'Lip-to-Tip' study: comparison of three methods to determine optimal insertion length of endotracheal tube in neonates.

The aim of this prospective observational study was to compare the incidence of endotracheal tube (ETT) malposition using weight-based (Tochen), gestation-based (Kempley), and nasotragal length (NTL) methods in deceased neonates and fresh stillbirths. We enrolled deceased neonates and fresh stillbirths within 2 ± 1 h of death or delivery, respectively; without hydrops, tracheostomy or major congenital anomalies affecting face, neck, or thorax. Each enrolled subject was intubated orotracheally, with lip-to-tip distance determined by three methods in random succession. Chest X-ray was acquired after each insertion. The primary outcome was proportion of malpositioned ETTs on chest X-ray (defined as ETT tip not lying between upper border of T1 and lower border of T2 vertebrae), assessed by two experts masked to the methods used. The proportion of malpositioned tubes was not significantly different with any of the three methods: (weight 27/50 (54%), gestation 35/50 (70%), and NTL 35/50 (70%), p value 0.055). The malpositioned tubes were too far in (87/150; 58%) than too far out (10/150; 6.7%).Conclusions: None of the currently recommended methods accurately predicts optimal ETT length in neonates. There is an urgent need for newer bedside modalities for estimating ETT position in neonates. What is known? • NRP guidelines recommend gestation-based and nasotragal length (NTL) methods to estimate initial ETT depth in neonates. Weight-based (Tochen) method is still widely used in neonatal units for ETT depth estimation. Evidence till date has not proven superiority of one method over the other. What is new? • All three methods for ETT depth estimation (Tochen, gestation-based, and NTL) resulted in high rates of ETT malposition in neonates. Formulae, devised from this study based on linear regression models, did not perform well for estimation of optimal ETT position.