Acute lung injury monitored with radiolabelled transferrin and lung volume measurements

Anesthetized pigs (n = 12) were given oleic acid (OA) to induce acute lung injury. Three additional pigs were used as uninjured controls. Six of the animals were pretreated with terbutaline before OA infusion. 113mIn-labeled transferrin and 99mTc-labeled erythrocytes were used for tracing of extravascular plasma leakage. A computerized gamma camera supplied image analysis of the radioactivities over the heart and lungs. A lung transferrin index (LTI), which describes the net accumulation of plasma equivalents in the lung, was calculated. OA caused an immediate increase in LTI and concurrent, correlated decreases in functional residual capacity, lung thorax compliance and arterial PO2. LTI was also correlated to the content of plasma equivalents in lung tissue samples and also to the wet weight/dry weight-ratios of the same tissue samples. Finally, LTI was correlated to the calculated plasma loss from the circulation. Changes in all these parameters were correlated to the dose of OA. We conclude that this noninvasive double radioisotope technique can detect plasma protein leakage in lung injury of different degrees. We found no significant anti-edema effect of terbutaline.