Ethchlorvynol-induced pulmonary edema: a chronically instrumented, awake sheep model mimicking human disease

Ethchlorvynol injection in humans leads to a clinical picture consistent with increased permeability pulmonary edema, ie, the adult respiratory distress syndrome. There has been only one such case reported in which the pulmonary wedge pressure was measured. In an attempt to mimic the human disease, the authors established the awake, unanesthetized chronic sheep lung lymph fistula model and injected 15 mg/kg of ethchlorvynol intravenously after a baseline period. There were transient increases in pulmonary artery and systemic blood pressure with decreases in cardiac output. Lymph flow increased five-fold and remained elevated for 24 hr, returning to normal by 48 hr. All animals survived. Pulmonary morphologic changes consisted of alveolar and interstitial edema and some disruption of endothelial and epithelial cells. These findings resolved by 48 hr postinjection. The authors conclude that this model mimics the findings in humans who have injected ethchlorvynol intravenously.