Usefulness of laryngeal ultrasonography for screening of postoperative vocal cord paralysis in children

Abstract

Objective: Laryngeal ultrasonography has gradually been gaining popularity as a screening tool for vocal cord paralysis in children. The aim of this study is to evaluate the diagnostic accuracy of pediatric laryngeal ultrasonography by pediatric intensivists in identifying postoperative vocal cord paralysis in PICU. Methods: Thirty patients who had hoarseness or inspiratory stridor after postoperative tracheal extubation in PICU at Kobe Children’s Hospital from October 2017 to July 2019 were enrolled in this retrospective study. They underwent bedside laryngeal ultrasonography by two pediatric intensivists for the assessment of vocal cord movement. Subsequently, flexible nasolaryngoscopy was performed to confirm the ultrasonographic findings. Results: The median age of the study group was 2.5 [interquartile range (IQR) 1-6] months, and the median body weight was 5.1 [IQR 3.4-6.5] kg. Hoarseness was observed in 23 of 30 patients (77%) after postoperative tracheal extubation, and inspiratory stridor in 15 of 30 patients (50%). The median duration between extubation and laryngeal ultrasonography was 2 [IQR 1-3] days, and between extubation and nasolaryngoscopy was 4 [IQR 3-6] days. Vocal cord movement was visualized by ultrasonography in all patients. It revealed vocal cord paralysis in 19 patients and normal vocal cords in 11 patients. In 26 out of 30 patients, the ultrasonographic findings corresponded with the results of flexible nasolaryngoscopy. The sensitivity and specificity of laryngeal ultrasonography was 86% and 89%, respectively. Conclusions: Laryngeal ultrasonography by pediatric intensivists is a reliable method of screening of postoperative vocal cord paralysis in children. It can be used as an initial assessment tool for pediatric vocal cord paralysis in PICU.