INITIAL TREATMENT CONSIDERATIONS
Often before specific treatment for ATE can begin, more life-threatening conditions need to be addressed.
Congestive heart failure
Critical initial treatment most often involves treating CHF. Standard treatment for CHF involves oxygen and furosemide. Most
cats are tachypneic, but tachypnea does not always correlate with the presence of CHF. In one study, tachypnea or panting
was present in 88% of cats without CHF.2 Pain and anxiety likely play a role in tachypnea in patients without CHF. Perform a thoracic radiographic examination to
confirm pulmonary edema or pleural effusion before initiating treatment since diuresis caused by furosemide could impair perfusion.
The ischemic neuromyopathy that results from ATE is extremely painful, so pain control is a priority. Most cats require an
opioid to achieve adequate pain control. Hydromorphone (0.1 mg/kg intravenously every two to four hours),29 buprenorphine (0.02 mg/kg intravenously every six to eight hours),30 and fentanyl (2 to 3 μg/kg intravenous bolus followed by 2 to 3 μg/kg/hr continuous-rate infusion)31 are good choices. Butorphanol (0.2 to 0.4 mg/kg intravenously, intramuscularly, or subcutaneously)32 provides minimal analgesia but does have some sedative and anxiolytic effects.
Maintaining perfusion to the liver and kidneys will help counteract the toxic byproducts produced during ischemia. Fluid therapy
may be needed in cats that do not have CHF, especially if the patient is dehydrated. Administer the fluids judiciously since
most of these cats have cardiac disease and may be susceptible to the development of fluid overload. Nasoesophageal tube trickle
feeding not only provides a source of nutrition but also is a source of free water that will maintain hydration without the
risk of intravenous fluid overload.
Other supportive therapy
Positive inotropic agents or vasopressors may be needed in severely affected patients with depressed cardiac function or refractory
hypotension, but they should be used with caution and with the full understanding of any impact on the underlying cardiac
Treatment of severe hyperkalemia (serum potassium concentration > 8 mEq/L or symptomatic bradyarrhythmia) involves administering
an intravenous bolus of 1 ml/kg 25% dextrose with or without an intravenous injection of 0.5 U/kg regular insulin. Refractory
hyperkalemia may require the cautious administration of sodium bicarbonate at a dose of 0.5 to 2 mEq/kg given intravenously
over 30 minutes.33