vasospasm, subarachnoid hemorrhage, ICP

Question 1

After a vasospasm, when would a subarachnoid hemorrhage occur?

Answer 1

3-12 days

Question 2

What is most likely to cause vasospasm?

Answer 2

Inflammatory response

Question 3

Describe triple H therapy and nimodipine therapy given for vasospasm.

Answer 3

Tripe H therapy

Hypervolemia expansion
Given to increase intravascular volume and decrease blood viscosity. Through hypervolemia, cerebral vessels dilate and MAP increases therefore improving CPP. Pt will need to be monitored for pulmonary edema and CHF. PAP will need to be monitored.
Hemodilution
Administration of IVF decreases blood viscosity, increases CBF , and may decrease infarction size and increase oxygen transport. Goal is to decreases HCT by 15%Should be 30-33% which helps improve CBF without causing hypoxia.
Induced hypertension
Goal is to maintain BP > 20% above baseline. Increases BP to maintain cerebral perfusion and improve sx.
Nimodipine-calcium antagonist
Use from onset SAH to 21 days
Limits collateral damage that is mediated by calcium

Question 4

Describe the controversy of hyperventilation to decrease ICP.

Answer 4

Hyperventilation is controversial
Would only see concepts of hyperventilation in impending herniation.
Decreases arterial carbon dioxide tension (PaCO2) and results in vasoconstriction. As a result , the CBF is reduced due to the strong vasoconstrictive effect of hypocarbia on the cerebral arteries.
PaCO2 should be lowered gradually to avoid rebound vasodilatation from overcorrection.
Hyperventalation used and discontinued, should gradually return to normal!

Question 5

What is mannitol and what is the typical dose?

Answer 5

Hypertonic crystalloid solution that decreases cerebral edema, is also used as a first tier therapy for reducing ICP after brain injury.
Typically administer bolus intravenous infusion over 10-30 minutes . Dose: 0.25g to 2g/kg body weight.

Question 6

How does mannitol work? How is it excreted? How do you monitor is effectiveness?

Answer 6

Has immediate plasma- expanding effects which reduce blood viscosity, increases CBF, and cerebral oxygen metabolism, permitting cerebral arterioles to decrease in diameter. Lowers CB volume and ICP, while maintaining a constant CBF.
It is excreted in urine , can cause tubular necrosis and renal failure.
Must place Foley catheter to monitor UO.
check for decreased ICP

Question 7

What are some things to avoid in patients with an increased ICP?

Answer 7

No Acidosis
No Suctioning
No hyperexsteion or flexion
No low protein diet
Try to avoid wrist restraints.