Ultrasound as an Assessment Method in Predicting Difficult Intubation: A Prospective Clinical Study.

OBJECTIVE: Aim of the study is to predict the difficulty in intubation preoperatively using ultrasonography.

METHODS: One hundred and thirty-seven patients underwent ultrasound followed by surgery under general anesthesia. A experienced radiologist examined the airway and performed measurements of specific airway parameters: visualization of hyoid bone, visualization of vocal cords through thyroid cartilage, visualization of epiglottis, distance from base of tongue to hyoid bone, distance of hyomental region distance of thyrohyoid region, distance between skin and fat pad thickness to thyroid cartilage, thickness of submental region, distance from epiglottis to skin (above hyoid), and visualization of cricothyroid membrane. After performing ultrasound, patient was presented for surgery. An experienced anesthesiologist who is associated with this study did all the laryngoscopy and intubation.

RESULTS: We were able to visualize all relevant anatomical structures in all the participants using ultrasound. The receiver operating characteristic curve analysis results showed that hyomental is ≤ 1.09 ( P value < 0.01) to classify difficult in intubation.

CONCLUSION: The study shows that ultrasound can reliably image all the airway structures. This study suggests that hyomental distance is a more valid criterion in predicting difficult intubation. Further, case control study is needed for assessing the ease of intubation.