The Utility of Lung Ultrasound Scoring in Predicting Post-Extubation Respiratory Support After Congenital Heart Surgery

Abstract

Objectives: Lung ultrasound (LU) is effective in diagnosing the accumulation of extravascular lung water and assessing real-time fluid status in infants following congenital cardiac surgery with cardiopulmonary bypass. This study evaluated whether LU can be used as a prognostic marker for changes in noninvasive respiratory support after extubation.

Methods: Infants with congenital heart disease (CHD) <1 year of age requiring mechanical ventilation for more than 24 hours postoperatively were included. Using a linear probe, 3 scan fields from each hemithorax were assessed for B-lines and consolidations, with scores ranging from 0 to 3 assigned per area. LU scores were rated then by 4 independent operators. After extubation, patients were monitored for respiratory support modifications over the following 48 hours and were divided into 3 subgroups: steady state, escalation, and de-escalation, accordingly.

Results: In this single-center observational pilot study, a total of 30 patients with a median age of 116 (interquartile range: 17-196) days were included in the prospective analysis between July 2022 and December 2023. LU scores differed significantly among groups: 3.47 ± 2.3 (steady state), 6.14 ± 2.55 (escalation), and 1.63 ± 1.41 (de-escalation), P = .002. ROC analysis identified a cut-off score of ≥5 as predictive of escalation risk with a sensitivity of 86% and specificity of 83%. A score <2 suggested potential for de-escalation within 48 hours, with a sensitivity of 75% and specificity of 73%.

Conclusions: LU scoring may be a valuable tool for optimizing ventilator weaning and post-extubation respiratory strategies in infants undergoing congenital cardiac surgery. Further studies are warranted to validate these findings.

Keywords: cardiac surgery; congenital heart disease; lung ultrasound; pediatric intensive care; post extubation strategy.

Figure 1

Boxplot of LUS in the 3 subgroups; the Shapiro–Wilk test revealed normal distribution (P = .615), n = 30. Analysis of variance showed statistically significant differences—steady state group versus escalation group P = .023, escalation versus de‐escalation group P = .001 (bars with *). Between the steady state and de‐escalation groups, there was no statistically significant difference—P = .062. LUS, lung ultrasound score.

Figure 2

A, ROC curve demonstrating the sensitivity and specificity of LU to predict the increase in respiratory support within 48 hours following extubation. B, ROC curve demonstrating the sensitivity and specificity of LU to predict the decrease in respiratory support within 48 hours following extubation. ROC, receiver operating characteristic curve.