Abstract
BackgroundThe risk of spinal haematoma in patients receiving epidural catheters is estimated using routine coagulation tests, but guidelines are inconsistent in their recommendations on what to do when results indicate slight hypocoagulation. Postoperative patients are prone to thrombosis, and thromboelastometry has previously shown hypercoagulation in this setting. We aimed to better understand perioperative haemostasis by comparing results from routine and advanced tests, hypothesizing that patients undergoing major upper gastrointestinal surgery would be deficient in vitamin K-dependent coagulation factors because of malnutrition, or hypocoagulative because of accumulation of low molecular weight heparin (LMWH).MethodsThirty-eight patients receiving epidural analgesia for major upper gastrointestinal surgery were included. We took blood at the time of preoperative epidural catheterization and at catheter withdrawal. Prothrombin time-international normalized ratio (PT-INR), activated partial thromboplastin time (aPTT) and platelet count (Plc) were analysed, and also albumin, proteins induced by vitamin K absence (PIVKA-II), rotational thromboelastometry (ROTEM®), multiple electrode aggregometry (Multiplate®) and activities of factors II, VII, IX, X, XI, XII and XIII.ResultsPostoperative coagulation was characterized by thrombocytosis and hyperfibrinogenaemia. Mean PT-INR increased significantly from 1.0 ± 0.1 to 1.2 ± 0.2 and mean aPTT increased significantly from 27 ± 3 to 30 ± 4 s. Activity of vitamin K-dependent factors did not decrease significantly: FIX and FX activity increased. FXII and FXIII decreased significantly. Mean Plc increased from 213 ± 153 × 106/L while all mean ROTEM-MCFs (maximal clot firmnesses) especially FIBTEM-MCF increased significantly to above the reference interval. All mean ROTEM® clotting times were within their reference intervals both before and after surgery. ROTEM® (HEPTEM minus INTEM) results were spread around 0. There were significant correlations between routine tests and the expected coagulation factors, but not any of the viscoelastic parameters or PIVKA-II. Multiplate® area under curve and EXTEM-MCF correlated significantly to Plc as did EXTEM-MCF to fibrinogen, FIX, FX and FXIII; and FIBTEM-MCF to Plc, FII, FXI and FXIII.ConclusionsThe increase in PT-INR may be caused by decreased postoperative FVII while the elevated aPTT may be caused by low FXII. The mild postoperative hypocoagulation indicated by routine tests is not consistent with thromboelastometry. The relevance of ROTEM® and Multiplate® in the context of moderately increased routine tests remains unclear.Trial registration number is not applicable since this is not a clinical trial.Electronic supplementary materialThe online version of this article (doi:10.1186/s13741-016-0053-0) contains supplementary material, which is available to authorized users.
Highlights
The risk of spinal haematoma in patients receiving epidural catheters is estimated using routine coagulation tests, but guidelines are inconsistent in their recommendations on what to do when results indicate slight hypocoagulation
Coagulative deficits are often noted after major surgery (Anveden et al 2010) and increase the risk of spinal haematoma, which may be caused by loss of coagulation factors (F) and platelets due to haemorrhage, systemic inflammation, disseminated intravascular coagulation (DIC), preoperative malnutrition, accumulation of thrombosis prophylaxis or deficiency of vitamin K due to prolonged antibiotic treatment
The changes in coagulation factors shown in this study do provide some tentative explanations for the elevated routine tests of coagulation, and it would be reasonable to conclude that the risk of hypocoagulation due to thrombocytopenia or low levels of coagulation factors is greatest during the first days after major operations, after which a systemic inflammation and hyperfibrinogenaemia compensates for potential deficits due to deficiencies in coagulation factors and patients generally become hypercoagulable
Summary
The risk of spinal haematoma in patients receiving epidural catheters is estimated using routine coagulation tests, but guidelines are inconsistent in their recommendations on what to do when results indicate slight hypocoagulation. We aimed to better understand perioperative haemostasis by comparing results from routine and advanced tests, hypothesizing that patients undergoing major upper gastrointestinal surgery would be deficient in vitamin K-dependent coagulation factors because of malnutrition, or hypocoagulative because of accumulation of low molecular weight heparin (LMWH). Coagulative deficits are often noted after major surgery (Anveden et al 2010) and increase the risk of spinal haematoma, which may be caused by loss of coagulation factors (F) and platelets due to haemorrhage, systemic inflammation, disseminated intravascular coagulation (DIC), preoperative malnutrition, accumulation of thrombosis prophylaxis or deficiency of vitamin K due to prolonged antibiotic treatment (van Lier et al 2011; Gogarten et al 2010). Some recommend whole-blood tests such as viscoelasticity and platelet aggregometry (for example rotational thromboelastometry (ROTEM®) and Multiplate®), but how these complement routine tests and how to interpret inconsistencies between routine and whole-blood tests is unclear (Breivik et al 2010; Thomas et al 2013; Tanaka and Dietrich 2011)
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