Objective: To assess the application of the nasal-tragus length (NTL) to predict the proper endotracheal tube (ETT) depth; also, as relatively thinner size of Asian than Caucasian, the fitness of using the NTL to estimate the optimal ETT depth for neonates in Taiwan was examined.
Methods: The newborn infants who do need intubation orally were included. Those with midface dysmorphism, craniofacial anomalies, head trauma and/or facial injury in whom it was unable to measure NTL, were excluded. The data were collected after a satisfactory ETT tip position was confirmed on chest roentgenogram. Equations were established via the polynomial and the linear regression of the NTL and the actual ETT; simplified formulae as NTL+0.5 and NTL+1 were assumed accordingly. Paired t test was used to assess the coefficients.
Results: The 63 neonates, weighing 410 through 4,196 g and with gestation 21 through 41 weeks, were enrolled. No statistical difference was found between the actual ETT depth and the estimated ETT depth via the NTL+1 cm in neonates weighing ≤ 2,500 g (n=41, p=0.06), and also between the actual ETT depth and the estimated ETT depth via the NTL+0.5 cm in group weighing >2,500 g (n=22, p=0.171).
Conclusions: Using the NTL to predict the optimal ETT depth with the formula, NTL plus 1 cm, was clinically practical for newborn infants in Taiwan weighing ≤ 2,500 g, and a modified formula, NTL plus 0.5 cm, was more suitable for neonates weighing >2,500 g.