[A standardized in vivo model for determining the effectiveness of surfactant preparations].

The premature rabbit neonate of the 27th day of gestation is a useful model for testing intratracheally applied surfactant preparations. Immediately after application of an effective surfactant the thorax lung compliance--as the decisive measure--rises significantly. We could exclude effects of the applied fluid per se. The most reliable result about the efficiency of a surfactant preparation is given by the cumulative dose response relationship. In a semilogarithmic system there is a linear relationship between the surfactant dose (25-200 mg phospholipids per kg b.w.) and the thorax-lung-compliance.