1

Introduction

Electronic transnasal flexible laryngoscopy (EFL) is widely used in laryngopharyngeal disease diagnoses, biopsies, and minor surgeries of vocal cord and laryngeal mucosa. The procedure causes some degree of discomfort to the patients such as taste unpleasantness, nausea, vomiting, and even accidental decannulation due to the high sensitivity of pharyngeal mucosa. Various types of topical anesthetics have been commonly used, including tetracaine, lidocaine, cocaine and levobupivacaine . These agents allow for a smooth operation and help make procedures faster and more tolerable for patients. Tetracaine spray (TS) administered in three doses in a fixed interval is the most commonly used anesthesia method despite concern of high toxicity .

Oral dyclonine hydrochloride mucilage (ODHM) is a new local anesthetic compound with less toxicity, low central shadow effect, and a faster and longer lasting effect, which can be applied to skin and mucosal anesthesia. The compounds initially used in gastrointestinal endoscopy included dyclonine hydrochloride, deformer, carboxymethylcellulose sodium and sweeteners. Eleven clinical trials showed that ODHM is more effective than lidocaine in local anesthesia with regards to deforming taste and general effect in gastrointestinal endoscopy . However, dyclonine hydrochloride mucilage is rarely reported as a topical anesthetic in patients undergoing EFL. Our hypothesis is that ODHM is superior to tetracaine spray (TS) in patients undergoing EFL.

2

Methods

This study was approved by the Medicine Ethics Committee of China–Japan Union Hospital. This prospective, single-blinded, randomized study was conducted in the Ear Nose and Throat (ENT) Outpatient Department from February 2015 to May 2015. Informed consent was acquired from patients before the EFL procedure. Allergy information and family history were recorded during examination.

Inclusion criteria were patients with planned EFL who were greater than 18 years of age. Patients under the age of 18 were excluded. All consecutive patients undergoing EFL with or without minor surgeries were randomly divided into two groups: 1) ODHM group, in which patients received dyclonine hydrochloride mucilage (Yangtze River Pharmaceutical Co. LTD, China). The 10 ml dose was orally administered: The first 5 ml was swallowed slowly to allow observation of possible allergic reaction and the second 5 ml was maintained in the mouth for 5–10 min before the EFL procedure. In this trial, there was no allergic reaction to ODHM. 2) TS group received a spray three times at a dose of 5 ml of a 1% tetracaine (Yukang Pharmaceutical Co. LTD, China) solution to the pharyngolaryngeal mucosa 5–10 min before procedure (spray interval was 3–5 min). Administration occurred in a single disposal room by a nurse. Cotton with 0.05% Oxymetazolin hydrochloride (Daphne Pharmaceutical Co. LTD, China) was used to constrict blood vessels in the nares and chose the larger nasal cavity to intubation. Randomization was performed according to the visiting number: odd numbers were assigned to the ODEM group and the even numbers were assigned to the TS group. The investigators were blind to which agent was being administered; however, the patients were made aware of their treatment.

A 4.9 mm diameter flexible PENTAX-VNL-1570STK insertion tube in a Naso-Pharyngo-Laryngoscope was placed through the nasal cavity and into the laryngeal cavity. In each case, after the procedure, the patients and doctors were asked by the investigator to evaluate the degree of comfort they suffered during the EFL. A visual analog scale (VAS) fitted with a special VAS (0–10) ruler was used to assess the comfort: range 0–10; 0 = intolerable/not able to complete the procedure and 10 = no discomfort/completed procedure. Procedure time was recorded from start of EFL access in the nostril until completion or removal of the tube.

Statistical analysis was performed using the SPSS 17.0. Unless otherwise stated, values are expressed as means ± SD. To compare the differences between the two groups, Mann–Whitney U test was used for continuous variables. A value of p < 0.05 was considered statistically significant.

2

Methods

This study was approved by the Medicine Ethics Committee of China–Japan Union Hospital. This prospective, single-blinded, randomized study was conducted in the Ear Nose and Throat (ENT) Outpatient Department from February 2015 to May 2015. Informed consent was acquired from patients before the EFL procedure. Allergy information and family history were recorded during examination.

Inclusion criteria were patients with planned EFL who were greater than 18 years of age. Patients under the age of 18 were excluded. All consecutive patients undergoing EFL with or without minor surgeries were randomly divided into two groups: 1) ODHM group, in which patients received dyclonine hydrochloride mucilage (Yangtze River Pharmaceutical Co. LTD, China). The 10 ml dose was orally administered: The first 5 ml was swallowed slowly to allow observation of possible allergic reaction and the second 5 ml was maintained in the mouth for 5–10 min before the EFL procedure. In this trial, there was no allergic reaction to ODHM. 2) TS group received a spray three times at a dose of 5 ml of a 1% tetracaine (Yukang Pharmaceutical Co. LTD, China) solution to the pharyngolaryngeal mucosa 5–10 min before procedure (spray interval was 3–5 min). Administration occurred in a single disposal room by a nurse. Cotton with 0.05% Oxymetazolin hydrochloride (Daphne Pharmaceutical Co. LTD, China) was used to constrict blood vessels in the nares and chose the larger nasal cavity to intubation. Randomization was performed according to the visiting number: odd numbers were assigned to the ODEM group and the even numbers were assigned to the TS group. The investigators were blind to which agent was being administered; however, the patients were made aware of their treatment.

A 4.9 mm diameter flexible PENTAX-VNL-1570STK insertion tube in a Naso-Pharyngo-Laryngoscope was placed through the nasal cavity and into the laryngeal cavity. In each case, after the procedure, the patients and doctors were asked by the investigator to evaluate the degree of comfort they suffered during the EFL. A visual analog scale (VAS) fitted with a special VAS (0–10) ruler was used to assess the comfort: range 0–10; 0 = intolerable/not able to complete the procedure and 10 = no discomfort/completed procedure. Procedure time was recorded from start of EFL access in the nostril until completion or removal of the tube.

Statistical analysis was performed using the SPSS 17.0. Unless otherwise stated, values are expressed as means ± SD. To compare the differences between the two groups, Mann–Whitney U test was used for continuous variables. A value of p < 0.05 was considered statistically significant.