目的　探讨血清对肺表面活性物质 (PS)功能的影响。方法　用血清将PS稀释溶解配制成 2 0、4 0、6 0、8 0、10、12、2 4mg/ml的实验液体。同时作为对照将PS溶解于醋酸林格液中配成相同的浓度。用表面张力计测定实验液体的表面张力。未成熟胎兔 36只随机分为 4组 (每组 9只 ) :A组 ,经气道内注入溶解于醋酸林格液的PS 2 4mg/ml;B组 ,注入溶于血清的PS 2 4mg/ml;C组 ,注入溶于醋酸林格液的PS 4 0mg/ml;D组 ,未注入任何物质 ,进行人工通气。通气后 5、10、15、2 0min测定动物的潮气量。结果　溶解于醋酸林格液的PS浓度在 2 0mg/ml时 ,最小表面张力 (γmin)小于3 0mN/m。溶剂为血清时 ,γmin增至 30mN/m (P <0 0 1)。PS的浓度增加到 6 0mg/ml时 ,γmin降至 9 0mN/m。人工通气 2 0min时 ,A组动物的潮气量大于 15ml/kg ,而B组小于 8 0ml/kg (P <0 0 5 ) ,C组未超过 5 0ml/kg ,D组未超过 2 0ml/kg。 结论　血清明显抑制PS的功能 ,抑制程度与PS剂量有关 Objective To investigate the effect of serum on the function of pulmonary surfactant (PS). Methods The serum was diluted with PS to prepare 20 0, 40, 60, 0, 10, 12, 24mg / ml experimental liquid. At the same time as a control of PS dissolved in Ringer’s acetate solution dubbed the same concentration. Surface tensiometer was used to measure the surface tension of the test liquid. Thirty-six immature fetuses were randomly divided into 4 groups (n = 9): group A, 4 mg / ml PS 2 dissolved in acetate Ringer’s solution was injected into the airway; group B, PS 2 4 mg / ml; group C, injected with PS 4 0mg / ml dissolved in acetate Ringer’s solution; group D, no substance was injected and artificial ventilation was performed. Tidal volume was measured at 5, 10, 15, 20 min after ventilation. Results The minimum surface tension (γmin) was less than 30 mN / m when the concentration of PS dissolved in Ringer’s solution was 20 mg / ml. When the solvent was serum, γmin increased to 30 mN / m (P <0.01). When the concentration of PS increased to 60mg / ml, γmin decreased to 90mN / m. At 20 minutes of artificial ventilation, the tidal volume of animals in Group A was greater than 15ml / kg, while in Group B less than 80ml / kg (P <0.05), in Group C did not exceed 50ml / kg and in Group D did not exceed 20ml / kg . Conclusions Serum significantly inhibits the function of PS, the degree of inhibition is related to the dose of PS