Identifying And Preventing K9 Heat Injuries

Hyperthermia/Heat Injury

DHS Working Dog Handler Medical Care Manual 2017

Action: Provide first aid for heat injury in a canine.

Condition: A canine is exhibiting clinical signs of heat injury.

Standard: Recognized the signs of and provided first aid for heat injury in a canine without causing

further harm to the canine.

Performance Steps

1. Heat injuries

A. Heat injuries result when the body’s natural cooling mechanisms fail in response to

internal overheating.

B. People regulate body temperature mostly by sweating. Since dogs do not sweat effectively, when their body temperatures exceed ambient temperatures, they dissipate heat primarily by panting. If a canine is unable to cool-off enough, his/her internal temperature rises and may lead through different stages of heat injury.

C. Normal body temperature for a canine is 100.5 °F to 102.5 °F. However, absolute temperature can range. Most canines work normally at temperature ranges of 105 °F to 107 °F with no ill effect, due to acclimation.

D. The progression of heat injuries can be quite rapid, sometimes taking only a few minutes. Occasionally, there is little or no warning and the progression is so rapid that the canine might already be suffering heatstroke when the situation is discovered.

E. Short-term effects on a canine suffering from a heat injury may include shock, organ damage, or death. Long-term effects may include brain damage and the increased possibility of recurrence of a heat injury.

F. Immediate first aid is required for any canine with suspected heat injury.

2. Causes of heat injury are divided into environmental causes and exertion causes

A. Environmental causes are due to exposure to high environmental temperature and humidity.

a. Exposure to high heat, humidity, or both.

b. Confinement to a small, hot space such as a crate, kennel run, or vehicle.

c. Poor acclimation to heat and humidity.

d. Inadequate water intake.

B. Exertion causes are due to increased body temperature that develops with exercise or work.

a. Strenuous work or exercise (worsened by hot, humid, or hot and humid environments).

b. Existing or undiagnosed disease or illness.

c. Medications or drugs.

d. Age.

e. Previous heat injury.

C. The combination of exposure to high environmental temperatures and exertion can markedly increase the risk of heat injury.

3. Heat injury prevention

A. Canines rely on their handlers to take care of them and make decisions for them, especially in extreme environments. Take care of, monitor, and know your canine.

B. Acclimation.

Follow the human rules of acclimation. Increase workload and exposure to the environment gradually over

a 14 day period. Use an acclimation period if the canine is recovering from an illness.

C. Hydration.

a. Make sure your canine is properly hydrated by allowing frequent water breaks.

b. Ensure your canine always has access to water, whether in his/her kennel, exercising, or resting.

c. Dehydration is difficult to detect. One method is to check the canine’s mucous membrane color and mucous membrane moistness in the tissue covering the gums in the mouth:

i. Gently pull the top lip up or the bottom lip down to expose the gums.

ii. Note the moistness of the gums by gently touching your finger to the exposed gum.

iii. Normal mucous membranes are moist or slippery.

iv. Mucous membranes that are dry or tacky to the touch are abnormal and suggest dehydration.

d. Dehydration makes your canine more susceptible to heat injury and causes decreased performance.

e. Allow your canine to drink when you drink–typically a small amount every 10 to15 minutes in an extreme or high activity environment.

f. Use fresh water or veterinary-approved electrolyte solution.

D. Canines need a physical training program to remain in shape. Out of shape canines are more prone to heat injuries.

E. DO NOT confine a canine in a small, poorly-ventilated, hot area at any time.

NOTE: Large areas of asphalt are especially hot. Take extra precautions if your canine is working, exercising, kenneled, or in a trailer near airstrips or paved roads.

F. If the canine has had a prior heat injury, consider ceasing exercise when the temperature reaches 90 °F. For all other canines, consider ceasing exercise when the temperature reaches 95 °F.

NOTE: Work/rest cycles have not been developed for canines. Use this guide unless mission requirements supersede it. Check local policy letters to verify time and temperature requirements for working your canine team.

G. DO NOT use muzzles unless required for safety reasons. Loosen muzzles when possible to allow the canine to pant more easily. A canine’s cooling mechanism is the ability to pant.

4. Recognize signs of heat injury

Mild heat injury (heat stress) is characterized by development of excessive thirst, discomfort associated with physical activity, and sodium and chloride abnormalities, but with controlled panting (i.e., the patient can control or reduce panting when exposed to a noxious inhalant such as alcohol or when offered food or water). Generally, treatment of heat stress involves removing the patient from the source of heat, stopping exercise, and cooling by use of fans or movement to an air-conditioned area. Close monitoring for several hours is necessary to ensure heat stress does not progress, or rebound low body temperature (hypothermia) does not develop. Key parameters to monitor, in addition to frequent body temperature measurement, include changes in mentation, anxiety, or restlessness.

5. Working Dog Handler

Moderate heat injury (heat exhaustion) is present when the signs of heat stress are present, as well as weakness, anxiety, and uncontrolled panting (i.e., the patient cannot reduce panting when exposed to a noxious inhalant). Generally, treatment of heat exhaustion is the same as for heat stress, but more aggressive cooling measures are often necessary. The canine must be removed from the source of heat and all activity must be stopped. Cooling by use of fans or movement to an air-conditioned area should be done if possible. The hallmark treatment for moderate and severe heat injury is to thoroughly soak the hair to the skin with cool water in conjunction with application of cooling fans or A/C to reduce core body temperature. Close monitoring for several hours as stated for heat stress is necessary to ensure heat exhaustion does not progress, or rebound hypothermia does not develop. Severe heat injury (heatstroke) is present when signs of heat exhaustion coupled with varying degrees of central nervous system (CNS) abnormalities. The most common CNS abnormalities include changes in mentation and level of consciousness (e.g., obtunded, stupor, coma), seizures, abnormal pupil size, blindness, head tremors, and ataxia. Heatstroke is a life-threatening condition. It is characterized by a severe increase in core temperature and widespread, multiple organ injury with risk of progression to multiple organ failure. No specific body temperature defines heatstroke in veterinary patients; however, temperatures as low as 105.8 °F have been associated with pathology. Laboratory studies using animals have established that heat directly induces tissue injury. Handlers must be prepared to rapidly recognize and treat heat-related illnesses, because the severity of organ injury related to heat injury is directly related to the length of time the patient is hypothermic. Retrospective veterinary studies report multiple, serious complications and high fatality rates in heatstroke patients despite proper treatment. These cases are challenging and require intensive treatment and monitoring. With aggressive medical therapy and intensive nursing care, many of these patients can successfully recover. Emergency care must be performed immediately to improve outcome. If the canine is not breathing or breathing is not adequate, start rescue breathing and seek a higher level of care. Canines with clinical signs of heatstroke (manifested by neurological deficits) require emergency cooling measures. The rate of cooling should be as rapidly as possible until the body temperature is 103.5 °F to 104 °F. The most practical, expedient, and rapid method to reduce body temperature is an ice water immersion or soaking the canine to the skin with cool water. The key is to soak the entire patient as rapidly as possible through the hair, soaking the skin thoroughly. Additional cooling methods can be used to supplement wetting the skin thoroughly. Fans or A/C should be directed on the canine to facilitate convective surface cooling, remembering that the skin must be thoroughly wet for fans to be effective. Once the body temperature is less than 104 °F, the rate of cooling can be reduced to avoid rebound hypothermia. Ancillary cooling measures can be removed (e.g., remove fans, return room temperature to normal), and the patient’s skin can be dried. At this point, all cooling efforts must cease, continuous temperature monitoring must continue, and the handler should be prepared to actively warm the patient to prevent an excessive drop in body temperature (rebound hypothermia) from aggressive cooling measures. Although warming a patient with a temperature of 100 °F may seem counterintuitive, the handler should anticipate a period of rebound hypothermia. Monitor for and treat concurrent problems. Canines with heatstroke often present in shock and may develop sustained hypotension.

6. Severity Of Heat Injury

A. Mild heat injury (heat stress).

- Heavy, controlled panting.

- High rectal temperature, usually 105 to 106 °F.

- Fast, strong pulse.

- Slightly decreased performance.

- Normal otherwise.

NOTE: Controlled panting means the canine can stop panting when an alcohol-soaked gauze is put in front of the nose or when the canine becomes interested in something. Uncontrolled panting means the canine cannot stop panting even when offered a treat or exposed to alcohol.

B. Moderate heat injury (heat exhaustion).

- Very high rectal temperature, usually 106 to 108 °F.

- Uncontrolled panting.

- Fast, strong, OR weak pulse.

- Failure to salivate.

- Tacky or dry nose and mouth.

- Unwillingness to work or exercise; acts tired.

- Loss of appetite.

- Unresponsive to handler and commands.

- Staggering, weakness, depressed, or acting “out of it.”

- Bright red mucous membranes.

- Severe heat injury (heatstroke).

- Extremely high rectal temperature, usually over 108 °F.

- Body is hot to the touch.

- Vomiting.

- Pale mucous membranes.

- Abnormal mentation or level of consciousness – completely “out of it,” seizures, or coma.

- Diarrhea, sometimes with blood (bright red blood or dark, tarry feces).

- Shock.

- Death.

7. First aid for heat injury

First aid for mild heat injury (heat stress) is to cease working the canine and cool the canine externally.

- Immediately cool the canine using one or more of the following methods:

i. Spray or pour cool water on the canine. SOAK THE CANINE TO THE SKIN!!

ii. Move the canine to a shaded area if outdoors or into a cool building.

iii. Circulate cool air near the canine using fans.

iv. Loosen the muzzle and collar. Remove these if possible and safe. Remove any vests or harnesses.

v. Monitor and treat for shock, if shock develops.

vi. Monitor vital signs every 5 minutes.

vii. Discontinue cooling efforts when the rectal temperature reaches 103 °F.

First aid for moderate (heat exhaustion) and severe heat injury (heatstroke) is to cease working the canine, cool the canine, and monitor the canine for heat injury.

i. Cool the canine as for mild heat injury.

ii. Monitor and treat for shock, if shock develops.

iii. Monitor vital signs every 5 minutes.

iv. Discontinue cooling efforts when the rectal temperature reaches 103 °F.

v. Initiate an aeromedical transportation request.

vi. Report, record, and evacuate.

vii. Contact supporting veterinary staff to request further instructions.

viii. Initiate an aeromedical evacuation request.

ix. Keep a written record of the treatment. Include the date and time, actions taken, observations, and outcome