Hyperthermia-induced pulmonary edema

The effects of temperature (37-45 degrees C) on pulmonary edema formation and transendothelial albumin clearance were investigated using isolated perfused guinea pig lungs and bovine pulmonary arterial endothelial cells grown to confluency on a gelatinized membrane. Perfusion of isolated lungs with Ringer-albumin solution at 37 or 41 degrees C for 90 min produced no change in lung wet-to-dry weight ratios (W/D) or in pulmonary capillary pressure (measured by the double-occlusion method). When perfused at 43 degrees C, lung wet weight increased 0.8 +/- 0.4 g over base line (final W/D = 7.43 +/- 0.7) within 90 min. Perfusion at 45 degrees C increased lung weight by 2.7 +/- 0.9 g over base line (final W/D 11.8 +/- 2.3 vs. control value of 5.2 +/- 0.23 at 37 degrees C perfusion) within 60 min. The changes in pulmonary capillary pressure were small (from a base-line value of 4.3 +/- 0.8 to 4.9 +/- 0.4 at 43 degrees C and from a base-line value of 4.9 +/- 0.8 to 5.9 +/- 0.6 at 45 degrees C). The clearance of 125I-albumin (microliter/min) across the endothelial monolayer system increased threefold (from 0.295 +/- 0.035 to 1.048 +/- 0.107) at 45 degrees C, an effect comparable to positive controls of trypsin (from 0.272 +/- 0.046 to 1.595 +/- 0.138) or oleic acid (from 0.278 +/- 0.043 to 0.672 +/- 0.26). An increase in temperature from 37 to 45 degrees C had no effect on the permeability of the gelatinized membrane alone.(ABSTRACT TRUNCATED AT 250 WORDS)