Brachycephalic Obstructive Airway Syndrome
10-year-old FS Boston Terrier

By:  Jacqueline Nobles, DVM, DACVECC

Brachycephalic obstructive airway syndrome (BOAS) is a condition characterized by anatomic anomalies predominately observed in brachycephalic breeds in both dogs and cats. The syndrome is characterized primarily by narrowing of the nostrils, an elongated soft palate, large tongue, small trachea, and eversion of tissues in the larynx. The resistance to breathing through small, convoluted airways results in functional changes to the tissues of the larynx. As the patient ages, the tissues of the larynx undergo structural changes that result in impaired function and collapse of the airway or laryngeal collapse. 

Symptoms of BOAS include snoring, inspiratory stridor (loud, open-mouth breathing, especially during inspiration), cyanosis (blue mucous-membrane color), rapid breathing, and even collapse. Additionally, patients may also experience concurrent gastrointestinal disease, which may or may not be related to the airway syndrome. 

A diagnosis is based on breed, characterization of breathing (inspiratory stridor), an exam of the upper airway (sedated exam visualizing the larynx and soft palate), and chest x-rays to evaluate the trachea and lungs. If available, a CT scan of the head and thorax is ideal to enable evaluation of the entire upper and lower respiratory system. 

The advanced stage of disease ultimately results in laryngeal collapse, when we are often forced to perform surgery to alleviate the obstruction. In the early stages of the disease process, options for surgery include trimming the soft palate, removing the saccules, and opening up the nares by removing wedges of tissue. Because most brachycephalics are born with BOAS, surgical interventions should be performed as early as possible in order to improve breathing. In the later stages of BOAS, patients develop complete collapse of the larynx and the aforementioned surgical procedures may not provide a long-term solution. Therefore, in certain cases, we may recommend bypassing the damaged upper airway and creating a permanent opening in the trachea (tracheostomy). 

Breeds predisposed: Brachycephalics
  • Pugs
  • Boston Terriers
  • English Bulldogs
  • French Bulldogs
  • Pekingese
  • Shih Tzus 
  • Boxers
Symptoms: Respiratory and often concurrent gastrointestinal 
  • Inspiratory stridor (loud, open-mouth breathing during inspiration)
  • Cyanosis (blue gum color)
  • Rapid breathing
  • Snoring
  • Acute collapse
  • Retching
  • Vomiting
  • Diarrhea
Diagnosis: Exam, sedated upper airway exam, thoracic radiographs, CT of head and thorax
  • Stenotic nares
  • Elongated soft palate
  • Everted laryngeal saccules
  • Hypoplastic trachea
  • Laryngeal collapse
Treatment of BOAS: Surgery
  • Intubation
  • Trimming the soft palate
  • Sacculectomy
  • Wedge resection of nares
  • Permanent tracheostomy
  • Short-acting steroids

Patient: Maggie, a 10-year-old, spayed, female Boston Terrier, was transferred to our hospital for severe respiratory distress and suspected cardiac disease. Upon arrival at our hospital, Maggie was sedated and placed in oxygen. Despite supplemental oxygen, Maggie continued to struggle and the work of breathing warranted placement of an endotracheal tube. Immediately upon intubation, her condition improved. An ultrasound of the heart was performed, and it was concluded that Maggie's heart was functioning normally. Chest x-rays, ultrasound of the heart (echocardiogram), ultrasound of the lungs, and an upper airway exam were performed. The chest x-rays showed changes consistent with chronic lower airway disease. The echocardiogram failed to show evidence of cardiac disease. The ultrasound of the lungs showed suspected pneumonia. The upper airway exam showed a severely elongated soft palate, swelling of the laryngeal tissues, and collapse of the larynx consistent with severe end-stage BOAS. Due to the severity of her condition, we felt it was in Maggie's best interest to completely bypass her upper airway by performing a permanent tracheostomy. Following surgery, Maggie did have complications, including pneumonia (which we had suspected on presentation), vomiting, and diarrhea. However, Maggie fought hard for six days until she was successfully discharged. According to Maggie's family, she is doing well at home and breathing better than ever. 

TECH TIP:  Gastric Dilatation-Volvulus  and Lactate Levels

By: Cody R., LVT, and Jacqueline Nobles, DVM, DACVECC
Lactate, a by-product of anaerobic metabolism, is a prognostic biomarker of severe hypoperfusion. Disease processes which impair cardiac output and oxygen delivery to tissues force the body to transition to anaerobic metabolism resulting in hyperlactatemia and lactic acidosis. The clinical use of lactate as an indicator of hypoperfusion has been demonstrated in several species including dogs. With the advent of lactate point of care analyzers, lactate can be measured and used to guide therapeutic decisions. 

Gastric dilatation volvulus (GDV) is a life threatening condition characterized by rapid dilation and torsion of the stomach. The dilated, twisted stomach obstructs blood flow, thereby, decreased oxygen delivery to tissues. In some cases, especially those with prolonged history of clinical signs, blood flow to the gastric wall is severely compromised and results in necrosis. While it is impossible to determine the presence of gastric necrosis pre-operatively, lactate levels have been useful in predicting necrosis and outcome. 

One study published in the  Journal of the American Veterinary Medical Association showed that 99% of patient with a lactate reading of less than 6.0mmol/L survived, while only 58% of patients with readings greater than 0.6mmol/L survived. (1) The probability of gastric necrosis was also greatly increased when the concentration was greater than 6.0mmol/L. However, a subsequent study found no statistically significant relationship between survival and the presence of macroscopic gastric wall necrosis with lactate levels > 6.0mmol/L. (2) The data from that study did show that decreases in plasma lactate concentrations greater than or equal to 50% of the baseline within 12 hours may be a good indicator for survival. (2) Hence, as always, the use of lactate trends provides a better clinical picture than a single value alone. 

(1). de Papp, E. et al. Plasma lactate as a predictor of gastric necrosis and survival among dogs with gastric dilatation-volvulus: 102 cases (1995-1998). Journal of the American Veterinary Medical Association, 1999 Jul 1:215(1); 49-52

(2). Green, T. et al. Evaluation of initial plasma lactate values as a predictor of gastric necrosis and initial and subsequent plams lacate values as a predictor of survival in dogs with gastric dilatation-volvulus: 84 dogs (2003-2007).  Journal of Veterinary Emergency and Critical Care, 2011, Feb 21(1): 36-44.
Join Us at the Fetch DVM 360 Conference 

Hospital Manager Danielle Russ,  BS, BA, AS, LVT  will be speaking at the Fetch DVM360 conference in beautiful San Diego, CA, December 13-16. Her lecture topics include: Needs Care, No Money...Now What? and What You Didn't Learn in Vet School (leadership).  Click  here  to register. We hope to see you!
Ophthalmology Services Now Available on Fridays
Welcome, Heather Brookshire, DVM, DACVO

Starting this month, The COVE will be offering ophthalmology clinic hours on Fridays from 9:00am - 12:00pm. Services will be provided by Dr. Heather Brookshire, owner of the Animal Vision Center of Virginia in Virginia Beach. As demand grows, we will expand the schedule. 
Dr. Brookshire was recently named to  Inside Business magazine's prestigious listing of "Forty Under 40" business leaders succeeding in diverse professions in Hampton Roads. She was selected for her leadership skills, innovation, business achievements and community service involvement.
We are honored to have her join The COVE team. Please call 757.935.9111 for more information or to make a referral.
Save the Dates! 
May 28-31, 2019: The COVE Seaside CE Event in Virginia Beach

Enjoy the salty air, let down your hair and join us for a complimentary continuing education event for doctors, technicians, and managers featuring topics in cardiology, surgery, critical care, and dentistry. Attend one or attend them all - a unique opportunity to earn up to 9 CE credits.  Look for registration information in a few months.
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