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Published on: November 28, 2018
Rotational Thromboelastometry Values After On-Pump Cardiac Surgery - A Retrospective Cohort Study
Maria S Gauger1, Philip Kaufmann1, Firmin Kamber1
1Clinic for Anaesthesia, Intermediate Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital Basel, Basel, Switzerland.
Background:
Viscoelastic coagulation monitoring is recommended for coagulation management after cardiac surgery, but optimum target values are poorly defined.
Aims:
To determine "to-be-expected" values in rotational thromboelastometry (ROTEM) after heparin reversal, to correlate ROTEM parameters with fibrinogen levels and platelet count, and to estimate the effect of hemoglobin levels on these measurements.
Methods:
We retrospectively analyzed 571 consecutive adult patients undergoing cardiac surgery with cardiopulmonary bypass from 12/2018 to 08/2020. ROTEM and conventional laboratory measurements were performed 5 to 10 minutes after protamine administration.
Results:
Clotting times in EXTEM, INTEM, and FIBTEM were significantly prolonged (72.6%, 96.1%, and 31.8% above reference ranges, respectively). Clot firmness parameters in EXTEM and INTEM were relevantly reduced (7.9% to 14.4% and 9.1% to 32.3% below the reference ranges, respectively). There was an excellent linear correlation of FIBTEM amplitude after 10 min (A10) and of maximal clot firmness (MCF) with fibrinogen concentrations (r = .81 and .80). Areas under receiver operating characteristic (AUROC) for identifying hypofibrinogenemia <1.5 g/L were between .80 and .87. No effect of hematocrit was observed. We also found a linear correlation of EXTEM, INTEM, and EXTEM-FIBTEM at both A10 and MCF with platelet counts (.32 to .68). The AUROCs for identifying thrombocytopenia (<100,000/μL) were .79 to .84, and were greater for A10 than for MCF measurements (P=.074, .001, and <.001, respectively).
Conclusions:
"To-be-expected" ROTEM values after CPB are different from the published reference ranges. ROTEM parameters might allow for reliable estimation of fibrinogen level and platelet count without being influenced by hematocrit.
