Neuroanesthesia

Question 1

Cerebral blood flow is what % of cardiac output?

Answer 1

20%

Question 2

What is a potential consequence of increasing IC?

Answer 2

Brain herniation

Question 3

What is flow-metabolism coupling?

Answer 3

As the metabolic rate (CMR) of the brain increases, the cerebral blood flow (CBF) also increases

Question 4

What is normal ICP?

Answer 4

10-15 mmHg

Question 5

What is cerebral perfusion pressure?

Answer 5

MAP - ICP

Question 6

What is the Cushing’s reflex?

Answer 6

Hypertension and bradycardia due to an increase in ICP

Hyperventilation helps resolve this

Question 7

What is the most potent regulator of CBF?

Answer 7

Arterial CO2 tension

Question 8

What level of PaCO2 may result in ischemic injury to the brain?

Answer 8

20 or less

Question 9

A PaO2 of what will cause an increase in CBF?

Answer 9

50 or less

Question 10

How does prolonged hypoxemia result in vasodilation?

Answer 10

Hypoxemia -> lactic acidosis -> vasodilation

Question 11

How do CBF and CMR change with body temperature?

Answer 11

7% increase in CBF and CMR per 1 degree C increase in body temp

Question 12

How does blood viscosity influence CBF?

Answer 12

Increase viscosity (e.g. polycythemia vera) will decrease CBF

Decrease in viscosity (e.g. anemia) will increase CBF

Question 13

Which drug is contraindicated in patients with seizure?

Answer 13

Acepromazine

Question 14

Best pre-med choice for patients with seizures?

Answer 14

Benzodiazapines

Question 15

Which drug is known to cause a decrease in CBF in isoflurane-anesthetized patients?

Answer 15

Dexmed

Can mimic Cushing’s reflex

Question 16

Which drug increases CBF and CMR?

Answer 16

Ketamine

Question 17

What qualities should injectable anesthetics have?

Answer 17

Decrease ICP
Decrease CBF
Decrease CMR

Question 18

Which injectable anesthetics decrease ICP, CBF, CMR?

Answer 18

Propofol
Alfaxalone
Etomidate

Question 19

Which is the preferred inhalant and why?

Answer 19

Sevoflurane

Increases CBF to lesser degree than isoflurane

Question 20

Inhalant anesthetics minimally affect CBF when used at what concentration?

Answer 20

Below 1 MAC

Question 21

The effects of inhalants on CBF and ICP can be minimized by

Answer 21

Hyperventilating

Mild hypocapnia

Question 22

What are the goals of fluid therapy?

Answer 22

1. Maintain euvolemia
2. Avoid hypervolemia
3. Correct blood loss

Question 23

What can you do to minimize chance of retching/gagging during intubation?

Answer 23

Make sure patient is in good plane of anesthesia

Lidocaine topically or IV