Brachycephalic Airway Syndrome

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Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)

Key Points

Breathing difficulty in a brachycephalic breed of dog or cat is commonly due to

  • stenotic nares

  • elongated soft palate

  • everted lateral ventricles of the larynx

The best prognosis following surgery is in pets that are immature


Anatomy

Air is passed from the nares (nostrils), through the nasal cavity and back of the throat, and into the trachea via the larynx.

Definitions:

  1. Nares = nostrils
  2. Nasal cavity = the nose cavity
  3. Turbinates = scroll like bones in the nasal cavity that are lined with mucosa which serve to warm and moisten inhaled air
  4. Mucosa = the skin like tissue that lines the inside of the nose (like the gums that line the mouth)
  5. Trachea = windpipe
  6. Larynx = voice box
  7. nasopharynx = airway passage that connects the nasal cavity to the back of the throat called the pharynx
  8. Lateral ventricles = cavities that are located adjacent to the opening of the voice box
  9. Hard palate = roof of the mouth (hard portion) that separates the mouth cavity from the nasal cavity
  10. Soft palate = a soft tissue structure extending from back of the hard palate which separates the back of the throat (pharynx) from the nasopharynx

 

What is brachycephalic airway syndrome?

This condition is due to compaction of the upper airway during development which distorts the normal anatomy. The result is that structures that normally fit well within the head and neck are disproportionate, thus the airway is not as open as it ought to be. The soft palate is frequently elongated in brachycephalic breeds (bulldog, Boston terrier, Shar pei, Pug, Himalayan cats, etc) and frequently will occlude the opening of the larynx. In addition, the nares commonly are smaller than normal in such breeds. Secondarily, the lateral ventricles which are normally concave pockets along side of the larynx become everted to form balloon-like structures which further occlude the opening of the larynx. The larynx may also become weakened with time and collapses together, which will further reduces the flow of air from the nose to the trachea. Another anatomical abnormality is an abnormally narrow windpipe called a hypoplastic trachea.

Weight gain is common in affected animals due to sleep apnea in brachycephalic breeds. This condition puts the pet in a state of low metabolism due to oxygen depravation. Fat accumulates in the back of the throat which further impairs the breathing.

 

Signs

Warning signs of brachycephalic airway syndrome include snoring when sleeping, snorting noises when breathing, collapsing when playing, and a purple color of the tongue. Signs are worsen with heat, exercise, and excitement. Other secondary signs may include vomiting which is due to stimulation of the receptors in the back of the throat. Aspiration pneumonia may also be present with this condition, and signs may include coughing, fever, lethargy, and inappetance.

 

Diagnostic testing

Standard testing prior to surgery should include chest radiographs to rule out heart disease and conditions of the lungs such as pneumonia. A side view x-ray of the neck is helpful to check for a hypoplastic trachea. Blood testing including a complete blood count, chemistry panel, and urinalysis should be done to rule out other conditions that may complicate surgery. An examination of the back of the throat is performed under general anesthesia. I generally perform this examination at the time of the proposed surgery.

 

Preparation for surgery

The pet should be fasted prior to surgery, as instructed by the surgical team. Water is usually permitted up to the time of admission to the hospital. The surgical team should be informed of any medications that your pet is currently receiving. Just prior to surgery, your pet will receive a sedative, have an intravenous catheter placed for the administration of intravenous fluids and intravenous medications, be induced under general anesthesia with medication(s), and have a breathing tube (endotracheal tube) placed to allow delivery of oxygen and gaseous anesthesia. While under general anesthesia, the pet's breathing will be assisted with a ventilator and vital parameters such as heart rate, respiratory rate, core body temperature, blood pressure, oxygenation of the blood (pulse oximetry), exhaled carbon dioxide (capnography), and heart rhythm (EKG) will be monitored to ensure the pet's well being. Pain will be controlled both during and after surgery with analgesics (pain-controlling medication). Please note that each surgical and anesthesia team may elect to chose a different, but effective analgesia protocol.

 

Surgery

Nares are surgically opened if they are stenotic. This generally necessitates removal of a wedge of tissue from the sides of each nare. In addition, I feel that it is important to also remove tissue extending deep to the nares to fully open the nasal passage. The photo right shows a severe case of stenotic nares that is surgically corrected.

 

 

The soft palate can be shortened using a number of potential methods. The traditional method involves simply cutting the tip of the soft palate off and over sewing the edges of the palate. The second method is cutting the tip of the palate off with a laser and the third method is performed using a specialized cautery unit called the ligasure. Swelling of the palate can occur with any of these methods of treatment. It seem that the older the dog, the greater the risk for having breathing difficulty after surgery. Without intervention after surgery, breathing difficulties can result in death of the patient. In fact, one surgeon whom I have highly respect (DJ Krawinkle), indicated that 50% of the mature bulldogs will have swelling postoperatively that requires intervention. In some cases, a tracheostomy is needed after surgery, but this significantly increases patient morbidity and hospital stay. Another study demonstrated that placement of nasotracheal catheters at the time of surgery to deliver oxygen, eliminated the need for tracheostomy in the postop period following soft palate surgery.

Finally, the everted saccules, if present are removed. This is a relatively fast procedure and only involves grasping and snipping this tissue off with scissors.

 

Care after surgery

Most pets having this type of surgery will stay in the hospital at least over night to monitor the pet for breathing difficulties. While in the hospital, intravenous fluid therapy likely will continue until the pet goes home. Oxygen therapy may be needed via a nasotracheal catheter. If severe breathing difficulties are present after surgery due to swelling and the oxygen therapy via the nasotracheal catheter is inadequate, a tracheostomy may be required. This necessitates making an incision over the neck and creating a hole in the trachea, through which a breathing tube (trach tube) is placed. This tube will need to be replaced every 6 to 8 hours and the tracheostomy site cleansed on a regular basis. This type of care should only be done in the hospital by an experienced team, as occlusion of the tube with mucus can create a life-threatening situation.

At home, medication to control pain after surgery should be administered for a few days. Antibiotics are commonly prescribed, but only may be needed for a week or two, unless the pet has pneumonia. If prescribed by the surgeon, cortisone may be needed for only a very short period of time after surgery. Exercise should be restricted for two weeks, but leash walks are generally permitted. A follow-up examination should be done in 2 weeks after surgery to evaluate the healing process.

 

Results

Most immature dogs that have surgical correction of the problem usually recover uneventfully. As a dog ages with untreated brachycephalic airway syndrome, secondary changes such as laryngeal collapse may complicate the recovery and worsen the prognosis. Aspiration pneumonia will complicate the recovery and in some cases can be fatal. A successful surgery will result in much better breathing, snoring will be reduced, exercise tolerance is greatly improved, sleeping will be much better, and weight loss with an appropriate dietary restrictions can be achieved. Although surgery can be successful, it is imperative that weight gain is not occur, as this will result in breathing difficulties again.

A complication that is seen following laser surgery on the nose in very small animals such as a cats is permanent structuring (narrowing) of the nares. This is caused by collateral damage to neighboring tissues. Below is a cat that has stenotic nares prior to laser surgery and then the disaster that followed. Take note that the photo below right shows that the nostrils have healed closed and the nose is gone, as a result of failed laser surgery. As a warning, only select a surgeon that has good experience with this technique. Be aware that the cold scalpel blade is unlikely to have this kind of end result versus when treated with laser.

Another potential complication of soft palate surgery is resecting the soft palate too short, which results in reflux of food into the nasal cavity with subsequent chronic nasal infection.

 

Frequently Asked Questions After Surgery

When should my dog have the first bowel movement after surgery?

  • Many dogs will not have a bowel movement for the first 4 to 5 days after surgery
  • Reasons that a dog will not have regular bowel movements after surgery include:
    • The dog has been fasted prior to surgery
    • Dogs do not eat well during the hospital stay
    • They frequently do not eat well when they go home
    • They are fed highly digestible food that produces little stool
    • Pain medication that contain narcotics (such as morphine, fentanyl patches, and tramadol) can be constipating
  • If a pet does not have a bowel movement on the 5th day of being home, a stool softener such as metamucil can be fed
    • Dose of metamucil is 1 tsp per 25 Kg mixed in with each meal (canned dog food); feed immediately after mixing, as the metamucil will gel the food and may make it less palatable

My pet had surgery and will not eat.  What can be done?

  • Dogs
    • Most pets will not eat their regular dog food after surgery, especially if it is kibble.
    • Offer a cooked diet having a 1:1 ratio of a protein source and carbohydrate source.  The protein source can be any meat (example: chicken breast, turkey breast, lean hamburger) that is low in fat and should be cooked (drain off all fat after the meat has been cooked).   The carbohydrate can be pasta, potato or white rice.
    • Try canned dog food; to enhance the flavor sprinkle a very small amount of garlic powder or chicken or beef broth (Chicken-in-a- MugTM or Beef-in-a-MugTM products)
    • Try Gerber strained meats for babies such as the chicken, beef, turkey, or veal
    • Try Hill's A/D diet available at most veterinary hospitals
    • Hand feeding: place a small amount of food in the mouth so that your dog gets the flavor
    • Warm the food slightly in a microwave, as the food will be more aromatic; stir the food before feeding and test the temperature on the bottom side of your wrist; it should only be luke warm.
    • Remember that most pets will not eat the first day or two after they get home from surgery
  • Cats
    • Offer smelly foods that contain fish such as tuna or smelly cat foods
    • Try Gerber strained meats for babies such as the chicken, beef, turkey or veal
    • Hand feeding:  with your finger place a small amount of food on the roof of your cat's mouth; use a syringe to get soft food into the mouth
    • Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature; it should be only luke-warm
    • Some cats will only eat dry food, try kibble if your cat normally has been fed that food
    • Petting and stroking your cat frequently will help to stimulate appetite
    • Remember that most pets will not eat the first day or two after they get home from surgery
    • Appetite stimulants such as cyproheptadine may be helpful
    • If your cat refuses to eat anything for 7 days a stomach tube or nasogastric tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop

My pet is vomiting.  What can be done?

  • The first thing for you to discern is whether your pet is vomiting or regurgitating.  Both will result in fluid or food being brought up.  Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus.  Regurgitation is not associated with heaving and the pet usually just opens the mouth and fluid or food will be expelled.  Usually the regurgited material will be clear or brown colored fluid. 
  • Next is to identify the cause of the vomiting or regurgitation.
  • Causes and treatment of vomiting after surgery
    • When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be the case, the water should be limited to frequent smaller amounts.
    • Medications such as antibiotics, narcotics or nonsteroidal anti-inflammatory medication commonly cause vomiting after surgery.  In order to see which medication is causing the problem, the administration of each drug should be separated 2 hours apart.  Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to.  The antibiotic in some cases may be changed to a different one, or may be discontinued. 
    • Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days. 
    • An uncommon cause of vomiting after surgery is internal organ failure.  Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.
    • If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present.  Do not ignore this sign.
    • Symptomatic treatment of vomiting involves withholding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then gradually wean him/her back onto the regular diet after 3 days.  In order to decrease the acidity of the stomach, Pepcid AC 0.5 mg/kg can be given by mouth twice daily for 5 days.  Metoclopramide and Cerenia are good anti-vomiting medications for dogs and cats.  You should always consult a veterinary healthcare professional before administering medication.
  • Causes and treatment of regurgitation after surgery
    • The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia.  Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, called esophagitis.  This results in poor motility of the esophagus, therefore water and food will accumulate in this structure.  In most cases, esphagitis is self-eliminating and will resolve within two or three days. 
    • If the esophagitis is severe the esophagus may develop one or more strictures.  A stricture is a narrowing or stenosis of the esophagus and does not allow passage of food down the esophagus, in regurgitation that lasts longer than one week.  This problem should be brought to the attention of your pet's doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure, as it is done with the aide of an endoscope).  If an esophageal stricture is chronic surgery is needed.
    • Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent (sucralfate) and an acid blocker (omeprazole or other).  Consult a veterinary health care professional if the regurgitation continues for more than a couple of days.

How do I know that my dog is in pain following surgery?

  • Signs of pain include
    • crying
    • biting if you get near the surgical site
    • grimacing (lips are pulled back and the the dog looks anxious)
    • tragic facial expression
    • panting
    • restlessness and unable to sleep; pacing
    • if abdominal surgery was done the pet will not lie down on the incision, or will continually sit up in spite of appearing very tired
    • the worst pain will be for the first 2 to 3 days after surgery

What can I do to control my dog's pain?

  • Narcotic medications that control pain: tramadol, butorphanol, Duragesic (fentanyl patch)
  • Anti-inflammatories used to control pain: Deramaxx, Rimadyl, Previcox, or Etogesic
  • If an orthopedic surgery has been done cold packing the surgical site may be helpful
    • A cold pack may be a pack of frozen peas, crushed ice in a Ziploc bag, or a cold gel pack; place a thin barrier between the skin and the cold pack.  An alternative to a cold pack is to freeze water in a styrofoam cup; after frozen cut the bottom of the styrofoam cup out. Cool the surgical site around the incision by rubbing the exposed ice directly on the skin in a circular pattern.  Cooling the surgical site helps to numb the area.

How do I know that my cat is in pain following surgery?

  • Pain is more difficult to assess in cats versus dogs, as signs can be more subtle and they usually do not vocalize when in pain
  • Signs of pain in a cat include the following:
    • biting if you get near the surgical site
    • growling or deep cry
    • not wanting to eat
    • hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)

What can be done for pain at home for my cat?

  • Pain medication such as buprenorphine or a Duragesic (fentanyl) patch
  • Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver
  • Anti-inflammatories can be used, but the dose is much less than dogs

Is it okay for my pet to lick the incision?

  • If a dog licks the incision, the healing process may be delayed.
  • Licking can remove stitches and cause the incision to open
  • Licking can become a severe habit that is difficult to break
  • Licking can cause infection as the mouth has many bacteria
  • Dogs will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.
  • To stop your pet from licking the following can be tried:
    • Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region
    • Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site
    • A tee shirt can be used to cover an incision on the chest or front part of the abdomen; gather the waist of the shirt up over the dog's back and wrap an elastic band around this part of the shirt.
    • A bandage or sock can be used to cover an incision on a limb; fasten the top of the sock to the dog's limb with tape.
    • Bitter apple can be applied around the incision; many dogs will continue to lick  after application of this topical
    • Bitter Apple and Liquid HeetTM (obtain this from a drugstore...it is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision
    • Antipsychotic medication in some cases is needed

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  • Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree

  • Experience in the development of new surgical treatments

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  • Assurance that a veterinarian is a surgical specialist

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