Does incorporation of thromboelastography improve bleeding prediction following adult cardiac surgery?

Cardiopulmonary bypass (CPB) coagulopathy increases utilization of allogenic blood/blood products, which can negatively affect patient outcomes. Thromboelastography (TEG) is a point-of-care measurement of clot formation and fibrinolysis. We investigated whether the addition of TEG parameters to a clinically based bleeding model would improve the predictability of postoperative bleeding. A total of 439 patients' charts were retrospectively investigated for 8-h chest tube output (CTO) postoperatively. For model 1, the variables recorded were patient age, gender, body surface area, clopidogrel use, CPB time, first post-CPB fibrinogen serum level, first post-CPB platelet count, first post-CPB international normalized ratio, the total amount of intraoperative cell saver blood transfused, and postoperative first ICU hematocrit level. Model 2 had the model 1 variables, TEG angle, and maximum amplitude. The outcome was defined as 0-8-h CTO. The predictor variables were placed into a forward stepwise regression model for continuous outcomes. Analysis of variance with adjusted R was used to assess the goodness-of-fit of both predictive models. The predictive accuracy of the model was examined using CTO as a dichotomous variable (75th percentile, 480 ml) and receiver operating characteristic curves for both models. Advanced age, male gender, preoperative clopidogrel use for 5 days or less, greater cell saver blood utilization, and lower postoperative hematocrit levels were associated with increased 8-h CTO (P < 0.05). Adding TEG angle and maximum amplitude to model 1 did not improve CTO predictability. When TEG angle and maximum amplitude were added as predictor factors, the predictability of the bleeding model did not improve.

Oxido nítrico e substância vasoativas derivadas do endotélio: papel no controle do tônus vascular / Nitric oxide and endothelium-derived vasoactive factors: role inthe vascular tone control

O endotélio de artérias e veias vem sendo estudado, há muito tempo, por médicos e pesquisadores que lidam com doenças cardiovasculares ou complicaçöes cardiovasculares da idade avançada.Entretanto, a visäo globalda funçäo endotelial näo foi possível até duas décadas atrás, quando se testemunhou a descoberta da produçäo da prostaciclina, do óxido nítrico (NO) derivado do endotélio ede outros fatores vasoativos.Longe de ser uma barreira passiva de interface entre o fuxo sanguíneo e o corpo, o endotélio deve ser considerado um sistema orgânico cuja funçäo é crítica na manutençäo da anticoagulaçäo sanguínea "in vivo", na manutançäo do tônus vascular e na regulaçäo da perfusäo.Acresça-se que a lesäo ou disfunçäo endotelial é uma via comum a diversas doenças cardiovasculares, incluindo a aterosclerose, as doenças vasoespásticas e a hipertensäo arterial.Este texto tem a finalidade de revisar os fatores vasoativos produzidos pelo endotélioe discutir aspectos da regulaçäo parácrina do tônus vascular.Seräo revisados os fatores relaxantes (PGI2-prostaciclina; EDRF/NO - fator relaxante do endotélio/óxido nítrico; e EDHF -fator hiperpolarizante derivado do endotélio) e os fatores contráteis derivados do endotélio (EDCFs).Após a revisäo desses fatores, seräo discutidas, de forma crítica, suas açöes isoladas e/ou sinérgicas na regulaçäo do tônus vascular.