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Flashcards in Acute Intracranial Problems Notes Deck (47)
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1

3 essential volume components of the skull

Brain Tissue
Blood
Cerebrospinal Fluid (CSF)

2

Primary Injury

Occurs at the initial time of injury

3

Secondary Injury

Effects of the primary injury that can appear in a few hours to a few days.

4

Intracranial Pressure (ICP)

Pressure of CSF fluid within the brain.

5

Factors that influence ICP

Arterial Pressure
Venous Pressure
Intraabdominal Pressure
Posture
Temperature
Blood Gases

6

Monro-Kellie Doctrine

The 3 components must stay in a constant volume overall.
Only affects when the skull is closed.
Brain compensates in any component if one component is displaced more than others.

7

Normal ICP ranges

5-15 mmHg

8

Cerebral Blood Flow (CBF)

Blood supply given to the brain in any given time period, usually 1 minute.

9

Cerebral Autoregulation

Automatic adjustment that the brain does to maintain a constant blood flow when arterial BP changes.

10

Normal MAP

60-100 mmHg
Most people have 70mmHg
Critical to maintain MAP when ICP is increased

11

Cerebral Perfusion Pressure (CPP)

Pressure needed to ensure blood flow to the brain.

12

Normal CPP

60-100 mmHg

13

How to calculate MAP

(SBP+2(DBP))/3

14

How to calculate CPP

CPP=MAP - ICP or
CPP= Flow x Resistance

15

Factors Affecting Cerebral Blood Flow

CO2
O2
Hydrogen ions (H+)

16

Why is it critical to maintain CBF?

To preserve tissue and minimize secondary injury.
Prevent brainstem compression and brain herniation.

17

3 Types of Cerebral Edema:

Vasogenic
Cytotoxic
Interstitial

18

Vasogenic Cerebral Edema

Most common type
Characterized by leakage of large molecules from capillaries into surrounding extracellular space.

19

Cytotoxic Cerebral Edema

The cell membrane breaks and moves fluids and proteins into cells.

20

Interstitial Cerebral Edema

Result of hydrocephalus (buildup of brain fluid)

21

C/M on Increased ICP

Changes in LOC - most reliable indicator of neuro status
Cushing's Triad - MEDICAL EMERGENCY
Compression of Cranial Nerve III - fixed unilateral dilated pupils - MEDICAL EMERGENCY
Blurred vision, diplopia, and extraocular eye movements
Compression of Cranial Nerves II, IV, and VI.
Contralateral hemiparesis or hemiplegia
Decorticate or Decerebrate posturing
Headache
Unexpected vomiting
Projectile Vomiting

22

Cushing's Triad

MEDICAL EMERGENCY
Systolic HTN with widening pulse pressure
Bradycardia with bounding peripheral pulses
Irregular Respirations

23

Which is worse: decorticate or decerebrate

Decerebrate

24

Why do we have to monitor for headache?

Headache may appear benign but that's an early symptom of cerebral edema and increase ICP that can lead to coma and death

25

2 Major Complications:

Cerebral Perfusion
Cerebral Herniation

26

Tentorial Herniation

Mass lesion in the cerebrum forces brain to herniate downwards

27

Uncal Herniation

Lateral and downward herniation

28

Cingulate Herniation

Lateral displacement of brain tissue under falx cerebri (dura wall that separate's 2 cerebral hemispheres)

29

Diagnostic Studies

CT and MRI
Cerebral angiography
EEG
PET
Transcranial Doppler Studies
Infrascanner - detects life-threatening intracranial bleeding
ECG
Lumbar Puncture (LP)
Lab Studies

30

Why should you not perform a LP when an ICP is suspected?

Possible cerebral herniation can occur when the pressure is released during a LP.