Neuromuscular blocking agents and intubation: a reply

We thank Sorbello et al. for their thoughtful comments on our study comparing postoperative laryngeal morbidity and intubating condition using a McGRATH MAC video laryngoscope with or without neuromuscular blocking agents (NMBA) [1]. We did not use a depth of anaesthesia monitor or neuromuscular blockade monitor in this study. Such monitoring methods should be used in future dose– response studies using videolaryngoscopy without NMBAs. The dosage of rocuronium used in our study was not 6– 8 mg.kg 1 but 0.6–0.8 mg.kg ; this misprint was corrected immediately after the first online publication. We used smaller tracheal tubes than previous studies using direct laryngoscopy [2, 3]. We agree with Sorbello et al.’s comment that using a smaller tracheal tube reduces laryngeal complications. We used a stylet to make it easier for the tip of the tracheal tube to reach the glottis without abutting the pharynx or laryngeal tissues. We agree that videolaryngoscopy further reduces laryngeal complications during tracheal intubation compared with direct laryngoscopy. However, because other factors such as intubation time or extubation method can also affect laryngeal complications, we think that it is difficult to reduce the incidence of laryngeal complications beyond those reported in our research and other studies. We maintain that NMBAs are not always necessary for tracheal intubation when combining propofol, remifentanil and videolaryngoscopy, but agree that NMBAs should be used for patients with unstable haemodynamics and for surgery requiringmuscle relaxation.