Aim: To investigate whether prolonged compared with standard duration of targeted temperature management (TTM) compromises coagulation.
Methods: Comatose survivors after out-of-hospital cardiac arrest (n=82) were randomised to standard (24h) or prolonged (48h) duration of TTM at 33±1°C. Blood samples were drawn 22, 46 and 70h after attaining the target temperature. Samples were analysed for rotational thromboelastometry (ROTEM® (EXTEM®, INTEM®, FIBTEM® and HEPTEM®)) and thrombin generation using the Calibrated Automated Thrombogram® assay.
Results: With the 22-h sample, we revealed no difference between groups in the ROTEM® and thrombin generation results beside a slightly higher EXTEM® and INTEM® maximum velocity in the prolonged group (p-values≤0.04). With the 46-h sample, ROTEM® showed no differences when using EXTEM®; however, 11% (p<0.01) longer clotting time and 12% (p<0.01) longer time to maximum velocity were evident in the prolonged group than in the standard group when using INTEM®. The prolonged group had reduced thrombin generation compared with the standard group as indicated by 30% longer lag time (p=0.04), 106nM decreased peak concentration (p<0.001), 36% longer time to peak (p=0.01) and 411 nM*minute decreased endogenous thrombin potential (p<0.001). With the 70-h sample, no differences in ROTEM® results were found between groups. However, the prolonged group had reduced thrombin generation indicated by longer lag time, decreased peak concentration and longer time to peak (all p-values≤0.02) compared with the standard group.
Conclusion: Prolonged TTM in post-cardiac arrest patients impairs thrombin generation. ClinicalTrials.gov identifier: NCT02258360.
Keywords: Coagulation; Haemostasis; Heart arrest; Hypothermia; Targeted temperature management.
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