Transnasal Fiberoptic Laryngoscopy (TFL) is a common procedure in the otolaryngology clinic for the examination of vocal cord appearance and function, inspection and follow up of benign and malignant lesions, and investigating foreign body ingestion.

There are many forms for applying preprocedural local nasal anesthesia such as atomizers, nebulizers, spray, soaked pads, or local anesthetic gel application.

This study compares the effect of buffered versus plain lidocaine for local nasal anesthesia.

Transnasal Fiberoptic Laryngoscopy (TFL) is a common procedure in the otolaryngology clinic for the examination of vocal cord appearance and function, inspection and follow up of benign and malignant lesions, and investigating foreign body ingestion.

There are many forms for applying preprocedural local nasal anesthesia such as atomizers, nebulizers, spray, soaked pads, or local anesthetic gel application.

Products containing lidocaine are used in everyday practice, sometimes combined with vasoconstrictors such as oxymetazoline or phenylephrine. Lidocaine does not require special storage conditions and is a relatively inexpensive product.

Besides its use for local nasal anesthesia, lidocaine is also widely used for local and regional anesthesia in dentistry, emergency medicine, and surgical or invasive procedures. The addition of bicarbonate for lowering the acidity level of the solution has been studied before in these applications. The buffered solution demonstrated decreased patients pain and increased patient preference[1,2].

Solutions containing lidocaine with a vasoconstrictor such as epinephrine are widely used for soft tissue injection. This combination allows the benefits of prolonged anesthetic and decreased bleeding of the surgical site. However, this combination disadvantage includes increased acidity of the solutions, which may cause increased pain or burning sensation during drug administration. Alkalinization of combined lidocaine and epinephrine solutions has shown decreased local site pain, shorter onset time, and longer duration of anesthesia[3]. The addition of bicarbonate may be done by mixing into a syringe or other suitable container in a relatively easy and fast application for clinical use. Alternatively, a designated device may be used, such as the Onpharma mixing system (Onpharma), commonly used in dentistry[4].

While the alkalinization of lidocaine had shown advantages in local injection into soft tissues, its efficacy for local nasal anesthesia was not previously examined.

This study compares the effect of buffered versus plain lidocaine for local nasal anesthesia.

Inclusion Criteria:

• Patients undergoing TFL exam as part of their medical investigation and treatment.
• Age above 18 years and under 65 years.
• Both sexes

Exclusion Criteria:

• Age under 18 years or above 65 years.
• Hypersensitivity to the experiment drugs- bicarbonate, lidocaine, or another drug from the Amid type local anesthetics group (such as Emla or bupivacaine).
• Pregnancy or lactation.
• Signs and symptoms of recent URTI (rhinitis, cough, fever, sinusitis, tonsillitis, pharyngitis).
• Recurrent epistaxis - once per year or more.
• Cardiovascular conditions- ischemic heart disease with decreased physical functions of climbing two staircases or walking 500 meters on a horizontal plane without difficulty. Arrhythmias including permanent or paroxysmal atrial fibrillation, or using a pacemaker.
• Dysphagia- difficulty with swallowing, recurrent aspirations or pneumonia, decreased sensation that may affect swallowing such as previous CVA, peripheral neuropathy from any reason including diabetes. Partial or complete vocal cord immobility.
• Previous TFL exam once in the past six months or twice in the past year.
• Anxiety disorder - with or without drug therapy.
• Recurrent syncope for any reason, including vasovagal syncope. Epilepsy or recurrent seizures.
• Nose and sinuses disease- chronic sinusitis, recurrent sinusitis four or more events per year, Surgical intervention of nose or sinuses in the past year including submucous resection of the septum, turbinectomy, or endoscopic sinus surgery.
• Daily use of a nasal spray of any kind- including steroids or vasoconstrictors.
• Oncologic patients- undergoing chemotherapy or radiation, known tumor in the present or past of the nose and sinuses, nasopharynx, pharynx, hypopharynx, larynx, or subglottis. Patients after resections in these areas or after radiation to head, neck, or chest.
• Severe kidney impairment- GFR under 30 mL/min or severe liver impairment.
• Systemic disease involving the upper airways (e.g. pemphigus).
• Immunosuppression- HIV, drug-induced or congenital
• Unable to give informed consent for any reason, including unable to read or understand the consent form, being under psychiatric assessment, or taking psychiatric drugs.
• Current therapy with known interaction to the experimental drugs- cimetidine, propranolol, phenytoin.
• Moderate to severe nasal polyposis.

Both solutions will be kept in identical syringes with an atomization tip (Teflex, MAD Nasal™ Intranasal Mucosal Atomization Device). Each product has a randomized serial number. Both the investigator and the participant are masked. The solutions are made by a different investigator who is not part of the clinical examination, questionnaire filling, patients selection, and recruitment.