Abstract
Experiments were performed on cardiopulmonary bypass and endotoxin shock in order to study pulmonary surfactant, which has recently aroused attention as the causative agent of pulmonary complication after extracorporeal circulation. The results were as follows :
1) Phosphatidyl choline (PC) in pulmonary tissue was not decreased at 1 hour of extracorporeal circulation, but markedly reduced at 3 hours. The decrease was inhibited by pretreatment with phenoxybenzamine (POB).
2) PC in lung washing was decreased in endotoxin shock. The decrease in this case was not inhibited by POB pretreatment.
3) After the application of the Dermer's method and the author's silver nitrate method to the normal and endotoxin shock lungs, these were observed electron microscopically. After the former method, reaction positive substance appeared as an electron dense mass, which was poorly reproducible. In the latter case, a stratiform structure, 50-100 Å in size, was distinctly visible in the alveolar lining layer. The stratification was similar to that of type II alveolar cell inclusions. This was assumed to be pulmonary surfactant.
4) During the application of cardiopulmonary bypass, pressure in the airway was elevated, eliciting change in its wave form. This is considered to indicate reduced pulmonary compliance.
Thus pulmonary surfactant was decreased in pulmonary complication following the extracorporeal circulation. The etiology seems to be hematogenous stagnant atelectasis produced by peripheral circulatory failure and hemolysis, which are attributable to the application of artificial cardiopulmonary bypass. The complication was improved with POB. It is necessary for the prevention of pulmonary complication after extracorporeal circulation, to avoid sludging of blood and hemolysis by the improvement of the cardiopulmonary apparatus and administration of anti-shock agent and to improve the peripheral, especially pulmonary circulation as well as to evade operative shock.
