Anesthetic Considerations for Brain Disorders, Diseases, Encephalitis

Question 1

Anesthesia Providers during brain cases control…

Answer 1

Blood flow and cerebral blood pressure.

Allow perfusion and prevent ischemia.

Question 2

Subdural hematoma look like…

Answer 2

Banana on imaging

Question 3

Epidural hematoma

Answer 3

Rearrange letters in epi to make “pie”, looks more spherical on imaging compared to subdural hematomas that look like bananas.

Blood gets trapped in your brain= builds up pressure = causes hemorrhage = further presses on other tissue= causes ischemia in these areas

Question 4

Cranial Vault =

Answer 4

= rigid structure with fixed total volume, brain (80%), blood (12%), and CSF (8%).

Any increase in one component must be offset by an equivalent decrease in another to prevent a rise in intracranial pressure.

This is known as the Monro-Kellie doctrine.

Question 5

Cerebrovascular Diseases; Hemorrhagic Stroke

Anesthetic Management

Answer 5

Best treatment = Immediate surgical intervention. Blood product/Factor replenishment ineffective (may cause risk of arterial thrombosis)

Anesthetic:
Sedate the pt enough so the surgeons can do what they need to do to stop the bleeding
-> Propofol infusion = lowers BP
-> Benzo’s = great for sedation
-> Protect Airway with intubation for respiratory management
-> Muscle paralysis helpful with prolonged intubations
-> ICP monitor (try to maintain CPP of 61-80 mmHg).

Question 6

Overall CBF averages =

Answer 6

50 mL/100 g/min at a PaCO2 of 40 mmHg.

Question 7

How long can the brain tolerate a lack of blood flow before irreversible cellular injury occurs?

Answer 7

3-8 min
Bc 3 to 8 min is how long it takes for the brain to use all of its ATP stores. Once the ATP stores are depleted, irreversible cellular injury occurs.

Question 8

Relation btw blood viscosity and CBF?

Answer 8

Largest determinant of blood viscosity is hematocrit.

Elevated hematocrit, as may be seen with marked polycythemia, increases blood viscosity and can reduce CBF.

However, Hct is important for O2 delivery so we cannot simply lower it.

Best O2 delivery may occur at 30%Hct?? (morgan+mikhails pg985)

Question 9

What low CBF value do we avoid? Why?

Answer 9

When CBF decreases below
10 mL/100g/min.

Cell function is deranged. Ion pumps fail to maintain cellular vitality.

Question 10

Monro-Kellie doctrine

Answer 10

Cranial Vault = rigid structure with fixed total volume brain (80%), blood (12%), and CSF (8%)
Any increase in one component must be offset by an equivalent decrease in another to prevent a rise in intracranial pressure. This is known as the Monro-Kellie doctrine.

Question 11

Largest determinant of blood viscosity is

Answer 11

hematocrit

Question 12

Pinpoint pupils (1 mm) usually indicate…

Answer 12

opioid or organophosphate intoxication (this called miosis or mydriasis?)

Question 13

Pupils are usually ______in diameter, ____ bilaterally, and react ____ to light.

Answer 13

3–4 mm;
equal in size;
briskly

Question 14

Glasgow Coma Scale max score is

Answer 14

15

Question 15

Glasgow Coma Scale min score is

Answer 15

3 (not zero)

Question 16

What does the Glasgow Coma Scale asses?

Answer 16

It uses Eyes, Motor, and Verbal responses to assess severity of a coma

Question 17

What Glasgow Coma Scale score suggests a true coma? What does this tell us as anesthesia to do?

Answer 17

GCS score of 3-8 = true coma

Pt requires intubation

Question 18

In intubated patients, the maximum and minimum GCS score is:

Answer 18

Max: 10T
Min: 2T

Question 19

Imagine your intubated patient opens eyes to a painful stimulus and withdraws his limb from one. What score would yougive them for the GCS verbal component?

Answer 19

Just give him the lowest score (1) for the verbal component – E2M4V1
Write ‘V’ (ventilated) or ‘T’ (tube), eg. E2M4VT
You could also make it up, based on what you would expect the V score to be based on the E and M scores (perhaps not best practice).

Question 20

Cerebrovascular Diseases;
Ischemic Stroke
Anesthetic Management->

Answer 20

• airway,
• oxygenation,
• ventilation,
• systemic blood pressure,
• blood glucose concentration, and
• body temperature
  Intravascular volume replacement in patients with acute stroke improves CO + Cerebral perfusion.
  Hypervolemic hemodilution may be considered in an attempt to increase CBF while decreasing blood viscosity without causing a significant decrease in oxygen delivery.
  Other drugs; Aspirin, tPA

Question 21

BIGGEST Risk Factor for pts with Transient ischemic attack (TIA)=

Answer 21

Systemic HTN

Question 22

Acute Hemorrhagic Stroke =

Answer 22

Extravasation of blood in the cranial vault, resulting in impaired perfusion of normal brain tissue.

Question 23

Acute Hemorrhagic Stroke -

Two best Predictors of outcome:

Answer 23

1) Estimated volume of extravasated blood (non-contrast CT scan)
2) The level of consciousness (GCS)

Question 24

Severe head injury defined as GCS score =

Answer 24

< 8

Question 25

Allodynia

Answer 25

Perception of non-noxious stimulus as pain

Ex: Sunburn