Induction

The induction phase begins when the premedications are deemed to have taken full effect.

The goals of the induction phase include: 

  1. A calm and anxiety-free patient 
  2. Rapid unconsciousness with muscle relaxation
  3. A secure airway
  4. Maintainence of acceptable frequency and depth of breathing,
  5. Maintainence of good tissue perfusion
  6. A smooth transition to inhalant or injectable maintenance anesthesia

Induction with Alfaxan® injectable anesthetic

Alfaxan is being used as the principal induction agent in more and more U. S. veterinary anesthetic procedures because of its versatility, its effectiveness and its wide safety profile.  Alfaxan is FDA-registered for use as both an induction and a maintenance agent in both cats and dogs. It can be used with all common premedications.

The recommended dose rates for Alfaxan in unpremedicated cats and dogs are 5 milligrams per kilogram and 2milligrams per kilogram, respectively. Alfaxan is known to have  minimal dose dependent effects on key cardiopulmonary functions in anesthetized dogs and cats. Blood pressure is generally well maintained and provides acceptable tissue perfusion, important in sustaining normal tissue and organ function. 

Intubation

Rapid onset of unconsciousness allows for airway evaluation and endotracheal intubation.
Choose the largest diameter endotracheal tube that will fit easily through the arytenoid cartilages without damaging them.  The tube itself should be premeasured for the patient such that the distal tip lies midway between the larynx and the thoracic inlet. 

Once the patient’s airway has been secured and the transition phase to inhalant anesthesia has begun, check all cardiopulmonary values against the pre-anesthetic baseline. 
 
Inflate the cuff of the endotracheal tube sufficiently to create a seal for adequate positive pressure ventilation. It is a best practice to conduct a leak test to ensure a good seal of the endotracheal cuff.  

Take care not to over-inflate the cuff due to the risk of tracheal damage. Lubricating the cuff will decrease the amount of pressure required to create an effective seal. To avoid the risk of tracheal tears, disconnect the endotracheal tube from the anesthetic machine when re-positioning the patient.

Transition to the maintenance anesthetic begins with the completion of the intubation process
With the patient transitioned and positioned for surgery apply corneal lubrication to protect the eyes from corneal ulceration.

Administration of Intravenous Fluids – Upon introduction of supplemental fluids into the IV catheter, double check the flow rate and the fluid level.  For healthy patients, intravenous fluids should be administered as follows, adjusting for comorbidities:

  • Initial rate for cats - 3 milliliters per kilogram per hour
  • Initial rate for dogs -  5 milliliters per kilogram per hour
  • Procedures > 1 hour, reduce fluid administration by 25% every hour until maintenance rates are reached.

Finally, provide thermal support and monitor body temperature throughout the peri-anesthetic period.
 

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