# Evaluation of upper airway ultrasonographic measurements in predicting difficult intubation: A cross-section of the Turkish population

## TL;DR

This study evaluates how well upper airway measurements predict difficult intubation in the Turkish population, finding that combining clinical and ultrasonographic methods improves accuracy.

## Contribution

The study introduces the neck circumference/thyromental distance ratio and ultrasonographic skin–epiglottic distance as effective predictors for difficult intubation in Turkish patients.

## Key findings

- The neck circumference/thyromental distance ratio had 92.9% sensitivity and 88.3% specificity for predicting difficult intubation.
- Ultrasonographic skin–epiglottic distance was the most sensitive ultrasonographic measurement.
- Combining body proportion-based measurements with ultrasonography improves prediction accuracy for difficult intubation.

## Abstract

Studies have shown that there are differences in clinical evaluation parameters and difficult intubation rates among different ethnic populations. In our study, we aimed to evaluate the efficacy of upper airway clinical and ultrasonographic measurement methods in Turkish population.

Our study is a single-center, prospective, observational study conducted with 402 patients. All patients underwent clinical airway measurements which are routinely used in pre-anesthetic evaluation. In addition, ultrasonographic anterior neck soft tissue thickness measurements of each patient were made and recorded.

Among the clinical measurements, we found the neck circumference/thyromental distance (TMD) ratio to be significant with a cut-off value of 5.5 and a sensitivity of 92.9% and a specificity of 88.3%, while among the ultrasonographic anterior neck measurements, we found the skin–epiglottic distance to be the most sensitive measurement. We found that there was a positive relationship between the neck circumference/TMD ratio and skin–epiglottis.

In our study, we found that routine measurement methods used in airway examination alone are not sufficient, and measurements that take into account the body proportions of the patients, such as the neck circumference/TMD ratio and the ultrasonographic evaluations are more useful in predicting difficult intubation.