Height measurement and ultrasound assessment of subglottic region for the estimation of appropriate endotracheal tube size in pediatric population

Abstract

Background: Choosing the appropriate endotracheal tube (ETT) size in pediatric patients is crucial to guarantee well ventilation and reliable end-tidal gas monitoring. Different methods have been established for choosing appropriate ETT size with varied validities depending on the demographics of the patients. Objectives: The primary objective is to investigate a relationship between the height of the patient and the appropriate ETT size and form a predictive formula. Design: A prospective, observational study was conducted between November 2019 and March 2020 in a pediatric hospital, Riyadh, Saudi Arabia. Setting: Patients below 14 years of age admitted for elective day surgery with American Society of Anesthesiologist Class 1 or 2 were invited to participate. Patients with anticipated difficult airway or neck mass or those refused to enroll were excluded. Methods: After obtaining institutional review board approval, informed consents were taken from all patients' guardians. Collected data were gathered in excel sheet. Main Outcome Measures: Demographic and clinical data were collected. The subglottic area was measured before induction of anesthesia by bedside ultrasound machine. No formulas were used for ETT size used. Sample Size: 71 children were included in the study. Results: The ETT based on the height of the patient was estimated using the formula below as “estimated ETT size if other formula used:” {INSIDE:1] estimated based on height. Pearson's correlation results revealed a positive association between the ETT used and ETT estimated. The relationship between variables is insignificant, with a P > 0.05. There was an overestimation in both the ETT used and ETT estimated in the stepwise regression analysis. About 88.5% overestimate the ETT used based on age, and about 89.7% overestimate the ETT based on patient height. The F-value change statistics indicates a statistical significance of ETT used and ETT estimated. Conclusion: It is crucial to have an accurate ETT tube size used in children. The height of the child was found to have good correlation with ETT size in our Saudi population. Limitation: Part of the limitations faced was the fact that it was a single-center study which may not represent the population from other areas.