Background: The risk of spinal haematoma in patients receiving epidural catheters is estimated using routine\ncoagulation tests, but guidelines are inconsistent in their recommendations on what to do when results indicate\nslight hypocoagulation. Postoperative patients are prone to thrombosis, and thromboelastometry has previously\nshown hypercoagulation in this setting. We aimed to better understand perioperative haemostasis by comparing\nresults from routine and advanced tests, hypothesizing that patients undergoing major upper gastrointestinal\nsurgery would be deficient in vitamin K-dependent coagulation factors because of malnutrition, or hypocoagulative\nbecause of accumulation of low molecular weight heparin (LMWH).\nMethods: Thirty-eight patients receiving epidural analgesia for major upper gastrointestinal surgery were\nincluded. We took blood at the time of preoperative epidural catheterization and at catheter withdrawal.\nProthrombin time-international normalized ratio (PT-INR), activated partial thromboplastin time (aPTT) and\nplatelet count (Plc) were analysed, and also albumin, proteins induced by vitamin K absence (PIVKA-II),\nrotational thromboelastometry (ROTEMÃ?®), multiple electrode aggregometry (MultiplateÃ?®) and activities of\nfactors II, VII, IX, X, XI, XII and XIII.\nResults: Postoperative coagulation was characterized by thrombocytosis and hyperfibrinogenaemia. Mean PT-INR\nincreased significantly from 1.0 Ã?± 0.1 to 1.2 Ã?± 0.2 and mean aPTT increased significantly from 27 Ã?± 3 to 30 Ã?± 4 s. Activity\nof vitamin K-dependent factors did not decrease significantly: FIX and FX activity increased. FXII and FXIII decreased\nsignificantly. Mean Plc increased from 213 Ã?± 153 Ã?â?? 106/L while all mean ROTEM-MCFs (maximal clot firmnesses)\nespecially FIBTEM-MCF increased significantly to above the reference interval. All mean ROTEMÃ?® clotting times were\nwithin their reference intervals both before and after surgery. ROTEMÃ?® (HEPTEM minus INTEM) results were spread\naround 0. There were significant correlations between routine tests and the expected coagulation factors, but not any\nof the viscoelastic parameters or PIVKA-II. MultiplateÃ?® area under curve and EXTEM-MCF correlated significantly to Plc\nas did EXTEM-MCF to fibrinogen, FIX, FX and FXIII; and FIBTEM-MCF to Plc, FII, FXI and FXIII. Conclusions: The increase in PT-INR may be caused by decreased postoperative FVII while the elevated aPTT may be\ncaused by low FXII. The mild postoperative hypocoagulation indicated by routine tests is not consistent with\nthromboelastometry. The relevance of ROTEMÃ?® and MultiplateÃ?® in the context of moderately increased routine tests\nremains unclear.
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