Phosgene-Induced Lung Injury in Sheep

Inhalation of toxic doses of phosgene results in varying degrees of pulmonary edema, often after a symptom-free period. The sheep is an anatomically suitable animal in which to study the development of pulmonary edema during that symptom-free period. Five sheep were used in this study, and they were instrumented so as to provide simultaneous information on pulmonary vascular and interstitial fluid dynamics. Through a thoracotomy, the efferent duct of the caudal mediastinal lymph node was cannulated to monitor pulmonary lymph flow. The sheep were also instrumented with a carotid arterial catheter, a pulmonary artery catheter with thermistor, and a left atrial catheter to monitor systemic and pulmonary hemodynamics. After a 5– to 7-day recovery period, the sheep were given a 10-min nose and mouth exposure to 2.0–2.5 g/m3 of phosgene. Over the next 4 h, there was a two to threefold increase in pulmonary lymph flow, accompanied by a small but significant increase in mean pulmonary microvascular pressu...