ALVEOLAR LIQUID CLEARANCE IN MULTIPLE NONPERFUSED CANINE LUNG LOBES

We evaluated the ability of canine isolated nonperfused lung lobes to absorb fluid from their air spaces by simultaneously measuring alveola r Liquid clearance (ALC) in three lobes removed from the same dog. Aut ologous plasma was instilled in the air spaces of each lobe, and the i ncrease in plasma protein concentration resulting from fluid reabsorpt ion was used to calculate ALC. ALC after 4 h was 16.5 +/- 0.6% (SE) of the instilled fluid volume under baseline conditions and was 30.2 +/- 1.3% after terbutaline (10(-5) M) administration. These values were s imilar to those previously reported for intact dogs. Propranolol (10(- 4) M) and ouabain (10(-3) M) reduced ALC in terbutaline-stimulated lob es to 20.4 +/- 0.8 and 3.9 +/- 1.4%, respectively. There was no signif icant difference in ALC among the three lobes under either baseline co nditions or after terbutaline administration. These data indicate that the sodium and water transport mechanisms of the canine alveolar epit helium remain viable during 4 h of nonperfusion and that there are no intrinsic differences in the transport properties of individual lung l obes. The ability to study several lobes simultaneously without the ne ed for perfusion will allow for the design of experiments in which mul tiple interventions can be studied by using lung lobes from the same a nimal.