Effects of hypothermia and hyperpotassium on alveolar fluid clearance in the resected human lung

The effect of hypothermia and hyperpotassium on alveolar fluid clearance in the resected human lung was examined by instilling an isosmotic albumin solution with a potassium concentration of 0.3 mEq/l or 20 mEq/l into one segment of a resected lobe within 10 min of surgical removal for bronchogenic carcinoma. The experiments were carried out at 37 degrees C, 25 degrees C, and and 8 degrees C over 4 hr, after which the alveolar fluid was aspirated. Alveolar fluid clearance was calculated by a simple equation using the changes in the albumin concentration of the alveolar fluid. It was found that although hypothermia at 8 degrees C abolished alveolar fluid clearance completely, alveolar fluid clearance at 25 degrees C was not different from that at 37 degrees C. Moreover, although the potassium concentration increased in the alveolar fluid at 37 degrees C and 8 degrees C, hyperpotassium did not affect the alveolar fluid clearance. These findings indicate that the net transport of potassium leans to influx from the alveolar epithelial cells into the alveolar spaces when the alveolar potassium concentration is low, and to efflux from the alveolar spaces when the alveolar potassium concentration is high. Thus, we conclude that hypothermia abolishes alveolar fluid clearance in resected human lungs, but that the potassium concentration in alveolar fluid does not affect alveolar fluid clearance.