Tracheal mucosal edema in hydrostatic pulmonary edema

Abstract

Airway edema has been described in heart failure, and, in animal experiments, airway narrowing was observed with elevated left atrial pressure (Pla). On the basis of double-indicator-dilution principles using helium and dimethylether, we were able to measure a water compartment of the tracheal mucosa (VH2O) in dogs. Hypervolemia with an attendant increase in Pla caused by infusion of 2 liters of dextran increased VH2O from 368 +/- 71 (SE) to 794 +/- 177 microliters (P < 0.01). Pulmonary arterial wedge and central venous pressures (Pcv) rose concomitantly. Increases in pulmonary arterial wedge and Pcv by a left atrial balloon catheter produced similar increases in VH2O, whereas increases in Pcv alone by a right atrial balloon did not increase VH2O. Increasing VH2O by dextran infusion was associated with an increase in pulmonary resistance from 1.16 +/- 0.19 to 2.15 +/- 0.24 cmH2O.l-1.s (P < 0.01). These observations show that fluid accumulation in the lung during pulmonary congestion also involves extraparenchymal airways and is related to Pla rather than right atrial pressure. This indicates that sufficient collateral drainage exists during right-sided but not left-sided pressure elevations.