We measured the pulmonary clearance of inhaled 99mTc-DTPA and 99mTc-albumin in rabbits with surfactant dysfunction induced by dioctyl sodium sulphosuccinate and in rabbits with lung injury induced by oleic acid. The animals were tracheotomized and mechanically ventilated. After inhalation of 99mTc-albumin in ten animals, clearance of the tracer from the lungs was monitored for 90 min. The first 30 min was a control period. Dioctyl sodium sulphosuccinate was then administered in aerosol and after another 30 min oleic acid was injected intravenously. Ten other rabbits were given 99mTc-DTPA, and clearance was externally recorded for 60 min. Five animals inhaled detergent aerosol and five animals were given oleic acid intravenously after 30 min. Airway pressures, tidal volume, and arterial blood gases were measured before and after each intervention. The half-life of 99mTc-albumin in the lung was 442 +/- 123 min during the control period, 363 +/- 52 min after detergent administration, and 134 +/- 18 min after oleic acid administration (P less than 0.05 compared to control and P less than 0.01 compared to the period after detergent). The half-life of 99mTc-DTPA was 94 +/- 16 min before and 10 +/- 0.6 min (P less than 0.01) after detergent administration and 75 +/- 12 min before and 18 +/- 1.8 min (P less than 0.01) after oleic acid administration. Gas exchange was not affected by administration of dioctyl sodium sulphosuccinate but markedly impaired after injection of oleic acid. Compliance of the respiratory system remained unaffected by detergent but decreased after injection of oleic acid.(ABSTRACT TRUNCATED AT 250 WORDS)