Ultrasound as a Tool in the Assessment of Airway Difficulties – A Cross-sectional Study

Abstract Background and Aims: Airway management is fundamental to safe anaesthetic practice and is of paramount importance. This study aimed to determine the ability of ultrasound (US) measurements of anterior neck soft-tissue thickness at various levels in predicting difficult mask ventilation (DMV) and difficult laryngoscopy in patients undergoing elective tracheal intubation for general anaesthesia. Methodology: This cross-sectional study was done at a tertiary care hospital in Kerala, during 2020–2021, involving 83 patients sampled through convenience sampling. The anterior neck soft-tissue thickness was measured using a portable US machine in a supine position preoperatively. The next day, the patients were induced and mask ventilation was assessed using the four-level Han Scale. Direct laryngoscopy was performed and the Cormac–Lehane (CL) grading class III and IV was taken as a surrogate for a difficult airway. DMV was defined as Han Scale Grade 3 or 4. The collected data were entered in Microsoft Excel and analysed using STATA. Results: Majority belonged to MMPC 2 (51.8%) and MMPC 3 (34.9%). The majority had CL2A grade (51.8%) followed by CL1 (20.5%) and CL2B (19.3%). The Mean Distance from Skin to Hyoid Bone (DSHB) ( P 0.008) and Distance from Skin to Anterior Commissure of Vocal cord (DSAC) ( P 0.03) showed a statistically significant difference between the patients with different difficulty levels of mask ventilation. Conclusions: US measurements of anterior neck anatomy do not correlate with the degree of difficult intubation. DSHB and DSAC may be used as an adjunct, with DSHB showing a stronger positive correlation.