Heat stroke (hyperthermia) is a quick killer. Even well cared-for dogs die every year as a result of over-exposure to heat and humidity or too much activity on a fairly mild day.
Large dogs, heavily coated dogs and dogs that are not accustomed to warm climates are most likely to succumb to the deleterious effects of summer heat, but any dog, under the right circumstances can become a victim.
When a dog is exposed to elevated atmospheric temperature, such as that inside a closed vehicle, his body first responds by dilating blood vessels in the skin and peripheral tissues in an effort to cool the body by convection and radiation. The dog begins to pant, causing an increased loss of water from the body and a decrease in effective circulatory volume.
This establishes an inadequate return of blood to the heart if the atmospheric temperature is not reduced, a vicious cycle develops in which inadequate circulation prevents effective cooling of the dog’s body. The body temperature rises, noticed first in the animal’s extremities, increasing metabolism and oxygen needs. Very quickly, this results in fatigue and failure of central control mechanisms and a rise in trunk body temperature.
The problem is compounded by panic as the animal struggles harder and harder to breathe.
Shock ensues as the dog’s body temperature reaches 107 to 109 degrees Fahrenheit. Temperatures of this degree can only be tolerated for a few minutes before severe and irreversible central nervous system and cardiac damage occur. By this point, circulatory and body fluid levels have become so decreased that inadequate oxygen reaches the dog’s brain, and he loses consciousness. Death follows rapidly.
Treatment: must be rapid in order to save a dog’s life.
Ensure that the dog’s airway is unobstructed
Reduce the animal’s temperature rapidly by immersing him in cool water or rubbing alcohol (because alcohol evaporates more rapidly than water. It is more effective.
Massage the dog’s skin vigorously and flex his limbs to encourage venous return and stimulate circulation.
If the animal has stopped breathing, apply mouth-to-muzzle resuscitation until respiration returns. Do not attempt CPR unless you have been professionally trained.
Get the dog to a veterinarian as soon as possible, even if your first aid administrations seems to be all he needs.