Accurate endotracheal tube placement in children: depth of insertion is part of a process

Comparison of four formulas for nasotracheal tube length estimation in pediatric patients: an observational study

BACKGROUND

Correct endotracheal intubation results in better ventilation, prevents hypoxia and its possible damages, such as brain injury, and minimizes attempts for re-intubation. Up to now, several formulas have been published to estimate nasotracheal intubation tube length. This study aims to compare the accuracy of different suggested formulas to find the one that better estimates the tube insertion distance.

METHODS

This cross-sectional retrospective study was carried out in 102 (51 female, 51 male) children who underwent cardiac surgery under general anesthesia. Inclusion criteria were correct nasotracheal intubation according to the postintubation chest X-ray (CXR). The estimated tracheal tube length was calculated by four different formulas. Pearson...s correlation coefficient was used to find the correlations between the estimated length of each formula and the correct nasotracheal tube length. Also, linear regression was used to obtain a formula to estimate nasotracheal tube length by weight, height, and age.

RESULTS

The formula L=3*tube size+2 had the best correlation with tube length (r ...=...0.81, Confidence Interval: 0.732...0.878, p-value < 0.001). Among demographic variables, height had the highest correlation coefficient with the tube length (r...=...0.83, Confidence Interval: 0.788...0.802, p-value < 0.001). Therefore, considering the height as an independent variable and tube length as a dependent variable, using linear regression, the following formula was achieved for determining tube length: nasotracheal tube length...=...0.1*Height+7.

CONCLUSIONS

The formula L=3*tube size+2 and the new suggested formula in this study can be used to estimate nasotracheal tube length in children under 4 years old. However, these formulas are only guides and require confirmation by auscultation and CXR.

New formulae for predicting tracheal tube length

BACKGROUND

The aim of this study was to determine the accuracy of standard techniques for estimating oral and nasal tracheal tube length in children and to devise more accurate predictive formulae that can be used at the bedside.

METHODS

Data were collected from 255 children who required tracheal intubation whilst on the Pediatric Intensive Care Unit over a period of 1 year. Age, weight, the final length of the tracheal tube and the internal diameter were documented. Patients with a tracheostomy were excluded from the study.

RESULTS

Using linear regression the following formulae best predicted final tracheal tube length. For children over 1 year of age: Insertion depth (cm) for orotracheal intubation = age/2 + 13 Insertion depth (cm) for nasotracheal intubation = age/2 + 15 For children below 1 year of age: Insertion depth of orotracheal tube (cm) = weight/2 + 8 Insertion depth of nasotracheal tube (cm) = weight/2 + 9

CONCLUSIONS

Current Advanced Paediatric Life Support guidelines underestimate the appropriate tracheal tube lengths for orotracheal intubation in children over 1 year of age. Similarly, the novel weight-based formulae for tracheal tube lengths in children below the age of 1 year proved more accurate than standard reference charts. We therefore recommend that these new formulae are prospectively evaluated.