Combined Echocardiography and Lung Ultrasound for Extubation Outcome Prediction in Children after Cardiac Surgery

Abstract

Background: Children are at risk of extubation failure after congenital heart disease surgery. Such cases should be identified to avoid possible adverse consequences of failed extubation. This study aimed to identify ultrasound predictors of successful extubation in children who underwent cardiac surgery. Methods: Children aged 3 months to 6 years who underwent cardiac surgery (if they were intubated for >6 h and underwent a spontaneous breathing trial) were included in this study. Results: We included 83 children who underwent surgery for congenital heart disease. Transthoracic echocardiography and lung ultrasound were performed immediately before spontaneous breathing trials. Upon spontaneous breathing trial completion, respiratory parameters, including arterial blood gas analysis and frequency-to-tidal volume ratio, were similarly recorded. For outcome assessment, all children were followed up for 48 h after extubation. We successfully extubated 57 children (68.7%). These children were significantly older and weighed more but had shorter aortic cross-clamp and cardiopulmonary bypass times. Children who could not be weaned or extubated had prolonged total mechanical ventilation and pediatric intensive care unit stay. In the multivariate regression analysis, a lung ultrasound score ≥12 and ejection fraction ≥40% immediately before spontaneous breathing trials were the only independent predictors of successful extubation. When combined, the lung ultrasound score and an ejection fraction ≥40% showed a better diagnostic performance than every other isolated variable (lung ultrasound, N-terminal-pro-B-type natriuretic peptide, and frequency-to-tidal volume ratio). Conclusions: The combination of lung ultrasound and transthoracic echocardiography immediately before the spontaneous breathing trial effectively predicts extubation outcomes in children after cardiac surgery.