BACKGROUND: Endotracheal intubation is an important procedure in critical care and emergency medicine settings. Optimal depth of the tube placement has been a serious concern because of several complications associated with its malposition. OBJECTIVE: The aim of the current study was to find a new formula to estimate the proper endotracheal tube depth when using ultrasonography or lighted stylet device in order to increase the accuracy of determining Endotracheal tube (ETT) depth and decrease the side effects of ETT misplacement. METHOD: Patients older than 18 years of age admitted to Imam emergency department who needed tracheal intubation were included. Tube's length at the angle of the mouth while the tube passed the suprasternal notch, ETT depth after insertion and the distance from ETT's tip to carina were recorded. Ultrasonography and portable chest x-ray were used as tools for measuring these lengths. RESULTS: A total number of 91 patients including 55 men and 36 women were eligible for inclusion in the study. Not placing the tube at proper depth was considered as the failure of intubation. This failure rate was 9.9% in the standard method which would have been 1.1% if our proposed formula was used. CONCLUSION: The findings of this study suggest that the use of this new formula may help in predicting the proper intubation tube placement. Further studies are warranted to confirm these findings.
