Effect of acute hypoxia on lung fluid balance in the prerecruited dog lung.

Lung lymph flow and protein transport were measured in eight anaesthetized dogs while acute hypoxic exposure (FIO2 = 0.10) was performed on prerecruited lung (achieved by an increased left atrial pressure). It was found that the lung lymph flow increase observed during hypoxia (from 71.8 +/- 47.5 to 100.8 +/- 78.4 microliters X min-1; p less than 0.05) was associated to an unchanged lymph/plasma protein concentration ratio (from 0.60 +/- 0.9 to 0.60 +/- 0.11). During recovery from hypoxia, lymph flow remained at a higher level than before hypoxia (respectively 87.8 +/- 49.5 and 71.8 +/- 47.5 microliters X min-1). These results suggest that the mild hypoxia-induced oedema is rather a high permeability oedema than an haemodynamic oedema. A graphic representation of protein clearance changes versus lymph flow changes was used in order to discriminate between high permeability and haemodynamic oedemas at their early stage.