Lung expansion in premature newborn rabbits treated with emulsified synthetic surfactant; principles for experimental evaluation of synthetic substitutes for pulmonary surfactant.

This paper presents a sequence of tests for experimental evaluation of potential substitutes for pulmonary surfactant. Differential thermal analysis and the pulsating bubble technique were applied to identify an emulsified mixture of synthetic lipids with properties similar to those of natural surfactant. Instilled into the airways of premature newborn rabbits, this emulsion improved pulmonary pressure-volume characteristics and enhanced lung-thorax compliance during artificial ventilation. However, the in vivo effect was inferior to that of natural surfactant, especially as the emulsion failed to prevent the development of bronchiolar epithelial lesions.