The clinical value of passive leg raising plus ultrasound to predict fluid responsiveness in children after cardiac surgery

Abstract

Background: There are few non-invasive monitoring methods that can reliably predict FR in children, this article aims to investigate the value of the doppler ultrasound evaluation of passive leg raising (PLR) induced changes in stroke volume (SV) and cardiac output(CO) in predicting the fluid responsiveness (FR) in children with mechanical ventilation after congenital cardiac surgery. Methods: A total of 40 children with mechanical ventilation after congenital cardiac surgery who requiring volume expansion (VE) were eventually included in this observational study. Hemodynamic parameters such as heart rate (HR), blood pressure, SV, and central venous pressure (CVP) were monitored before and after PLR and VE respectively, and changes of SV and CO were assessed by bedside ultrasound as well. The patients showing an increase in SV >10% in response to VE were considered responders (26 patients), and the rest were defined as nonresponders (14 patients). Results: The results showed that ΔSV-PLR and ΔCO- PLR were positively correlated with ΔSV-VE (r = 0.683, P<0.001 and r= 0.374, P = 0.017, respectively), and the area under the ROC curve (AUC) of ΔSV-PLR was 0.879 (95% CI [0.745 1.000], P < 0.001). The best cut-off value of ΔSV-PLR for predicting FR was 13%, with its sensitivity and specificity was 81.8% and 86.3%, respectively. ΔCVP, ΔHR, and ΔMAP were weak predictive FR in children patients. Conclusion: Our study demonstrated that SV changes assessed by noninvasive ultrasound combined with PLR could be a feasible method for evaluating fluid responsiveness in children with congenital cardiac surgery and mechanical ventilation. Keywords: congenital heart surgery; fluid responsiveness; passive leg raising; ultrasound.