Renal, Hepatic, and CNS Disease

Question 1

Which drugs should be avoided in patients with renal disease?

Answer 1

• those causing hypotension or requiring renal excretion

- NSAIDs (decrease PGs)

Question 2

Which drugs should be avoided in a cat with urethral obstruction?

Answer 2

Ketamine

Question 3

Which drugs should be used in a cat with urethral obstruction?

Answer 3

CV-sparing drugs

opioids, benzodiazepines

Question 4

Describe the Cushing Reflex

Answer 4

• severe increase in ICP leads to poor perfusion
• sympathetic response: vasoconstriction, increased CO, and hypertension
• baroreceptors respond to hypertension and cause reflex bradycardia
• increased ICP also causes dysfunction of
  respiratory center

Question 5

Which sedatives can be used in a patient with CNS disease?

Answer 5

• acepromazine
• benzodiazepines
• opioids
• alpha-2 agonists

Question 6

Which sedatives used can have effects on a patient with CNS disease, and what are those effects?

Answer 6

acepromazine - may decrease seizure threshold

benzos - decrease CBF and ICP, and control seizures

Question 7

Which injectable anesthetics can be used in a patient with CNS disease?

Answer 7

• propofol and barbiturates
• etomidate
• alfaxalone

Question 8

What is a common affect on the CNS by injectable anesthetics?

Answer 8

decrease CBF and ICP

Question 9

Which injectable anesthetic is not recommended in patients with CNS disease?
Why?

Answer 9

ketamine

• increases CBF and ICP
• may cause seizures

Question 10

Which neuromuscular blocking drug is not recommended for patients with CNS disease?
Why?

Answer 10

Succinylcholine

- increases ICP

Question 11

When do inhaled anesthetics have negative effects on CNS patients?
What are those effects?

Answer 11

• at > 1 MAC, increase ICP and CBF

- due to cerebral vasodilation

Question 12

Which inhaled anesthetics are not recommended for patients with CNS disease?
Why?

Answer 12

• halothane
  (blocks autoregulation of CBF)
• nitrous oxide
  (increases CBF and ICP)

Question 13

What should be done at prep for an animal with intracranial disease?

Answer 13

• keep head elevated and straight neck
• do not occlude jugular vein
• prevent vomiting/coughing
• prevent hyperglycemia, hypercapnia, and hypoxemia

Question 14

If an animal has increased ICP, what should be given before induction?

Answer 14

mannitol

Question 15

What is the meaning of the Trendelenburg-like position?

Answer 15

• small decreases in CBF may cause ischemic injury in certain areas +/- clinical signs
• in horses, head down increases ICP by 80%, and decreases CBF by 20%

Question 16

What is caused by equine intracarotid injection?

How is it treated?

Answer 16

• violent behavioral reaction and seizures

- treat with thiopental +/- quafenesin

Question 17

What are the factors in liver disease that increase risk during anesthesia?

Answer 17

• low ALB or hypotension (ascites)
• decreased coag factors (hemorrhage)
• decreased gluconeogenesis
• increased ammonia and other toxins
  (encephalopathy, coma)

Question 18

Which drugs are preferred for a patient with liver disease?

Answer 18

• opioids
• propofol, etomidate, alfaxalone
• volatile anesthetics
• atracurium (NMBD)
• local/regional anesthetics

Question 19

Which drugs are contraindicated for a patient with liver disease?

Answer 19

• acepromazine
• alpha-2 agonists
• barbiturates
• halothane
• succinylcholine
• guaifenesin