EDEMA DEVELOPMENT AND RECOVERY IN NEUROGENIC PULMONARY-EDEMA

We determined the time course of changes in extravascular lung water ( EVLW) that occur after massive sympathetic activation produced by intr acisternal veratrine administration in chloralose-anesthetized dogs. T hree groups of dogs were studied. In the first group (n = 9), acute in creases in EVLW (occurring within minutes) were determined both by mea suring extravascular thermal volume and by gravimetric analysis. In th e second (12 = 6) and third (n = 7) groups, changes in EVLW were follo wed for 2-3 h after veratrine administration. Extravascular thermal vo lume was measured in the second group. In the third group, right atria l injections of a vascular indicator (I-125-labeled serum albumin) and an extravascular indicator ((HOH)-H-3) were made while blood was samp led from the pulmonary artery (PA) and left atrium, and EVLW was deter mined by deconvolution of the left atrial and PA concentration-time cu rves. Indicater-dilution and gravimetric EVLW increased acutely only i n dogs in which PA pressure exceeded 60 Torr, with two- to fourfold in creases in EVLW being observed in dogs that developed the highest PA p ressures (maximum 94 Torr). Thus, severe edema can develop rapidly aft er massive sympathetic nervous system activation but requires extreme degrees of pulmonary hypertension. In several dogs after the acute inc rease in EVLW associated with the pulmonary hypertension, the indicato r-dilution EVLW decreased with time. These decreases appear to reflect clearance of edema fluid rather than alterations in perfusion.