ABSTRACT
BACKGROUND: Viscoelastic near-patient assays of global hemostasis have been found useful and cost-effective in perioperative settings. Shortcomings of current systems include substantial laboratory intensity, user-dependent reproducibility, relatively large sample volumes, sensitivity to ambient vibration and limited comparability between techniques and devices. The aim of this study was to assess feasibility of a new, resonance-based viscoelastic whole blood methodology (TEG6s) in cardiac surgery with cardiopulmonary bypass (CPB) and to compare the parameters this system produces with the ROTEM delta system and standard coagulation tests. METHODS: In a prospective evaluation study, twenty-three consecutive cardiac surgery patients underwent hemostasis management according to current guidelines, using the ROTEM delta system and standard coagulation tests. Blood samples were collected prior to CPB before anesthetic induction (pre-CPB), during CPB on rewarming (CPB), and 10 minutes after heparin reversal with protamine (post-CPB). ROTEM and standard coagulation test results were compared with TEG6s parameters, which were concurrently determined using its multi-channel microfluidic cartridge system. RESULTS: TEG6s provided quantifiable results pre-CPB and post-CPB, but only R (clotting time) of CKH (kaolin with heparinase) was measurable during CPB (full heparinization). Spearman's correlation coefficient (rs) was 0.78 for fibrinogen levels and MA CFF (functional fibrinogen). Correlation of several TEG6s parameters was good (0.77 to 0.91) with MCF FIBTEM, and poor (<0.56) with prothrombin time and activated partial thromboplastin time (<0.44). Rs with platelet count was moderate (0.70, MA CK; 0.73, MA CRT). Accuracy of MA CFF for detection of fibrinogen deficiency < 1.5 g/L was high (ROC-AUC 0.93). CONCLUSIONS: The TEG6s system, which is based on resonance viscoelastic methodology, appears to be feasible for POC hemostasis assessment in cardiac surgery. Its correlations with standard coagulation parameters are quite similar to those of ROTEM and there is good diagnostic accuracy for fibrinogen levels lower than 1.5 g/L. During full heparinization, TEG6s testing is limited to R measurement. Larger studies are needed to assess superiority over other POC systems.
Subject(s)
Afibrinogenemia/diagnosis , Cardiac Surgical Procedures/adverse effects , Cardiopulmonary Bypass/adverse effects , Intraoperative Complications/diagnosis , Monitoring, Intraoperative/instrumentation , Adult , Afibrinogenemia/blood , Afibrinogenemia/etiology , Afibrinogenemia/prevention & control , Aged , Blood Coagulation , Blood Coagulation Tests/instrumentation , Blood Coagulation Tests/methods , Blood Coagulation Tests/standards , Cardiac Surgical Procedures/methods , Cardiopulmonary Bypass/methods , Feasibility Studies , Female , Humans , Intraoperative Complications/blood , Intraoperative Complications/etiology , Male , Middle Aged , Monitoring, Intraoperative/methods , Monitoring, Intraoperative/standards , Practice Guidelines as Topic , Prospective Studies , Reproducibility of ResultsABSTRACT
INTRODUCTION: Hemostatic and coagulation disorders related to severe liver disease may cause massive bleeding beyond what can be expected from surgical trauma in liver transplantation. Fluid resuscitation and fibrinolysis may aggravate the problem, as plasma fibrinogen decreases in all patients. The objective of this review was to update the criteria for fibrinogen replacement in liver transplantation. METHODS: A PubMed and Scopus search from 1990 to 2015 was made. The following key words were used: fibrinogen, liver transplantation, coagulation, and blood product replacement. Controlled trials and observational studies were selected on the basis of clinical relevance. RESULTS: There is a scarcity of published controlled studies on perioperative fibrinogen replacement. Most articles refer to expert opinion; therefore, criteria for the administration of fibrinogen have been empirically established. The response to cryoprecipitate or fibrinogen concentrate administration in liver transplantation has not been established. Viscoelastic platelets free tests have been reported to have a good correlation with Clauss-measured plasma fibrinogen concentration. In surgical patients, the median increase in fibrinogen plasma level per gram injected has been determined in 0.2375 g/L. Alternatively, fibrinogen replacement can be guided based on viscoelastic hemostatic assays. CONCLUSIONS: In liver transplantation, plasma fibrinogen levels are low in most patients during surgery. Fibrinogen administration to correct hypofibrinogenemia has a positive impact on surgical bleeding. However, there is a scarcity of literature about fibrinogen administration; therefore, administration should be adjusted to replace plasma fibrinogen levels in the range of normal and guided by thromboelastometry.
