[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, normal saline (NS) 5 ml/h was intravenously given in model group, or dopamine 5, 10, 20 microg*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 of dopamine intravenously, both MAP and PAP are elevated. The increase in resistance of pulmonary microcirculation is the main reason for the elevation of PAP.