Indian journal of anaesthesia
-
Thyromental height test (TMHT) is a recently described anatomical bedside screening tool in predicting difficult laryngoscopy. It has been shown to be more accurate than the modified Mallampati score, thyromental distance (TMD), and sternomental distance with regard to sensitivity and positive predictive value (PPV). Airway assessment studies based on the anatomic parameters of the upper airway are limited in the subcontinent population. We attempted this study to evaluate and validate the predictive value of TMHT at 50 mm in an Indian population in predicting difficult laryngoscopy. ⋯ TMHT appears promising as a single anatomical measure to predict the risk of difficult laryngoscopy, however, validation will require further studies in more diverse patient populations.
-
Topicalisation of the airway by various techniques has routinely been recommended for awake fibre-optic bronchoscopy in cases of difficult airway. However, topicalisation by itself can cause airway obstruction by decreasing the tone of the laryngeal muscles and causing a dynamic air inflow obstruction. Two cases of difficult airway are illustrated where anaesthetising upper airway with nebulisation with 4% lignocaine (Xylocaine™) or 2% lignocaine (Xylocaine™) jelly resulted in stridor and upper airway obstruction. ⋯ We would like to highlight that topicalisation of airway, once thought as a relatively safe technique, can cause airway collapse if not detected and anticipated at the earliest. Pre-operative spirometry and airway ultrasonography can be useful in detecting the patients at risk of developing airway obstruction. Using a nasopharyngeal airway during topicalisation can serve as a valuable device in preventing total airway obstruction in susceptible patients.