How To Do Mirror Laryngoscopy

Laryngoscopy may be indicated to evaluate (2):

• Chronic cough

• Dysphagia

• Odynophagia

• Hoarseness or change in voice

• Dysphonia

• Chronic throat pain

• Sensation of a lump or foreign body in the throat

• Symptoms of aspiration (eg, coughing, choking, and wheezing progressing to fever; chest pain and shortness of breath if there is lung involvement)

• Sometimes hemoptysis

In particular, patients at high risk of head and neck cancer (eg, those who smoke heavily or those who regularly use alcohol) may benefit from laryngoscopy, especially if they have had hoarseness, sore throat, or ear pain for > 2 weeks. Patients who have had or require thyroid and parathyroid surgery should also undergo laryngoscopy to assess the function of the recurrent laryngeal nerve and to identify vocal cord paralysis (3).

Laryngoscopy may also be useful to evaluate the airway prior to orotracheal intubation.

Absolute contraindications

• Suspected epiglottitis

• Ludwig angina

• Angioedema

In such cases, stimulation of the laryngopharynx may further compromise the airway. If laryngoscopy is essential, it should be done in the controlled setting of an operating room in the presence of a clinician skilled at difficult airway management (including surgical techniques), and ideally performed using direct laryngoscopy (eg, flexible laryngoscopy) rather than mirror laryngoscopy (4).

Relative contraindications

• Stridor

• Trismus

• Strong gag reflex

• Extensive surgery or radiotherapy to the mouth

• Anatomical limitations (eg, presence of palatal obturators)

• Injury to the mucosa, which may cause bleeding

• Laryngospasm and airway compromise

The procedure may cause gagging, coughing, and/or vomiting.

• Gloves

• Protective eyewear

• Mask

• Tongue depressor

• Curved dental mirror

• Antifogging solution, warm water (approximately body temperature), or alcohol swab

• Headlamp or other external light source that can be used hands-free if possible

• Gauze pad 10 cm × 10 cm (4 in × 4 in)

• Topical anesthetic spray (eg, lidocaine, benzocaine)Topical anesthetic spray (eg, lidocaine, benzocaine)

• Most patients can tolerate mirror laryngoscopy without anesthesia of the oropharynx; however, topical anesthesia may be needed.

• If the patient does not tolerate this procedure, flexible laryngoscopy should be done.

• Mirror laryngoscopy only provides a limited view of the subglottic larynx and proximal trachea. If pathology is suspected in these regions, use another procedure, such as bronchoscopy.

• The pharynx includes the nasopharynx, oropharynx, and hypopharynx.

• The larynx connects the pharynx to the trachea and is suspended from the hyoid bone. It includes 3 single and 3 paired cartilage structures: single (epiglottis, thyroid, and cricoid) and paired (arytenoid, cuneiform, and corniculate). The larynx extends from the tip of the epiglottis down to the inferior aspect of the cricoid cartilage and includes the vocal folds.

Anatomy of the Larynx

3D Model

• Patient should sit upright with the head against a headrest, and leaning slightly forward, facing the clinician. The proper position is sometimes called the "sniffing position" because the patient appears to be leaning forward as if to smell a flower.

• Legs should not be crossed.

• Direct the external light source toward the patient's oral cavity.

• Warm the mirror with warm water (approximately body temperature) to prevent fogging (check to make sure mirror is not too hot). Alternatively, coat the mirror with antifogging solution or alcohol.

• Wrap the patient's tongue with gauze and grasp it with your nondominant hand. The gauze will prevent the tongue from slipping and protect it from injury by the lower incisor teeth.

• Gently pull on the tongue.

• Instruct the patient to breathe deeply through the mouth, to help prevent gagging.

• Slide the mirror into the oropharynx without touching the tongue or any mucosa.

• Place the back of the mirror against the uvula and gently insert it further until the larynx can be clearly seen.

• If gagging occurs, remove the mirror and spray the posterior oropharynx with a topical anesthetic.

• Move the mirror gently and as little as possible to inspect the base of the tongue, valleculae, epiglottis, piriform sinuses, arytenoids, false and true vocal cords, and if possible to visualize, the larynx below the vocal cords.

• Rotate the mirror from side to side between the thumb and forefinger to bring lateral structures into view.

• Fully inspect the vocal cords.

• Instruct the patient to say "eeee," which will contract the vocal cords, thereby permitting assessment of their function.

• Instruct the patient to avoid eating and drinking for at least 20 minutes after the procedure to avoid aspiration due to residual laryngopharyngeal anesthesia.

• Failure to align the light source as closely as possible with the line of sight

• Failure to warm the mirror, because a cold mirror will fog

• Failure to maintain an adequate hold of the patient's tongue to keep it retracted

• Allowing the patient to lean back, which will prevent full visualization

• Positioning the mirror at the wrong angle to see the larynx

• To avoid neck strain, raise the patient's chair so that the mirror can be held close to the examiner's eye level.

• Use one finger of the hand holding the mirror to elevate the upper lip.

• Touching the uvula alone should not elicit the gag reflex, but avoid touching the back or sides of the throat, which can.