The pulmonary ultrastructure in septic shock

The ultrastructural alterations in the lungs of the monkey after intravenously administered lethal injections of live E. coli organisms or endotoxin are markedly similar. Edema of the perivascular space was seen in all lung tissues examined. Pulmonary capillaries were engorged with polymorphonuclear leukocytes undergoing fragmentation 15 minutes after injections of endotoxin or E. coli organisms. The endothelial cytoplasm contained large vacuoles and many vesicles, but there was no evidence of actual rupture of the cytoplasmic membranes. Endothelial cellular membranes appeared fuzzy and indistinct at sites where polymorphonuclear leukocytes were adhering. Fragmentation and loss of specific granules in polymorphonuclear leukocytes were noted 1 hour postinjection. The loss of specific granules, fragmentation of polymorphonuclear leukocytes, and focal areas of pulmonary edema were observed 4 hours after the injection of endotoxin or live E. coli organisms. In marked contrast to a previous report on the primate administered endotoxin, this investigation revealed no evidence for intravascular coagulation of fibrin and platelet aggregates. The widespread morphological alterations could explain some of the functional derangements previously observed in monkeys in shock.