Influence of serum on surfactant function / 中华麻醉学杂志

ABSTRACT

Objective To examine the influence of serum on pulmonary surfactant (PS) function.Methods Caesarean section was performed on 26-day pregnant Japanese white rabbits (full term=31 days). The pre-term rabbits weighing 20-34g were anesthetized with intraperitoneal(ip) pentobarbital sodium 0.5mg. Tracheotomy was performed. Test liquids were prepared by suspending PS in rabbit serum or acetate Ringer solution at concentration of 2.0,4.0,6.0,8.0,10,12,24 mg/ml. The surface tension of test liquids was measured by pulsating bubble technique. Test liquid 10ml/kg was instilled in the lungs of PS-deficient pre-term rabbits via tracheotomy cannula.Animals were ramdomly divided into 4 groups according to the test liquid used group A 24mg/ml PS suspended in acetate Ringer solution; group B 24mg/ml PS suspended in serum; group C 4.0mg/ml PS suspended in acetate Ringer solution; group D nothing was instilled. Rabbits were placed in plethysmograph. Siemens-Elema ventilator was used for mechanical ventilation. PIP was set at 22.5cmH 2O, PEEP=0,respiratory rate=40 frequency/min, IE=11,FiO 2=100%. Tidal volume was measured at 5,10,15,20 min after the start of mechanical ventilation.Results When concentration of PS suspended in acetate Ringer solution was 2.0 mg/ml, the minimum surface tension (?min) was less than 3.0 mN/m; when suspended in serum, ?min was significantly higher than 30 mN/m (P15 ml/kg, but in group B the mean tidal volume was