PULMONARY SURFACTANT SUBFRACTIONS IN PATIENTS WITH THE ACUTE RESPIRATORY-DISTRESS SYNDROME

Changes in the surfactant system have been observed in patients with a cute respiratory distress syndrome (ARDS). These alterations in surfac tant are thought to contribute to lung dysfunction in this disease. In this report we describe the changes in surfactant subfractions in bro nchoalveolar wash obtained from five patients with established ARDS co mpared with five non-ARDS patients. Our results show that, in addition to the changes in surfactant composition and yield reported previousl y, the ratio of small to large surfactant aggregates is significantly increased in patients with ARDS compared with non-ARDS patients (0.48 +/- 0.09 versus 0.20 +/- 0.05 respectively [p < 0.05]). This increased ratio was associated with a decreased level of SP-A in the large aggr egate fraction. We suggest that this increased ratio represents a mark er for surfactant alterations in ARDS that is independent of lavage te chnique and can be measured in a very small surfactant sample.