Topical anaesthesia for awake fibreoptic intubation

In the recent article by Pirlich et al. [1], comparing airway topical anaesthesia for awake fibreoptic intubation using the Enk Fiberoptic Atomizer Set (Atomizer group) with boluses of 2% lidocaine (control group) administered via the working channel of fibreoptic bronchoscope (FOB), patients in the Atomizer group experienced a reduced number of coughs and fewer distinct coughing episodes. During awake intubation, coughing is commonly reported as one of the most distressing symptoms and described as an unacceptable feature [2]. The incidence of coughing is a surrogate measure of the quality of awake fibreoptic intubation [3]. In both groups in this study, however, the incidence of coughing during tracheal stimulation was as high as 85–88% and the median number of coughs was 4–7, suggesting that airway topical anaesthesia for awake fibreoptic intubation was inadequate. This may have resulted from inadequate doses of lidocaine spray and a short interval between sprays (2 min): in the control group, only one supraglottic spray was performed using 5 ml of lidocaine 2% plus 5 ml air in a 10 ml syringe via the working channel of the FOB. This is not a standard technique for spray-asyou-go topical airway anaesthesia, which requires that after the nasal and/or oral mucosa is anaesthetised by direct spray of local anaesthetic, the FOB is advanced to a position in the hypopharynx where the epiglottis, glottis, and other glottic structures are sprayed successively. For each target site, aliquots of local anesthetic should be sprayed through the working channel. To ensure that all of the injected local anaesthetic is ejected from the working channel and adequate spreading of the injected solution onto the target mucosa is achieved, most commonly 1 ml of 2% lidocaine plus 9 ml air in a 10 ml syringe is applied for each spray. Furthermore, a second 10 ml of air is often injected immediately after the first [4]. Before the FOB is advanced into the trachea for further spray, adequate topical anaesthesia of the glottis with cessation of the laryngeal response to further lidocaine administration, must also be achieved [5]. In this study, it was unclear why no extra lidocaine aliquot was used as a rescue treatment in the control group, though incidence of distinct coughing episodes during tracheal stimulation was as high as 27%. In this study, patients in the Atomiser group reported a better median level of comfort on the first postoperative day compared with those in the control group. We are interested to know whether the two groups were comparable with respect to postoperative pain management and opioid dosages. When early postoperative comfort levels between the groups are compared, standardisation of postoperative analgesia must be a crucial component of study design. In the absence of comparisons of postoperative pain management and opioid dosages, the primary findings and their subsequent conclusions on early postoperative comfort level must be interpreted with caution, as they may have been obtained using incomplete methodology. Finally, as far as we know, the manufacturer, Cook Medical (Limerick, Ireland) is no longer providing the Enk Fiberoptic Atomizer Set and the product information on manufacturer website has been deleted (https://www.cookmedical.com/products/, accessed 15/06/ 2016). At the present time, there is no commercial Enk Fiberoptic Atomizer Set available.