Intracranial Pressure

Question 1

3 components of the skull

Answer 1

Brain tissue
Blood
CSF (majority)

Maintain ICP of 5-15 mm Hg

Question 2

Cerebral Perfusion Pressure

Answer 2

Pressure needed to ensure blood flow to the brain
CPP = MAP - ICP
-normal is 70-100 mm Hg
- <50 mm Hg is ischemia and neuronal death

Question 3

Factors that influence ICP

Answer 3

• arterial pressure
• venous pressure
• intraabdiminal and intrathoracic pressure
• posture
• temperature
• blood gases

Question 4

Causes of ICP

Answer 4

• lesion
• cerebral edema
• head injury
• brain inflammation
• metabolic insult

Question 5

Symptoms of increased ICP

Answer 5

Opposite of shock
-HTN
-low pulse
-low respirations 
Cushings Triad

Question 6

Sustained increased in ICP

Answer 6

Results in brain stem compression and herniation of brain

• herniations force cerebellum and brain stem downward
• Respiratory arrest if brain stem compression is unrelieved

Question 7

Clinical Manifestations of increased ICP

Answer 7

• changes in LOC, headache, vomiting
• change in body temp
• papilledema, diplopia, changes in extraocular eye movement, Doll’s eyes
• hemiparesis or hemiplegia
• decorticate then decerebrate posturing
• fixed, unilaterally, dilated pupil = brain herniation

Question 8

Compression of oculomotor nerve (CN3)

Answer 8

Dilation of the pupil ipsilateral to mass
Sluggish or no response to light
Inability to move the eye upward
Ptosis of eyelid

Question 9

Decorticate posture

Answer 9

Flexor
Arms are like Cs: moves in towards cord
Problems with cervical spinal tract or cerebral hemisphere

Question 10

Decerebrate Posture

Answer 10

Extensor
Arms are like e’s
Problems with midbrain or pons

Question 11

Complications of uncontrolled increased ICP

Answer 11

• inadequate cerebral perfusion

- cerebral herniation

Question 12

Measuring ICP

Answer 12

Pressure Transducer
Measured in:
-ventricles
-subarachnoid space
-epidural space
-brain parenchyma tissue

Question 13

ICP Monitoring

Answer 13

• Glasgow less than 8
• abnormal CT/MRI
• gold standard: ventriculostomy
• LICOX brain tissue oxygenation catheter
• jugular venous bulb catheter

Question 14

Measurement of ICP

Answer 14

• infection
• mean pressure at the end of expiration
• waveform shaped similar to arterial pressure trace
• catheter can remove CSF

Question 15

Inaccurate readings

Answer 15

• CSF leaks
• catheter obstruction
• differences in height of bolt/transducer
• kinks
• incorrect height of drainage system

Question 16

ICP care

Answer 16

• O2 at 100mm Hg or greater
• ABGs
• mechanical ventilation
• hyperventilation therapy: no found to increase risk of ischemia
• diet with high glucose, normovolemic (IV 0.9%)

Question 17

ICP Drug Therapy

Answer 17

• Mannitol
• Corticosteroids
• Barbs
• anti seizure drugs
• H2 receptor antagonists or PPIs