Nasal-tragus length for estimating optimal insertion depth of endotracheal tube in Thai neonates

Objective To develop a nasal-tragus length (NTL)-based table for estimating the endotracheal tube (ETT) insertion depth. Study design A prospective study of 110 Thai neonates was conducted in a NICU in Bangkok, Thailand. The correlation between the optimal insertion depth (Opt-Depth) and NTL was determined, and then an NTL-based table for estimating ETT depth was developed. The accuracy of using various methods in estimating ETT depth was compared. Results A strong correlation between Opt-Depth and NTL was found (r = 0.897, p < 0.001). There was no significant difference between ETT depth estimated by the NTL-based table and Opt-Depth [mean difference (95% CI) -0.75 (-12.11 to 10.61) mm, p = 0.22]. The accuracies of using NTL + 1, NTL-based, GA-based, and BW-based tables for estimating ETT depth were 32.7%, 55.5%, 61.8%, and 52.7%, respectively. Conclusion Our NTL-based table for estimating the ETT depth had an acceptable accuracy while using NTL + 1 resulted in overestimating ETT depth.