Objective:

The aim of this study is to prove that ultrasound is a helpful tool for predicting difficult airways.

Material and methods:

This is a descriptive, retrospective, and transversal study, which is based on a 30-patient sample, ASA ≤ 3, who needed endotracheal intubation prior to operation. We measured the distance from skin to epiglottis, through the thyrohyoid membrane, with an ultrasound. We used a cut-off value of 27.5 mm in order to predict difficult airways. We compared the result to the gold standard, which was a laryngoscopy, and we considered as “difficult airway” those in which: a) three or more attempts to intubate were needed, b) took more than 10 minutes to intubate, and c) had Cormack-Lehane grades III and IV.

Results:

We found that an ultrasound with a sensitivity of 50% CI 95% [21.5-78.5], specificity of 90.9% CI 95% [72.2-97.5], PPV 66.7% CI 95% [30-90.3] NPV 83.3% CI 95% [62.7-90.5], and accuracy of 80% CI 95% [62.7 a 90.5]; 10 OR CI 95% [1.34-74.5] predicts difficult airway.

Conclusion:

The ultrasound is a valuable tool for the prediction of difficult airways because of its accessibility and its high specificity and negative predictive value.