Improving mucosal anesthesia for awake endotracheal intubation with a novel method using dyclonine hydrochloride: A prospective, assessor-blinded, randomized controlled trial

Background: Topical anesthesia is a crucial step in awake endotracheal intubation for providing favorable intubation conditions. The standard of care technique for awake intubation at our institution, which consists of oropharyngeal tetracaine spray, can result in inadequate mucosal anesthesia. Therefore, we sought to compare the effectiveness of dyclonine hydrochloride mucilage to the standard of care tetracaine in achieving anesthesia of the upper airways for awake endotracheal intubation. Methods: This is a randomized, assessor-blinded, prospective study. From Jun. 1st, 2019 to Aug. 1st, 2019, patients scheduled for either endoscopic submucosal dissection or peroral endoscopic myotomy were enrolled and randomly allocated into two groups after obtaining written informed consent: patients allocated to novel awake intubation care (Group N-AIC) received a single administration of oral dyclonine hydrochloride mucilage, whereas patients allocated to standard awake intubation care (Group S-AIC) received three oropharyngeal tetracaine sprays before transcricoid tetracaine injection before awake intubation. Mean arterial pressure (MAP), which was the primary outcome of this study, as well as heart rate (HR) were recorded throughout the procedure and compared between the two groups. Feeling of numbness, nausea, and intubation conditions after topical anesthesia were also assessed. Results: Sixty patients were enrolled and completed the study. Baseline MAP and HR were similar between the two groups. However, hemodynamic responses to intubation and gastrointestinal endoscopy, especially MAP, were significantly less elevated in Group N-AIC. The degree of numbness of the oropharyngeal mucosa after topical anesthesia did not differ between the two groups, neither did the feeling of nausea during laryngoscopy. The amount of pharyngeal secretions before intubation was less in Group N-AIC. Total intubation time was significantly shorter in Group N-AIC when compared to Group S-AIC (18.4 ± 2.86 vs. 22.3 ± 6.47, P < 0.05). Extubation bucking was significantly less frequent in Group N-AIC (13.3% vs. 76.7%). Patients received in Group N-AIC had a lower rate of post-extubation sore throat compared to Group S-AIC (6.7% vs. 43.3%). Conclusions: In awake endotracheal intubation, novel care using oral dyclonine mucilage can provide more favorable mucosal anesthesia and better intubation conditions compared to standard of care practice using oropharyngeal tetracaine spray.