Perioperative Coagulation Dynamics Assessed by ROTEM and Conventional Assays: A Prospective Longitudinal Study with Focus on Fibrinogen in Major Non-Cardiac Surgery

Background: Perioperative assessment of hemostasis remains challenging, particularly in non-cardiac surgery, where the incidence of clinically significant bleeding is relatively low. Viscoelastic testing enables real-time evaluation of whole-blood coagulation, but its perioperative dynamics and agreement with conventional assays require further characterization. Methods: In this prospective single-center observational study, 53 patients undergoing major non-cardiac surgery were included in the final analysis. Hemostatic parameters were assessed preoperatively, intraoperatively at two-hour intervals, and 24 h postoperatively using ROTEM (EXTEM, INTEM, and FIBTEM) and conventional coagulation assays. Longitudinal changes and correlations between fibrinogen concentration according to Clauss and ROTEM-derived parameters were analyzed. Results: Fifty-three patients undergoing major hepatopancreatobiliary surgery completed longitudinal perioperative monitoring. Pancreaticoduodenectomy and liver resection accounted for 60.7% and 39.3% of procedures, respectively. Serial perioperative ROTEM and laboratory assessments demonstrated time-dependent changes in coagulation parameters, including decreased intraoperative fibrinogen and antithrombin III levels and shortening of INTEM clotting time. Clinically significant bleeding was infrequent, with severe intraoperative bleeding observed in 7.4% of patients. Strong correlations were confirmed between fibrinogen concentration according to Clauss and FIBTEM-derived parameters, particularly FIBTEM MCF (r = 0.811, p < 0.001), whereas the correlation with FIBTEM A10 was moderate (r = 0.574, p < 0.001). No significant association was observed between preoperative fibrinogen concentration and perioperative blood loss. Conclusions: This study provides a longitudinal characterization of perioperative coagulation dynamics and demonstrates strong agreement between fibrinogen concentration according to Clauss and ROTEM-derived parameters. The findings are primarily descriptive and highlight the methodological consistency between viscoelastic and conventional fibrinogen assessment. Further studies are required to determine their clinical relevance in perioperative management. These findings suggest that ROTEM-derived parameters may provide a rapid functional estimate of fibrinogen status in the perioperative setting, potentially supporting clinical assessment, although their role in guiding management requires further validation.