多巴胺对内毒素休克犬肺动脉压力的影响

目的 通过观察多巴胺对内毒素休克犬肺动脉压力的影响,评价多巴胺用于内毒素休克治疗的临床意义.方法 选择健康雄性杂种犬20只,随机分为4组,每组5只.以静脉注射脂多糖(LPS)1 mg/kg制备内毒素休克模型,2 h后分别静脉泵人生理盐水5 ml/h(模型组)和多巴胺5、10、20 μg·kg-1·min-1(分别记为D5组、D10组、D20组).经股动、静脉及开胸行肺动脉穿刺测压,记录制模前、给药前及给药后5、10、30、60及120 min时平均动脉压(MAP)及平均肺动脉压(MPAP).结果 不同浓度多巴胺均能升高MPA和MPAP,与模型组比较差异均有统计学意义(P<0.05或P<0.01);且D10组和D20组MAP较D5组升高幅度大,D20组MPAP较D5组和D10组升高幅度大(P<0.05或P<0.01).给予多巴胺后120 min各组MAP/MPAP比值均高于模型组,以高剂量组显著(P均<0.05).结论 不同浓度的多巴胺均能在升高MAP的同时使肺循环阻力增加致肺动脉压力也升高,且体动脉压力升高幅度明显大于肺动脉压力.

The effects of dopamine on pulmonary artery pressure in dogs with endotoxic shock

Objective To evaluate the values of dopamine in treating endotoxic shock by observing the changes in the pulmonary artery pressure (PAP) during the treatment. Methods Twenty healthy dogs were randomly divided into four groups with 5 in each group. Endotoxic model was reproduced by injecting lipopolysaccharides (LPS) 1 mg/kg intravenously. Two hours later, nomal saline (NS) 5 ml/h was intravenously given in model group, or dopamine 5, 10, 20 μg·kg-1·min-1 was given in D5 group, D10 group, D20 group intravenously. Femoral artery pressure, femoral vein pressure and PAP were measured, and mean arterial pressure (MAP) and mean pulmonary artery pressure (MPAP) were recorded at 0, 5, 10, 30, 60, 120 minutes after infusion of NS or dopamine. Results Compared with the model group, all different concentrations of dopamine could elevate MAP, MPAP (P<0.05 or P<0.01). Compared with D5 group, the percentage of elevation of MAP of D10 group and D20 group was greater, and the percentage of elevation of MPAP of D20 group was greater than that in D5 group and D10 group (P<0.05 or P<0.01). The ratio of MAP/MPAP in each dopamine group was higher than that of model group, and the increase was more marked in the groups of higher concentrations (all P<0.05). Conclusion MAP of endotoxic dog lowered obviously, while there was little change in PAP. After infusion ot dopamine intravenously, both MAP and PAP are elevated. The increase in resistance of pulmonary microeirculation is the main reason for the elevation of PAP.