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Laryngeal, Pharyngeal, and Oral Examination



AUTHOR: BERTRAND. LUSSIER




SYNONYMS


Laryngoscopy, pharyngoscopy



OVERVIEW AND GOAL


Complete examination of oral cavity, oropharynx, larynx, and part of the nasopharynx



INDICATIONS



• Anorexia (secondary to oral discomfort)

• Oronasal fistula evaluation

• Mandibular/maxillary fracture assessment

• Cervical/oral/facial trauma

• Precise occlusion evaluation

• Ptyalism/hypersalivation

• Gagging

• Halitosis

• Facial deformity

• Voice change

• Dysphagia

• Noisy respiration, especially inspiratory stridor with a radiographically normal trachea

• Respiratory distress, especially inspiratory


CONTRAINDICATIONS


Severe respiratory distress necessitating oxygen supplementation, endotracheal intubation, or emergency tracheostomy



EQUIPMENT, ANESTHESIA


VENOUS ACCESS:


• Hair clippers with a #40 blade

• Surgical skin scrub preparation materials

• IV over-the-needle catheter of appropriate size for the animal (18-24 gauge)

• T-port or PRN to cap catheter

• White cloth tape, 1½ inches (3.5 cm) and 1 inch (2.5 cm), for catheter fixation

• 5 mL heparinized saline

ANESTHETIC AGENTS:


Premedication:
• It may be preferable to avoid premedication when evaluating laryngeal function. The use of thiopental without premedication significantly increases arytenoid motion before recovery, which is optimal when compared to other protocols (propofol, ketamine, and diazepam; acepromazine and thiopental; acepromazine and propofol). This is the recommended protocol for evaluating laryngeal function (Tobias et al., 2004).

• If the lack of premedication when potentially evaluating laryngeal function is unacceptable to the clinician, an alternative is glycopyrrolate (0.01 mg/kg IV, IM, or SQ) and butorphanol (0.1 mg/kg IV, IM, or SQ).

• If no evaluation of laryngeal function is judged necessary, a standard sedation or premedication protocol is acceptable if the animal is stable. Examples (see also inside back cover of book):
○ Glycopyrrolate (0.01 mg/kg IV, IM, or SQ) + acepromazine (0.05 mg/kg IM or SQ) + butorphanol (0.1 mg/kg IM or SQ); or

○ Glycopyrrolate (0.01 mg/kg IV, IM, or SQ) + hydromorphone (0.1 mg/kg IM) ± acepromazine (0.05 mg/kg IM or SQ)

Induction:
• For evaluation of laryngeal function, thiopental (20 mg/kg IV, give half the volume as a bolus and then “to effect”) or propofol (2 mg/kg with premedication, or 6 mg/kg if no premedication) are preferred over ketamine-diazepam (Gross et al., 2002).

• If no evaluation of laryngeal function is judged necessary, routine agents are appropriate. Examples in stable animals include:
○ Thiopental (as above); or

○ Propofol (as above); or

○ Ketamine (10 mg/kg) + diazepam (0.5 mg/kg) IV

Stimulation of respiration:
• The use of doxapram HCl helps differentiate normal dogs from dogs with laryngeal paralysis. In these dogs, administration of doxapram seems to enhance paradoxical arytenoid motion:
○ Doxapram HCl, 5-10 mg/kg IV

POSITIONING:


• To maintain head in the upright position:
○ Conformable roll gauze (e.g., 2-inch [5 cm] Kling)

○ Two poles (of the type used for IV fluid administration, optional)

ORAL EXAMINATION:


• Oral speculum (mouth gag)

• Light source/transilluminator

• Laryngoscope

• Dry gauze sponges:
○ For manipulating the tongue

○ To dry up secretions

LARYNGEAL EXAMINATION:


• Oral speculum

• Light source/transilluminator

• Laryngoscope

• One or two tongue depressors taped end to end for dorsal retraction/elevation of the soft palate

OROPHARYNGEAL AND NASOPHARYNGEAL EXAMINATION:


• As for oral and laryngeal examination (above) + spay hook for cranial retraction of soft palate

• Small mirror used in dentistry, with antifogging agent or immersed in warm (38○C) water/saline

• Small flexible endoscope (see Alternatives section, below)

FINE-NEEDLE ASPIRATION/BIOPSIES:


• A set of 10-mL syringes, 22-gauge needles, and microscope slides for fine-needle aspiration and cytologic examination

• Biopsy kit:
○ A #15 scalpel blade

○ Adson forceps

○ Needle holder

○ Small scissors

○ Suture scissors

○ Appropriate size resorbable suture (surgeon’s preference)

ENDOTRACHEAL INTUBATION:


• Appropriate size tube (see p. 1293)

• Conformable 1- or 2-inch tape or gauze for tube fixation

• A 5- to 10-mL empty syringe for cuff inflation

• Anesthesia machine verified with appropriate circuit for the animal (semiopened or semiclosed):
○ Functional

○ Oxygen

○ Inhalant anesthetic agent


ANTICIPATED TIME


About 15-30 minutes



PREPARATION: IMPORTANT CHECKPOINTS



• Use preoxygenation with a mask if possible.

• Always perform this examination on animals that have been fasted, because the airway is not always protected during the exam. There is the possibility of regurgitation of gastric contents and subsequent aspiration pneumonia.

• Always be prepared for orotracheal intubation of animal and possible ventilation with oxygen through an anesthetic circuit.

• In animals in respiratory distress, always be prepared to perform an emergency tracheostomy (see p. 1344).

• In animals with moderate or marked inspiratory stridor or any degree of upper airway distress, owners must pre-emptively hear and understand options to consider (surgical intervention if problem correctable, euthanasia on the table if noncorrectable obstructive disorder) in case severe laryngeal infiltration, a nonresectable mass, or other equally serious problem is identified.


POSSIBLE COMPLICATIONS AND COMMON ERRORS TO AVOID



• Incomplete examination

• May give a false-positive diagnosis of laryngeal paralysis because animal is too heavily sedated or not enough time is given for animal to come out of light anesthesia. To minimize the occurrence of this situation, prepare doxapram HCl and administer if needed.


PROCEDURE


When dogs are extremely dyspneic due to laryngeal paralysis, the diagnosis often can be made on the awakened animal: a bright light source (e.g., Finnoff transilluminator) is directed into the oral cavity during the severe dyspnea, and failure of the arytenoid cartilages to abduct is clearly apparent in the conscious animal. Otherwise, proceed as follows:


Venous access:
• Prepare site for IV catheter insertion (clip, clean, and prep skin).

• Insert IV catheter.

• Close catheter with a T tube or a PRN.

• Fixation of catheter to skin

• Flush catheter with heparinized saline.

Premedication:
• Administer premedication if judged necessary.

Preoxygenation:
• Animal in sternal recumbency

• If possible, use a mask to preoxygenate animal for 5 minutes.

Induction of anesthesia:
• IV administration of predetermined anesthetic agent:
○ Very light anesthetic plane is used for evaluation of laryngeal function:
▪ If anesthetic plane is too deep, give time (5-10 minutes) for animal to partially recover from anesthesia, and then continue to evaluate.

○ Deeper anesthetic plane is used for evaluation of oral cavity and pharynx and anatomic evaluation of the larynx.

Positioning of the head:
• Assistant holds head upright using a piece of conformable roll gauze (Kling) passed behind the upper canine teeth.

• Alternatively, two IV poles, one on each side of the table, can be used; the conformable gauze is passed behind the upper canine teeth, and the gauze is attached to each IV pole, thus supporting the head in the upright position.

• Place oral speculum of appropriate size.

Oral examination:
• All structures of the oral cavity should be evaluated:
○ Lips, cheeks, teeth (abscess, fracture, occlusion), gingiva, tongue (under and at the base), hard palate, soft palate (mass, elongation), tonsillar crypts/tonsils.

Oropharyngeal examination:
• Soft palate should be palpated for thickness, mobility.

• Elevate soft palate dorsally with a tongue depressor or two depressors taped end to end in a large dog.

• Depress base of the tongue ventrally with a laryngoscope. This permits evaluation of the upper esophageal sphincter.

Laryngeal examination:
• After the evaluation of the oropharynx, it is appropriate to evaluate the anatomy of the larynx: epiglottis, aryepiglottic folds, arytenoid cartilages (cuneiform and corniculate processes) vocal cords, laryngeal ventricles.

• Then evaluate the function of the larynx:
○ Normal:
▪ Observe active abduction of the arytenoid cartilages synchronized with inspiration.

▪ Observe passive adduction of the arytenoid cartilages synchronized with expiration.

○ Abnormal:
▪ Observe no movement of cartilages:
□ Is it significant? Animal is usually too deeply anesthetized; wait until motion returns or administer doxapram HCl (see p. 635).

▪ Observe paradoxical movement of arytenoid cartilages, indicating laryngeal paralysis:
□ Adduction at inspiration

□ Abduction at expiration

Nasopharyngeal examination:
• Palpate the soft palate, then press firmly to detect masses that could be in the nasopharynx (e.g., a nasopharyngeal polyp could deform the soft palate and could be palpated).

• Use a spay hook to retract the caudal edge of the soft palate cranially, permitting the visualization of part of the nasopharynx.

• Use a small, dental-type mirror to “look back” into the nasopharynx.

• Use a small flexible endoscope if available.


image LARYNGEAL, PHARYNGEAL, AND ORAL EXAMINATION Typical appearance of glottis of a healthy, anesthetized cat. Tongue is depressed with a laryngoscope, revealing epiglottis ventrally (tip appears as a white triangle in center of image), soft palate dorsally, and arytenoid cartilages laterally (asterisks). Slightly deeper and ventral to arytenoid cartilages, vocal cords are seen (slight obliquity; animal’s left vocal cord is seen more clearly here than right one).


POSTPROCEDURE



• Airway protection:
○ When the examination is completed, perform orotracheal intubation, inflate cuff, and secure tube to avoid complications secondary to regurgitation/aspiration pneumonia.

• Administer oxygen via anesthesia circuit.

• Monitor recovery from anesthesia.

• Extubation of animal when reflexes are reestablished, especially the deglutition reflex.


ALTERNATIVES AND THEIR RELATIVE MERITS


In a study comparing three techniques for the diagnosis of laryngeal paralysis, direct per os laryngoscopy combined with the knowledge of the clinical history and physical examination was preferred over echolaryngoscopy and transnasal endoscopy (Radlinsky et al., 2009).


NASOPHARYNGEAL ENDOSCOPY:


• The use of a small flexible endoscope can permit a more precise evaluation of the nasopharynx because it can be retroflexed 180○ over the soft palate and advanced in the nasopharynx, permitting visualization of the nasal choanae.

• Involves a substantial investment (endoscope, monitor, camera, image processor, light source).

TRANSNASAL ENDOSCOPY:


• The use of transnasal endoscopy has been reported in large dogs (over 20 kg) for the evaluation of the nasopharynx and of laryngeal structure and function. General anesthesia is not required, which might be an advantage. Dogs are heavily sedated, and topical anesthesia (2% lidocaine) is used in the left nasal passage.

• This technique does not permit evaluation of the oral cavity and oropharynx, so it is of limited use for a complete evaluation as described here.

• Involves a substantial investment (endoscope, monitor, camera, image processor, light source)

ULTRASOUND:


• Sonographic evaluation of laryngeal paralysis has been evaluated in 40 dogs (30 with laryngeal paralysis and 10 normal). Results have shown a high degree of sensitivity and specificity with this technique.


SUGGESTED READING



Gross ME, et al. A comparison of thiopental, propofol, and diazepam-ketamine anesthesia for evaluation of laryngeal function in dogs premedicated with butorphanol-glycopyrrolate. J Am Anim Hosp Assoc. 2002;38:503.


Monnet E. Laryngeal paralysis and devocalization. In: Slatter D, editor. Textbook of small animal surgery. ed 3. Philadelphia: WB Saunders; 2003:837-845.


Radlinsky MG, Mason DE, Hodgson D. Transnasal laryngoscopy for the diagnosis of laryngeal paralysis in dogs. J Am Anim Hosp Assoc. 2004;40:211.


Radlinsky MG, et al. Comparison of three clinical techniques for the diagnosis of laryngeal paralysis in dogs. Vet Surg. 2009;38:434-438.


Rudorf H, Barr FJ, Lane GJ. The role of ultrasound in the assessment of laryngeal paralysis in the dog. Vet Radiol Ultrasound. 2001;42(4):338-343.


Tobias KM, Jackson AM, Harvey RC. Effects of doxapram HCl on laryngeal function of normal dogs and dogs with naturally occurring laryngeal paralysis. Vet Anesth Analg. 2004;31(4):258.


Tobias KM, et al. Effects of various anesthetic agents on laryngeal motion during laryngoscopy in normal dogs. Vet Surg. 2004;33(2):102.



Lithotripsy



AUTHORS: ALICE. DEFARGES, MARILYN. DUNN




SYNONYMS


Stone fragmentation, electrohydraulic lithotripsy (EHL), laser lithotripsy (holmium-doped yttrium, aluminum, garnet [Ho : YAG] laser)



OVERVIEW AND GOALS


Removal of urinary tract stones through natural orifices



INDICATIONS


Treatment of bladder and urethral stones in dogs



CONTRAINDICATIONS


Untreated coagulopathy



EQUIPMENT, ANESTHESIA


General anesthesia, flexible ureteroscope (males), rigid cystoscope (females), saline, protective eyewear, Ho : YAG laser or EHL probe, stone basket, 60-mL syringes



ANTICIPATED TIME


Variable (mean 60 minutes). Depends on stone location (longer in bladder than in urethra), sex of the patient (longer in males than in females), number, size and shape of the stones (longer for smooth and large stones)

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on L

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