by Vikki Fenton-Anderberg

Search and rescue personnel are trained to recognize and treat hypothermia and frostbite in the victim and their fellow searchers. Canine handlers must remember to consider the same possibility in their four legged partners.

Hypothermia
Hypothermia occurs when the core body temperature falls below the normal range (99 to 100 degrees Fahrenheit). This occurs when heat loss exceeds heat production. Loss of body heat occurs through four primary mechanisms. Conduction is an exchange of heat between two objects of different temperatures, such as from the warm dog to the cold rock upon which he is sitting. Convection is the loss of heat due to the movement of air from around the body. An example of Convection is when wind carries away warmed air from around the dog and replaces it with colder air which the dog then needs to warm back up. Radiation is known as the transfer of heat by an infrared process between two objects of different temperatures. Evaporation of water from the skin, mucous membranes, and through the respiratory passages is also a significant source of heat loss.

If a human gets cold they will attempt to reduce heat loss by adding clothing, seeking shelter, and /or eating. The dog's only conscious action is an attempt to optimize heat production and minimize heat loss by seeking shelter from the cold. There are some involuntary body responses which are the key to heat conservation and production: Piloerection, the erection of the individual hair follicles causing the hair to stand up, minimizes loss of heat to the environment by creating a zone of trapped air that acts as an additional layer of insulation. Vasoconstriction, causing the blood vessels to become smaller thus carrying less blood flow, in peripheral tissues directs blood away from exposed surfaces (feet, ears, and face) toward the core where it is most needed by the body. Shivering, which is an involuntary heat generating response by the skeletal muscles to cold conditions, is the primary heat producing activity. Piloerection and vasoconstriction try to conserve heat, while shivering tries to generate it.

Hypothermia can be divided into 3 categories. Mild: Above 36 C or 96 F. Shivering is increased. Lethargy and increased muscle tone are noted. Moderate: 32-34 C or 90-94 F. Typified by stupor, incoordination , loss of shivering reflex, and unconsciousness. Severe: 28-26 C or 82-86 F. Collapse, agonal breathing, and fixed, dilated pupils.

Field treatment of hypothermia focuses on prevention of further heat loss. Passive rewarming includes insulating from cold surfaces, gently drying the dog; wrapping in blankets, towels or "space blanket"; and body to body contact. It is not necessary the handler to remove all of his own clothing, but curl around the dog so that there is as much body contact as possible depending on the size of the dog. Covering both with a sleeping bag, or jacket will help prevent further heat loss. Watch carefully for painful rewarming reactions as the dog may strike out and injure the handler or itself. Active external rewarming is applied only to the thorax (the core) of the dog. Methods used include: a circulating warm water blanket wrapping only the thorax; a warm water bath, taking care to leave the extremities and head out; heat packs and hot water bottles placed around the dog to create a “warm tent “ of air; and heat lamps and floor heaters.The treatment needs to take place in a controlled environment where the temperature of the water and the dog can be closely monitored. Precautions include: monitoring the hot water bottles to insure that the heat does not flux back from the dog to the bottles; avoiding direct contact with skin to prevent possibility of burns; and placing a thermometer between the lamps and the dog. Internal rewarming is generally reserved for severely hypothermic animals and includes: warmed IV fluids and inspired air; peritoneal dialysis; and flushing stomach or rectum with warm isotonic fluids. This is only done in a hospital setting under the care of a veterinarian.

Frostbite
The definition of frostbite is the same for all mammals: damage to tissue caused by subfreezing temperatures. The severity of the frostbite is based on the extent of blistering, swelling, and skin color of the affected tissue.

In dogs, the early signs of frostbite are easily missed as the areas affected are usually covered with hair. These areas are the ear tips, tail, scrotum, and face. When frozen or near-frozen, the skin appears very pale. As the skin warms, it becomes reddened and the area becomes painful. Eventually the skin becomes scaly. If the circulation has been severely affected, the tips or edges of the tissue may slough off . Severe cases of frostbite may necessitate amputation of the affected tissue. If amputation is necessary, this determination is made over a length of time which depends on the severity of the frostbite. The affected area will have a definite line (demarcation) between live and dead tissue.

First aid in the early stages, when the tissue is still soft, involves warming the affected tissue with warm water. Do not massage the area as this may cause the release of toxins which may further damage already impaired tissues. Instead, gently apply a protective Vaseline- based ointment and cover the area if possible. If the ointment is warm, it will spread more easily, especially in those areas covered with hair. This can be done in the field by placing the ointment tube next to your skin. If the tissue is not malleable and/or the possibility of refreezing exists, don't attempt field rewarming. Instead transport to base or to a veterinarian ASAP. The rewarming that can occur during transport in a warm vehicle is painful. Do not turn the heat on high, but keep the vehicle at a cool to moderate temperature. If possible, the handler should not be driving but should sit with or hold the dog to prevent the scratching or biting at the painful area.

Recommended Cold Weather First Aid Kit Additions
For handlers who frequent working their dogs in cold weather conditions, these addtions to their first aid kits should be considered:

1. Absorbent towels for drying dog;
2. Space blanket or other heat reflective blanket;
3. Thick sport weight or wool socks (kid's size to fit paws) 2 pair;
4. Cold weather dog jacket if appropriate for dog;
5. Vaseline based ointment.

Prevention of frostbite and hypothermia is possible by observing your dog frequently and providing the necessary support before trouble arrives. If your dog does not have an adequate coat, provide it with an artificial coat. Have a pad to insulate the dog from the cold ground when it must be in one place. Make sure that when you take a break and warm up, you get out the pad and give food and water. Check the temperature of the ears, scrotum and face, watching for signs of frostbite. As the "thinking" 1/2 of the team, it is the handler's responsibility to monitor the canine partner thus helping to continue on a search that may depend on the team.