A Case Report of Severe Factor XI Deficiency during Cardiac Surgery: Less Can Be More.

Severe congenital Factor XI (FXI) deficiency (<20% normal activity) can be associated with significant bleeding disorders, and there has been great concern for severe bleeding following cardiac surgery requiring cardiopulmonary bypass (CPB) in this patient population. Over the past four decades remarkably different approaches to this problem have been taken, including the administration of blood volumes of fresh frozen plasma, administration of activated recombinant Factor VII, and diminutive administration of heparin. We describe a case wherein the patient was assessed in the perioperative period with a point-of-care, viscoelastic hemostasis device (ROTEM), with changes in the intrinsic/Factor XII-dependent coagulation pathway determined before, during, and after CPB. Fresh frozen plasma was administered in small amounts (5−7.5 mL/kg) just before surgery began and just before cessation of CPB. Administering fresh frozen plasma to the patient to nearly normalize in vitro ROTEM hemostasis values at times when hemostasis was needed resulted in no important bleeding occurring or need of further transfusion of other blood products. In conclusion, by using small amounts of fresh frozen plasma guided by ROTEM, an evidenced-based, precision medicine approach resulted in optimized patient care and outcome.

Effects of cupric chloride on coagulation in human plasma: role of fibrinogen.

INTRODUCTION: Copper poisoning is associated with severe multiorgan injury and potentially death if chelation therapy is not administered. Of interest, while important gastrointestinal and urinary tract hemorrhage is associated with copper poisoning, very little is known concerning the nature of copper induced coagulopathy. METHODS: Using thrombelastography, we assessed changes in coagulation kinetics in human plasma following exposure to copper concentrations encountered during poisoning. RESULTS: While time to commence coagulation was not compromised, both velocity of thrombus growth and final strength were diminished. This result was duplicated with one concentration of copper in factor XIII deficient plasma. This pattern of coagulation kinetic response was interpreted as copper mediated fibrinogen dysfunction, perhaps via oxidation of key fibrinogen disulfide bridges. Lastly, experiments wherein glutathione was added implicated copper generated radical oxygen species as one of the mechanisms responsible for compromised coagulation kinetics. CONCLUSIONS: While chelation therapy is the key to survival following copper poisoning, perhaps this and future investigations of how copper affects coagulation may provide insight into effective supportive therapy for patients with active bleeding.

The ratio of concentrations of aminocaproic acid and tranexamic acid that prevent plasmin activation of platelets does not provide equivalent inhibition of plasmatic fibrinolysis.

Aminocaproic acid (EACA) availability has recently been decreased whereas tranexamic acid (TXA) is still available as an antifibrinolytic agent to decrease blood loss associated with procedures involving cardiopulmonary bypass (CPB) by inhibiting plasmin mediated platelet activation. Given that the clinical inclination is to substitute TXA for EACA, we sought to compare the antifibrinolytic efficacy of the two agents using the clinically accepted molar ratio of EACA:TXA (7.9:1) that prevents platelet activation in a viscoelastic based system under a variety of conditions in human plasma; 25-50% therapeutic concentration (EACA 32.5-65 µg/ml, TXA 5-10 µg/ml) in the presence of 1500-3000 IU tissue-type plasminogen activator, with 0-50% dilution of plasma with buffer. In all equipotent concentrations, TXA provided superior antifibrinolytic action compared to EACA. It is hoped that this work will serve as a rationale to further investigate these and other similar agents, especially now in a time of unpredictable unavailability of key medications needed to optimize patient care. It is also our wish that these data assist perfusionists, anesthesiologists and cardiothoracic surgeons with their consideration of using an antifibrinolytic agent when managing complex patients with hypercoagulable states (e.g., ventricular assist device explant, infective endocarditis) undergoing CPB.

Burn-induced cardiac dysfunction increases length of stay in pediatric burn patients.

The aim of this study was to evaluate cardiac function and clinical outcomes in perioperative pediatric burn patients. Transesophageal echocardiography data were collected on 40 patients from 2004 to 2007. Of the 40 patients who received exams, a complete set of cardiac parameters and outcome variables was obtained in 26 patients. The mean age of the patients was 9.7 ± 0.9 years, and the mean TBSA burn size was 64 ± 3%. Patients were divided into two groups based on systolic function. One group represented patients with ejection fractions of >50% and the other ≤50%. Clinical variables were then compared among the groups. In our cohort, systolic dysfunction was observed in 62% of patients (EF ≤ 50%). Systolic dysfunction was associated with a statistically significant increase in number of surgeries, ventilator days, and length of stay in the intensive care unit. The length of stay in patients with preserved systolic function and those with systolic dysfunction was 34.3 ± 3.3 days and 67.2 ± 4.0 days, respectively. Diastolic function measurements were obtained in 65%, and 88% had evidence of diastolic dysfunction. Diastolic dysfunction was not associated with any statistically significant correlations. This study lends evidence to the well-supported basic science models showing cardiac dysfunction after burns. Additionally, it shows that cardiac dysfunction can have clinical consequences. To our knowledge, this is the first study that shows the clinical sequelae of systolic dysfunction in the perioperative pediatric burn population.