Clinical and haemostatic parameters related to thromboembolism and low-dose heparin prophylaxis in major surgery.

In a study of 112 patients undergoing elective major surgery clinical and haemostatic data was followed in connection with a double-blind investigation on the effect of subcutaneous low-dose heparin prophylaxis. None of the patients developed severe thromboembolism but according to lung photoscanning and leg scanning 41 of the patients had deep vein thrombosis and/or pulmonary embolism. Clinically thromboembolism appeared within 4 days after operation. In 22 patients with epidural anaesthesia the incidence of thromboembolism was lower than in the patients with general anaesthesia. The extension of the operation was positively correlated to a higher incidence of thromboembolism. The surgical trauma was reflected in most of the routine haemostatic laboratory parameters, hiding possible minor changes caused by subclinical thromboembolic complications. The low doses of heparin could only be detected with more sensitive methods. A comparison of sodium and calcium heparin administered subcutaneously revealed no significant differences.