BREATHLESS

Bulldogs, pugs need protection from the heat

By Dr. Tony Johnson

Universal Uclick

Mother Nature usually does things pretty economically, trying to get genes passed on from one generation to the next with a minimum of fuss.

When people step in and start mucking about is usually when the troubles begin. When we breed for a particular look (rather than for a purpose intended to maximize the chances of passing on genes), function gets tossed out the window at the expense of form, and things can get bogged down pretty quickly.

Lots of different dogs suffer from problems because of fad breeding, but perhaps none so much as the short-nosed, or “brachycephalic” breeds such as pugs, English Bulldogs and the like. As the weather turns warmer, we see a lot more of these dogs suffering from heat stroke in our emergency unit at Purdue’s School of Veterinary Medicine.

Dogs are largely unable to sweat. Maybe a little around the feet (sometimes my more nervous patients will leave cute little paw-shaped sweat prints on the exam table), but not through their skin as people can. They regulate their body temperature largely though panting, which dumps heat from their bodies through evaporation of water from their tongues rather than their skin.

In order to keep cool through panting, dogs need a good airway. Brachycephalic dogs almost all have narrower windpipes relative to other dogs of comparable size — a condition known as “tracheal hypoplasia.” Bulldogs often have a trachea that would keep a Yorkie quite happy, but for the bulldog, it must be like breathing through a coffee stirrer. When we have to intubate brachycephalic dogs for surgery (which involves placing a soft, plastic tube into their trachea to deliver oxygen and anesthetic gases), they will often wake up with the tube in place after the procedure and seem quite happy to have an open and bigger airway for the first time in their lives. Most other dogs can’t wait to get the dang tube out!

Brachycephalic dogs can also have little blobs of tissue in the back of their throat (known as “laryngeal saccules”) that can turn inside out and block the airway, and they often have teensy-weensy little nostrils that look cute but don’t move too much actual air. Together, tiny tracheas, lumps of flesh and wee nostrils are called a “brachycephalic airway syndrome,” and while surgery can fix a few of the problems and provide for a better life for some of these dogs, the threat of heat exhaustion always remains.

When they try to dump excess body heat through panting, brachycephalics have to work so hard to move enough air through their tiny tracheas that they actually end up generating more heat and making things worse. It would be like having a coal-fired air-conditioner in your house; when the house gets warm, the A/C kicks on, but the heat from the coal fire would make the house warmer.

When the weather turns warm and humid, these dogs need to stay in a carefully controlled and cool environment to avoid overheating.

Signs of heat exhaustion — the last step before heat stroke — include bright red gums, an inability to get up and loud, raspy panting. Dogs that are going into full-on heat stroke often vomit, become severely lethargic and can have explosive diarrhea. Once heat stroke develops, cooling them down is the top priority but it often is not enough. Some dogs will go down the slippery and tragic slope into multi-organ failure and be unable to be saved, even with days of ICU-level care.

Prevention is the key with this condition, so remember to keep these dogs in a cool environment and always watch out for heat exhaustion.

If you think your dog is suffering from heat stroke or exhaustion, douse them in cool water, get them out of the heat and calmed down, and head for the nearest veterinarian without delay. Even a few minutes can make all the difference in the world.

Dr. Tony Johnson is a board-certified specialist in emergency and critical care and a professor at the Purdue University School of Veterinary Medicine. He is on the Pet Connection advisory board.