Ultrasound vs Clinical Parameters for Difficult Airway Prediction in Obesity

Condition(s) studied

Investigational drug(s) / intervention(s)

Airway Ultrasonography: Preoperative airway ultrasonography will be performed by a trained anesthesiologist using a linear ultrasound probe with the patient in the supine position and head in neutral position. The following measurements will be obtained: (1) minimum distance from skin to hyoid bone (DSHB) at the transverse view of the hyoid bone level, (2) anterior neck soft tissue thickness at the thyrohyoid membrane level, and (3) hyomental distance ratio (HMDR), calculated as the ratio of hyomental distance in full extension (HMDe) to hyomental distance in neutral position (HMDn). These ultrasonographic parameters will be correlated with intraoperative Cormack-Lehane laryngoscopy grade and Han Scale mask ventilation score to assess their predictive value for difficult airway in obese patients.

Study summary

Obesity is associated with anatomical changes in the upper airway that increase the risk of difficult laryngoscopy and difficult mask ventilation during anesthesia. Conventional airway assessment parameters such as Mallampati score, neck circumference, and STOP-BANG scale are widely used but have limited predictive accuracy in obese patients. Airway ultrasonography has emerged as a promising non-invasive tool for difficult airway prediction; however, ultrasonographic criteria have not yet been standardized.

This prospective observational study aims to evaluate the utility of airway ultrasonography in predicting difficult airway in adult obese patients (BMI \>30 kg/m²) scheduled for elective surgery under general anesthesia. Ultrasonographic measurements will include the distance from skin to hyoid bone (DSHB) at the level of the hyoid bone, the anterior neck soft tissue thickness at the thyrohyoid membrane level, and the hyomental distance ratio (HMDR). These parameters will be compared with conventional airway assessment tools and correlated with intraoperative Cormack-Lehane laryngoscopy grade and Han Scale mask ventilation score to determine their predictive value for difficult airway.

Eligibility

Primary outcome measure(s)

• Correlation of Ultrasonographic Airway Parameters (DSHB and HMDR) with Cormack-Lehane Laryngoscopy Grade — Perioperative/Periprocedural
  Preoperative ultrasonographic measurements including the minimum distance from skin to hyoid bone (DSHB) at the hyoid bone level and the hyomental distance ratio (HMDR, calculated as hyomental distance in full extension divided by hyomental distance in neutral position) will be correlated with the intraoperative Cormack-Lehane laryngoscopy grade. Cormack-Lehane grades III and IV will be defined as difficult laryngoscopy. The diagnostic accuracy of DSHB and HMDR in predicting difficult laryngoscopy will be assessed using ROC curve analysis.

Trial sites (1)

More Fatih Sultan Mehmet Training and Research Hospital trials in Turkey

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