To the Editor:
I read the interesting paper by Bartle et al,1 and there are a few points from the article I would like to discuss. The authors affirmed that appropriate endotracheal tube (ETT) position on chest radiograph in the newborn is approximately at the second or third thoracic vertebrae; I do not completely agree with this statement. In evaluating endotracheal intubation in the neonatal emergency transport setting to establish a nomogram for appropriate ETT depth, my colleagues and I reported2 that the mid-carina position corresponds with the ETT tip at the level of the T1–T2 vertebrae. An ETT tip positioned at the C7 vertebra was defined as being high but still inside the trachea, while an ETT tip positioned at the T3 vertebra was considered as being low but still above the carina. Positioning at either the C7 or the T3 vertebra was considered acceptable, while other positions on the chest radiograph were considered incorrect.2 I agree with the authors that it is difficult to correctly assess the tip position on chest radiograph; however, it has been reported that if the correct mid-trachea position is achieved (ie, T1–T2), neck movements do not significantly influence a safe and correct tube position.3 Although our study2 described nasal intubation results and Bartle et al evaluated oral intubation,1 I believe our observations are relevant to the study by Bartle et al.1 Using our parameters to reassess their results could potentially change the authors' conclusions that their weight-based institutional formula has a low sensitivity for predicting proper ETT depth in newborns with very low birth weight.
I partially agree with the authors when they affirmed that ETT depth is poorly correlated with birthweight, and I have stated that estimated tracheal length by weight still remains an approximation.2 However, we need to have a reference nomogram to determine the depth of ETT insertion. It is well known in clinical practice that ETT position must be clinically verified following intubation by the presence of symmetrical chest expansion and breath sounds, the absence of loud inspiratory sounds in the epigastric region, and the prompt increase in heart rate and oxygen saturation levels. Bartle and colleagues1 came to this conclusion, too. This practice means that slight corrections to the initial tip position are usually performed, at a maximum of 0.5 cm up or down, and only at a later time after chest radiography. Thus, the use of a nomogram based on the birthweight is certainly useful, and it may be the only viable option as a reference, but caution is recommended in using this reference, especially in very tiny babies.
Footnotes
Dr Bellini has disclosed no conflicts of interest.
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