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Heat Stroke In Dogs and Cats

Sweltering summer days can pose a serious health threat to pets unless owners take preventive measures to protect animals from exposure to excessive heat.

There are no specific drugs required for heat stroke, and therapy depends upon clinical presentation. Sedation is sometimes needed, although acepromazine should be avoided if the pet is epileptic (may trigger a seizure) or used cautiously if the animal is in shock (may trigger hypotensive crisis because of vasodilatory effects). The following drugs may be helpful in supportive treatment of complications associated with heat stroke:

Acute Renal Failure: Dopamine continuous-rate IV infusion (2 to 5 mcg/kg/minute); furosemide (2 to 4 mg/kg IV prn).

Cerebral edema: Mannitol (1 g/kg IV over 15 to 30 minutes); furosemide (1 mg/kg IV) 30 minutes after mannitol infusion; corticosteroids such as dexamethasone sodium phosphate (1 to 2 mg/kg IV), prednisone sodium succinate (10 to 20 mg/kg IV), or methyl prednisolone (15 mg/kg IV). Ventricular arrhythmias: Lidocaine bolus (2 mg/kg IV) followed by continuous-rate IV infusion (25 to 75 mcg/kg/minute) or procainamide (6 to 8 mg/kg IV)

Metabolic acidosis: (blood pH < 7. 1) Sodium bicarbonate (0.3 x BW(kg) x bicarbonate deficit IV; S2 dose as IV bolus; recheck blood gas and give remaining dose over 12 hours as a constant infusion if needed).

Seizures: Diazepam (0.5 mg/kg IV); pentobarbital constant rate infusion (0.2 to 1 mg/kg/hour IV); phenobarbital (6 mg/kg IV).

Disseminated intravascular coagulation (DIC): fresh frozen plasma (10 ml/kg IV incubated with 75 U/kg heparin); heparin (150 to 200 U/kg SC QID, following plasma).

Sepsis: Consider prophylactic use of broad-spectrum antibiotics if significant gastrointestinal disruption is present.

Antipyretics are contraindicated in heat stroke. These drugs, such as aspirin or flunixin meglumine, reduce fever by decreasing the hypothalamic set point through antiprostaglandin effects. Since the set point is normal during heat stroke, these drugs are riot indicated and in fact may be harmful. Administration of antipyretics may create a hypothermic state (possibly predisposing the pet to future hyperthermic episodes) and may produce severe gastrointestinal side effects, especially in animals that may have a compromised GI tract and perfusion and coagulation defects.