Neuro #1

Question 1

Pia Mater

Answer 1

Thin cerebral cortex cover, similar to the outside of a grape.

Question 2

Arachnoid Membrane

Answer 2

• CSF location = subarachnoid space
• between arachnoid and Pia matter
• CSF is created 500 mL every day replaces whole CSF fluid three times a day.

Question 3

Dura matter outermost layer

Answer 3

Tough outer covering that is adhered very tightly to skull

• requires pliers for separation
• very high pressure is required for bleeding to occur (arterial)
• causes lenticular shape bleed

Question 4

Dura Matter inner layer

Answer 4

Tentorium or tent like structure (the shelf)

• separates upper brain from lower brain
• Tentorium Incisure - hole where upper/lower brain (uncus) meets in middle.

Question 5

Two classifications of Head injuries

Answer 5

1. Supratentorial (above) herniation attempting to force upper brain through incisure. Descending herniation. Most common.
   - Uncal Herniation: brain attempting to shift down through Tentorium incisure.
2. Infratentorial Herniation.

Question 6

Epidural space versus subdural space

Answer 6

Epidural space- potential space between the skull and the dura

Subdural Space - potential space between the dura and the arachnoid membrane

Question 7

Monitoring ICP - transducer needs to be even w/

Answer 7

Must be even w/ foramen of Munro (Little tube connects the lateral ventricles with the third ventricle then through the aqueduct of Silvius to the fourth ventricle)
-level with ear canal or bony prominence behind ear

Question 8

Cerebral Perfusion Pressure Calculation

Answer 8

CPP = MAP - ICP

• normal ICP 0-10 mmHg
• goal CPP : >60 mmHg

Question 9

MAP calculation

Answer 9

MAP = (SBP + 2(DBP)) / 3

Or

MAP = DBP + 1/3(Pulse Pressure)
Pulse Pressure = SBP - DBP

Question 10

Decorticate posturing indicates:

Answer 10

Damage above the cerebellum & brainstem

-supratentorial

Question 11

Decerebrate indicates:

Answer 11

Damage to brainstem. Or compression of the thalamus and brain stem.

Question 12

Causes of signs in cushings triad

Answer 12

HTN: increased systolic pressure w/ decrease vascular compliance
- defensive mechanism
Bradycardia: pressure on vagus nerve (theorized)
Respiratory changes: blue wire has been cut, not compensatory.

Question 13

Positioning head injury

Answer 13

Eyes forward (natural inline position)

• allows venous drainage of brain.
• blood drainage from one part of the brain allows drainage from parts that do not easily drain.
• head turned to R is worse than to the L

HOB 15-30%
-gravity helps evacuate head.

Question 14

Other treatment for head injuries

Answer 14

Limit noxious stimulus
-suctioning, invasive procedures
noise - ear plugs even in coma state
Limit atmospheric changes
Keep patient tanked up - dry head injury will not survive
Normothermia
Normal electrolytes

Question 15

Sedation for head injury patients

Answer 15

Propofol is best as it wears off quickly

Benzos take longer to wear off.

Question 16

What happens with hypoventilation and head injury patients?

Answer 16

Cerebral steal or luxury perfusion

• vasodilation due to increased co2
• non-injured areas of brain vasodilate and rob essential blood from injured site.

Question 17

What happens with hyperventilation and head injury patients?

Answer 17

Reverse steal or Robin Hood Effect

• Rob from rich and give to the poor
• blood vessels leading to injured brain relax and open in attempt to perfuse. Non-injured brain is vasoconstricted to an unhealthy level in attempt to push blood to injured area.

Question 18

Hypertonic solutions to use

Answer 18

Mannitol or hypertonic saline

• assure adequate resuscitation first
• foley Cath must be in place
• ideally, CVP pressure should guide use of these drugs.

Question 19

Barbiturate coma

Answer 19

Decreases O2 demand

• minimizes brain function
• requires neurologist decision
• complications exist
• thiopental too short acting
• Phenobarbital drug of choice

Question 20

Skull to brain

Answer 20

Skull => epidural space => Dura matter (outermost Layer) => Tentorium Dura matter (inner layer) => sub dural space => arachnoid membrane => subarachnoid space => Pia matter => brain