ABSTRACT
Objective:To investigate the effect of dosages of propofol on pulmonary artery pressure (PAP) and hypoxic pulmonary vasoconstriction(HPV) reaction. Method:Isolated rat lungs were perfused with whole blood at the rate of flow 10ml/min and ventilated with air+4％CO_2(n=5) or 3％ O_2+4％CO_2+93％ N_2(mixed gas, n=11).PAP was measured continuously during the whole procedure. Result:PAP decreased significantly in air+4％ CO_2 ventilation following administralion of propofol 4 mg/kg,6 mg/kg and 8 mg/kg respectively.The varied degrees at 6 mg/kg and 8mg/kg were even more marked than that at 4mg/kg. When mixed gas was ventilated into lung, PAP increased from 1.60+0.23kPa to 2.384?0.31kPa to produce HPV,PAP decreased abruptly in HPV rats when administered 4mg/kg, 6mg/kg and 8mmg/kg propofol respectively and HPV reaction was inhibited by 47％, 867％and 71％ respectively,the inhibition extent was more at 6mg/kg or 8mg/kg than that at 4mg/kg. Conclusion:Propofol can decrease PAP and inhibite HPV in dose-dependent way.