HEMOSTASIS DURING INFRARENAL AORTIC-ANEURYSM SURGERY - EFFECT OF VOLUME LOADING AND CROSS-CLAMPING

Objectives: To study thrombin and plasmin activation during elective a bdominal aortic aneurysm surgery. Design: Prospective study. Setting: University Hospital. Materials: Nine consecutive patients undergoing e lective surgery were included. The mean age was 72 years (range 60-79) . Blood samples were drawn: (1) before induction of anaesthesia; (2) a fter induction and Swan Ganz catherisation; (3) just before cross-clam ping; (4) before declamping; (5) 8 h postoperatively; (6) 18 h postope ratively. Chief outcome measures: Assays included: prothrombin time (P T), activated partial thromboplastin time (APTT), fibrinogen, prothrom bin fragments (F 1 + 2), anti-thrombin III (ATIII), plasminogen, alpha 2-antiplasmin, haematocrit, platelet and serum protein for correction of haemodilution. Data were expressed as mean (S.D.). Differences bet ween mean values were tested by means of the ANOVA for repeated measur es and the Wilcoxon signed rank test. Main results: The APTT and TT di d not change until heparinisation. The F 1 + 2 were already elevated p reoperatively. After correction for haemodilution the AT III and alpha 2-antiplasmin decreased in time (p = 0.009 and 0.0023, respectively) and the F 1 + 2 increased (p < 0.0001). Postoperatively (t5 and 6) the values normalised again. Conclusions: The coagulation and fibrinolyti c systems are activated during and after elective aortic replacement. Standard tests, like the prothrombin and partial thromboplastin time, are unreliable when assessing the coagulation status of the patient.