Oral dyclonine hydrochloride mucilage versus tetracaine spray in electronic flexible laryngoscopy: A prospective, randomized controlled trial

Background: Topical anesthesia is important for electronic flexible laryngoscopy (EFL) utilization. We hypothesized that oral dyclonine hydrochloride mucilage (ODHM) is superior to tetracaine spray (TS) in patients undergoing EFL examination. Methods: This study included 932 patients randomized into either an ODHM or TS group, in which patients received either a single utilization of ODHM or TS administered via spray in three intervals. A 4.9 mm diameter flexible PENTAX-VNL-1570STK insertion tube placed into a Naso-Pharyngo-Laryngoscope (PENTAX Medical, Japan) was used in the procedure. Visual analogue scale (VAS) (0-10) was used to evaluate patient tolerance and procedure success by the operator, independently. Procedure time was also recorded. Results: Both patients' and doctors' VAS scores were significantly higher in the ODHM group compared to the TS group. When subgroup analysis was made according to the procedure length (100 s), there was no significant difference in VAS between ODHM and TS groups in the short time procedure (<= 100 s), while VAS in the ODHM group was higher compared to the TS in the long time procedure (>100 s), as assessed by both patients and doctors. Conclusion: A single use of ODHM seems to be superior to three doses of TS in patients undergoing EFL, specifically in procedures longer than 100 seconds. (C) 2016 Elsevier Inc. All rights reserved.