Experimental model of respiratory distress syndrome by lung lavage with fluorocarbon

The purpose of this study was to determine how much alveolar surfactant is washed out by lung lavage with fluorocarbon and also to find out whether or not instillation of artificial surfactant can restore pulmonary function after lung lavage in rats. The lung lavage was performed manually, administering a tidal volume 5 mg (2 mg/100g body weight) of fluorocarbon for about eight seconds. This process was repeated more than 40 times. In the study group, 4 ml/kg (120 mg/kg) of artificial surfactant was instilled into the trachea, and the same amount of normal saline was instilled in the control group. The amount of phospholipids extracted in lung lavage was 16.6 +/- 3.6 mg/kg body weight in the control group and 18.9 +/- 3.7 mg/kg body weight in the experimental group. Immediately after instillation of the surfactant, arterial oxygen pressure increased from 84 +/- 17 mmHg to 195.1 +/- 26.7 mmHg, and remained high, at about 170-260 mmHg. In contrast the physiological saline treated group did not show any change. We conclude that lung lavage with fluorocarbon is an adequate ideal experimental model of respiratory distress syndrome and suggests that combination of artificial surfactant treatment after lung lavage with fluorocarbon might be a new pulmonary washing method for severe lung disease.