Perioperative Coagulation Monitoring

The establishment of reference intervals for the ClotPro thromboelastometry device in healthy dogs

OBJECTIVE

To establish reference intervals using a new point-of-care thromboelastometry device in dogs for the extrinsically activated test (EX-test), intrinsically activated test (IN-test), fibrin polymerization test (FIB-test), ecarin test (ECA-test), and tissue plasminogen activator test (TPA-test) and to investigate the effects of storage time on the results.

DESIGN

Prospective clinical study in 2022.

SETTING

University teaching hospital.

ANIMALS

Forty-eight healthy privately or university-owned dogs were prospectively enrolled and included on the basis of normal physical examination and normal baseline laboratory results (CBC, biochemistry profile, prothrombin time, and activated partial thromboplastin time [aPTT]).

INTERVENTIONS

After a 30-minute storage time, the EX-test, IN-test, FIB-test, ECA-test, and TPA-test were performed on citrated blood samples. To determine the effect of storage time, 11 samples had the EX-test, FIB-test, and IN-test repeated 90 and 150 minutes after sample collection.

MEASUREMENTS AND MAIN RESULTS

Ten thromboelastometry parameters were evaluated for each test. Reference intervals were calculated using the robust method for parametric data, and the robust Box-Cox transformed or nonparametric methods were used for nonparametric data. Increasing storage time resulted in more hypocoagulable tracings. A correlation was found between the IN-test and aPTT (r = 0.62, P < 0.0001). Other weak to moderate correlations were seen between thromboelastometry parameters and platelet count and hematocrit.

CONCLUSIONS AND CLINICAL IMPORTANCE

The development of reference intervals for the thromboelastometry device allows for the clinical use of this technology. Analyzing samples after a prolonged storage time of more than 30 minutes may result in erroneous results. Results may also be affected by an abnormal hematocrit or platelet count.

Emergency Blood Transfusion for Trauma and Perioperative Resuscitation: Standard of Care

Uncontrolled and massive bleeding with derangement of coagulation is a major challenge in the management of both surgical and seriously injured patients. The underlying mechanism of trauma-induced or -associated coagulopathy is tissue injury in the presence of shock and acidosis provoking endothelial damage, activation of inflammation, and coagulation disbalancing. Furthermore, the combination of ongoing blood loss and consumption of blood components that are essential for effective coagulation worsens uncontrolled hemorrhage. Additionally, therapeutic actions, such as resuscitation with replacement fluids or allogeneic blood products, can further aggravate coagulopathy. Of the coagulation factors essential to the clotting process, fibrinogen is the first to be consumed to critical levels during acute bleeding and current evidence suggests that normalizing fibrinogen levels in bleeding patients improves clot formation and clot strength, thereby controlling hemorrhage. Three different therapeutic approaches are discussed controversially. Whole blood transfusion is used especially in the military scenario and is also becoming more and more popular in the civilian world, although it is accompanied by a strong lack of evidence and severe safety issues. Transfusion of allogeneic blood concentrates in fixed ratios without any targets has been investigated extensively with disappointing results. Individualized and target-controlled coagulation management based on point-of-care diagnostics with respect to the huge heterogeneity of massive bleeding situations is an alternative and advanced approach to managing coagulopathy associated with massive bleeding in the trauma as well as the perioperative setting.