PULMONARY-EDEMA ASSOCIATED WITH UPPER AIRWAY-OBSTRUCTION IN DOGS

In order to evaluate the effect of acute upper airway obstruction upon pulmonary edema (PE) formation, we studied seven dogs that were subje cted to inspiratory obstruction for three hours. Hypoxia was avoided b y the administration of supplemental oxygen during the study period. S ix dogs developed pulmonary vascular congestion, and four developed hi stologic findings of PE. Inspiratory intrapleural pressure decreased t o -28 +/- 4 mmHg in dogs that developed PE and to -23 +/- 2 mmHg in do gs that did not. Transmural pulmonary artery pressure and pulmonary ar tery wedge pressure did not increase significantly. Central venous pre ssure during inspiration (CVPi) increased in all dogs, and CVP at end expiration (CVPe) was significantly higher in dogs with PE. Dogs that developed PE experienced a decrease in cardiac output and an increase in systemic vascular resistance. Furthermore, alveolar ventilation dec lined in dogs with PE, ultimately resulting in ventilatory failure. Pu lmonary edema formation was not preceded by an increase in pulmonary v ascular pressures but was associated with higher CVP, pulmonary vascul ar congestion, and hypercarbia.