Stroke

Question 1

Describe a stroke

Answer 1

A stroke occurs when there is ischemia (inadequate BF) to a part of the brain that results in the death of brain cells.

Synonyms: CVA (cerebral vascular accident, cerebral ischemia)

Question 2

Strokes are the ___ leading cause of death in Canada

Answer 2

3rd

Question 3

What % of cardiac output goes to the cerebral BF?

Answer 3

20%

Question 4

How long after full neurological BF occlusion does cellular death occur?

Answer 4

after 5 minutes

Question 5

Describe cerebral autoregulation

Answer 5

Changes in diameter of cerebral BVs in response to changes in BP so the brain BP stays constant.

CO would have to be reduced by a third to reduce cerebral BF due to cerebral autoregulation shunting BF to the brain.

Question 6

Compensating function of the Circle of Willis

Answer 6

If a blockage stops BF in a connected artery, the change in BP causes blood to flow forward or backward in the circle of Willis to compensate

Question 7

What is a vasovagal response?

Answer 7

When BP temporarily drops causing pallor and fainting due to overactivity of vagus nerve.

Question 8

What gender experiences more strokes?

Answer 8

Men

Question 9

What gender dies more frequently due to strokes?

Answer 9

Women

Question 10

What races have a higher risk factor for strokes?

Answer 10

African Americans, African-Canadians

Question 11

What is one modifiable risk factor specifically in women for strokes?

Answer 11

Oral contraceptives and HRT (hormone replacement theory - used in menopause to give estrogen)

Question 12

3 Contributing factors to strokes

Answer 12

1. Hypertension (risk for atherosclerosis, thrombotic stroke, aneurysms)
2. Diabetes (macrovascular complications)
3. CAD (pooling blood from atrial fib can cause clots)

Question 13

Describe Thrombosis

Answer 13

• more common
• platelet clot aggregation that forms, stays, and can eventually block vessel
• slower symptom onset

Question 14

Describe embolism

Answer 14

• clot that develops, travels, and causes blockage somewhere else in the body

Question 15

Describe hemorrhage

Answer 15

• breaking the vessel wall
• often atherosclerotic rupture

Question 16

2 Types of strokes and their %s

Answer 16

1. Ischemic Strokes (85%)
2. Hemorrhagic Strokes (15%) POORER PROGNOSIS

Question 17

3 types of Ischemic strokes and which is more common

Answer 17

1. TIA
2. Thrombotic (more common)
3. Embolic (less common)

Question 18

2 types of hemorrhagic strokes and which is more common

Answer 18

1. Intracerebral (more common)
2. Subarachnoid (less common)

Question 19

Explain how cerebral ischemia can come from thrombosis/embolism or HTN/aneurysm

Answer 19

Thrombosis/embolism -> cerebral infarction (loss of BS) -> less cerebral perfusion & increased intracranial pressure

HTN/Aneurysm -> cerebral hemorrhage -> less cerebral perfusion & increased intracranial pressure

Question 20

How long does a TIA last?

Answer 20

Often after 15 mins

Question 21

What causes a TIA?

Answer 21

microemboli

Question 22

Difference in symptoms between thrombotic and embolic strokes

Answer 22

Thrombotic: slow and progressive, may not have LOC change in first 24 hours

Embolic: sudden, no chance to develop collateral circulation

Question 23

Describe an intracerebral hemorrhagic stroke

Answer 23

bleeding occurs in the cerebrum
- HTN is a big risk factor
- occurs during activity
- sudden onset
- headache, NV, altered LOC, HTN

Question 24

Describe a subarachnoid hemorrhagic stroke

Answer 24

bleeding in-between the pia mater and arachnoid mater of the brain
- Intracranial bleeding into cerebrospinal fluid space
- rupture of cerebral aneurysm, trauma, or cocaine
- headache, NV, altered LOC, HTN

*silent killer

Question 25

What's the chance of dying within 30 days after a hemorrhagic stroke?

Answer 25

40-80%, but over half die soon after the initial hemorrhage

Question 26

What's the chance of dying during the first episode of a ruptured aneurysm?

Answer 26

40%

Question 27

What do clinical manifestations of strokes depend on?

Answer 27

location, not type of stroke

Question 28

Right-brain damage symptoms:

Answer 28

- paralyzed L side - spatial deficits - minimize problems - quick performance - short attention span - impulsive - impaired time concepts

Question 29

Left-brain damage symptoms:

Answer 29

- paralyzed R side - aphasias (speech) & math difficulties - impaired R & L discrimination - slow performance - aware of deficits (depression)

Question 30

Diagnostics for strokes

Answer 30

Primary diagnostic: CT scan Cardiac function: Troponin and CKMB, ECG, chest x-ray, cardiac markers, echocardiogram Clotting factors: CBC, WBC, hemoglobin, electrolytes, glucose, A1C, lipid profile, renal and hepatic studies

Question 31

What is a carotid endarterectomy?

Answer 31

Removes plaque surgically

Question 32

FAST stroke warning signs

Answer 32

F - facial droop A - arm weakness S - speech difficulty T - time to call 911 additional signs: vision problems, severe headaches, dizziness

Question 33

How fast from the onset of stroke symptoms should assessment, diagnostic studies, and thrombolytic therapy occur?

Answer 33

3-4 minutes from onset

Question 34

3 things to assess in stroke patients

Answer 34

Glasgow coma scale PERRLA (dilation and non-activity is caused by low O2 to the brain) Vitals

Question 35

Why is N&V a symptom of a stroke?

Answer 35

Increased ICP in medulla oblongata causes N&V

Question 36

4 key interventions for acute ischemic stroke

Answer 36

1. Airway: O2 therapy, artificial airway 2. Baseline neurological assessment 3. BP meds not recommended unless SBP > 220 or MAP > 130 4. Fluid and electrolyte balance - restriction of 1.5-2L/day, no hypotonic fluids that pull fluid into tissue which increases cerebral edema

Question 37

Formula for cerebral perfusion

Answer 37

Cerebral perfusion = MAP - ICP

Question 38

Priority Nursing interventions for strokes

Answer 38

Restore and maintain BF to the brain: - HOB elevated to 30 to reduce ICP - monitor BP - give mannitol IV as a diuretic to decrease cerebral edema - never give a stroke pt anything PO unless swallowing is assessed

Question 39

Medication Tx for acute ischemic strokes

Answer 39

- tPA (clot buster so there is a risk of bleeding, given within 4.5 hours of onset) - ASA - anticoagulant and antiplatelet after stabilization (could increase risk for hemorrhage)

Question 40

Medication Tx for hemorrhagic strokes

Answer 40

- Nimodipine - relaxes BVs for more BF, calcium channel blocker - SBP should be normal to high but < 160

Question 41

Formula for MAP

Answer 41

[ SBP + (2xDBP) ] /3

Question 42

Describe MAP

Answer 42

Average arterial pressure throughout one cardiac cycle, systole, and diastole

Question 43

Describe Cushing's Triad

Answer 43

3 primary signs that often indicate an increase in ICP 1. ↑ SBP 2. ↓ HR 3. ↓ RR

Question 44

Interventions to decrease ICP

Answer 44

- providing O2: rest, reduced stimulation - postures promoting venous return - no bearing down (Valsalva maneuver) - medically induced coma

Question 45

Medications to decrease ICP

Answer 45

Mannitol - diuretic draws fluid out of tissue Hypertonic saline - draws water out of tissue Steroids Anti-seizure meds given prophylactically BP meds