Accuracy of ultrasound to measure the cricoid cartilage diameter in children.

BACKGROUND Ultrasonography is used to preoperatively predict the endotracheal tube size required for intubation by measuring the cricoid cartilage diameter. This study aimed to determine the accuracy of ultrasound measurements of the transverse diameters of the cricoid cartilage in children. METHODS We examined 50 children who underwent magnetic resonance imaging (MRI) scans at the HongHui Hospital, Xi'an Jiaotong University, from February 2019 to December 2019. Each child underwent MRI and ultrasound scans for measurement of the transverse diameters of the cricoid cartilage. The data measured by each technique were compared using Bland-Altman analysis and linear regression analysis. RESULTS Results of linear regression and Bland-Altman analysis showed strong correlation in the level of agreement between MRI and ultrasound measurements (r=0.94, p<0.001). The estimated bias was 0.11 mm; precision, 0.25 mm; and the limit of agreement, -0.47 to 0.70 mm. CONCLUSION Ultrasound is a reliable tool for measuring the transverse diameters of the cricoid cartilage in children.