Supplementary Material for: Estimation of Optimal Nasotracheal Tube Insertion Depth in Neonates Based on Fetal Biometric Measurements

<b><i>Background:</i></b> Current recommendations for neonatal endotracheal tube (ETT) insertion depths require the knowledge of anthropometric measurements, which are not immediately available in the delivery room setting. <b><i>Objective:</i></b> This study aimed to develop recommendations based on prenatally available fetal biometric measurements. <b><i>Methods:</i></b> In this retrospective study, the optimal ETT depths for nasotracheal insertion were correlated with fetal demographic and biometric data. Using linear regression analysis, diagrams with best-fit lines and tables for the recommendation of ETT insertion depth based on the prenatally available data were generated. <b><i>Results:</i></b> We analyzed optimal nasotracheal ETT insertion depth in 98 neonates (gestational age range: 23.7–42.0 weeks). Linear regression analysis revealed high correlations between fetal measurements and the optimal ETT insertion depth (<i>R</i>² = 0.712–0.837). <b><i>Conclusion:</i></b> We provide recommendations for neonatal nasotracheal ETT insertion depths based on prenatally available data with the potential to facilitate rapid and accurate intubation of neonates.