Predicting optimal endotracheal tube depth in children based on height and middle finger length.

Background: Current calculation formulas cannot accurately predict intubation depth in children due to variations in growth and development patterns and unique anatomical characteristics of the pediatric airway. This study aims to develop a method for determining the appropriate ETT insertion depth in pediatric patients.

Methods: This study included 205 patients aged 4-12 years who underwent elective surgery under general anesthesia with tracheal intubation. The general condition of the enrolled children was recorded, and growth parameters were measured preoperatively. Multivariate linear regression analysis was employed to develop a new formula for predicting intubation depth.

Results: The novel multivariate-based formula was derived using height and middle finger length [D (cm) = 0.06 × height (cm) + 0.89 × middle finger length (cm) + 3.4] as reference variables. Bland-Altman analysis demonstrated mean differences between the optimal depth and ETT depth was -0.05 cm (95% LOA, -1.38 to 1.28 cm) for the new formula and 1.24 cm (95% LOA, -0.74 to 3.23 cm) for the traditional formula, respectively. This study demonstrated significant individual variations in tracheal intubation depth in pediatric patients.

Conclusion: The height- and middle finger length-referenced formulas predicted the depth of intubation more accurate than the traditional age-based formula in pediatric patients.

Impact: The prediction formula is effective in reducing the misalignment rate in children undergoing tracheal intubation under general anesthesia. The new formula, which incorporates both height and middle finger length, was found to predict the optimal endotracheal intubation depth with greater accuracy than the traditional formula. This provides an accurate and easy way for clinicians to calculate the depth of intubation.