A positron emission tomographic comparison of diffuse and lobar oleic acid lung injury

We tested whether severity of injury measured from the pulmonary transcapillary escape rate for transferrin (PTCER), lung water accumulation, and changes in regional pulmonary blood flow (PBF) would be similar after oleic acid (OA) injection into either all lung lobes or directly into the pulmonary artery feeding the left caudal lobe (LCL) only. Measurements were made with positron emission tomography. After 0.015 ml/kg OA was injected into the LCL (Lobar, n = 5), lung water increased in the left dorsal region from 37 +/- 5 to 50 +/- 8 ml/100 ml lung (P less than 0.05), PTCER was 533 +/- 59 10(-4)/min, and regional PBF decreased 62%. No significant change occurred in the uninjured right dorsal lung where PTCER was 85 +/- 32. In the left ventral region PTCER was 357 +/- 60, PBF decreased only 31%, and the increase in lung water was less (25 +/- 3 to 30 +/- 6). In contrast after 0.08 ml/kg OA was injected via the right atrium (Diffuse, n = 6), PTCER (283 +/- 94) was lower in the left dorsal region of this group than in the corresponding region of the Lobar group (P less than 0.05). The increase in lung water, however, was the same, but no change occurred in PBF distribution. These results indicate important differences between the two methods of causing lung injury with OA. After injury lung water accumulates primarily in dependent portions of lung and is not always accompanied by a decrease in regional PBF. These decreases, when they occur, may instead indicate severe vascular injury.