Supplementary Material for: Prospective Validation of a Length-Based Nasotracheal Intubation Depth Table ('Hamburg NNTT Table') in Neonates

Background: Accurate endotracheal tube (ETT) placement is crucial for safe ventilation in neonates. Traditional formulae based on weight or gestational age often yield suboptimal accuracy. The length-based “Hamburg Neonatal Naso-Tracheal Tube Table” (Hamburg NNTT Table) was proposed to improve precision. This study aimed to evaluate the clinical applicability and accuracy of the Hamburg NNTT Table in a tertiary neonatal intensive care unit (NICU).
Methods: In this prospective single-centre study, 72 neonates (58 preterm, 14 term) requiring nasotracheal intubation were enrolled. Crown-heel length was measured, and ETT depth determined according to the Hamburg NNTT Table. Correct placement was defined radiographically as the ETT tip in the middle third of the trachea.
Results: Correct positioning occurred in 90.3% of cases. Accuracy was lower in extremely preterm infants (<28 weeks; 80.6%) compared to older infants (97.6%; p=0.016).
Conclusions: The Hamburg NNTT Table provides a simple and accurate method for neonatal nasotracheal tube placement, though refinement is warranted in extremely preterm infants.