63 | BOAS patients: How to manage them successfully as a vet nurse

PodcastRespiratory
Written By Laura Jones

If you’ve ever worked with a snorty Frenchie, a struggling Pug, or a Bulldog who just can’t catch their breath, you’ll know first-hand the issues that BOAS can cause.

 

Brachycephalic obstructive airway syndrome (BOAS) has become increasingly common with the rise in popularity of brachycephalic breeds. And while those squishy faces might be seen as cute, they come with serious anatomical challenges that impact breathing, exercise tolerance, and overall quality of life.

But how can we help these patients, and what do we need to know about caring for them? Well, it starts with understanding precisely what BOAS is, why it happens, and how it impacts our patients - which is exactly what we’re diving into in this episode.

So what IS brachycephalic obstructive airway syndrome, and how does it impact our patients?

BOAS is a congenital disorder caused by conformational abnormalities in brachycephalic breeds, i.e. dogs and cats with short skulls and flattened faces. 

Because of their facial changes, their upper airways are structurally compromised, making it difficult for them to breathe efficiently. The classic congenital changes seen in BOAS patients include:

Stenotic nares
Narrowed nostrils causing decreased airflow.

An elongated soft palate
Excess soft tissue in the oropharynx which partially obstructs the airway, causing increased airway resistance, reduced airflow and secondary changes.

A hypoplastic trachea
A congenital lower airway abnormality often seen in BOAS patients, where the trachea is smaller in diameter than normal.

But we see more than congenital changes—these patients also develop a whole host of acquired abnormalities.

The chronic airway resistance seen in these patients means they work harder and harder to ‘suck’ air in. This causes their laryngeal saccules (small soft tissue masses usually contained within the laryngeal folds) to evert or ‘pop out’, which protrude into the airway, further impacting airflow.

Laryngeal collapse can also occur in severe cases. This is a progressive condition in which the laryngeal cartilages weaken and ultimately collapse.

Another issue commonly seen in BOAS patients is regurgitation. Though this isn’t strictly a respiratory sign, it is related to their BOAS changes—the airway resistance increases negative pressure inside the chest, which can cause a hiatal hernia. A hiatal hernia occurs when part of the stomach herniates into the distal oesophagus when a patient breathes. This herniation causes regurgitation, which can lead to additional respiratory complications like aspiration pneumonia.

  • Everted laryngeal saccules – Soft tissue structures that protrude into the airway due to chronic airway resistance.

  • Laryngeal collapse (in severe cases) – A progressive condition where the cartilage supporting the larynx weakens and collapses.

These structural defects and associated changes result in increased airway resistance, laboured breathing, and an increased risk of respiratory distress—especially with excitement, exercise, or heat exposure.

Ok, so that’s what BOAS is. But which patients do we see it in?

As the name suggests, BOAS primarily affects brachycephalic dog breeds, including:

  • French Bulldogs

  • English Bulldogs

  • Pugs

  • Boston Terriers

  • Shih Tzus

  • Pekingese

  • (Less commonly) Boxers

While we tend to think of BOAS as a predominantly canine disease, brachycephalic cats can also develop airway issues.

We might not discuss it as much, but breeds like Persians, Exotic Shorthairs, and Himalayans are also at risk of BOAS due to their shortened nasal passages and flat facial structure. Respiratory changes are reported in these breeds, similar to those of brachycephalic dogs.

So, that’s what BOAS is and the patients we see it in. But what signs do we see - and what other issues could we see - in these patients?

BOAS patients often present with very classic clinical signs - in fact, if I asked you to list those signs now, I’m sure you’d already have a recent patient you’ve seen in mind.

We frequently see:

  • Stertor (A low-pitched, abnormal upper respiratory noise similar to snoring. Clients will often mention their pet snores even whilst awake - this technically isn’t snoring, it’s stertor.)

  • Stridor (A higher-pitched, musical, abnormal upper respiratory noise due to breathing in through a narrowed or partially obstructed airway)

  • Exercise intolerance

  • Gagging or retching, particularly after eating or drinking

  • Heat sensitivity

  • Collapse (in severe cases, usually preceded by respiratory distress, high levels of stress or excitement, or hyperthermia)

  • Upper respiratory obstruction (in severe cases)

  • Cyanosis (in severe cases - but remember, patients can still be hypoxaemic without being cyanotic because cyanosis only occurs when oxygen levels are very low!)

We know that BOAS significantly impacts quality of life. 

These patients have chronically increased respiratory effort as they work harder to breathe, leading to fatigue and reduced activity levels. 

They also can’t pant normally, so they’re inefficient thermoregulators and particularly sensitive to hyperthermia.

They’re also at risk of those chronic gastrointestinal signs due to their risk of gastroesophageal reflux, regurgitation and aspiration. As their BOAS progresses, they can develop progressive airway deterioration, increasing their risk of airway obstruction and respiratory crisis.

But not every BOAS patient will present in a respiratory crisis - many will have these clinical signs “normally”.

Clients often think many of these signs are ‘normal’ for their pets, and it’s our job to educate them and help them see that this isn’t the case.

Client support is really important for brachycephalic animals, and it’s vital that we provide it in an open way that doesn’t make clients feel shame or alienation. 

There can be quite a lot of judgment surrounding the adoption or purchase of brachycephalic pets, and the last thing we want is for clients not to listen to or trust us—after all, we all want the same thing—for their animal to be healthy.

Talking to clients about the anatomical changes we see in these breeds and how they cause the clinical signs we see is essential so that we can implement long-term management strategies to help them.

But we’re getting ahead of ourselves - we’ve not even diagnosed our patient yet!

So, how do we diagnose them? The good thing is that we rarely need to do a lot of testing—it’s usually obvious based on our clinical examination.

On exam, we’ll see stenotic nares and hear upper respiratory abnormalities. We can also assess nasal airflow if needed by placing a microscope slide over the nose and looking for condensation when the patient breathes.

The rest of our examination will need to be performed under light sedation. This involves examining the back of the mouth, determining how much redundant pharyngeal tissue is present, and determining whether the larynx is collapsed or the saccules are everted.

Top tip: Have a tongue depressor, spay hook, and laryngoscope available for this, as well as emergency intubation equipment!

We may also perform diagnostic imaging to look for tracheal narrowing and secondary lung changes. Usually, thoracic radiographs are taken, though if you have access to fluoroscopy, you may choose to perform a dynamic study with fluoroscopy instead.

What about grading BOAS?

The BOAS research group at the University of Cambridge, in association with the Kennel Club, has created some fantastic resources on grading BOAS, including nasal stenosis grading and a general BOAS scoring system. 

BOAS is graded from grade 0 (BOAS-free and clinically unaffected animal) all the way to grade III (severe BOAS and clinically affected animal) based on the patient’s examination findings and clinical signs before and after an exercise test. Grade III patients should not be used for breeding.

Are there any other tests we perform?

Some patients may require additional testing based on the individual. This includes:

  • Routine bloodwork - to rule in or out concurrent or associated conditions, such as hypoxia-induced polycythemia, which is where chronic hypoxia causes PCV increases

  • Arterial blood gas analysis - usually only performed in respiratory distress patients with severe hypoxaemia, to assess their ventilation and oxygenation

  • Gastrointestinal endoscopy or fluoroscopy - to look for evidence of hiatal hernia and gastroesophageal reflux disease in BOAS patients with GI signs.

Ok, so we’ve got a BOAS patient on our hands. How will we manage them, and how can we give them great nursing care?!

BOAS isn’t just a surgical disease - these patients need a multimodal approach, incorporating medical management, surgery and lifestyle modifications in many cases.

Let’s talk about BOAS crisis patients.

Patients presenting in acute respiratory distress will require stabilisation with oxygen therapy, active cooling if they are hyperthermic, and usually sedatives and steroids.

Stress, panting, and vocalisation increase oxygen demand and cause upper airway swelling and oedema, worsening upper respiratory obstruction. Anxiolytic medications, low doses of ACP, dexmedetomidine, or even a dexmed CRI are all beneficial in keeping these patients calm. Steroids may also be used to reduce upper airway inflammation, swelling, and oedema.

It goes without saying that if your patient is obstructing, they need urgent airway protection—either by intubating them or, if this isn’t possible, by performing an emergency tracheostomy. These need intensive management, including humidification, suction, site care, and careful aseptic management.

Most of the time, when we think BOAS, we think surgery.

Surgical management is indicated in most BOAS patients, particularly those with grade II or III disease.

BOAS surgery involves performing a rhinoplasty to widen the nostrils, a staphylectomy to shorten the overlong soft palate, and a sacculectomy to remove the everted laryngeal saccules (if present).

Most patients do very well following surgery, though the initial period of recovery is challenging, and these patients are at a high risk of upper airway obstruction postoperatively. So always have emergency airway equipment on hand and maintain IV access, even if they’re awake and seem stable. 

In recovery, keep these patients calm and quiet, keep them cool (or at the very least monitor their temperature closely and stop active warming when they reach 37 degrees) and discharge them as soon as reasonably possible. 

The last thing we want is to get stuck in a cycle of stress -> barking/panting -> swelling -> obstruction because these situations are incredibly challenging to manage.

Some hospitals will now recover their BOAS patients with their families to help keep the patients calm. This isn’t something we do in my hospital, but I’d love to hear more about it, so if you’re doing this, drop me a message on Instagram and let me know!

But it’s not just about surgery - there are lots of medical considerations, too.

Whilst we might have fixed what we can surgically, these patients are still at risk of BOAS complications. They could still have a hypoplastic and narrowed trachea and still have regurgitation and aspiration. This means that ongoing medical management is essential, including:

  • Weight management to help minimise airway resistance

  • Avoiding heat, stress and overexertion

  • Medications to manage gastrointestinal signs

These considerations should be prioritised in all BOAS patients, regardless of whether or not they’re undergoing surgery.

And what about nursing these patients?

Aside from monitoring, providing analgesia, being prepared for anything in the clinic and supporting their feeding and regurgitation, there is a LOT more we can do to support BOAS patients and their families. 

This begins with education and support, encouraging weight control, helping clients recognise respiratory emergencies, giving them first aid steps and support, and providing ongoing advice and guidance.

BOAS might be a serious and increasingly common condition, but it’s manageable. With the right care—stabilisation, surgical intervention where needed, monitoring, weight management, and supportive care—we can make a significant difference to these patients. And, of course, nurses and technicians are heavily involved in that process, using a ton of skills throughout.

Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!

Thanks for learning with me this week, and I’ll see you next time!


References and Further Reading

Laura Jones
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