BOAS: Diagnosis and Surgery Flashcards
Which breeds (2) with stridor are very likely to have laryngeal collapse and surgeries are likely to be tricky, potentially requiring a temporary tracheostomy tube.
French and English Bulldogs
Looking for a diagnosis starts with asking the relevant questions and clinical signs assessment
What are you looking for in the history? (6)
Audible “noisy” breathing
Exercise intolerance - any difference in summer vs winter?
Sleep disorders - snoring excessively? disturbing at night? excessive day time sleepiness?
Regurgitation or eating disorders
Heat intolerance
Collapse
Clinical signs (6)
Noisy breathing: stertor, stridor
Exercise and heat intolerance
Hyperthermia
Cyanosis and collapse
Regurgitation and vomiting
Flatulence
The regurgitation and vomiting from increased gastro-oesophageal reflux results in?
Oesophagititis
The following tools are also important to achieve and accurate diagnosis? (6)
Respiratory functional grading (see lesson 1)
Oral examination under sedation/GA
Head CT and thoracic radiographs or CT
Examination of the nasopharynx with an endoscope
Fluoroscopy
(Plethysmography - flow volume respiratory traces)
A CT scan of the head will reveal (2)
turbinate morphology
the soft palate thickness
What 2 conditions in brachycephalic is fluroscopy useful for?
hiatal hernia
slow motility
What we have shown is that every increase in body condition score in Pugs equates to ?% increase in the BOAS index obstructive score
6
If your patient is overweight rule out what in older dogs?
endocrinopathies
What GI meds for regurgitators?
1 mg/kg omeprazole, initially once daily up to twice daily
If a dog V+/D+ on omeprazole. What do we do?
Switch to cimetidine, ranitidine or famotidine
When to reassess BOAS post surgery?
6-8 weeks
Some dogs (particularly ?) have little response to palate and nostril surgery and may benefit from further surgical intervention.
French Bulldogs
If the animal is a frequent regurgitator; how long to give omeprazole pre op?
5-7 days
What “sign” may a regurgitator show? (other than physical regurg!)
Frequent gulping
What CRI is an option for regurgitators in surgery?
Metoclopramide
How to suspend head in surgery for BOAS (3)
Table arms
Drip stands
BOAS stand
How to tie the head to maximise the space at the back of the pharynx?
Tie the lower jaw and tongue down
How often do RFG grade 1 need surgery? Specify pugs
Dogs rarely require surgery. Some mildly BOAS-affected pugs that have epilepsy seem to show improved seizure control after airway surgery.
How often do RFG grade 2 need surgery? Specify french bulldogs
Dogs that are young and active generally benefit from surgery, particularly French Bulldogs with regurgitation. Older and more sedentary grade 2 dogs may benefit more from initial weight loss, if overweight, or may be monitored if comfortable in a non-stressful home environment.
How often do RFG grade 3 need surgery?
Dogs usually require surgery and marked weight loss for morbidly; obese pugs.
Name 3 complicating risk factors for a dog presenting for BOAS sx?
- Previous BOAS sx
- Emergency presentation
- Inappropriately low temp at admit
Other than omeprazole/metopclopramine. What other meds should be given peri + post op for the BOAS?
Maropitant
Drug of choice for anxious patient?
Trazadone
What is the effect of fat around neck on resp function? (2)
Increased obstruction
Reduced tidal volume
What is the nasoplasty performed with?
No 11 blade
What is used for haemostasis if doing a folding flap palatoplasty. (2)
Sterile cotton bud
bipolar electrosurgery
What equipment is useful for the folding flap palatoplasty?
Loupes with a central light
BOAS surgery premed?
low dose dexmedetomidine or medetomidine with butorphanol or methadone or acepromazine/methadone.
It is sensible to have a range of endotracheal tubes (ET) sizes available and, if any signs of laryngeal collapse are evident clinically then smaller tubes such as (2)
urinary catheters
stylet
Pre op - what should be given?
O2
Keep anaesthesia light 0 why?
assess the laryngeal movement prior to intubation
What cuff ET tube is used?
A low-pressure high volume cuffed ET tube
At induction what should be given alongside propofol; why?
Intravenous dexamethasone is given at induction to try and avoid airway swelling
What block is effective at reducing arousal during nasoplasty?
Nerve blocks (maxillary)
hat drug i used, and what is the max amount for bupivicaine maxillary block?
bupivacaine at 1-2 mg/kg total dose for local blocks. Usually for maxillary blocks the volume used is up to 1 ml
The following techniques may be performed in patients with BOAS (6)
Tonsillectomy
Soft palate shortening and thinning
Opening of nostrils
Resection of laryngeal ventricles
Resection of cuneiform process/aryepiglottic fold
+/- turbinate resection
Many surgeons now incorporate bilateral tonsillectomy or partial tonsillectomy into routine BOAS surgery if ?
The tonsils are everted and enlarged
By removing only the extruded part of the tonsil, what is the benefit?
less haemorrhage occurs,
What coagulation techniques are used in tonsilectomy? (3)
bipolar coagulation,
a harmonic scalpel,
a laser
How to reduce excessive pendulous lateral tissue with a partial tonsillectomy?
The palate can then be sutured to the tonsillar crypts
What does a extended staphylectomy involve?
trimming the palate in a smooth U-shape to the rostral tip of the tonsils.
What are the techniques for extended staphylectomy? (3)
arbon dioxide laser and vessel sealing resection techniques + incisional
Generally what may a palatoplasties involved? (2)
Thinning the palate
Shortening the palate
Aim for extended staphylectomy (anatomically)?
When shortening the soft palate, the aim is for the palate to be at rostral/mid edge of tonsils, just contacting the epiglottis when the mouth is closed
Staphylectomy:
Steps (incision, suturing,)
1 Start mid tonsillar crypt and curve the palate incision forward to the rostral tonsil crypt.
2mSuture with a 1.5 M vicryl (or other 4/0 suture); sutures can be simple interrupted or continuous.
3 Cut half the palate and then suture before cutting the second half. Ensure you are suturing the nasal mucosa to the oral mucosa.
4 Alternatively use a vessel sealing device such as the Enseal.
The folding flap palatoplasty
Describe the location for Prof Oechetering’s modified technique.
The original folding flap palatoplasty had the rostral cut 1-2 cm caudal to the palatine process. We use Prof Oechetering’s modified folding flap with seemingly good results which has the rostral incision a little further caudal.
Palatoplasty complications?
Little information;
- Complications related to cutting too short are often mentioned in the literature but not accurately reported. We have had two dogs that occasionally gagged after drinking but interestingly had no problems eating.
What equipment does Modified folding flap need?
electrosurgery- bipolar or monopolar.
Modified folding flap:
Initial incision?
1 U-shaped incision is made through the oral mucosa from the back of the palate extending to rostral to the palate.
2 The underlying stroma and muscles are stripped from the nasal mucosa, work initially laterally and then towards the median raphe (where the tissue is more adherent)
Modified folding flap where do vessels come in?
dorsolaterally
Modified folding flap:
Where is the palate cut? How to then suture?
Cut - caudal edge so nasal mucosa is left exposed, leaving nasal mucosa 1-3 cm longer than the oral mucosa.
4 nasal mucosa is folded over and sutured. Sutures - simple interrupted vertical mattress sutures of 1.5 M vicryl.
Modified folding flap:
This nasal mucosa is folded over and sutured. What does this result in?
This results in a thinner section of caudal soft palate.
What should the lateral suture of modified folding flap incorporate?
The lateral sutures should incorporate the caudal tonsillar crypt and the palate
What does Nasoplasty involve?
The nares surgery we perform now involves resection of the inner alar fold within the vestibule (alar fold or second stenosis) along with resection of the wing of the nares (Oechtering personal communication).
What technique is used for extneral nares?
Trader technique
Do nares re pigment after?
Yes - few weeks
Steps for Alar fold resection?
1 Grasp the alar fold with a delicate curved haemostat.
2 Cut medial to lateral to nasal wall, 1/3 from base of alar fold dorsally.
3 Pull alar fold medially.
4 Slip scalpel around alar fold and connect two cuts.
Describe Trader technique
Cut at an angle across the lateral nasal cartilage with the blade slightly rotated so that more pigment than submucosa is showing.
Why is Trader technique left until last?
The nostrils will bleed - the head can be lowered, and the blood does not trickle down the back of the throat.
How to stop the bleeding after Trader technique?
Pack the nostrils with a large adrenaline-soaked cotton bud (which should fit into the vestibule after surgery) and leave this cotton bud for at least 10 minutes.
Wedge resection techniques; How to perform?
V-shaped incision is made into the nasal planum lateral cartilages. cut as deep as possible with the blade to involve some of the alar fold.
Why does a Wedge resection techniques initially look more cosmetic?
A couple of sutures are placed to close the wedge
How to recover a patient after nasal surgery?
check the pharynx for blood at the end of surgery - clean carefully with cotton buds/suction and then recover with head down.
2 anatomical areas involved in BOAS of nares sx?
resection of the inner alar fold within the vestibule
resection of the wing of the nares
After surgery, the patient must be monitored. The following actions must also be considered (4) What might be needed?
- Keep the ET tube in as long as possible at the end of surgery, until the dogs can swallow.
- Use supplemental oxygen until fully recovered.
- BOAS cases require close monitoring for the first 24 hours as post-operative swelling or haemorrhage can cause upper airway obstruction.
- Advise soft food for the next couple of weeks.
Might - need tracheostomy
When is ABx needed with BOAS?
Aspiration pneumonia
Post op analgesia? Why is this the choice
- Paracetamol (DONT FORGET dexamethasone given on induction!)
Post op :
How to prevent crusty secretions forming?
nebulise the dogs with steam every 3-4 hours to moisten airways
If any dogs are showing respiratory effort after surgery what will reduce some airway swelling and seems particularly effective in pugs.
nebulizing with adrenaline
Many of the tracheostomy tubes are placed pre-emptively; when? why?
n the grade 3 laryngeal collapse cases to allow a smooth and less distressing recovery for the dog
