ABSTRACT
A simple and inexpensive method of isolating surfactant was devised. The in vivo function of surfactant isolated from saline alveolar washes of adult sheep lungs by foam formation using nitrogen gas was evaluated. The foam was organic solvent extracted with chloroform:methanol:saline (2:1:1 v/v) either once or twice. Part of each lipid extract surfactant (LES) was autoclaved. The total phosphorus (TP) and saturated phosphatidylcholine (sat PC) measurements were used to quantify these phospholipids in the LES. The mean sat PC:TP ratio was 0.54 and there were no changes with sterilization. to evaluate in vivo function, surfactant deficient preterm rabbits were treated intratracheally with either 100 mg/kg of the isolated sheep surfactant extracted twice with chloroform:methanol (LES-2), surfactant extracted only once (LES- 1), 4 ml/kg Survanta (S), or air (control, Cx). The rabbits were then ventilated with dital volumes of 8 ml/kg and 3 cm H20 positive and expiratory pressure (PEEP). Ventilation pressures (peak inspiratory pressure-PIP in cm H20, mean +/- SE) of animals treated with LES-2 (14.4 +/- 0.7) were lower (p 0.01) than Cx (22.8 + 0.5) and LES-1 (19.5 + 0.6), and not different from S (14.6 +/- 1.1). Dynamic compliances (ml/cmH20/kg) in animals treated with LES-2 (0.6 +/- 0.0) were higher (p 0.01) than Cx (0.4 +/- 0.0) and LES-1 (0.4 +/- 0.0), and not different from S (0.6 +/- 0.1). The initial inflation pressure from pressure-volume curve measurements was lowest for LES-2 treated animals (p0.01 at 20cm H20). Survanta and LES-2 treated animals retained more volume on deflation than Cx and LES-1 animals (p 0.01 at 0 cm H20). The ventilation and pressure-volume curve measurements for the autoclaved LES and non-autoclaved LES were similar. Based on the invivo performance of the LES, recommendations are made for improvements of the isolation procedure. (Author)