Sugammadex and rocuronium-induced anaphylaxis

drawn through this area as it corresponded to where the airway passage normally occurs. At all other sections, the curve was drawn in the middle of the airway, not the surface of the tongue. The computer software was programmed to measure the area bounded by the line of the airway curve and the line of sight. The outline of the tongue was not used in the calculation. ‘As demonstrated by their quoted pictures from Adnet and colleagues, the tongue does not always correlate with the primary curve. This confuses the explanation even further’. We do not feel that the tongue surface is the correct reference for the primary curve. The primary curve is in the middle of the airway passage. ‘The relationship between the alpha angle and ease of direct laryngoscopy is not directly intuitive’. We are sorry if angle alpha is not intuitive. It does, however, correlate with changes in the relationship of the supraglottic and tracheal axes which makes it important for intubation. It is therefore an important parameter for this reason. ‘The area posterior to the line of vision represents the amount of tongue that needs to be displaced during “direct laryngoscopy” in order to view the glottis. Head extension reduces the amount of tongue that needs to be displaced’. We agree and have shown this in our study. ‘The sniffing position enables more head extension on a flat table surface’. On a flat surface, head extension is maximal when upper thoracic/lower cervical spine is flexed. This may be achieved with shoulder bolster and no head lift (e.g. extension position used by ENT during laryngoscopy), ramped position in morbid obesity when shoulder bolster is used and two or more pillows under the head and the sniffing position in non-obese patients. ‘The sniffing position also facilitates ease of “intubation” by aligning the tracheo-laryngeal axis with the line of vision (via neck flexion)’. We agree and that has been shown in our study. ‘The theory of two curves does not clearly explain laryngoscopy and intubation’. We would disagree. In our opinion, the three-axes alignment theory needs to be modified by more contemporary data that will be applicable to all laryngoscopy devices, such as direct laryngoscopy, videolaryngoscopes, and fibreoptic intubation. We hope this may clarify the concerns raised with this study.