Heatstroke Prevention

Cricket Hollow Farm

Heat stroke and overheating in dogs:
treatment & prevention

An article by Nate Baxter, DVM

The introductory comment is by the person who reposted the article to Canine-L.
This article was reposted on Canine-L, Discussion Forum for Dog Lovers on 6/8/1999.

Dearest Canine-L'er's:

I am taking the opportunity here to re-post (with permission, and permission is granted to re-post again as long as the originals are not edited and credit is given) a critical reminder about our beloved furbabies and their risk for heat stroke.
I was ... fortunate? ... that in the beginning of the first summer I had [my dog] I was at the vet's at a routine visit . . . a woman rushed in completely hysterical . . . her dog was incapacitated in the back seat of her car, heat-stricken..........they couldnt' save her, and I will never forget this big doggie's death-wracked gasps and gurgles and pants as she struggled to live while they were attempting to cool her down. Sorry to be so explicit but it's a deadly serious issue for our kids. She didn't make it :-(
The vet told me at the time to never push [my doberman] to even *walk* his regular route if he were reluctant, to wet him down, to respect any sign of exhertion and give lots of rest, shade & fluids. Anyway, enough of me.....

BEGIN ARTICLE

Guideline and overview for dogs that overheat.

This is posted with the permission of the author Nate Baxter, DVM and is a guideline and overview for dogs that overheat. While it was written for working retrievers the information applies to any dog exerting itself in warm or very humid conditions.

Nate wrote:

. . . . .The first thing that needs to be understood is that dogs and people are different enough that most of the info cannot cross lines. I do not profess to know what the appropriate procedures for people other than what I learned in first aid.

Electrolyte replacement: Dogs do not lose enough electrolytes thru exercise to make a difference, but if the dog gets truly into heat stroke the physiology changes will make them necessary. BUT oral replacement at that point is futile, they need IV and lots of it.

Cooling: The point of evaporative cooling being the most efficient is correct. However, in a muggy environment, that will not help as much, so I do cool with the coldest water I can find and will use ice depending on the situation. The best way is to run water over the dog, so there is always fresh water in contact. When you immerse a dog in a tub, the water trapped in the hair coat will get warm next to the dog, and act as an insulator against the cool water and cooling stops. If you can run water over the dog and place it in front of a fan that is the best. Misting the dog with water will only help if you are in a dry environment or in front of a fan.

Just getting the dog wet in not the point, you want the water to be cool itself, or to evaporate.

For MOST situation all you will need to do is get the dog in a cooler environment, ie shade, or in the cab of the truck with the air conditioning on (driving around so the truck does not overheat and the AC is more efficient).

This past summer I was very concerned about my dogs getting too hot in the back of my black pickup with a black cap. Boy I wish I got another color 6 years ago<G>.

When I had one dog I just pulled the wire crate out of the car and put it in some shade and hopefully a breeze. But having 2 dogs and running from one stake to another, that was not feasible. So I built a platform to put the wire crates on, this raises the dog up in the truck box where air flow better. Then I placed a 3 speed box fan in front blowing on the dogs with a foot of space to allow better airflow.

I purchased a power inverter that connects to the battery and allows the 3 speed fan to run from the truck power. It has an automatic feature that prevents it from draining the battery. When I turned that fan on medium I would find that the dogs where asleep, breathing slowly and appeared very relaxed and comfortable in a matter of 20 minutes or less, even on very hot muggy days.

Alcohol: {Rubbing Alcohol] I did not carry it but probably will next year. It is very effective at cooling due to the rapid evaporation. It should be used when other methods are not working, but do not hesitate to use it. Due to the thicker skin and rapid evaporation I do not worry about it being absorbed. Plus we recommend using rubbing alcohol, which is propylene alcohol, not ethyl, for those of you not aware. So do not try to drink it<VBG>.

I purchased those cooling pads, but found that the dogs would not lay on them. I would hold them on the back of a dog that just worked to get a quick cool, but probably will not mess with them next summer. I also bought a pair of battery operated fans but found them pretty useless. Spend your money on the power inverter and get a real fan.

Watching temp: If you feel your dog is in danger of heat injury, check its temp and write it down. Keep checking the temp every 3 minutes. Don't forget to shake it down completely each time, sounds silly, but when are worried about your companion, things tend to get mixed up.

This is VERY IMPORTANT:
Once the temp STARTS to drop, STOP ALL COOLING EFFORTS. The cooling process will continue even though you have stopped. If the temp starts at 106.5, and then next time it drops to 105.8, stop cooling the dog, dry it off, and continue monitoring. You will be amazed how it continues to go down. If you do not stop until the temp is 102, the temp will drop on down to 99 or even lower. I cannot emphasis that point enough.

Limit water: When the dog is so heated that it is panting severely, only let it have a few laps of water. Water in the stomach does not cool the dog, you just need to keep the mouth wet so the panting is more effective. Do not worry about hydration until the temp has started down. A dog panting heavily taking in large amounts of water is a risk of bloat. Due to the heavy panting they will swallow air mix in a large amount of water they can bloat. Once the temp is going down and panting has slowed to more normal panting then allow water. The dog will rehydrate it self after temp is normal.

If the dog has a serious problem and even though you have gotten the temp normal, get the dog to a vet, as it can still need IV fluids and some medication. Also, a case of heat stroke can induce a case of hemorrhagic gastroenteritis (not parvo), with a ton of very bloody diarrhea and a lot of fluid and electrolyte loss. These cases need aggressive treatment.

Prevention: The best method of treatment is prevention. Learn to watch your dog, and see the changes in the size of the tongue, and how quickly it goes down. Learn your dogs response to the different environments, and be careful when you head south for an early season hunt test or trial. I have been to Nashville at the end of May the last 2 years, only 5 hours away, but the difference in temp and humidity did effect the dogs as they were used to more spring weather in Ohio. Try different things in training to help the dog cool and learn what works better.

Another very important point:
Do not swim your hot dog to cool it then put in put in a box/tight crate. Remember, evaporation can not take place in a tight space, and the box will turn into a sauna. Carry a stake out chain, and let the dog cool and dry before putting it up.

Whew!! Did not think this would get so long. I hope this is easy to understand and helps provide some info that will be useful.

Remember: Prevention, learn your dog. It is worth the time and effort.

Now all we need is for spring to get here and we can hit training hard!!

Nate Baxter, DVM
Northstar Labradors
Lebanon, OH

Article #2

Dr. Henry De Boer Jr. on Heatstroke

Question:
A friend of mine lost his dog early this spring to heat stroke. What is heat stroke and how should it be prevented or treated?

Answer:
In my experience as a veterinarian and as a working dog trainer and handler, I have attended to far more cases of heat stroke in the spring or fall than I have during the summer months. Most people are conscious of the risks and predisposing causes of heat stroke in the
summer and take appropriate precautions. Many people, however, drop their guard during other seasons, which can lead to a possible disaster. Heat stroke is most likely to occur when we are less conscientious about how heat, muscular exertion and confinement can affect our dogs.

Heat stroke occurs when the dog's ability to regulate its body temperature is lost. A dog regulates body temperature primarily through respiration. When the respiratory tract cannot evacuate heat quickly enough, the body temperature rises. Normal body temperature
is less than 103F, but once the temperature goes over 105F a number of physiologic events can occur that make it even more difficult for the animal to regain control of its temperature. At this time, oxygen delivery to the system cannot keep up with rapidly elevating demand. If the temperature exceeds 108F, cellular damage starts to occur in a number of organ systems including the kidneys, liver, gastrointestinal tract, heart and brain. The extent of the cellular damage depends on the magnitude and the duration of the temperature elevation. Clearly, this can be a life-threatening situation, but for those animals that survive there is the possibility of long term problems after the occurrence.

There are a number of predisposing factors for heat stroke. Some of the most significant are listed here.
• * Heat
• * Humidity
• * Muscular activity
• * High body mass
• * Anxiety
• * Poor ventilation
• * Dehydration
• * Obesity
• * Antihistamines
• * Phenothiazines (some medications for vomiting)
• * Brachycephalic breeds (short-nosed breeds)
• * Increased age

Dogs experiencing heat stroke will have a muddy pink color of their gums instead of the nice red-pink color that normally exists. Their heart rate will be dramatically elevated, and they will be panting
furiously. They tend to stand or walk very slowly without regard to where they are. Some will lay on their sternum. Most dogs will have a wild or panicked expression and are not particularly aware of their environment. Any combination of these symptoms should have an owner scrambling for a rectal thermometer and taking those steps necessary to help drive the temperature back down. If a thermometer is not available, presume it to be heat stroke and initiate
treatment. If the animal does not respond favorably, the diagnosis can be reevaluated later. Significantly delaying the treatment of heat stroke can dramatically increase the risk of long-term consequences or likelihood of death.

Heat stroke is an emergency that requires veterinary assistance, but you can effectively initiate treatment in most cases before heading for the veterinary hospital. You must aggressively assist the dog's efforts to lower body temperature with the use of water and air. Since the lungs cannot keep up with the heat buildup, we now have to cool the skin and associated blood vessels so the body's temperature will decrease. Submersion of the dog in cool water will start to bring the temperature down quickly. You will want to avoid extremely cold water or ice since they cause the blood vessels in the skin to constrict and will not allow for a meaningful heat exchange. If there isn't anything available to submerse the dog in, you can start wetting him down with a hose. Wet him down all over, but let the water run continuously in the groin area since there are large
numbers of significant and relatively superficial blood vessels in that area that will allow for more rapid cooling of the blood. The dog should be in a well-ventilated, shady area to allow for evaporation of the water. Evaporation cools body temperatures very
effectively. When you are transporting him to the veterinary hospital, keep the air conditioner on or the windows open, or use the back of a truck to increase evaporation. Do not use an enclosed style crate since it allows for very little evaporation or fresh cool air for the lungs. Do not cover the dog with a wet towel as it
will prevent evaporation.

Once the temperature starts dropping, you should seek veterinary assistance. It is advisable in most cases to start these animals on intravenous fluids and monitor kidney and liver function for at least several days. The necessity for this laboratory work depends on the magnitude and the duration of the elevated temperature, but even in relatively short mild occurrences, it is a wise precaution to take.

Obviously prevention of heat stroke is a far better alternative than treatment. Everyone is aware of the risks of having a dog in a vehicle in the summer, but there are some less obvious risk factors that we all need to be aware of. Even moderate environmental
temperatures can be very significant when there is little or no ventilation. Heavy muscular activity drives body temperatures up with alarming speed. Following intervals of high activity, return the dog to an air conditioned vehicle, or wet the dog down and go to
an area that is shaded and preferably breezy to allow for evaporation. Do not wet the dog down and return it to an enclosed style crate, as you will be creating a steam bath like environment. Make sure there is access to reasonable volumes of cool fresh water both before and after activity. We also need to be conscious of
those animals that are at increased risk, which would include those dogs that have high body mass, older dogs, and those that are carrying more weight than is normal for them. Being aware of the various risk factors as well as the environmental considerations should help all of us avoid this potentially devastating problem.

Dr. Henry De Boer Jr. practices veterinary medicine at his Pioneer Valley Veterinary Hospital in western Massachusetts. An accomplished competitor in the sport of Schutzhund, his involvement with working dogs dates to the mid 1960's when he began training and handling
hunting dogs. In 1984 he became involved with the sport of Schutzhund and has gradually risen to the level of national competitor. Known primarily as a motivational trainer, he also provides training assistance to others to help them achieve their
training goals. His wide range of experience lends a unique understanding to the special veterinary problems of working canines and their handlers. Dr. De Boer provides specialized online veterinary services to working dogs and their owners on his innovative web site http://www.workingk-9vet.com Working K9
Veterinary Consultation Services.

FYI:

Heat stroke (severe hyperthermia), the most frequent occurrence following rigorous physical exertion in hot weather, is by far the most deadly among all the syndromes experienced by working canines.

It is probably more common for dogs to experience heat stroke in the first few days they are acclimating to heat and for it to occur in conjunction with excitement or exercise. Dogs do not have an efficient method of managing heat stress because they don't sweat like we do. Heat stroke is most common in the large breeds and in dogs with short noses. Death from heat stroke can occur quickly, as quickly as 20 minutes in some cases. Clinical signs start with panting and anxiety. The gums get dark, and the dog has an increased heart rate that is weak in character, and an increased temperature. After a short while, the dog develops severe respiratory distress and goes into a stupor. The dog may have bloody vomit and diarrhea before having a seizure, going into a coma and dying. If there is no thermometer available, and all other signs
point to heat stroke, treat as heat stroke until you get to a veterinary facility.

Body temperatures over 107 degrees Fahrenheit are a critical emergency,because organ damage can occur at this temperature and at higher temperatures. Heatstroke affects all body systems. Once the
temperature reaches 109 degrees, the pet has only a few minutes before the heat destroys all tissues.

Factors that predispose canines to be more susceptible to heat stroke are:
-physical condition (obesity, musculature, coat density, age and acclimatization);
-environmental (excessive heat, humidity and radiant heat from the sun; )
-underlying medical problems (drug assimilation, underlying cardiovascular, upper respiratory and/or neurological disease);
-previous episodes of heat stroke or heat exhaustion.

The last one: "previous episodes" is all too often disregarded or forgotten as a significant factor in the overall health of the canine. Like humans, continued exposure to hot environments, especially to the point of dehydration, engages all of the body's vital organs affecting them harshly at the cellular level.

Canines who have experienced severe metabolic heat exhaustion while running hard in a search mission, training or playing in hot, humid environments may not eat well or hydrate adequately at the end of the day. Consequently, their body won't absorb sufficient nutrients and the canine begins its next day in a deficit. When continued metabolic exertion is required over several days, a domino effect can happen that can be devastating to your partner.

If your dog experiences a heat emergency and has been properly treated, do not train, search or exert the dog in any way for at least the following 24 hours.

Treatment:
While getting your dog to the vet is a priority, initial rapid cooling is a must prior to transport. Do not delay beginning the cooling process in favor of transporting to the vet, especially if there is some distance between you and the closest veterinary facility.

Treatment includes rapid cooling of the dog using cool, not COLD water. However, in a humid environment, that will not help as much, so, in that case, cool with the coldest water you can find and use ice depending on the situation. DO NOT lay wet towels over the dog, as you will actually trap the heating coming off of the dog and not allow it to cool.

Just getting the dog wet is only the first step, however. The best way is to run water over the dog, so there is always fresh water in contact with the dog and then take advantage of evaporative cooling by having fans blowing on the dog during the cooling process. You
might invest in an inverter for your vehicle and purchase some small fans to have on hand to use in this type of emergency. Keep in mind that when you immerse a dog in a tub, or put the dog in a lake or creek without removing the dog, the water trapped in the hair coat
will get warm next to the dog, and act as an insulator against the cool water and cooling stops. Additionally, you can use rubbing alcohol. It is very effective at cooling due to the rapid evaporation. It should be used when other methods are not working, but do not hesitate to use it. Due to the dogs thicker skin and the
alcohols rapid evaporation, do not worry about it being absorbed.
Remember, this is rubbing alcohol, which is propylene alcohol, not ethyl alcohol: it is NOT to be ingested!

It is incredibly important to continually watch your dog's temperature during the cooling process. Take the temperature, rectally, every few minutes, using a digital thermometer. (be careful not to get the digital thermometer wet… most do not fare well when wet.) When the dogs temperature hits 103, STOP all the
cooling processes. Continue to monitor the temperature, however, and watch for signs that the dog is getting too cool.

And of course, somewhere in this process get the dog to the nearestveterinary facility. Don't worry about getting your dog to drink when it has overheated to this point. Water in the dog's stomach will not cool the dog and with the rapid panting combined with water
drinking increases the risk of bloat, which creates an entirely different emergency. The veterinarian will start and IV and get fluids and electrolytes into the dog as rapidly as possible.

If your dog has suffered a heat emergency, it is important to have blood values checked to discover if internal organs have been affected, or if coagulation issues may have developed. In my experience, the after affects of heat stroke have included (but are NOT limited to) kidney damage, cardiac damage, gastrointestinal damage, bleeding disorders and even permanent neurological problems. I have even seen one dog become permanently blind.

Prevention: The best method of treatment is prevention. Learn to watch your dog, and see the changes in the size of the tongue, and how quickly it goes down. Learn your dog's response to the different environments, and be careful when you head to searches that are in climates different from what your dog is used to. The difference in temp and humidity from one region to the next can affect your dogs ability to effectively cool. Experiment with different things in training to help the dog cool and learn what works better.

And a final, very important point: Do not swim your hot dog to cool it then put in put in a box or crate. Remember, evaporation can not take place in a tight space, and the box will turn into a sauna.
Carry a stake out chain, and let the dog cool and dry in the shade before putting it up.

Information gathered from articles written by:
Nate Baxter, DVM
Kathryn Doherty

Cricket Hollow Farm cannot warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process herein disclosed.