Alterations in the mechanism of haemostasis in the post-surgical patient associated with the development of a hypercoagulable state

Griffiths, Brian L. (1974) Alterations in the mechanism of haemostasis in the post-surgical patient associated with the development of a hypercoagulable state. Masters thesis, Memorial University of Newfoundland.

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Abstract

Sequential testing, using a wide spectrum of clotting tests, most of which were designed for this study, was performed on dilute whole blood samples obtained from a series of 25 patients who underwent a variety of major elective surgical procedures. Testing commenced prior to surgery and thereafter at intervals during the first 7 to 10 days postoperatively. Clotting test results were compared to the pre-operative mean values so that each patient acted as his own control. -- Very shortly after surgery, increased in vitro coagulability was demonstrated in almost all patients by the use of the phase 1, phase 2, heparin resistance, autocoagulography and autocoagulography control tests. A peak increase in coagulability was found between days 3 to 5, with a smaller peak occurring on or around the eight day postoperative. The results of the phase 3 test showed marked dispersion in some patients, while others gave results consistent with increased coagulability. -- Plasma fibrinogen concentration and the platelet count both increased early in the postoperative period and thereafter increased progressively. The results of the two universally used tests of haemostasis, namely the prothrombin time and the kaolin-cephalin clotting time were comparatively poor indicators of the postoperative increase in coagulability demonstrated by the phase 1, phase 2, heparin resistance, autocoagulography and autocoagulography control tests, although the results of the phase 3 test were somewhat similar to those found using the prothrombin time. -- This study has demonstrated that in the majority of patients a postoperative increase in the concentration of serum fibrin(ogen) degradation products is found at some time during the first 7 days following surgery. -- Clot retraction, studied with an original technique, was found to increase in approximately 50% of patients during the first 3 postoperative days. -- During the first 7 days following major elective surgery, the rise in the fibrinogen concentration and in the platelet count, and the increase in the concentration of serum fibrin(ogen) degradation products indicates that, in attempting to detect haemostatic failure in the postoperative patient, evaluation of haemostatic tests should not be made using the so-called "normal values". The author suggests that postoperative evaluation of haemostasis be compared to values obtained prior to surgery.

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