Breathing Problems in Flat Faced Dogs – Brachycephalic Obstructive Airway Syndrome

What are brachycephalic dogs? What is Brachycephalic Obstructive Airway Syndrome (BOAS)?

Brachycephalic describes those breeds of dogs that are bred to have short noses or flat faces.   These would include those cute roly poly French Bulldogs, Pugs, Boston Terriers, and English Bulldogs.  Boxers, Shih Tzus, Pekingese, and Bull Mastiffs are also included in this group, but tend to have a lower rate of breathing problems.  Some non-brachycephalic dogs, such as Shar-Peis, may also experience some of these airway problems.  

The changes that have occurred in these breeds to give them their unique facial appearance has unfortunately also resulted in some common deformities to their airways that may interfere with breathing.  These combined airway deformities are referred to as Brachycephalic Obstructive Airway Syndrome (BOAS). 

What airway changes cause Brachycephalic Obstructive Airway Syndrome (BOAS) in flat faced dogs?

The following are anatomic changes that, while not necessarily present in all brachycephalic dogs, are very common in these breeds and can obstruct the flow of air to contribute to breathing problems.  

Narrow Nostrils (Stenotic Nares)

One of the most visible respiratory changes we see in brachycephalic dogs are narrowed or pinched nostrils.  Rather than having round openings in the nose to breathe through, these dogs will commonly have narrowed slit-like openings.  These narrowed openings can increase airway resistance significantly.  This is similar to trying to drink a milk shake through a straw that is collapsing.  Stenotic nares are easily diagnosed on visual exam and can be corrected with a simple surgery called a rhinoplasty as early as 5 months of age.  Shown are pictures of a dog affected by stenotic nares immediately before surgery (with the tissue wedges that will be removed outlines in surgical marker) (top picture), and after healing has taken place (bottom picture).  

Elongated Soft Palate

The flap of tissue making up the back part of the roof of the mouth is called the soft palate.  It separates the mouth from the nasal cavity and is involved in swallowing.  The problem in many brachycephalic dogs is that the soft palate is the same length as if their faces were not flat (i.e. the soft palate is too long relative to the length of the mouth in a flat faced dog).  This causes the soft palate to protrude too far back into the throat and obstruct air flow into the wind pipe (trachea).  In some breeds, such as English bulldogs, the soft palate tends to be thicker than normal as well, which further complicates breathing and swallowing.  Elongated soft palate is generally suspected in flat faced dogs that exhibit loud breathing, and is diagnosed with visual exam of the back of the throat under light anesthesia.  Surgery can be performed to shorten the soft palate to a more normal length.  

Everted Tonsils

The increased negative pressure exerted on the airway in brachycephalic dogs, as well as the associated inflammation, can cause the tonsils located in the back of the mouth near the throat to become enlarged and protrude into the oral cavity.  This can further obstruct the flow of air during breathing.  This problem is diagnosed by visual exam of the back of the throat under light anesthesia.  Correction can be done through surgical removal of the tonsils. 

Everted Laryngeal Saccules

The voice box, or larynx, has two pouches or pockets called saccules.  However, when brachycephalic dogs use excess negative pressure to suck air into the lungs, this can cause these saccules to pop out (evert) into the airway, and further block the flow of air.  This change is diagnosed visually under light anesthesia, and can be corrected by surgically removing the everted saccules. 

Narrow Windpipe (Tracheal Stenosis/Hypoplastic Trachea)

The windpipe, or trachea, of flat faced dogs is commonly more narrow than it should be relative to the size of the dog.  This is especially common in English bulldogs.  This condition is diagnosed on x-rays, and can increase the risk of breathing difficulty and anesthetic complications.  However, there is no way to reverse or correct this change. 

Enlarged Tongue (Macroglossa)

Relative to the size of their shorter mouths, the tongues of many brachycephalic dogs can be long and thick, taking up more room in the mouth and throat and further occluding the airway.  This is especially common in English and French bulldogs.  This issue can be diagnosed visually.  There is no way to correct it.  

Small Epiglottis

Some flat faced dogs may also have a smaller than normal epiglottis.  The epiglottis is flap of tissue that covers and protects the airway during swallowing.  In dogs in which it is undersized, they may have trouble protecting their airway and be more prone to aspiration pneumonia (inhaling food or fluid).  There is not way to correct a small epiglottis.  

Airway inflammation and swelling

The above anatomic differences common in brachycephalic dogs cause obstruction of the airway and interfere with airflow into the lungs.  This causes chronic secondary trauma to the tissues of the back of the throat and airway, which then tend to become inflamed and swollen, further occluding the airway and reducing the pet’s ability to breathe.  The addition of excitement, activity, stress, or heat can further worsen airway inflammation and swelling, possibly leading to an episode of respiratory distress or collapse.  Airway inflammation and swelling is diagnosed on visual exam under light anesthesia, and is treated by surgically correcting the airway abnormalities, avoiding stress/activity/heat, and possibly starting anti-inflammatory medications (generally steroids). 

Laryngeal Collapse

If left untreated, moderate to severe BOAS can eventually progress to collapse of the larynx, or voice box.  This is an end-stage change that generally causes severe breathing difficulty.  It is diagnosed by visual exam of the voice box under light anesthesia.  These pets generally need surgical removal of some of the cartilage of the voice box that is occluding the air way, and/or placement of a permanent tracheostomy (hole made in the windpipe) to allow them to breath comfortably.  

What are the symptoms of breathing problems in brachycephalic (flat faced) dogs? What are the risks and complications of untreated breathing problems in brachycephalic (flat faced) dogs?

Symptoms of breathing problems in flat faced dogs can vary from very mild to severe, depending on a variety of factors, such as the number and severity of airway problems present, the pet’s weight (obesity further compromises the respiratory tract), weather (heat stress worsens respiratory signs), the presence of aspiration pneumonia (see below), and other factors.  Signs are generally mild in young dogs, but can progress in severity over time as their airway changes continue to worsen.

One of the most common signs that your brachycephalic pet may be suffering from BOAS is noisy breathing.  This may occur all the time or only during certain times, such as with activity or excitement, or when sleeping.  The noise may be soft and resemble a piglet snuffling/snorting or progress to a loud raspy pant.  These classic “bulldog” noises are actually indicators that your pet is having trouble breathing.  The pet may not seem distressed, because this is their “normal,” but it is still potentially dangerous.

Affected dogs may not tolerate exercise well, and may seem to tire easily.  They may also stress very easily and have worsening breathing effort and noise with excitement, activity, anxiety or heat stress. Some dogs may even collapse/pass out as a result of their disease.  Heat, excessive activity, and stress can make symptoms worse because flat faced dogs cannot effectively pant to lose excess heat like a non-brachycephalic dog would.  They cannot adequately move enough air due to their obstructed airway, so they tend to over-heat, which worsens their panting and distress, which increases their body temperature, and the cycle continues.  The excessive panting also increases inflammation and swelling of the airway, which further worsens the airway obstruction.  Without efforts to calm and cool the pet (and possibly provide emergency oxygen support), heat stroke, respiratory failure, and death can result.  

Due to the excessive negative pressure needed to suck air past the obstructed airways and into the lungs, stomach acid may also be sucked upwards into the esophagus (GERD or gastroesophogeal reflux disease) and create inflammation (esophagitis), which can predispose to spitting up food and/or stomach contents (regurgitation).  This can be displayed as choking and gagging, or fluid or food being spit up and out of the mouth.  Regurgitation can then lead to aspiration pneumonia if the stomach contents get inhaled into the lungs.  Symptoms of aspiration pneumonia include increased breathing difficulty, respiratory distress, lethargy, and/or decreased appetite.   Interestingly, not all brachycephalic dogs display symptoms of aspiration pneumonia if it is mild (or symptoms are masked by their baseline respiratory BOAS symptoms).  However, aspiration pneumonia can be fatal if severe or left untreated. 

Whether due to aspiration pneumonia or worsening airway obstruction, especially during periods of sudden stress, the tongue, lips and/or gums may develop a blue or purple tinge.  This is an indicator that the pet is in severe distress and needs to be kept calm and cool while emergency veterinary attention is sought.  

Unfortunately, if not prevented or treated, BOAS can negatively impact a pet’s quality of life, and potentially result in eventual respiratory failure and death.  

What can be done at home to help brachycephalic (flat faced) dogs?

While not a replacement for surgical intervention in affected dogs, there are strategies that pet parents can take to help their flat faced family member breathe more comfortably and reduce the risk of heat stroke and respiratory distress:

1. Keep your brachycephalic dog lean.   Being overweight increases overall inflammation, puts additional stress on the respiratory tract, and increases the risk of overheating.  The ideal weight, or body condition, for a dog is one in which the ribs are not visible, but can be felt with light pressure (similar to the back of your hand).  If you are having to push through a layer of fat to feel the ribs, then the pet is overweight and weight loss efforts should be started.  Weight loss should be accomplished with careful calorie restriction, not exercise.  Extra activity can place additional stress on their fragile respiratory tracts and cause more harm than good. 

2. Avoid heat.  As previously stated, these dogs are very sensitive to heat stress and prone to heat stroke.  Even 10 minutes outside in the summer heat can be problematic.  They should be kept indoors in a cool environment during the day, with very short, supervised breaks outside to use the restroom.  If possible, try to avoid having them go outside during the hottest part of the day (generally between 10am and 2pm).  Especially avoid exercise or activity when it is hot outside. 

3. Avoid excessive activity or exercise.  Again, these dogs cannot pant effectively, and can experience heat stroke and/or respiratory distress with activity. What may be considered normal exercise for a non-flat-faced dog, could easily be too much to be safe in a brachycephalic animal. Walks should be taken when it is cool outside, and be kept short and slow paced to avoid panting.  

4. Avoid stress and anxiety.  Special consideration may be needed when considering activities such as having guests over, grooming, boarding, and veterinary visits.  If needed, you can ask your veterinarian about anxiety medication or mild sedatives that can be given prior to these events to prevent an episode of respiratory difficulty due to stress.  It is currently recommended by many anesthesiologists that these dogs be given a dose of anxiety medication prior to dropping off at the vet’s office for surgery.  This helps to reduce their risk with anesthesia.  

5. Monitor your pet for GI signs.  Intermittent vomiting or regurgitation (spitting up food or water), gagging when eating or drinking, or changes in appetite could indicate inflammation in the stomach or esophagus secondary to their airway disease.  If seen, these signs should be brought to the attention of your veterinarian so they can prescribe appropriate treatment. It is especially important that this be treated prior to any anesthetic episodes to reduce the risk of regurgitation and aspiration pneumonia in recovery. 

How are breathing problems in brachycephalic (flat faced) dogs treated? 

Surgery is strongly recommended to correct stenotic nares, elongated soft palate, everted tonsils, and everted laryngeal saccules.  If addressed early, later stage changes of BOAS, such as laryngeal collapse, may be prevented entirely.  

Ideally, your pet should be evaluated by a veterinarian familiar and comfortable with treating BOAS in brachycephalic dogs.  Upon visual exam, the veterinarian should be able to assess the nostrils for stenotic nares and evaluate the pet’s overall breathing and health status.  They may recommend blood work, chest x-rays, GI medications, and anxiety medication in preparation for anesthesia. It’s generally recommended that an upper airway exam to evaluate the back of the throat and corrective surgery be performed as early as 5 months of age.  This may coincide with a spay or neuter procedure. For more complicated or higher risk patients or procedures, your veterinarian may recommend referral to a board-certified veterinary surgeon.   

What can you do to prepare your brachycephalic (flat faced) dog for surgery?

Most veterinary anesthesiologists currently recommend special care be taken with brachycephalic dogs undergoing anesthesia, especially if upper airway surgery is to be performed.  In general, it is recommended that any underlying GI disease (e.g. regurgitation, vomiting, appetite changes) be treated and stabilized as much as possible before anesthesia.  GI medications, such as stomach coating agents and antacids, may be prescribed to be given for 1-2 weeks before anesthesia.  Anti-nausea medications may be recommended to be given at home or as an injection at the vet clinic the morning of anesthesia.  These measures help to reduce the risk of regurgitation and aspiration pneumonia in recovery.

The ideal fasting time (time pet should be without food before anesthesia) is also different for flat faced dogs.  Instead of an overnight fast, it is recommended by many anesthesiologists that these dogs receive a small snack or partial meal 3-4 hours before dropping off at the vet’s office.  This further reduces the risk of regurgitation and aspiration.  Water should not be withheld.  

Many times, an anti-anxiety medication and/or mild sedative will be recommended to give the pet the night before the procedure, with a second dose given a couple of hours before dropping off at the vet’s office.  This is to prevent the pet from becoming nervous and stressed before anesthesia.  

If your pet is currently taking an anti-inflammatory pain medication, such as an NSAID (e.g. Rimadyl, Metacam, Previcox, Galliprant) or aspirin, ask your veterinarian if you should stop the medication a week or two before anesthesia in case steroids are needed to control airway inflammation.  Also ask your veterinarian about alternative pain relievers to use in the mean time. 

What are the risks associated with anesthesia and upper airway surgery in brachycephalic (flat faced) dogs?

Due to the challenges posed by their unique respiratory tracts, flat faced dogs have a higher risk of post-operative complications than non-brachycephalic dogs.  In one study, brachycephalic dogs were 1.57 times more likely to have complications during anesthesia, and 4.33 times more likely to have complications during recovery from anesthesia.  Complications can be even more common in recovery after upper airway surgery to correct BOAS.  In another study, 23.4% of dogs undergoing surgery on structures in the throat to correct BOAS (i.e. surgery on the palate, tonsils and/or larynx) developed post-operative complications, ranging from mild to severe.  However, overall mortality was low at 2.4%. 

The actual risk of complications varies depending on the individual dog, as factors such as obesity, age, breed, concurrent diseases, stress, and the severity of their airway disease can affect their anesthetic risk.  For example, a young, lean pug with mild airway changes and respiratory symptoms, and no GI symptoms, would have a much lower risk than an older, overweight English bulldog with severe BOAS and breathing trouble, and a history of regurgitation.  Ask your veterinarian about the risk factors of your individual pet.  

Risk can also vary depending on the procedure being performed.  The risk associated with correcting stenotic nares (rhinoplasty), tends to be minimal and comparable to the risk associated with non-airway related surgeries in these dogs.  However, when operating on structures in the back of the throat, such as surgery to correct elongated soft palate or everted laryngeal saccules, the risk of complications increases.

The main risks associated with anesthesia and surgery in brachycephalic dogs include aspiration pneumonia and airway swelling/obstruction.  If severe enough, these complications could potentially lead to respiratory failure and death (similar to untreated severe BOAS).  

These risks can be lowered by following recommendations leading up to anesthesia and performing a good pre-anesthetic work up (physical exam, chest x-rays, and blood work based on the veterinarian’s recommendations).  In one study, 40% of dogs that had aspiration pneumonia after surgery, actually had evidence of pneumonia on x-rays before anesthesia.  These dogs may not show overt symptoms, especially if any breathing signs are attributed to their BOAS.  This is why chest x-rays before anesthesia in flat faced dogs are important.  

Your veterinarian may also utilize techniques such as: using a drug protocol that minimizes stress and nausea; keeping your pet in a calm environment and giving mild sedatives if needed; controlling pain during and after surgery; giving anti-inflammatory medications such as steroids to help with airway swelling; using topical medications to reduce swelling in the throat after soft palate or laryngeal saccule surgery; and ice packing the back of the throat immediately before and after soft palate or saccule surgery.  

Depending on the surgeon and the availability of overnight hospitalized nursing care, the veterinarian may recommend placement of a temporary tracheostomy tube when performing soft palate or laryngeal saccule surgery.  A temporary tracheostomy is a surgery done on the neck to place a hole in the front of the trachea (windpipe) so that a tube may be placed to allow breathing while by-passing the throat.  This then protects the airway from aspiration and allows breathing even if upper airway swelling is present after surgery.  The tube is carefully cleaned and monitored and left in place for a few days until the airway swelling has resolved, at which time the tube is removed and the hole allowed to close.  

It is possible for abnormal scar tissue to form after laryngeal saccule or soft palate surgery.  If breathing difficulties recur after the pet has healed from upper airway surgery, another upper airway exam may be warranted to evaluate for scar tissue or other changes to the larynx (voice box) that may not have been previously present.

How should you care for your brachycephalic (flat faced) dog after surgery?

In general, pets should be carefully monitored after anesthesia for worsening breathing or regurgitation/vomiting. Pain should be well managed to reduce stress and anxiety. Give pain medications, anti-inflammatories (such as steroids), sedatives, GI medications, and any other medications prescribed by your veterinarian as directed.  Elizabethan collars (E-collars, “cones of shame”) should be worn to prevent licking of any external incisions or rubbing of the nose after a rhinoplasty.  Activity should be restricted and stressors avoided.  A harness instead of a collar should be used during walks to use the restroom to avoid putting pressure on the neck. 

If surgery was performed on the throat (soft palate correction, removal of everted tonsils, or removal of everted laryngeal saccules), then it is recommended to offer small portions of soft food, ideally in “meatball” form (smash up canned food or soaked kibble and press into a small ball) fed by hand for several days after surgery to help prevent throat irritation or aspiration.  Feeding can generally be started 12 to 24 hours after surgery. 

If at any point your pet’s breathing worsens or signs of respiratory distress occur (e.g. very loud breathing, purple or blue tongue or gums, unable to rest or calm down), then emergency veterinary care should be sought immediately.  

What are the typical outcomes of upper airway surgery on brachycephalic (flat faced) dogs?

The goal of surgery is to improve the pet’s breathing quality, reduce or prevent progression of BOAS, and help treat the secondary effects on the GI tract. This would help improve the pet’s quality of life and longevity.  

The prognosis for dogs after BOAS surgery depends on the airway abnormalities found and addressed:

1. If only stenotic nares is present, 96% of dogs improve after rhinoplasty surgery.

2. If only an elongated soft palate is present, an average of 85-90% of dogs improve after resection surgery.  Young dogs less than 2 years of age have a higher rate of improvement (90%) than dogs older than 2 years of age (70%). 

3. If stenotic nares AND an elongated soft palate are present, and both are surgically addressed, 96% of dogs have a favorable outcome.

4. If an elongated soft palate AND everted laryngeal saccules are present, and both are surgically addressed, 80% of dogs experience significant improvement after surgery. 

Dogs that have had surgery to correct their BOAS have fewer complications during recovery from later anesthetic events compared to untreated dogs. In fact, the risk of having complications after anesthesia on subsequent procedures decreases by 79% in these dogs. 

If you think your dog may be affected by BOAS, we urge you to talk to your veterinarian about diagnostic and treatment options so that your little one has the best chance of living a long and happy life.