As the weather gets warmer and our dogs have yet to acclimatize to the change in temperature, more cases of canine heat stroke are seen. The primary goal in the treatment of heat stroke is to actively facilitate cooling. Methods of cooling in the heat stroke patient focus on evaporative and conductive mechanisms of heat dissipation.
Evaporative cooling is the most commonly used method, and typically involves soaking the patient with cool or tepid water and directing fans at the patient. Ice water can also be used but may result in inhibition of cooling due to peripheral vasoconstriction, although muscle massage can help to stimulate circulation to the periphery. Alcohol should not be used to soak the whole body. The effectiveness of soaking the paw pads in alcohol has not been investigated, but may not be a very useful measure due to the small surface area involved.
Conduction is a mechanism of heat loss that occurs when the body comes into direct contact with a cooler surface. In active cooling, conduction can be facilitated via external or internal methods. External methods include ice packing the jugular veins, or immersing the patient in cool water or ice baths. Avoid placing towels or blankets in the patient’s cage or on the exam table during the active cooling phase, as contact with a cool metal surface will better facilitate heat dissipation. Internal conduction methods are used less commonly due to their invasiveness. Gastric lavage with ice water can be performed, but there is risk of aspiration pneumonia with this method. Iced peritoneal lavage is another option but carries a risk of septic peritonitis. Cold water enemas may make it more difficult to accurately monitor body temperature.
After initial cooling measures have been initiated, intravenous access should be obtained and room temperature IV fluids should be administered.
Dantrolene has been investigated experimentally in a canine heat stroke model and was not found to be effective (Amsterdam JT et al, Am J Med 1986).
Importantly, active cooling of the patient should be discontinued once the temperature reaches 103°F, as rebound hypothermia can occur.
