Comparing Sedation Regimens for Awake Fiberoptic Intubation

Correspondence To the Editor: In a single‑center, prospective, randomized double‑blind clinical study comparing dexmedetomidine‑ midazolam and sufentanil‑midazolam sedation regimens for awake fiberoptic intubation (AFOI) in 50 patients with difficult airways due to limited mouth opening, Li et al. show that both dexmedetomidine and sufentanil are effective as an adjuvant for AFOI under airway topical anesthesia combined with midazolam sedation, but respiratory depression is a potential risk in the sufentanil‑midazolam regimen. Given that AFOI has been established as the gold standard for difficult airway management, [2] their findings have potentially clinical implications. In our view, however, there are several aspects of this study that need to be clarified and discussed. First, the severity of a cough during fiberoscopy and tracheal tube placement was stated as a primary endpoint. In baseline characteristics of study population, however, the authors did not specify whether patients' comorbidities were comparable between groups. History of smoking, chronic cough, asthma, chronic obstructive pulmonary disease, airway infection, and bronchiectasis can increase airway reactivity, [3] resulting in the airway more sensitive to fiberoptic procedure, lidocaine spray, and tracheal tube insertion. Furthermore, the authors did not describe the experience of intubators in the AFOI. The experience and competence with the airway procedures are critical for their successful use, especially when there is a difficult airway. It must be emphasized that for the results of a comparative airway management study to be valid, participants must be equally proficient with tested airway procedures to avoid bias. In addition, ease of both fiberoscopy and tracheal tube placement depends on patient's head position and airway clearance procedures, such as sniffing position, jaw‑thrust, lingual traction, and external laryngeal manipulation. In this study, it was unclear whether two groups were comparable with respect to patients' head position and airway clearance procedures during fiberoscopy and tracheal tube placement. Second, to shorten the time of fiberoscopy, a modified " spray‑as‑you‑go " technique with 2% lidocaine 2 ml/spray at a 15‑s interval was used for airway topical anesthesia in this study. It must be pointed out that as with other local anesthesia methods, " tincture of time " is one of the most useful supplements to airway topical anesthesia. About 2–4% lidocaine applied to the airway mucosa begins to produce topical anesthesia in about 1 min and 3–5 min of contact time is usually required to provide adequate penetration of lidocaine into the airway mucosa for maximal effect. [4] Thus, …