Interstitial pulmonary edema following bromocarbamide intoxication.

Bromocarbamides are sleep-inducing drugs which can lead, in man, to intoxication and death due to respiratory failure. To prove whether hemodynamic factors or the changed endothelial permeability induce pulmonary edema, animal experiments were performed. The fine structural changes in pulmonary edema in rabbits were observed at 60, 90 and 120 minutes after oral administration. The major findings were a) large blebs between capillary endothelium and alveolar epithelium and b) interstitial edema of the vessel wall. The bleb contents were much less electron dense than the blood contents in the capillary. Colloidal carbon did not enter the bleb or the edematous interstitial tissue. Exogenous peroxidase uptake in pinocytotie vesicles increased in pathologic cases. The hemodynamic measurements in animal receiving artificial respiration which maintained the blood pO(2) at a steady state showed similar blebs in the pulmonary vessels, indicating that anoxia is not the major cause of the vascular lesion. Moreover, pulmonary arterial pressure and pulmonary vascular resistance could be held in the normal range in artificially respirated animals under bromocarbamide intoxication. Thus, hemodynamic factors are not likely to play a pathogenetic role in bringing about pulmonary edema. The chief, early factor is the increased endothelial permeability due to increased cytoplasmic transport. From this a practical suggestion for treating patients with bromocarbamide intoxication is derived: the usual fluid replacement in shock patients should be handled with great care to avoid fluid overload of the lung.