High levels of B-type natriuretic peptide predict weaning failure from mechanical ventilation in adult patients after cardiac surgery

OBJECTIVE: The failure to wean from mechanical ventilation is related to worse outcomes after cardiac surgery. The aim of this study was to evaluate whether the serum level of B-type natriuretic peptide is a predictor of weaning failure from mechanical ventilation after cardiac surgery. METHODS: We conducted a prospective, observational cohort study of 101 patients who underwent on-pump coronary artery bypass grafting. B-type natriuretic peptide was measured postoperatively after intensive care unit admission and at the end of a 60-min spontaneous breathing test. The demographic data, hemodynamic and respiratory parameters, fluid balance, need for vasopressor or inotropic support, and length of the intensive care unit and hospital stays were recorded. Weaning failure was considered as either the inability to sustain spontaneous breathing after 60 min or the need for reintubation within 48 h. RESULTS: Of the 101 patients studied, 12 patients failed the weaning trial. There were no differences between the groups in the baseline or intraoperative characteristics, including left ventricular function, EuroSCORE and lengths of the cardiac procedure and cardiopulmonary bypass. The B-type natriuretic peptide levels were significantly higher at intensive care unit admission and at the end of the breathing test in the patients with weaning failure compared with the patients who were successfully weaned. In a multivariate model, a high B-type natriuretic peptide level at the end of a spontaneous breathing trial was the only independent predictor of weaning failure from mechanical ventilation. CONCLUSIONS: A high B-type natriuretic peptide level is a predictive factor for the failure to wean from mechanical ventilation after cardiac surgery. These findings suggest that optimizing ventricular function should be a goal during the perioperative period.

Medicina baseada em evidências em terapia intensiva / Evidence-based intensive care medicine

A Medicina Baseada em Evidência (MBE) se refere ao uso consciente e criterioso da melhor evidência científica para a tomada de decisões nada mais do é do que o uso de princípios de epidemiologia e bioestatística aplicados a estudos clínicos, que devem ser permanentemente atualizados à luz de novos achados em um processo contínuo, vivo, e submetidos ao juízo clínico do médico responsável pelos cuidados. Inicialmente os autores discutem as dificuldades de encontrar estudos clínicos que forneçam evidências consistentes em terapia intensiva. Sob este ponto, são abordadas maneiras de contornar a possível inexistência destes estudos por meio de análise criteriosa de revisões sistemáticas. Os problemas encontrados em revisões sitemáticas também são revistos, buscando mostrar que a visão integrada de diversas formas de conhecimento seja talvez a melhor estratégia.

Emergencias hipertensivas / Hypertensive emergencies

Crise hipertensiva e definida como uma elevacao severa da pressao diastolica acima de 120 a 130mmHg.O termo emergencia hipertensiva e utilizado para as situacoes em que exite lesao de orgaos alvo em andamento, havendonecessidade de controle imediato(minutos) da pressao arterial para preservar a vida ou a funcao de orgaos vitais.