Preventing Bloat in Dogs
There are many injuries and physical disorders that represent life-threatening emergencies. There is only one condition so drastic that it over shadows them all in terms of rapidity of consequences and effort in emergency treatment. This is the gastric dilatation and volvulus - the "bloat."
What Is it and Why Is it so Serious?
The normal stomach sits high in the abdomen and contains a small amount of gas, some mucus, and any food being digested. It undergoes a normal rhythm of contraction, receiving food from the esophagus above, grinding the food, and sending the ground food out to the small intestine at its other end. Normally this proceeds uneventfully except for the occasional burp.
In the bloated stomach, gas and/or food stretches the stomach many times its normal size, causing tremendous abdominal pain. For reasons we do not fully understand, this grossly distended stomach has a tendency to rotate, thus twisting off not only its own blood supply but the only exit routes for the gas inside. Not only is this condition extremely painful but it is also rapidly life threatening. A dog with a bloated, twisted stomach (more scientifically called "Gastric Dilatation and Volvulus") will die in pain in a matter of hours unless drastic steps are taken.
What Are the Risk Factors for Developing Bloat?
Classically, this condition affects dog breeds which are said to be "deep chested," meaning the length of their chest from backbone to sternum is relatively long while the chest width from right to left is narrow. Examples of deep chested breeds would be the Great Dane, Greyhound, and the setter breeds. Still, any dog can bloat, even dachshunds and Chihuahuas.
We usually do not know why a given dog bloats on an individual basis. No specific diet or dietary ingredient has been proven to be associated with bloat. Some factors found to increase and decrease the risk of bloat are listed below:
Factors Increasing the Risk of Bloating
- Feeding only one meal a day
- Feeding only dry food
- Having closely related family members with a history of bloat increases the risk 63%
- Having a deep, narrow chest
- Eating rapidly increases the risk 15%
- Being thin or underweight
- Fearful, nervous, or anxious temperament
- Stress increases the risk. This includes recent kenneling or a recent long car ride
- History of aggression towards people or other dogs
- Male dogs are slightly more likely to bloat than females
- Older dogs (7 - 12 years) were the highest risk group. For large breeds, the risk of developing bloat goes up 20% each year after the age of 5. For giant breeds, it goes up 20 % each year after the age of 3.
- Feeding a dry food containing citric acid that is moistened prior to feeding had a 320 percent higher risk for developing bloat
- Dogs fed dry food containing fat among the first four ingredients had a 170 percent higher risk for developing bloat
- Raising food bowls increases the risk 110%
- The breed with the highest average lifetime likelihood of a bloat episode is the Great Dane, at 42.4%. Other breeds with a higher than average risk include: the Bloodhound, Irish Wolfhound, Irish Setter, Akita, Standard Poodle, German Shepherd Dog, and Boxer. Other deep-chested breeds and deep-chested mixed-breed dogs are also at higher risk
Factors Decreasing the Risk of Bloat
- Inclusion of canned dog food in the diet
- Inclusion of table scraps in the diet
- Happy or easy-going temperament
- Eating 2 or more meals per day
- Feeding a dry food containing a calcium-rich meat meal (such as meat/lamb meal, fish meal, chicken by-product meal, meat meal, or bone meal) listed in the first four ingredients of the ingredient list decreases the risk 53%
Contrary to popular belief, the presence of cereal ingredients such as soy, wheat or corn in the first four ingredients of the ingredient list does not increase the risk of bloat. There is no correlation of bloat risk to exercise before or after eating. Most dogs bloat during the middle of the night with an empty, gas filled stomach. There is also no correlation to vaccinations, to the brand of dog food consumed, or to the timing or volume of water intake before or after eating.
How to Tell if Your Dog Has Bloated
The dog may have an obviously distended stomach especially near the ribs but this is not always evident depending on the dog's body configuration.
The biggest clue is the vomiting: the pet appears highly nauseated and is retching but little is coming up.
If this is seen, rush your dog to the veterinarian IMMEDIATELY.
What Has to Be Done
There are several steps to saving a bloated dogs life. Part of the problem is that all steps should be done at the same time and as quickly as possible.
First: The Stomach Must Be Decompressed
The huge stomach is by now pressing on the major blood vessels carrying blood back to the heart. This stops normal circulation and sends the dog into shock. Making matters worse, the stomach tissue is dying because it is stretched too tightly to allow blood circulation through it. There can be no recovery until the stomach is untwisted and the gas released. A stomach tube and stomach pump are generally used for this but sometime surgery is needed to achieve stomach decompression.
Also First: Rapid IV Fluids Must be Given to Reverse the ShockIntravenous catheters are placed and life-giving fluid solutions are rushed in to replace the blood that cannot get past the bloated stomach to return to the heart. The intense pain associated with this disease causes the heart rate to race at such a high rate that heart failure will result. Medication to resolve the pain is needed if the patient's heart rate is to slow down. Medication for shock, antibiotics and electrolytes are all vital in stabilizing the patient.
Also First: The Heart Rhythm Is Assessed and Stabilized
There is a special very dangerous rhythm problem, called a "premature ventricular contraction" or "PVC," associated with bloat and it must be ruled out. If it is present, intravenous medications are needed to stabilize the rhythm. Since this rhythm problem may not be evident until even the next day continual EKG monitoring may be necessary. Disturbed heart rhythm already present at the beginning of treatment is associated with a 38% mortality rate.
Getting the bloated dog's stomach decompressed and reversing the shock is an adventure in itself but the work is not yet half finished.
Surgery
All bloated dogs, once stable, should have surgery. Without surgery, the damage done inside cannot be assessed or repaired plus bloat may recur at any point, even within the next few hours and the above adventure must be repeated. Surgery, called gastropexy, allows the stomach to be tacked into normal position so that it may never again twist. Without gastropexy, the recurrence rate of bloat may be as high as 75%! Recurrences of bloat occur in 6% of dogs who have had the tacking procedure.
Assessment of the internal damage is also very important to recovery. If there is a section of dying tissue on the stomach wall, this must be discovered and removed or the dog will die despite the heroics described above. Also, the spleen, which is located adjacent to the stomach, may twist with the stomach. The spleen may require removal, too.
If the tissue damage is so bad that part of the stomach must be removed, the mortality rate jumps to 28% to 38%.
If the tissue damage is so bad that the spleen must be removed, the mortality rate is 32% to 38%.
After the expense and effort of the stomach decompression, it is tempting to forgo the further expense of surgery. However, consider that the next time your dog bloats, you may not be there to catch it in time and, according the study described below, without surgery there is a 24% mortality rate and a 76% chance of re-bloating at some point. The best choice is to finish the treatment that has been started and have the abdomen explored. If the stomach can be surgically tacked into place, recurrence rate drops to 6%.
Results of a Statistical Study
In 1993, a statistical study involving 134 dogs with gastric dilatation and volvulus was conducted by the School of Veterinary Medicine in Hanover, Germany.
Out of 134 dogs that came into the hospital with this condition:
- 10% died or were euthanized prior to surgery (factors involved included expense of treatment, severity/advancement of disease, etc.)
- 33 dogs were treated with decompression and no surgery. Of these dogs, 8 (24%) died or were euthanized within the next 48 hours due to poor response to treatment. (Six of these 8 had actually re-bloated).
- Of the dogs that did not have surgical treatment but did survive to go home, 76% had another episode of gastric dilatation and volvulus eventually.
- 88 dogs were treated with both decompression and surgery. Of these dogs, 10% (9 dogs) died in surgery, 18% (16 dogs) died in the week after surgery, 71.5% (63 dogs) went home in good condition. Of the dogs that went home in good condition, 6% (4 dogs) had a second episode of bloat later in life.
- In this study 66.4% of the bloated dogs were male and 33.6% were female. Most dogs were between ages 7 and 12 years old. The German Shepherd dog and the Boxer appeared to have a greater risk for bloating than did other breeds.
Another study published December of 2006 looked at 166 dogs that received surgery for gastric dilatation and volvulus. The point of the study was to identify factors that led to poor prognosis.
- A 16.2% mortality rate was observed. The mortality rate for dogs over age 10 years was 21%.
- Of the 166 going to surgery, 4.8% were euthanized during surgery, and the other 11.4% died during hospitalization (2 of dogs died during surgery). All dogs that survived to go home were still alive at the time of suture removal.
- 34 out of 166 dogs had gastric necrosis (dead stomach tissue which had to be removed). Of these dogs 26% died or were euthanized.
- Post-operative complications of some sort occurred in 75.9% of patients. Approximately 50% of these dogs developed a cardiac arrhythmia.
- Risk factors significantly associated with death prior to suture removal included clinical signs of bloating for greater than 6 hours before seeing the vet, partial stomach removal combined with spleen removal, need for blood transfusion, low blood pressure at any time during hospitalization, sepsis (blood infection, and peritonitis (infection of the abdominal membranes).
It is crucially important that owners of big dogs be aware of this condition and prepared for it. Know what to watch for. For emergency care during the night or on weekends, you can contact VETS in Charlottesville at 973-3519 or VRCC in Richmond at 804-784-8722.
Enjoy the special friendship a large dog provides but at the same time be aware of the large dog's special needs and concerns.
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