If your pet succumbs to heat exhaustion or heat stroke, the treatment you provide on the way to the clinic may mean the difference between life or death.  Apply copious amounts of tepid water to their entire body before transporting them.  Do not use cold water.  Cold water causes peripheral blood vessels to constrict which slows down heat exchange.  Drive to the hospital with all the windows open or the air conditioner on "max" to increase cooling through evaporation.  If possible take a rectal temperature every five minutes.  When the patient's temperature drops to 104.0 F or below, stop cooling.  (The normal temperature range for dogs and cats is 100.0 to 102.5 F.)  Excessive cooling may induce hypothermia.