Pediatric Endotracheal Tube Size Prediction: A Comparison among Ultrasound Measured Subglottic Diameter, Age-Formula and Little Fingernail Width Methods

Abstract

Background: There are many methods to estimate pediatric uncuff endotracheal tube (ETT) size. These methods have varied reliability, so this study aims to compare prediction accuracy between the three methods which are subglottic diameter measurement by ultrasound, age-based calculation and little fingernail width Methods: A total of 45 children, aged 1 -6 year who were scheduled for surgery and intubated for general anesthesia, were included in the estimation of uncuff ETT by the three methods. After the predictions were compared with the actual ETT, the primary outcome was to identify the accuracy of each of the three methods as a percentage. Subgroup analysis aims to find correlation between the accuracy of prediction and weight, height, ASA physical status of the patient Results: The accuracy of the ETT size prediction as a percentage using the three methods of subglottic diameter measurement by ultrasound, age-based calculation and little fingernail width comparison were 51.1%, 62.2%and 51.1% respectively. No significant difference was found between the three methods (P-value=0.47). There is no correlation between the accuracy of each methods and weight, height, ASA physical status of the patient Conclusion: There is no difference in accuracy to pediatric uncuff ETT estimation between the three methods discussed previously.