Definitions/General Overview

Question 1

What is general anesthesia?

Answer 1

Reversible state of unconsciousness secondary to drug effects on the central nevous system

Question 2

What are the goals of anesthesia

Answer 2

• Produce a state of
  
  • Unconsciousness
  • amnesia
  • analgesia
  • muscle relaxation

Question 3

What is the approach to anesthetic management?

Answer 3

• Preoperative patient evaluation
• Preparation of equipment
• Anesthetic protocol
• Monitoring
• Recovery
• Post-anesthesia evaluation

Question 4

What is part of the preoperative evaluation for anesthesia?

Answer 4

• Presenting complaint
• Hx:
  
  • includes all current mediation
  • pre-existing conditions unrelated to the current problem
• Physical examination
• Laboratory data and imaging results
• Patient problems by system
• Determine ASA status

Question 5

What is ASA status?

Answer 5

• American Society of Anesthesiologists system for evaluating patient risk for anesthesia
• ASA status from I - V with E designation for Emergency
• Describes overall health
• Higher ASA status patients have a greater risk for anesthetic complications
• May require more intensive monitoring and management
• Does not reflect the procedure being performed
• Somewhat subjective

Question 6

Describe ASA classification 1

Answer 6

normal healthy patient

Question 7

Describe ASA class 2

Answer 7

mild systemic disease (obesity, geriatric, cranial cruciate rupture)

Question 8

Describe ASA class 3

Answer 8

moderate systemic disease that limits activity but not incapacitating (dehydration, heart murmur, controlled diabetes, modest anemia)

Question 9

Describe ASA class 5

Answer 9

Moribund patient that is not expected to survive w/ or w/out the procedure (life threatening trauma, septic peritonitis w/ septic shock)

Question 10

Describe ASA class 4

Answer 10

Patient with severe systemic disease that is a constant threat to life (renal failure, pneumothorax, CHF

Question 11

Describe ASA class E

Answer 11

added to any classification when an emergency procedure applies

Question 12

What are the goals of the Preoperative evaluation?

Answer 12

• Identify any problems that may increase anesthetic risk and take any possible corrective measures
  
  • ex: treatment of hypovolemia or dehydration PRIOR to anesthesia
• Determine if any concurrent medications should be withheld prior to anesthesia
  
  • ex: angiotensin converting enzyme inhibitors may increase the risk for intraoperative hypotension
• Always a balance between how soon should we do the procedure and how stable is the patient

Question 13

What supplies and equipment is needed for anesthesia?

Answer 13

• Supplies for IV catheterization
• Supplies for endotracheal intubation
• Drugs
• Anesthetic machine and breathing circuit
• Monitoring equipment
• Anesthetic record

ALL should be prepared and ready before patient is brought into the room

Question 14

What are the goals of pre-anesthetic medication?

Answer 14

• Calm the patient and aid in restraint
• Decrease doses of anesthetic induction drugs and agents used to maintain anesthesia
  
  • decrease any dose dependent effects of the drugs used to maintain anesthesia
• Analgesia
• Minimize undesired effects of anesthetics such as:
  
  • nausea
  • Bradycardia
  • Muscle rigidity

Question 15

What is anesthetic induction?

Answer 15

• Induce a state of general anesthesia
• Intravenous anesthetic agents used for induction
  
  • Propofol
  • Ketamine
  • Ketofol
  • Alfaxalone
  • Etomidate
• Mask or chamber induction with an inhalant anesthetic is far less common
  
  • fractious cats
  • completion of induction after IV opioids
• Facilitates endotracheal intubation

Question 16

What are the andvatages of endotraceal intubation?

Answer 16

• Airway protection
• facilitates positive pressure ventilation
• facilitates administration of inhalation anesthetic

Question 17

What equipment is needed for endotracheal intubation?

Answer 17

• Laryngoscope
• Endotracheal tube
• Lubricant
• Endotracheal tube tie to secure the tube
• Lidocaine spray for some species (cats, small ruminants, pigs)
• Guide tube if difficult intubation anticipated

Question 18

How is Anesthesia maintained?

Answer 18

• Inhalant anesthetic most common
  
  • isoflurane
  • sevoflurane
• Total intravenous anesthesia
  
  • propofol
  • alfaxalone
  • Ketamine
    
    • generally in conjunction with other drugs such as alpha-2 agonist or a benzodiazepine
• Other drugs that have been administered to the patient prior to induction may be repeated throughout a procedure

Question 19

What does the anesthetist do to maintain anesthesia?

Answer 19

• Begin monitoring immediately
• Begin record keeping
• Observe and make changes to anesthetic delivery based on
  
  • Anesthetic depth
  • Response to noxious stimuli
  • Respiratory and cardiovascular data
• Address any side effects or complication such as
  
  • hypotension. arrythmias, changes in oxygenation, blood loss, hypoventilation
• Data recorded every 5 minutes

Question 20

What are the observational parameters for anesthetic monitoring?

Answer 20

• Palpebral reflex
• Corneal reflex
• Swallow reflex
• eye position
• jaw tone
• muscle tone
• movement

Question 21

What are the objective measurements for anesthetic monitoring?

Answer 21

• Heart rate
• blood pressure
• respiratory rate
• temperature
• end-tidal carbon dioxide
• End-tidal anesthetic agent
• Oxygen saturation of hemoglobin
• Laboratory test that might be indicated
  
  • PCV, TP
  • Arterial blood gas
  • Glucose

Question 22

When should a patient be extubated?

Answer 22

• When the patient has a sufficient level of consciousness that can swallow and protect its airway

Question 23

Why may patients need oxygenation during anesthesia recovery?

Answer 23

Residual drug effects can cause hypoventilation leading to hypoxemia when animal is breathing room air

Question 24

What needs to be managed during anesthetic recovery?

Answer 24

• Oxygenation
• Pain management
• Management of dysphoria

Question 25

Is there a recipe for anesthesia?

Answer 25

* No * every anesthetic should be tailored to the patient