Abstract

Antithrombin III concentrations were measured in 305 patients before and at intervals after operation for up to 12 days. The blood concentrations fell significantly after both major and minor surgery, but there was no relation between the expected degree of surgical trauma or the amount of blood transfused and the fall in concentration of antithrombin III. Some surgical procedures such as cholecystectomy, laparotomy, hernia repair, highly selective vagotomy, and transurethral resection of the prostate were associated with a greater depletion of antithrombin III than were other common operations and it is suggested that there are factors related to the actual site of the operation which affect the concentration of circulating antithrombin III in the postsurgical period.