Ultrasound Evaluation to Predict Difficult Laryngoscopy in Children below 2 Years

Abstract

Objective: To evaluate the feasibility of sonography as a tool to predict difficult airway in children less than 2 y of age.

Methods: Airway ultrasound was performed in 90 children below the age of 2 y to measure airway dimensions preoperatively. Hyomental distance ratio in predicting difficult laryngoscopy was recorded as the primary outcome. Secondary outcomes included tongue thickness/oral cavity thickness ratio and tongue thickness/thyromental distance ratio in predicting difficult laryngoscopy and difficult intubation, time taken for intubation, and any complications. The sensitivity, specificity, positive predictive value, and negative predictive value with 95% CI of all the parameters were recorded.

Results: Six out of 90 (6.7%) patients had difficult laryngoscopy. HMDR was significantly different between children with easy and difficult laryngoscopy (1.15 ± 0.11 vs. 1.03 ± 0.016, p = 0.001). The optimal cutoff points for HMDR, TT/OCT, and TT/TMD to predict difficult laryngoscopy (CL grade III, IV) were > 1.055 (sensitivity 100%, specificity 86.9%), 0.755 (sensitivity 100%, specificity 57%), and 0.445 (sensitivity 53.5%, specificity 66.7%), respectively, the AUC being highest for HMDR (0.959). The cutoff value of ≥ 1.055 of HMDR to predict difficult laryngoscopy had the highest AUC of 0.959, p < 0.001. Fifty-two children had IDS = 0, while 38 had IDS between 1 and 4. None of the patients had IDS > 5.

Conclusions: Ultrasound-guided airway assessment is a feasible option in children less than 2 y. Hyomental distance ratio can form a useful tool for predicting difficult airway in this age group.

Trial registration: The trial has been registered in Clinical trial Registry of India (CTRI/2019/05/019014) before enrollment of the first patient.

Keywords: Children; General anesthesia; Laryngoscopy; Ultrasonography.