A New Formula for Optimal Endotracheal Tube Depth using Mid-Sagittal Multidetector Computed Tomography Imaging

ABSTRACT

PURPOSE: This study was conducted to propose a new useful formula using the upper incisor-sternal notch length to predict the airway length for the optimal positioning of the endotracheal tube (ETT) through mid-sagittal multidetector computed tomography (MDCT). METHODS: From March 2014 through February 2015, 102 of 470 patients undergoing neck MDCT were randomly selected. Using the ViewRex program to analyze the mid-sagittal image of the MDCT, we measured the straight length from the upper incisor to the sternal notch and the curved airway length from the upper incisor to the carina. Linear regression was used to analyze the relationship among measured variables. RESULTS: The average age was 52.1±14.2 and 44 subjects were male. The straight length from the upper incisor to the sternal notch and the curved airway length from the upper incisor to the carina were 15.3±1.6 cm and 27.7±2.0 cm, respectively. The correlation between two variables was significant (p < 0.001). A formula was obtained by linear regression in which the airway length from the upper incisor to carina (cm)=1.02×the straight length from the upper incisor to sternal notch+12.1. CONCLUSION: The proposed simplified formula (Y=X+12; Y, curved airway length from upper incisor to carina; X, straight length from upper incisor to sternal notch) can provide a useful guide to determine the optimal positioning of the endotracheal tube in most of patients who required orotracheal intubation.