20%脂肪乳剂对大鼠血浆和心肌罗哌卡因水平的影响

目的 评价20%脂肪乳剂对大鼠血浆罗哌卡因浓度和心肌罗哌卡因含量的影响.方法 雄性SD大鼠60只,体重220～270 g,随机分为2组(n=30):生理盐水组和脂肪乳剂组.股静脉注射l%罗哌卡因5 mg/kg后,脂肪乳剂组股静脉注射20%脂肪乳剂注射液5 ml/kg;生理盐水组股静脉注射等容量生理盐水.分别于给予罗哌卡因后5、10、20、40、60和120 min时取5只大鼠,心尖取血样后取心肌组织,采用高效液相色谱法测定血浆罗哌卡因浓度和心肌罗哌卡因含量.结果 与生理盐水组比较,脂肪乳剂组给予罗哌卡因后20 min时血浆罗哌卡因浓度升高,给予罗哌卡因后5、10 min时心肌罗哌卡因含量降低(P＜0.01).结论 20%脂肪乳剂可在短时间内与大鼠血液中的罗哌卡因结合,减少在心肌组织中的分布,有助于降低其心脏毒性.

Effects of 20% Hpid emulsion on plasma and myocardial ropivacaine levels in rats

Objective To investigate the effects of 20% lipid emulsion on plasma ropivacaine concentration and myocardial ropivacaine content in rats. Methods Sixty male pathogen-free SD rats weighing 220-270 g were randomly divided into 2 groups (n = 30 each): group A normal saline and group B lipid emulsion.The animals were anesthetized with intraperitoneal 4% pentobarbital 40 mg/kg. The femoral vein was cannulated for drug and fluid administration. ECG (lead Ⅱ) was continuously monitored. 1% ropivacainc 5 mg/kg was injected iv. A bolus of 20% lipid emulsion 5 ml/kg was then injected iv in group B, while in group A equal volume of normal saline was administered instead of 20% lipid emulsion. The animals were sacrificed at 5, 10,20, 40, 60 and 120 min after ropivacaine infusion (5 animals at each time point). Blood samples and myocardial specimens were taken for determination of plasma and myocardial ropivacaine levels by HPLC. Results Plasma ropivacaine concentration at 20 min after ropivacaine administration was significantly higher in group B than in group A. The myocardial ropivacaine concents at 5, 10 min after ropivacaine administration were significantly lower in group B than in group A. Conclusion 20% lipid emulsion infusion can bind ropivacaine and decreasee myocardial ropivacaine content thus reducing the cardiac toxicity of ropivacaine.