Pre-operative ultrasound-based airway parameter evaluation predicts difficult airway

Clinicians who manage airways continue to be very concerned about unexpectedly difficult airways, which have the potential to be fatal. There are still few established clinical markers that may be used to anticipate the challenges that come with managing airways. A straightforward, non-invasive method utilised by anesthesiologists during perioperative care is ultrasound. The conventional screening tests and evaluation tools for difficult laryngoscopy, together with pre-operative ultrasound measurement of the anterior neck soft-tissue thickness at different levels, may improve the prediction of difficult laryngoscopy. Recently published research evaluated how well pre-operative neck ultrasonography examination predicted difficult airways in individuals having elective general anaesthesia.

In this research, 114 adult patients receiving elective procedures under general anaesthetic were included. Upper airway ultrasonography measures of the neck, namely the thickness of the base of the tongue, the distance from the skin to the thyroid isthmus, and the distance from the skin to the hyoid bone, were taken in the pre-operative room. Details of the clinical airway exam were taken from the pre-anesthesia assessment form. The method of airway control was observed. These upper airway ultrasound measures were evaluated for their diagnostic utility in predicting difficult airways using receiver operating characteristic curves. The problematic airway group had a substantially greater distance (0.37 ± 0.133 cm) from the epidermis to the thyroid isthmus than the non-difficult group (P = 0.007). Of the studied ultrasonography parameters, it seemed to be a stronger predictor of problematic airways and corresponded better with clinical assessments. The group with problematic airways had a substantially higher body mass index (P = 0.009).

The distance between the skin and the hyoid bone (DSHB), the distance between the skin and the thyroid isthmus (DSTI), and the thickness of the base of the tongue (TBT) were the detected ultrasonic characteristics that we found to be statistically insignificant in predicting a difficult laryngoscopy by CL grading. In this study, DSTI showed stronger correlation with clinical evaluation instruments and seemed to be a more accurate predictor of problematic airways. Measured ultrasonography parameters reveal a higher area under the curve (AUC) for the ROC curve and a significant mean difference between the difficult and non-difficulty airway groups. Researchers discovered that 0.285 cm is the ideal cut-off value for DSTI in order to anticipate challenging airways.

Reference –

Waindeskar, Vaishali; Padala, Sri Rama Ananta Nagabhushanam; Jain, Shikha; Kiran, Molli; Mandal, Pranita; Pakhare, Abhijit P.1. Prediction of the difficult airway by pre-operative ultrasound-based measurement of airway parameters: A prospective observational study. Indian Journal of Anaesthesia 67(9):p 785-790, September 2023. | DOI: 10.4103/ija.ija_464_23.