Hemodynamic changes in human anaphylaxis.

Human anaphylactic reactions are usually unexpected and catastrophic. Therefore, opportunities to record the physiologic changes that occur are uncommon. A patient is described who experienced an anaphylactic reaction to a penicillin drug while being monitored in an intensive care unit for ischemic heart disease. Hemodynamic monitoring indicated that the decrease in cardiac output was most likely due to a decrease in venous return. In addition, this patient's previous reactions to other penicillins demonstrated that variations in the clinical manifestations of systemic anaphylaxis can occur within the same person.