits (n=28) were randomly divided into four groups which are group B (n=7, treated with saline) group BF₃0(n=7, treated with lipid emulsion with 30% original concentration) group BF₂₀(n=7, treated with lipid emulsion with 20% original concentration) and group BF₁₀(n=7, treated with lipid emulsion with 10% original concentration). Bupivacaine was injected via rabbits'auricular vein,and MAP decreased to 60% of the basic value were served as evidence of successful establishment of cardiac depression models. A load quantity of 30%,20% and 10% lipid emulsion (1 ml/kg) was given in group BF₃₀,group BF₂₀ and group BF₁0, followed by continuous lipid emulsion infusion (0.5ml·kg^-1·min^-1) for 10 minutes. In group B,a load quantity of saline(1ml/kg) was given , followed by continuous saline infusion (0.5ml·kg^-1·min^-1) for 10 minutes. The treatment was success when MAP increased to 80% of the basic value. And respectively recorded the basic HR and MAP. Respectively detected the blood concentration of bupivacaine through HPLC when the rabbits occurred cardiac depression, successfully treated or failure treatment. Specimens of myocardial cell were taken for transmission electron microscope detection.Result: There was no significant difference in basic HR and MAP among the four groups. The result of transmission electron microscope on myocardial cell showed that the level of myocardial cell damage and mitochondria turgescence in group BF₃₀ was much less than those in group B. The level of myocardial cell damage and mitochondria turgescence in group BF₂₀ was less than those in group B, and there was no significant difference between group BF₍100 and group B. The result of HPLC showed that there was no significant difference in C0 among the four groups. C was significantly low in group BF₃₀,group BF₍200 and group BF₁₀ as compared with that in group B (P<0.01). C was low in group BF₃₀ as compared with those in group BF₂0 and group BF₁₀ (P<0.01).C was low in group BF₂₀as compared with that in group BF₁₀ (P<0.01).Conclusion: Lipid emulsion has rivalry effect on cardiac toxicity induced by bupivacaine. This rivalry effect increased progressively with the concentration of lipid emulsion. And it's possible mechanism was the lipid sink theory.