We read with interest the recent article by Mazères et al.,1 who evaluated the feasibility and tolerability of awake intubation with the Bonfils intubating fibrescope in adult patients with a predicted difficult airway undergoing ear, nose and throat cancer surgery. Their finding that the success rate of tracheal intubation with this device is up to 93.9% is promising. However, several aspects of this study need to be clarified and discussed. We believe that these issues are important for others who would like to try awake intubation with this technique in patients with a difficult airway.
First, in the method, the authors stated that hydroxyzine was chosen as the premedication because a benzodiazepine would have affected the patient's memory and reduced the muscular tone in the upper airways. The available evidence seems not to support this statement. It is generally believed that an adequate sedation and analgesia regimen for awake intubation should provide patient safety, sedation and comfort as well as prevention of negative recall of the procedure.2,3 Hydroxyzine is often used as a weak sedative or anxiolytic, but it is less useful as an amnesic agent. Owing to a prolonged onset time of action (30–60 min), moreover, hydroxyzine is not a suitable premedication agent when used alone.4 Although remifentanil can provide analgesia and help blunt airway reflexes, use of remifentanil alone fails to provide amnesia and adequate sedation. Thus, in clinical practice, an intravenous benzodiazepine is used commonly to provide amnesia and improve quality of opioid sedation for awake intubation. Furthermore, midazolam has much to recommend it because of its quick onset, fairly short duration of action and lack of pain with injection.3
Second, in this study, atropine was used as an antisialagogue agent and 0.5 mg was given orally 1 h before surgery. It has been shown that the use of antisialagogue agents can improve fibreoptic intubating conditions,5 because decreasing airway secretions will aid in effectiveness of topical agents and make fibreoptic intubation much easier. Although any anticholinergic agent, such as atropine or scopolamine, could be given for this purpose, glycopyrrolate is the one that is most commonly used due to its lack of central nervous system effects and relatively lesser likelihood of producing tachycardia.3 Compared with intravenous or intramuscular administration, moreover, oral atropine may have a low efficacy and a slow onset time.
Third, in the results, the authors should provide the time required for airway preparation, namely the period from initiation of airway topical anaesthesia to the start of tracheal intubation. This should be a pivotal parameter to evaluate the efficacy of their method. Also, a clinically accepted preparation time is important in a high-volume surgery programme, so that there is a safe but rapid turnover of patients requiring fibreoptic intubation.6
Fourth, the authors reported that the incidence of interventions which met the quality requirements was 78.8%. However, the postoperative interviews showed that 84–91% of patients rated their global perception of intubation as good or very good. That is, some of the patients whose interventions did not meet the quality requirements also had a good or very good global perception of intubation. It is somewhat difficult for the readers to understand these results. In the method, there was no mention of whether the postoperative interviews were done by an independent investigator unaware of the aims of the study. If this is not so, the validity of the postoperative interview data is questionable. Previous studies showed that when remifentanil alone was used for awake fibreoptic intubation, most patients had memories of details of the airway procedure and a few patients recalled pain and discomfort during airway preparation and intubation.7–9 Just like patients’ awareness during general anaesthesia, the memory and recall for awake airway procedures may lead to long-term adverse psychological effects, especially for the patients who have experienced many awake intubations because of difficult airway and surgical therapy.10 Thus, we argue that patients’ memory and recall for awake airway procedure should be included in the postoperative interview data.
None of the authors had financial support or potential conflicts of interest for this work.
1. Mazères JE, Lefranc A, Cropet C, et al. Evaluation of the Bonfils intubating fibrescope for predicted difficult intubation in awake patients with ear, nose and throat cancer. Eur J Anaesthesiol
2. Xu YC, Xue FS, Luo MP, et al. The median effective dose of remifentanil for awake laryngoscopy and intubation. Chin Med J (Engl)
3. Simmons ST, Schleich AR. Airway regional anesthesia for awake fiberoptic intubation. Reg Anesth Pain Med
4. Özge K, Hatice T, Arzu M, et al. Effects of hydroxyzine–midazolam premedication on sevoflurane-induced paediatric emergence agitation: a prospective randomised clinical trial. Eur J Anaesthesiol
5. Brookman CA, Teh HP, Morrison LM. Anticholinergics improve fibreoptic intubating conditions during general anaesthesia. Can J Anaesth
6. Wieczorek PM, Schricker T, Vinet B, Backman SB. Airway topicalisation in morbidly obese patients using atomized lidocaine: 2% compared with 4%. Anaesthesia
7. Puchner W, Egger P, Puhringer F, et al. Evaluation of remifentanil as single drug for awake fiberoptic intubation. Acta Anaesthesiol Scand
8. Rai MR, Parry TM, Dombrovskis A, Warner OJ. Remifentanil target-controlled infusion vs propofol target-controlled infusion for conscious sedation for awake fibreoptic intubation: a double-blinded randomized controlled trial. Br J Anaesth
9. Vennila R, Hall A, Ali M, et al. Remifentanil as single agent to facilitate awake fibreoptic intubation in the absence of premedication. Anaesthesia
10. Xue FS, Liao X, Li CW, et al. Clinical experience of airway management and tracheal intubation under general anesthesia in patients with scar contracture of the neck. Chin Med J (Engl)