New insights about the use of tranexamic acid in children undergoing cardiac surgery: From pharmacokinetics to pharmacodynamics

SCOPUS: ed.jinfo:eu-repo/semantics/publishe

The efficacy of antifibrinolytic drugs in children undergoing noncardiac surgery: A systematic review of the literature

Children undergoing major surgery are frequently exposed to a high risk of blood loss often requiring transfusion. Although the risks associated with blood product transfusion have considerably decreased over the last decade, transfusion is still associated with significant morbidity and mortality. Thus, rigorous efforts should be made to decrease surgical bleeding and the need for blood product transfusion. Antifibrinolytic drugs have been shown to be effective when used in both adult and pediatric surgical patients. While there are data in adults to support safety, data remain limited for pediatric patients. Since the restriction of aprotinin use in 2008, the most commonly used antifibrinolytic drugs have been the lysine analogs, tranexamic acid (TXA), and ε-aminocaproic acid, which inhibit the conversion of plasminogen to plasmin and decrease the degree of fibrinolysis. We performed a systematic review of the literature pertaining to the efficacy of antifibrinolytic drugs in children undergoing noncardiac surgery. During spine surgery, both TXA and ε-aminocaproic acid decrease blood loss and transfusion requirements; however, this information comes from small, mainly retrospective trials. Two prospective, randomized, controlled trials have tested the efficacy of TXA in children undergoing craniofacial surgery and have reported that TXA decreases transfusion requirements. Two pharmacokinetic trials were also recently published and are summarized in this review. No data have been published regarding the efficacy of TXA administration in the pediatric trauma population. Further data are still needed in this field of study, and we discuss some perspectives for future research. © 2013 International Anesthesia Research Society.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Quantification of fibrinolysis using velocity curves measured with thromboelastometry in children with congenital heart disease

BACKGROUND: In this pilot study, we hypothesized that velocity parameters obtained from changes in clot amplitude (A) and clot elasticity (E) measured with thromboelastometry (ROTEM®, Tem International GmbH, Munich, Germany) could improve detection of fibrinolysis in whole blood obtained from children undergoing surgery for congenital heart disease. METHODS: Whole blood samples were obtained after induction of general anesthesia. Seven conditions were studied: native whole blood (baseline) and samples with progressive tissue-type plasminogen activator (t-PA) concentrations (102, 255, 512, 1024, 1535, and 2539 units/mL). We calculated velocity curves based on changes in clot amplitude and elasticity between different time points using ROTEM data. The analysis allowed for the determination of the following parameters: the maximum rate of thrombus formation based on amplitude or elasticity and the maximum rate of thrombus lysis measured based on amplitude (MTL) or maximum rate of thrombus lysis measured based on elasticity (MTLe). We compared these parameters with the lysis in relation to maximal clotting firmness and measured 30 minutes after the clotting time (LI30, in percent). RESULTS: Concentrations of t-PA ≥ 255 units/mL resulted in a decrease in LI30 (mean difference, 255 units/mL versus baseline, -31.05%, P < 0.0001) and the maximum rate of thrombus formation based on amplitude (mean difference, 255 units/mL versus baseline, -7.5, P = 0.005). Concentrations of t-PA ≥ 512 units/mL resulted in changes in maximum rate of thrombus formation based on elasticity (mean difference, 512 units/mL versus baseline, -10.9, P = 0.010), MTL (mean difference, 255 units/mL versus baseline, -3.2, P = 0.016), and MTLe (mean difference, 255 units/mL versus baseline, -7.8, P = 0.004). For t-PA concentrations ≥ 512 units/mL, clot formation was abolished. The area under the receiver operating characteristics curves did not differ between LI30, MTL, and MTLe for the detection of minimal fibrinolytic activation (102 units/mL; 0.74, 0.75, and 0.72, respectively, P = 0.708), whereas sensitivity and specificity of the cutoff values 97% for LI30, -0.3 for MTL, and -0.5 for MTLe were 52% and 85%, 83% and 45%, and 83% and 45%, respectively. CONCLUSIONS: Velocity curves based on the amplitudes or clot elasticity could provide objective measurement of clot growth and clot lysis kinetics, allowing detection of even minor fibrinolysis. Further studies are needed to assess the clinical relevance of these parameters.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Bleeding Assessment Scale in Critically Ill Children (BASIC): Physician-Driven Diagnostic Criteria for Bleeding Severity

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