Background: The poor reliability of traditional screening tools to identify a potentially difficult
airway makes the difficult laryngoscopy and tracheal intubation rate remains at 1.5–13%.The
hypothesis is that fat pads affect the view during direct laryngoscopy so the increasing
thickness of pretracheal soft tissue or pre-epiglottic space could be strong predictors of difficult
laryngoscopy as the mobility of the pharyngeal structures is impaired. Upon that, we aimed to
evaluate ultrasound-measured distance from skin to epiglottis for prediction of difficult laryngoscopy in Egyptian population.
Methods: This was a prospective single blind randomized clinical study conducted on 80
patients requiring general anesthesia.Preoperatively, airway evaluation was performed using
three parameters including Mallampati score, thyromental distance and ultrasound-measured
distance from skin to epiglottis at the level of thyrohyoid membrane. The primary outcome was
to correlate ultrasound measured distance from skin to epiglottis with difficult laryngoscopy in
Egyptian population using Cormack – Lehane grading.
Results: Difficult laryngoscopy group displayed greater thickness of the ultrasound measured
distance from the skin to epiglottis(2 ± 0.3 cm versus 1.7 ± 0.3 cm; p = 0.002). The cut-off point
for difficult laryngoscopy was >1.85 cm with sensitivity of 80%, specificity of 70.8% and area
under the receiver operating characteristic curve was 0.759. Mallampati score and thyromental
distance had poor area under the curve = (0.651, 0.670 respectively).
Conclusion: Our study revealed good correlation between ultrasonograohic measurement of
the skin to epiglottis distance and Cormack-Lehane grade in Egyptian population, therefore it
might be considered as a predictor of difficult laryngoscopy. |
