Comparative study of different formulae for prediction of best fit endotracheal tube size in children

Abstract

BackgroundVarious formulae have been used to predict appropriate endotracheal tube (ETT) size in children, but there is no consensus regarding the best predictor. Recent use of ultrasonography (USG) to predict the ETT size may not always be feasible leaving the physical parameters as most useful and practical option. The present study was planned to compare age-, height- and weight-based formulae for ETT size prediction in children.ResultsThe accuracy in predicting ETT size was found to be 88.67%, 73.33% and 32.67% for height-based formula (HBF), age-based formula (ABF) and weight-based formula (WBF), respectively. Pearson correlation coefficient was best for HBF (0.968 with 95% CI of 0.937–0.999), followed by ABF (0.942 with 95% CI of 0.887–0.996) and WBF (0.874 with 95% CI of 0.794–0.953). HBF was found to be best suited for children 1–3 years, ≤ 90 cm and weight < 15 kg with accuracy of > 98%, while WBF was unsatisfactory across all age, height and weight groups.ConclusionsHBF is the best predictor of ETT size across all age groups with marginal superiority over ABF, especially in age group < 3 years. WBF was least effective in predicting ideal ETT size. It is recommended that HBF should be preferred over ABF and WBF for selection of ETT size in paediatric patients. This practice assumes greater importance especially in emergency situations where exact age and weight cannot be ascertained while height is easily obtainable.