Histamine release in the course of elective conventional cholecystectomy in aged patients: Problems in defining release in relation to specific intraoperative events

Abstract

The effectiveness of an H1 −+H2-prophylaxis against perioperative acute pseudoallergic reactions in which histamine is involved, and against postoperative complications the incidence of which may be increased by these reactions, was the central problem of a randomized trial in 162 aged patients during elective conventional cholecystectomy. As main endpoint it was planned to use the systemic histamine release reaction, as it already had been defined for the conscious and anaesthetized human subject. However, it had to be reassessed and redefined for the intraoperative period after improvement of the plasma histamine assay and new findings about stress-induced histamine release and the kinetics of histamine release during certain phases of operation. Intraoperative release is, at present, defined solely as an increase of plasma histamine values after a particular action (phase of operation). It includes criteria concerning plasma histamine changes either in comparison to the base value before surgery or to the preceding value before the last surgical action. Histamine elevations must exceed the last value by more than 3 standard deviations of the analytical error (i.e. 200% if value <0.25 ng/ml and 40% above). Basic requirements for the histamine assay (quality control), correct sample taking and appropriate preparation have to be fulfilled over the whole trial period. When these criteria were applied to the 162 patients an overall incidence of histamine release during cholecystectomy of 55.6% was found with 9.7–20% during an individual phase of operation. The data of this study, performed under routine conditions, with a sufficient number of patients with elevated risk and event controlled plasma histamine values, lead to a better understanding of intraoperative histamine release, its incidence and extent.