Thromboelastography, PFA100 and whole-blood aggregometry in patients undergoing a thoracic aortic operation with deep hypothermic circulatory arrest: 035
Introduction: Patients undergoing repair of an aortic aneurysm with deep hypothermic circulatory arrest (DHCA) often develop coagulation disturbances and require transfusion of many blood products . Thromboelastography (TEG, RoTEG) is an established bedside monitor of haemostasis, which has been used successfully in cardiac surgery. The PFA100 and whole-blood impedance aggregometry are simple and rapid tests of platelet-related haemostasis. The purpose of this study was to evaluate haemostatic changes during thoracic aortic surgery using these three tests.
Method: After approval by the local Ethics Committee and informed consent, 18 patients undergoing operations of the ascending aorta with DHCA and, as a control group, 9 patients undergoing similar procedures without DHCA were enrolled in this study. For each variable obtained, ANOVA for repeated measurements was used to assess changes from baselines. Differences between the DHCA and control groups were analysed with unpaired Student's t-test. P < 0.05 was considered significant.
Results: The mean DHCA time was 13 min with the mean nasopharyngeal temperature of 24°C. The mean duration of cardiopulmonary bypass (CPB) was 150min in the DHCA group and 105min in the control group (P = 0.000). The mean total postoperative chest tube drainage amounted to 973 mL in the DHCA group and 603 mL in the control group (P = 0.005). All TEG variables changed negatively during CPB but returned within the normal ranges postoperatively. Impedance values were abnormal postoperatively in the DHCA group, though normal in the control group. PFA values were abnormal preoperatively in both groups but became normal postoperatively.
Discussion: TEG (e.g. MA), PFA100 and aggregometry are influenced not only by platelet function but also other factors which may influence these tests differently. The discrepancies in the results might have been caused by such factors.
© 2004 European Society of Anaesthesiology
1 Westaby S. Coagulation disturbances in profound hypothermia: the influence of antifibrinolytic therapy. Semin Thorac Cardiovasc Surg