Treatment

Early treatment - Emergency treatment should be instituted by the owner immediately by taking steps to progressively cool the animal to normal temperature. If possible, dogs should be sprayed down by the owner before transport to the veterinary hospital. Evaporation can be enhanced by driving with all windows open or placing the dog by the air conditioning vent as this will help with convective losses.
Veterinary Treatment-
  1. Ensure patent airway - On presentation to the clinic the dog should be quickly evaluated for patent airway. Dogs with laryngeal paralysis may have to be given sedatives (Acepromazine 0.05 mg/kg IV and/or Butorphenol 0.4 mg/kg IV). There may be upper airway obstruction in which emergency tracheostomy may be in order. Nevertheless, always supply oxygen to the patient.
  2. External cooling - The dog should be sprayed down with water or immersed in a cold water bath and placed in front of fans. Massaging may help with cooling by increasing blood flow and vasodilation. Ice water baths are contraindicated as this may actually cause vasoconstriction, decreased cutaneous blood flow, and capillary sludging, which promotes DIC. Furthermore, ice water may cause a shivering response, which is a heat producing mechanism. Cold water enemas have been suggested and may help decrease core body temperature, however, they are usually not necessary as they inhibit temperature monitoring. Ice packs may be placed on the head and ventrum to hasten cooling also. Cooling should be discontinued when the temperature reaches 103oF as it may continue to drop precipitously.
  3. Obtain minimum database - Place an intravenous catheter and obtain a minimum database: PCV/HCT, total solids (TS), Azostick, blood glucose, urine dipstick and urine specific gravity. If available, an i-STAT can provide electrolyte and blood gas information.
  4. Administer IV Fluids - Commence IV fluid therapy at 90 mls/kg/hr of room temperature crystalloid balanced electrolyte solution (LRS or Normosol-R) to counteract cardiovascular shock. If Na+ is > 160 meq/L, use 0.45% NaCl and 2.5% dextrose. Decrease fluid rate to 4.4-6.6 mL/kg/hr when PCV decreases to mid-forties.
  5. Administer corticosteroids- Give corticosteroids to prevent cerebral edema and for its membrane stabilizing effects. (Prednisilone sodium succinate, Solu-Delta Cortif - 10-25 mg/kg IV or Dexamethasone sodium phosphate, 2-8 mg/kg IV).
  6. Administer antibiotics - Administer antibiotics to prevent sepsis from bacterial translocation and GI mucosal damage. Ampicillin at 22 mg/kg q 8 h IV and Enrofloxacin 5-7 mg/kg diluted 50:50 in saline q 12 h IV.
  7. Correct Hypoglycemia - If the blood glucose is less than 80 then dextrose is recommended. Dextrose can be added to the fluids by adding a 50 mL bottle of 50% dextrose to a 1 Liter bag of fluids making a 2.5% dextrose solution and running at maintenance rate.
  8. Protect the GI tract- Administer gastric protectants such as sucralfate at 1g q 8 h PO. Sucralfate can also be given as a slurry (1g/10mL water).
  9. Prevent DIC - Administer heparinized fresh frozen plasma (100 units/100 ml plasma) at 20-30 ml/kg/day. Incubate the plasma with the heparin for 30 minutes prior to administration. Heparin can also be given at 200-250 units/kg q 8 h SC.
  10. Correct acid base and electrolyte abnormalities- Administer potassium chloride for hypokalemia correction at a rate of no more than 0.5 meq/kg/hour. Sodium bicarbonate may have to be given for severe metabolic acidosis (pH < 7.2). Sodium bicarbonate (0.3 x body weight [kg] x base deficit IV) should be given at 50% calculated dose, with subsequent blood gas determinations.
  11. Monitor ECG for arrhythmias - If cardiac arrhythmias should arise, then continuous nasal oxygen therapy and lidocaine treatment should be considered. Administer individual dosages of 4 mg/kg slow IV until arrhythmias resolve. If after twice administration of lidocaine and the arrhythmias are still present, then consider 50 mcg/kg/min CRI IV. Change to oral procainamide after arrhythmias improve after 72 hours at a dosage of 10-20 mg/kg q 8.
  12. Urine output monitoring - Since acute renal disease is a potential sequela, urine output should be monitored. If urine output becomes > 1ml/kg after the patient is well hydrated, consider mannitol (0.5-1.0 g/kg IV), dopamine (3 mcg/kg/min), and furosemide (2 mg/kg IV bolus followed by 1 mg/kg/hr infusion). After urine flow is initiated, fluid therapy should be continued 2-3x maintenance levels and tapered off. Urine sediment, BUN, and creatinine should be monitored.
  13. XIII. Neurologic status - The neurologic status should be reevaluated constantly. If it is deteriorating, consider mannitol (1 g/kg IV) and repeat corticosteroids q hr. Monitor and correct hypoglycemia. Control seizures with diazepam (2-10 mg IV PRN).
The key to successful treatment and recovery of heat stroke is early recognition and treatment. Once the animal's temperature is reduced and condition is stabilized, careful continuous monitoring of the heat stroke victim is imperative because sequela can develop even several days down the road. Further diagnostic tests should be conducted to determine any underlying disease process that may have precipitated the hyperthermic event. Most dogs recover within one to five days with aggressive supportive care as non-survivors usually die during the initial 24 hours of treatment. The length of hospitalization will depend on how quickly the animal responds and can range from several days to weeks if complications arise. Animals that recover are usually those whose temperatures are returned to normal early in the course of the disease, since the longer the animal remains hyperthermic, the greater is the damage that occurs to vital organ systems.
Treatment
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