Ultrasonic prediction of weaning failure in children undergoing cardiac surgery: A prospective observational study

Abstract

Background and Aim: To assess the utility of ultrasonic markers like B-line score (LUS), diaphragm thickness (DT), thickening fraction (DTF), and excursion (DE) as predictors of weaning outcomes in children on mechanical ventilation (MV) after cardiac surgery. Methods: This was a prospective observational study done in postcardiac surgical intensive care unit (ICU) of a tertiary care hospital. Children aged 1 month to 18 years, on MV after cardiac surgery from January to November 2017, were included. They were extubated after satisfying institutional weaning criteria. Ultrasound for LUS, DT, DTF, and DE was performed preoperatively, during pressure support ventilation (PSV) before extubation and 4 h after extubation. Results: Patients were divided into weaning failure and success groups based on reintubation within 48 h of extubation. Of the 50 evaluated patients, 43 (86%) were weaned successfully and 7 (14%) had weaning failure. The left DTF during PSV was lower in patients weaning failure (0.00%, interquartile range (IQR) 0.00-14.28 vs 16.67%, IQR 8.33-22.20, P = 0. 012). The left DTF≤ 14.64% during PSV (area under receiver's operating curve 0.795, P = 0.014), 85% sensitivity, and 57% specificity (positive likelihood ratio 1.97, negative likelihood ratio 0.25) could predict weaning failure. Conclusion: The left DTF during PSV is a good predictor of weaning failure in children on MV in postoperative ICU after congenital cardiac surgery. Take home message In children on mechanical ventilation after cardiac surgery, left DTF during pressure support ventilation is a good predictor of weaning failure.