From Police K-9 Magazine
Heat Injury in Working Dogs: Practical Treatment Recommendations
Tuesday, 10 August 2010 00:45 Janice Baker, DVM
Heat
injury is a fairly common problem in working dogs and severe cases can be fatal.
Many recommendations by veterinarians or canine first aid references
offer conflicting and complicated recommendations on the best way to treat an
overheated dog. The single most
important factor to survival is immediate
treatment and rapid cooling to reduce
the dog’s core body temperature when the first signs occur.
For the working dog handler and tactical medical personnel supporting
units with canine teams, this means beginning treatment at the point of injury,
long before arrival to veterinary care.
While heat injury is a complex problem that can have serious
complications or outcome, immediate lifesaving treatment is relatively simple,
and does not need to be complicated.
Basic, rapid measures to cool the dog to a more normal body temperature
can greatly increase his chance for survival.
Recognizing Heat Injury
There are many definitions for heat injury, with temperature ranges from
105-107 depending on the source of information.
Normal temperature of dogs is usually between
99-102.5, however their temperature may go up as high as 106 to 107
during hard work and still be abnormal. Hyperthermia is the term meaning that
the body temperature is elevated above the normal range.
However, hyperthermia does not mean that there is something wrong
with the dog. The time that it
takes the temperature to return to normal after a dog stops working may be a
better indicator of if there is a problem, vs. the high temperature itself.
Different dogs will respond differently and it is important to know what
normal recovery time is for your dog. In general, all definitions
of heat injury include a significantly high body temperature in
combination with clinical signs such as abnormal behavior, exhaustion, or
collapse. With mild cases of heat
injury a dog may only show vague signs such as appearing tired, or slow or
reluctant to follow commands. In more serious cases the dog may collapse, lose
consciousness, and may have seizures.
Any sudden change in behavior, level of energy, or physical actions of a
dog during warm or hot weather should be considered possible heat injury until
proven otherwise.
An affected dog’s heart rate will likely be elevated, possibly at 150
beats per minute or greater for a typical 60 to 80lb dog, and his respiratory
rate and effort will likely also be increased.
Like his body temperature, this could be elevated from hard work and
still be considered normal for him.
The heart rate and respiratory effort of a normal dog should begin to
return to normal within a few minutes of when he stops working and rests.
Heat injury is usually categorized in different degrees of severity.
Mild cases are typically called “heat stress” or “heat exhaustion.”
These cases may resolve with adequate rest in a cool environment and
rehydration by drinking water or administration of IV or subcutaneous fluids.
More severe cases are typically called “heat stroke,” and can often have
serious complications. It is not as
important for you to know the definitions of the types as it is being able to
recognize the conditions in which it’s likely to occur, ways to prevent it, or
treat if when it happens.
Working dogs, with their high drive and desire to please their handlers,
may not show any signs at all of problems, then suddenly stagger for a few steps
and collapse. Any sudden change in
behavior, level of energy, or physical actions of a dog during warm or hot
weather should be considered possible heat injury.
Thermometers and Method of Taking a Temperature
Every canine first aid kit should contain a thermometer.
Rectal measurement of temperature is the most practical, accurate
representation of core, or inner body
temperature in dogs. Since many
working dogs don’t like having a thermometer inserted into their rectum, it
would be nice to have a less intrusive method of evaluating their temperature.
Unfortunately, there is currently no better way to do this.
Ear thermometers are generally designed for humans and are not long
enough to reach areas of the ear canal that give an accurate temperature
reading, and a lot of dogs resent those just as much as rectal thermometers.
Flexible digital thermometers, many of which give a reading within
seconds, are probably the best type to use as far as accuracy, safety, and
comfort for your dog.
Treatment
According to studies in both veterinary and human medicine, the most
important factor in treatment of heat injury is
immediate treatment.
The more quickly cooling occurs, the better chance for survival.
Specifically, if aggressive cooling begins within 10 minutes of collapse,
the patient has a significantly greater chance for survival that if cooling is
delayed longer than this. If you
have only one choice at a time between cooling the dog or transporting the dog,
cool him first, then transport him to a veterinarian.
Ideally, you would start rapid cooling first, then transport to a
veterinarian while continuing cooling if needed.
Air conditioning inside a vehicle would not be considered “aggressive
cooling.” Aggressive cooling would
include more rapid measures, such as immersion in cold water or placement
several ice packs around the dog’s body and head.
Some recommended methods of immediate cooling include:
-
Move into a cooler environment (shade, air conditioning, etc)
-
Immersion in cold or cool water
-
Wrap in cool or cold wet towels
-
Provide a strong breeze with fans or other air movement
-
Place ice packs around the body and head
-
Administer IV fluids if available
-
Place rubbing alcohol on wet fur (avoid the face)
-
Contrary to some recommendations, there are really no
“wrong” methods of cooling down an overheated dog, baring the extreme or
obviously unsafe. For years
veterinarians and canine first aid references have warned against immersion in
cold or ice water, claiming that those methods will actually slow down or
prevent cooling. This is based on
the idea that cold or ice water will cause the blood vessels in the skin to
constrict, preventing needed heat loss from the blood.
While the vessels will constrict to some degree, there is no scientific
evidence to show that this slows or prevents cooling overall, and there is also
no scientific evidence to show that this method is actually harmful to the
overheated patient. In fact, many
studies confirm that cold water immersion is the most rapid method for cooling
subjects with exercised-induced heat injury, and is the preferred method of
cooling down humans with heat stroke.
Similarly, some recommendations state not to place wet towels over a dog
to cool them down as the towels will actually “trap” the heat from escaping.
Similar to cold water immersion, there is no scientific evidence to back
up this recommendation either, and it may come down to common sense on that one:
If the water in the towels is colder than the dog, then heat will be
transferred from the dog to the towels and the dog
will cool down.
One study showed that cool water immersion cooled down overheated
subjects twice as fast as wrapping the patient in wet towels, but both methods
were effective in cooling overall.
If you or your teammates have the skills to place IV catheters and
administer fluids, this could also be considered.
However, do not delay cooling efforts in order to place an IV catheter.
And along that same line, once the dog has been cooled, do not delay
transport to veterinary care in order to place an IV catheter.
Subcutaneous fluids (fluids administered under the skin) may not help
much in a severe case of heat injury, but administered in an appropriate dose
may help with mild cases, and probably won’t hurt in more severe cases.
Do not attempt IV or subcutaneous fluid administration unless you have
been properly trained to do so, as serious complications could occur if not done
properly with the right type of fluid solution.
Many scientific studies have been done on dogs and humans to evaluate
which method and speed of cooling is best for survival,
and to date the only practical conclusion from these studies is that the
more rapid the cooling, the greater chances of survival.
The method used should be the one available to you that will cool him
most quickly.
Because your goal is to rapidly
cool the dog, you have to be careful not to overcool him and cause his
temperature to drop too low.
Overheating can alter the dog’s ability to regulate his temperature through
damage caused to his hypothalamus; a specific part of the brain that controls
temperature regulation. With loss
of his normal temperature regulation mechanisms, and your aggressive cooling
methods, his temperature can drop way below normal.
The general recommendation is to stop aggressive cooling when the dog’s
rectal temperature reaches 103 degrees F.
If his temperature continues to drop below that, you may need to take
measures to keep him warm and prevent even more heat loss.
Drying him with a towel and wrapping him in a dry blanket may be all that
is needed, but the most important part is to continue monitoring his temperature
every five to ten minutes after that until his temperature remains stable and he
is in the care of a veterinarian.
Conclusion
Practical treatment of heat injury in working dogs revolves around the
idea that the more rapid an overheated dog is cooled down after he reaches a
critical temperature, the more likely he is to survive this potentially fatal
condition. Don’t let yourself be
hindered by complicated recommendations of which methods of cooling are the best
or are detrimental to care. The
bottom line is that all of the practical methods seem to be effective and not
harmful if done with common sense and frequent monitoring of the dog’s
temperature. Cool the dog
first, then transport to a veterinarian unless aggressive cooling and
transportation can be done at the same time.
Checklist for Treatment: What You
Should Do
-Cease working the dog, and move him to a cooler environment if possible
(a/c is ideal)
-Remove his muzzle if he is wearing one
-Get him wet all over, with cold water if available. Immerse him in the
water if safe to do so, protecting his head from going under
-If the only water available is room temperature or slightly warmer (i.e.
warmed by the sun) use it anyway but do not immerse him in it—pour it over him
or sponge it on him to wet his fur. Do not use hot water
-Place ice packs around the dog’s head if he is unconscious.
-Provide a strong breeze with fans if available
-Provide oxygen by mask if available
-Take his rectal temperature as soon as possible, and repeat every
5minutes to monitor cooling.
-Stop cooling when his temperature reaches 103 degrees F.
-Be prepared to keep him warm if his temperature continues to drop or
goes below 99 degrees F.
-Administer IV or subcutaneous fluids if already trained to do so.
DO NOT delay other methods of cooling or transportation in order to place
an IV or administer fluids.
-Transport to a veterinarian for further care.
JaniceBaker, DVM
VeterinaryTactical Group