Chp. 2: Anesthetic Risk and Informed Consent

Question 1

ASA Physical Status

Answer 1

I. A normal, healthy patient (OVH, castration)

II. Mild systemic disease (fracture without shock, skin tumor, compensated heart disease, hernia)

III. Severe systemic disease (moderate anemia, hypovolemia, renal, or hepatic dysfunction)

IV. Severe systemic disease that is a constant threat to life (sepsis, marked hyperkalemia, end-stage organ disease, marked hypovolemia, severe anemia)

V. Moribund, not expected to survive 24hr without operation (massive trauma)

Question 2

Role of biochemical or hematologic screening

Answer 2

ASA I-II: Negligible benefit
ASA III-V: Reduced odds of death

Question 3

Small animal anesthetic mortality

Answer 3

General practice: 0.05-0.25%
Referral: 0.3-0.6%
Sick patients: 1-4%
Cats may carry greater risk
Rabbits are very high risk

Question 4

What is the most common period during anesthesia for dogs, cats, and rabbits to die? Horses?

Answer 4

Post-operative period

Question 5

Risk factors for anesthetic death in cats

Answer 5

Old age, extremes of weight, long duration of procedure, emergency procedure, increased ASA, major v. minor surgery, endotracheal intubation, use of fluid therapy

Question 6

Risk factors for anesthetic death in dogs

Answer 6

Old age, low weight, long duration of procedure, emergency procedure, increased ASA, major v. minor surgery

Question 7

Large animal anesthetic mortality

Answer 7

1-1.5%

decreased among non-emergency horses to 0.6-0.9

emergency anesthetics 3.5% or higher

Question 8

Risk factors for anesthetic death in horses

Answer 8

Orthopedic surgery, abdominal surgery, increased length of procedure, emergency procedure, hypotension, old age

Question 9

Causes of equine anesthetic death

Answer 9

• CV arrest and collapse are the major causes
• Respiratory complications infrequently reported
• Fracture on recovery, myopathy, sepsis, colitis