Histamine in the blood of patients during operations under epidural anesthesia

The content of histamine in venous blood in 59 patients was investigated during surgical treatment under epidural anesthesia on organs and tissues below the diaphragm. The concentration of histamine was the same in the blood in the blockade zone and outside it at all stages of the study. In the preoperative period, all patients had a higher histamine content than donors. A further increase in its concentration was observed after the transfer of patients to the operating room and, especially, after the epidural puncture, before the operation. During the operating period, the concentration of histamine decreased slightly, which is explained by the adequate analgesia achieved by the epidural block.