Upper Resp Surgery Flashcards
Brachycephalic Obstructive Airway Syndrome -Pathophysiology
- Congenital malformation
- Skull bones normal width but shortened length
> but still have all the same soft tissue!
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Bony changes > Soft tissue excess > Upper airway obstruction
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“Breathing through a straw”
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increased Airway resistance =
increased Negative P needed to maintain airflow
primary and secondary issues associated with BOAS
Primary:
- Stenotic nares
- Elongated soft palate
- Hypoplastic trachea
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Secondary:
- Everted laryngeal saccules
- Tonsillar eversion
- Laryngeal Collapse
why are brachycephalics more susceptible to hiatal hernias? what outward clinical signs can be associated? significance?
- dog is lip smacking
- they have been gasping for air their whole life, negative pressure sucks stomach into chest
> assume most frenchies have it
> but they dont all need surgery for it - creates a lot of silent regurgitation, which is where this lip smacking may come from
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Brachycephalic Obstructive Airway Syndrome -Possible GI signs
GI signs - regurgitation or vomiting
> Hiatal hernia
> Aerophagia
> Pyloric outflow
Brachycephalic Obstructive Airway Syndrome
-Pathophysiology of how laryngeal edema can arise
- Elongated soft palate, stenotic nares
> Increased inspiratory pressure
> Eversion of laryngeal saccules, soft palate stretching
> Further increased inspiratory pressure
> Laryngeal edema, eventual collapse
stages of laryngeal collapse
Stage I:
Eversion of laryngeal saccules without paradoxical collapse or corniculate or cuneiform processes
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Stage II:
Medial displacement of the cuneiform processes during inspiration
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Stage III:
Collapse or the corniculate processes with loss of the dorsal arch of the rim
Brachycephalic Obstructive Airway Syndrome
-Emergency Management
- Oxygen supplementation
- Sedation (acepromazine 0.02-0.05 mg/kg IV or IM)
- Cooling
- Calm environment
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If no improvement in a few minutes: - Intubation
- Temporary tracheostomy
Brachycephalic Obstructive Airway Syndrome -Which components can be addressed surgically? which cannot?
Can be addressed surgically:
- Elongated soft palate
- Stenotic nares
- Everted laryngeal saccules
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Cannot be:
- Hypoplastic trachea
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- Laryngeal collapse?- dont want it to get to this point
- difficult as complete tracheostomy is the only option
Brachycephalic Obstructive Airway Syndrome -Respiratory signs
- Stertor
- Stridor
- “Choking” / Gagging
- Collapse
Brachycephalic Obstructive Airway Syndrome
-Diagnosis
Sedated / light plane of anesthesia airway exam
> no need to do this unless planning surgery
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Intubate
+/- Bloodwork
Thoracic radiographs
Head CT
Brachycephalic Obstructive Airway Syndrome
-Surgical management
- who is a candidate?
- risks?
- Dogs in moderate to severe respiratory distress and those with exercise intolerance are candidates
<><><><> - BEWARE! Mortality from retrospective studies is 3.2-7%
- Inform owners fully of complications
- MY OPINION: Do not perform BOAS surgery if 24 hour care not possible
Brachycephalic Obstructive Airway Syndrome
- surgical approach
- Alar fold vestibuloplasty (NARES) FIRST
- Intra-oral procedures
> Tonsillectomy
> Folded flap palatoplasty…or aggressive palate surgery
> Sacculectomy
Brachycephalic Obstructive Airway Syndrome -Stenotic nares
Should I address stenotic nares at the time of OVH / neuter?
> wont necessarily hurt, but not going to save it from further surgery down the road… this is not the only component of BOAS, so wont necessarily be effective
surgical correction techniques for stenotic nares, considerations
- Vertical wedge resection
> #11 blade
> Cotton-tipped applicators and/or gauze
> Nasal cartilage highly vascular!
> big chunk of tissue further back that we are not addressing with the vertical wedge
<><> - Alar Fold Vestibuloplasty
> take much larger piece, going deeper
should we do a tonsilectomy for BOAS cases? why?
amit does it for most cases - any tissue that could get sucked into airway could be an issue
-Elongated soft palate
- how do we surgically correct this?
Traditional landmark:
- Soft palate should not extend beyond tip of epiglottis
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“cut the palate to the tip of the epiglottis” - is what we see in textbooks, but this can be hard to see with intubation
- amit has realized that this palate needs to be totally open…
> we need to be very very aggressive > you cannot take to much of it!!!!
- the cranial aspect of the tonsil is a fair place to take it to
Staphylectomy procedure
- Pull soft palate rostrally with stay sutures or forceps
- Cut soft palate to midline, then suture in continuous pattern
- Cut second half and finish suture line
- FULL THICKNESS BITES
- ATRAUMATIC TECHNIQUE
Folded Flap Palatoplasty
- how to perform
- complications
- 2x stay sutures On edge of soft palate
- -Removal of oropharyngeal mucosa / muscle
- Monopolar Electrosurgery
- -Suturing of flap
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Overall low rate - Incisional dehiscence
- Perforation of flap
-Everted laryngeal saccules
- are secondary to what? what is this?
- Secondary to increased negative airway pressure
- Mucosa covering laryngeal ventricle everts
- “Inside out pant pockets”
-Everted laryngeal saccules: how to fix surgically
- Visible at 5 and 7 o clock
- Grasp with forceps and cut base of saccule with long handled Metzenbaum scissors
- Single cut ideal
- Suture not required
- ATRAUMATIC
- Be weary vocal fold caudal to
when to extubate brachycephalics?
make sure they wide awake before you pull the tube!
Brachycephalic Obstructive Airway Syndrome -Postoperative treatment
- Corticosteroids - anti-inflammatory
> Dexamethasone - Brachy “cocktail”
- NPO 24hrs postoperatively
+/- Oxgyen supplementation
+/- Sedation - Be prepared for re-intubation +/- tracheostomy
- Calm, cool environment
brachycephalic felines - what is the main airway issue?
Stenotic nares appears to be the only component of BOAS
BOAS in felines solution
vestibuloplasty has worked out well
> they only have stenotic nares as the adverse component
Brachycephalic Obstructive Airway Syndrome -Take home messages
- Be aggressive with palate and nares
- Same day DC??
- Owner education essential
FUNCTIONS OF THE LARYNX
- what governs function?
- Regulate airflow
- Assist in voice production
- Prevent inhalation of food
- Laryngeal function governed by intrinsic muscles and nerve supply
pathogenesis of larygeal paralysis
- Only abductor of the larynx is cricoarytenoideus dorsalis (CAD) - opens rima glottidis
- Recurrent laryngeal n innervates all intrinsic muscles of larynx aside from cricothyroideus m.
<><><><> - Cricoarytenoideus dorsalis fails to contract
- Arytenoid cartilages fail to abduct
- Rima glottidis obstruction occurs
- Increased resistance to airflow
- Increased speed of airflow
- Decreased intraglottic pressure
- Laryngeal collapse
- Increased resistance to airflow….
who is most affected by laryngeal paralysis? etiology?
- Large breed dogs! almost exclusivery labs, 10-11 years old
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Congenital (<1yr) - Bouvier, Dalmation, Rottweiler, Siberian Husky
- Wallerian degeneration of nucleus ambiguous
<><><> - Acquired
- Idiopathic (old dogs with polyneuropathy
IDIOPATHIC LARYNGEAL PARALYSIS - prevalence
- origins?
- Most common
- Early manifestation of a systemic polyneuropathy
- GOLPP - geriatric onset laryngeal paralysis polyneuropathy
laryngeal paralysis common historical findings
- Progressive signs
- Change in bark
- Coughing, gagging
- Exercise intolerance
- Inspiratory stridor
- Dyspnea, collapse
- Male>Female
laryngial paralysis usual method of diagnosis
- Exam room diagnosis!!
- High index of suspicion based on history, signalment and clinical signs
- Neurological exam
- Thoracic radiographs and abdominal ultrasound
<><><><> - dont necessarily need an airway exam, can often tell in exam room with history, breed…
- upper airway exam can be used to confirm, vs tumor or mass… but not super needed
thoracic radiographs for laryngeal paralysis purpose?
- Baseline!
Check for: - Aspiration pneumonia
- Cranial mediastinal mass
- Megaesophagus
- Others
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but maybe we dont want to put these airway dogs in lateral recumbency
laryngeal paralysis - how to diagnose with larygoscope? considerations?
- Laryngoscopic evaluation under a LIGHT PLANE of anesthesia
- Evaluate arytenoid function and appearance
- Beware false positives…many anesthetic drugs can inhibit arytenoid function
- Doxopram - Be ready to intubate!
- Have an assistant identify aspiration and expiration (in, out, in…)
- Paradoxical movement of arytenoids
ANESTHESIA FOR LARYNGOSCOPY - drug of choice?
what drugs affect arytenoid function?
- Propofol is drug of choice for injectable induction
- Acepromazine depresses arytenoid function
- Doxopram increases arytenoid function
SURGICAL TREATMENT for laryngeal paralysis
- when do we do this?
- goal?
- For dogs with severe respiratory stridor
- Unilateral cases may not need surgery
- Ideal for pneumonia (or edema) to resolve prior to sx
<><> - Goal - enlarge rima glottidis area to decrease resistance of airflow while not increasing risk of asp. pneumonia
surgical procedure for correction of larygeal paralysis
- Unilateral arytenoid lateralization
- 1-2 sutures from cricoid through arytenoid at level of crico-arytenoid joint
- Prevents inward motion of arytenoid during inspiration
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> aretynoid will be permanently open, which is not super great for all purposes… - only do unilateral! lots of mortality from aspiration penumonia if bilateral
larygeal paralysis surgery
* Unilateral arytenoid lateralization
intraoperative complications
- Careful passage of needle through arytenoid cartilage
- Brittle cartilage predisposed to fracture
- If fracture can try to pass again or perform UAL on R
<><><><> - Surgical approach can be challenging
- Palpate for wing of thyroid cartilage
POST-OPERATIVE COMPLICATIONS for Unilateral arytenoid lateralization
Immediate / Short term:
* Inadequate lateralization
* Suture breakage
* Seroma formation
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* Aspiration pneumonia
* Coughing & Irritation
aspiration pneumonia after surgery for larygeal paralysis - how common over time? drug factors influencing?
- can we do anything to help?
- 1 year - 18.6%
- 2 year - 27.2%
- 3 year - 31.8%
- Risk of aspiration pneumonia increase w PO opioids
- DO: Line block w bupivacaine at surgical site
- Allows dogs to regain sternal recumbency rapidly
Unilateral arytenoid lateralization
- post operative care
- NPO for 12 - 24hrs after surgery
- Maintain on IV fluids overnight
- Give small quantities of ice chips or water morning after surgery
- If water tolerated small quantities of food meatballs can be re-introduced
- Feed small moist meatballs initially for 14 days - Continue to avoid stress
care after discharge for Unilateral arytenoid lateralization
- Exercise restriction for 4 - 6 weeks
- Avoid neck leashes
- Council owners as to life-long predisposition to aspiration pneumonia
- Care if further anesthesia procedures required
- Follow-up treatment for aspiration pneumonia if present
is surgery a decent options for laryngeal paralysis? prognosis?
- Majority of dogs having sx will greatly improve!
- Low perioperative morbidity - non-invasive procedure
- Client education critical
- Aspiration pneumonia
> Not necessarily fatal
