Chapter 22 Anesthesia Practice for Existing Conditions

Question 1

Describe the 5 ASA statuses and example of each

Answer 1

ASA 1 - no systemic illness - healthy animal
ASA 2 - Mild compensated systemic illness - hypothyroidism and obesity
ASA 3 - Moderate to severe compensated systemic illness - Heart disease, CRF, Liver disease, DM
ASA 4 - Patient has a disease that is a constant threat to life - CHF, Sepsis, GDV, pneumothorax
ASA 5 - Moribund patient not expected to survive 24 hours with or without treatment

Question 2

Malignant hyperthermia MOA/receptor and known triggers

Answer 2

Inherited condition
Defect in the cellular ryanodine receptor* which is involved in calcium-induced calcium release in muscles
Triggers: inhalants, succinylcholine, and stress

Question 3

Malignant hyperthermia effects on ETCO2

Answer 3

Abrupt increase in ETCO2 (or PaCO2) then elevation in temp and HR

Question 4

Treatment for malignant hyperthermia

Answer 4

If known concern - pretreat with dantrolene for one week prior
Treatment: discontinue inhalants and dantrolene

Question 5

Five causes of hypoxemia and which is the most common

Answer 5

Hypoventilation
Right to left anatomic shunt
Low FiO2 (inspired oxygen)
V/Q mismatch - most common
Diffusion impairment

Question 6

Causes of V/Q mismatch

Answer 6

Atelectasis or PTE

Question 7

Define functional residual capacity (FRC) of the lungs

Answer 7

Expiratory reserve volume plus residual volume
Amount of air remaining in the lungs after normal expiration
At the FRC, the inward pull of the lungs due to their elasticity equals the outward pull of the chest wall

Question 8

Which hypoxic circumstances respond very well to oxygen supplementation

Answer 8

Hypoventilation
Low FiO2
Diffusion impairment

Question 9

Which hypoxic circumstance has a limited response to oxygen supplementation

Answer 9

Low V/Q

Question 10

Which hypoxic circumstance has a good response to oxygen supplementation

Answer 10

Increased V/Q

Question 11

Which hypoxic circumstance does NOT respond to oxygen supplementation

Answer 11

right to left shunting

Question 12

What are the causes of high and low V/Q

Answer 12

Increased V/Q - PTE
Decreased V/Q - Pneumonia and alveolar collapse (from pulmonary mass, pneumothorax, or atelectasis)

Question 13

Max intra-abdominal pressure during laparoscopy and why

Answer 13

Max allowable pressure - 14 cm H2O
Compromises renal blood blow

Question 14

What intra-abdominal pressures are associated with anuria and ARF in patients undergoing laparoscopy

Answer 14

Prolonged pressures over 35 cm H2O

Question 15

Should ketamine be used in cats with lower airway disease why or why not

Answer 15

Yes. Ketamine maintains respiratory center sensitivity to PaCO2 and is a good choice for animals (esp cats) when a decreased respiratory drive will be detrimental