Diagnostic accuracy of airway ultrasound in confirming the endotracheal tube depth in critically ill children

Abstract

Background

Chest X-ray, the established standard of confirming endotracheal tube (ETT) position, has important drawbacks including radiation exposure. Point-of-care airway ultrasound, which has been insufficiently studied in children, can overcome these problems.

Materials and methods

This was a prospective cross-sectional study done on children aged 2 months to 17 years undergoing intubation with cuffed ETT in the PICU. The ETT cuff was filled with saline and three ultrasonographic techniques were used– 1) Suprasternal (SS) method 2) Cricoid (CC) metho and 3) Tracheal ring (TR) method. Position of the ETT as determined by ultrasound and X-ray were compared. The main outcomes were sensitivity, specificity, and area under curve (AUC) for ultrasound-based methods vs. X-ray. For the TR method, concordance between the X-ray and ultrasound categories were taken.

Results

Total 62 patients were enrolled. The sensitivity and specificity of SS method were 71% (95% CI: 57–83%) and 100% (40–100%). The CC distance method had an AUC of 0.94 (95% CI: 0.86, 1.0). In the TR method, 98% of correct position on X-ray were correctly classified by USG. The agreement between X-ray and ultrasound categories with the cuff between the first and third tracheal rings, was very good [kappa (95% CI): 0.87 (0.70, 1.00), p ≤0.001)].

Conclusion

Bedside ultrasound is a good method to confirm ETT depth in children. The tracheal ring method had the best diagnostic accuracy and is easy to perform. The new method using cricoid cuff distance needs further validation in different ICU settings.