WEEK 9: ISCHEMIC STROKE Flashcards
Athlerosis leads to … in heart in body in head/ neck
- heart -> CAD
- Body -> PAD
- Head/neck -> cerebrovascular disease & thrombotic stroke
blood clot leads to: in heart, in lungs, in body, in brain
- In heart -> MI
- In lungs -> pulmonary emboli
- In body -> acute arterial ischemia (if in arteries) or venous thromboemboli (if in veins)
- In brain -> embolic stroke
stroke/ CVA: what is
= inadequate blood flow & oxygen to an area of the brain -> death of brain cells
ischemic stroke what is
: Blocked blood flow in a cerebral artery
causes of the two types of ischemic strokes
a. Thrombotic stroke: caused when an artery in the brain become blocked, due to narrowing of the artery due to atherosclerosis and/or formation of clot
- Blood clots don’t travel from one area of the body to another
b. Embolic stroke: blood clot forms elsewhere and then travels to the brain & lodges in a blood vessel, blocking blood flow
- Important to know large vessel vs small vessel occlusion/disease
- Can influence symptoms and tx that’s most likely to be effective
parts of a stroke; infarct
blocked blood flow; area of cell death
- Brain cells die no matter how fast person receives tx
cause of hemorrhagic stroke
Blood vessel in brain ruptures & bleeds into brain
neurologic symptomes, death of brain cells
Neurological symptoms may start w/i minutes bc brain cells need a constant supply of oxygen & glucose
- Absence of blood flow causes death of brain cells in 4-10 min
parts of stroke: Penumbra
area of reduced blood flow; salvageable if blood flow is restored/pt receives tx immediately
- Surrounds infarct
- Brain cells are slowly starving/suffocating
- Prompt tx = limited damage
hot stroke
at least 1 pos FAST sign & symptoms have started w/i last 5 hrs
Step 1: Check BG (> 4?)
- Severe hypoglycemia can sometimes cause neurological symptoms (ex: confusion, ALOC, slurred speech) that may mimic signs of a stroke
Fast VAN
simple screening technique
- Need 1+ of FAS & 1+ of VAN
- Last seen normal (LSN) time must be <6 hrs
what does FAST stand for
Face: right droop? Left droop?
- Ask pt to smile
Arm: right weak? Left weak?
- Hold up arms, psalm facing up and close their eyes -> count to 10
- Pronator drift: if an arm starts to drift down while t
Speech: slurred?
- Ask to say a simple phrase
Time: <6 hrs or woke w symptoms?
if possible: what to know for medical and non medical people in FAST
Non medical ppl: should know that it’s an emergency & should call 911; get to hospital ASAP
Medical ppl: assess when symptoms first started
- When was the last time that they were seen to be normal?
- Has important implications for the tx the pt will receive
- Call ahead to hospital & let them know that you have a HOT STROKE
- Gather as much medical hx as possible
what is VAN
- Vision: right gaze? Left gaze?
- Aphasia: naming difficulties?
- Neglect: ignoring left side of body?
Function of FAST VAN
- Used to identify if the pt’s stroke might be caused by a lg occlusion
- Large vessel occlusions (LVOs) = primary arteries of the brain
ICA, MCA, AVA, BA, PCA
- ICA = internal carotid arteries
- MCA = middle cerebral arteries
- ACA - anterior cerebral arteries
- BA = basilar artery
- PCA = posterior cerebral arteries
step 2: gather as much medical histroy as possible why
- Allows healthcare team to identify any risk factors
- For ischemic stroke, are the same risk factors for developing atherosclerosis
modifiable risk factors (4)
- Obesity
- Smoking
- Dyslipidemia
- Heavy alcohol intake
non modifiable risk factors (5)
- Age
- Sex
- Genetics
- Family history
- Ethnicity
chronic health conditions (6)
- Diabetes & metabolic syndrome
- HTN
- CAD & MI
- AF
- Infections & chronic inflammatory conditions
- Sleep apnea
TIAs are risk factors for strokes (5) when do they occur, risk after getting for ischemic stroke
- TIAs are most likely to occur in the hours & days preceding an ischemic stroke
- After a TIA there’s a 1.5 - 3.5% risk of ischemic stroke in the next 48 hrs
After having a TIA, ppl w the highest risk for having a subsequent stroke are…
a. 60+
b. Hypertensive
c. Diabetic
d. TIA symptoms lasted longer than 1 hr
e. TIA involved unilateral weakness or speech disturbances
what is a TIA
transient ischemic attack)
- Temporary blockage in cerebral blood flow causing neurological symptoms
- Usually lasts < 1hr
- Does not last more than 24 hrs
- One of the most common symptoms = blindness in 1 eye
TIA episode
momentary loss of vision in right eye
- Like a horizontal window shade comes down over your vision
- It only lasts 20-30 sec
Q: pt w a hx of multiple TIAs reports new onset of left-sided weakness & difficulty speaking that developed about an hour ago
- Send to CT for picture of brain bc S/S of TIA may be exactly the same as a stroke
why should you not wait?
Should not wait to see if symptoms improve bc millions of brain cells may be dying every minute
- Waiting leads to worse outcomes & increased risk of death
seek immediate medical attention is pt demonstrates (2)
a. Clinical manifestations of a stroke
b. ANY sudden neurological changes
strokes and time: brain cells, blood flow, death
- 2 million brain cells die every minute
- Sooner that blood flow can be restored, the better the prognosis
- Risk of death increases as infarct gets larger
infarcts grow over time?
- Depending on affected blood vessel, initial infarct might be the size of a marble
- If blood flow can be restored to the brain when the size of the infarct is < 40ml (golf ball), pt will have much better chance of being able to regain function
Diagnostic tests: STAT (5)
- Complete blood count (check platelets)
- Electrolytes
- BG
- Coagulation panel (PTT, INR)
- Liver function tests (AST, ALT, GGT, bilirubin, alkaline phosphatase
Q: if blood tests show that pt w an acute stroke has severe liver disease & the pt will be receiving a thrombolytic drug (such as TPA) there’s an increased risk of
bleeding during tx
- Liver makes clotting factors for blood
- Severe liver disease: liver is unable to manufacture clotting factors & pt may experience complications w bleeding & bruising
Additional tests (2)
- Kidney function tests (urea, creatinine, GFR)
- BHCG in women <50 (pregnancy test)
CT scan
Non-contrast = most commonly used
- Contrast takes longer
- Non-contrast is quicker & readily available in most hospitals
- Primarily goal = to rule out hemorrhage
- Not used to look for signs of neurological damage yet bc signs of ischemic stroke may not show up for a few hours
Function of importance of the tests
- Will determine if there might be some other problem causing the neurological symptoms (such as a low BG)
- Provides helpful info to determine tx
- Pregnancy may affect what tx is offered
- Weigh pros & cons
- If severe kidney or liver disease, Dr may need to modify dose of any meds administered
other imaging
- Not as common
- MRI or MRI angiogram
- Downsides: slower & not available in many hospitals
Follow up scan: CT ____
CT angiogram
- To show the blood flow in the cerebral arteries
- Esp if pt tested pos on VAN criteria
- Images are used to select most appropriate tx
t-PA (tissue-plasminogen activator) - Alteplase
consider if no signs of hemorrhage
Criteria (4. 3)
- Diagnosed w ischemic stroke causing neurological deficits
- Pt can receive thrombolytic tx w/i 4.5 hrs of when symptoms started
- Appropriately trained Dr is available to supervise pt’s tx
- Only 7-10% of pts who get to hospital are eligible
- If symptoms started during the night we don’t know when stroke occurred
- Ppl may be unable (or don’t want) to seek medical attention - After too long, only option is rehabilitation
MoA drugs
thrombolytic/fibrinolytic drug
- Naturally secreted by blood vessel endothelium
- Converts plasminogen -> plasmin (enzyme that breaks down clots)
- Produced by recombinant DNA tech so it’s identical to t-PA produced by blood vessels
Use of MoA
- number of life-threatening conditions involving blood clots
a. Acute ischemic stroke
b. MI
c. Acute massive pulmonary embolism
MoA half life, and cos, where is it available
Half-life of 5 min BUT fibrinolytic activity may persist for up to 1 hr after infusion is complete
Cost = $10,560.43 per 100mg vial BUT
- May reverse effects of stroke
- Save a person’s life
- Prevent (or reduce) serious disability)
- Save even more money resulting from extended hospital stay & tx by multiple HCPs
Available in: Kelowna, Vernon, Penticton, Kamlooops, Cranbrook, Trail, Salmon Arm, Nelson, Williams Lake
Absolute contraindications
*everything = bleeding risk EXCEPT for BG <2.7 (hypoglycemia)
- BP > 185/110 despite two attempts to reduce BP
- History of intracranial hemorrhage, vascular malformation, neoplasm (except meningioma), or untreated aneurysm
- Stroke, intracranial surgery, or head injury w/ 3 months
- Symptoms suggestive of subarachnoid hemorrhage
- Arterial puncture at a non-compressible site w/i 7 days
- Evidence of active bleeding or acute trauma (fracture) on examination
- Acute bleeding diathesis (bleeding tendency)
- BG < 2.7
- Needs to be corrected before deciding to administer t-PA
- Anticoagulant use w INR > 1.7 or PTT greater than normal range (24-40s)
- Platelet count < 100 x109/L
- Apixaban, dabigatran, rivaroxaban use w/i last 48 hrs
Med contraindications (2)
a. Anticoagulants (heparin, warfarin): causes an INR >1.7 or a PTT outside of normal range
b. Factor Xa inhibitor anticoagulants (rivaroxaban) w/i 48 hrs
relative contraindications: weigh pros and cons
Pregnancy
- Risk to fetus = unknown
Past hx of MI, pericarditis, or aortic dissection w/i 2 months
- Bleeding risk
Witnessed seizure w postictal residual neurological impairments
- Other possible neuro cause
Major surgery or mahro trauma w/i 14 days
- Bleeding risk
GI or urinary tract hemorrhage w/i 21 days
- Bleeding risk
Time & thrombolytic tx
- Important bc w every hr that passes ..
- Chance of a favorable outcome decreases by 2-3%
- Chance of death increases by 1-2%
- => after 4.5 hrs there is no real benefit to using t-PA
why is thrombolytic time important
- When a clot initially forms it’s soft & squishy & so t-PA can penetrate the outer surface of the clot & break it down more effectively
- As times goes on, clot get more firm/dense -> t-PA can’t break it down as easily & bc it has such a short half-life it only has a short period of time to work
- => Canadian Stroke Best Practices recommends “door to needle” time of <60 min
- Hospitals should achieve this goal w at least 90% of pts
- Mean tx time should be 30 min
t-PA works best on …
(4)
- Smaller clots
- Located in smaller blood vessels
- Clots that are not as dense (that allow some blood to flow past or through)
- Clots that have developed in the last 4.5 hours or less
othertreatments if cant have t-PA
- Endovascular thrombectomy w a stent retriever:
- Preventative measures:
- Balloon angioplasty w placement of a stent (not tx)
- Carotid endarterectomy
Intra-arterial mechanical thrombectomy/endovascular thrombectomy (EVT)
- Catheter is used to manually remove the clot
- Available since 2003 using the MERCI receiver (1st gen device)
- 2nd gen catheters & techniques have since been developed
- Use a stent retriever: snags clot & pulls it out instead of being left inside
- Used to treat occlusions in lg proximal blood vessels
- Clots in these are often too big for t-PA to break apart
- Several lg research trials have supported benefits of endovascular thrombectomy
- 1 in 5 pts have a good income & 1 in 3 have some improvement
- Performed if a pt presents w/i 6 hrs of symptom onset
- Compared to 4.5 hrs for tPA
- Certain situations: may receive tx up to 24hrs after symptom onset
- Not offered by many facilities
- Need special type of imaging software + medical specialists
- Kelowna DOES
Smaller hospitals may “drip and ship”
- Smaller hospital begins tx (including tpa)
- Then ships off to stroke centre (for possible EVT)
Stroke deficits/disabilities (6)
- Dysphagia
- aphasia/dysphasia
- Altered mobility
- Altered sensation
- Altered vision
- Altered elimination (bowel or bladder)
Q: if pt understands but can’t find right words …
expressive apahasia (brocas aphasia)
Categories of aphasia (4)
a. Expressive aphasia: understands but can’t speak
b. Receptive aphasia: difficulty understanding spoken or written language
c. Anomic aphasia: pt can’t find correct names for specific objects, people, places, events
d. Global aphasia: loss of all expressive and receptive function
Other complications (8)
- falls
- UTI
- Chest infection
- Pressure sores
- Depression
- Shoulder pain
- DVT
- PE
Maintaining musculoskeletal system
- Position pt appropriately to prevent contractures and maintain joint stability
- Limbs in neutral position
- Pillow to support affected arm when sitting so it doesn’t pull down on shoulder (causes joint dysfunction & pain)
- Progress ambulation/mobility 3x/day or as tolerated
musculoskeltal complications (2)
- Shoulder subluxation
- Frozen shoulder
Q: If after a stroke a pt initially has flaccid muscle on the R side but 48 hrs later the muscles start to show spasticity w exaggerated reflexes
- A: sign of improvement as pt is slowly starting to regain muscle function
- Immediately after stroke: may develop flaccid paralysis
- If doesn’t improve -> muscles will atrophy & limbs are at risk for developing contractures
- As nerves on affected side begin to regain function, they may intermittently fire -> muscles show small spastic or abnormal movements
- May be involuntary but good sign
- Rehabilitation = important to help w ROM
- Over time, spasticity may become worse before becoming better
Falls
- Non-skid socks and hip protectors
- Bed alarm and/or falls mat for confused & impulsive pts
- R-brain stroke (L weakness) tend to be impulsive & present safety risk
- After stroke ppl have decreased bone mineral density (increases risk for fracture)
- Bc of reduced mobility
- Most common # = hip fracture
- # usually occurs on affected side bc ppl tend to fall towards weaker side
- Also may not have any protective mechanisms on that side (such as putting out an arm)
UTIs
- Avoid indwelling catheters if possible!!
- Longer remains in place, higher the risk that catheter will develop a biofilm
- Encourage fluids during day
- Minimize fluid intake after dinner
- Disrupts sleep
- Falls risk
- Schedule toileting q2h
- Urinary incontinence = associated w more severe strokes
q; After a stroke a pt has urinary incontinence due to an impaired awareness of bladder fullness. Which nursing intervention is best to include?
- A: assist pt to commode q2h
- Regular voiding schedule will prevent incontinence & may increase pt’s awareness of a full bladder
Pulmonary complications - Aspiration pneumonia (d/t dysphagia)
- Keep pt NPO until swallowing can be assessed
- Teaspoon of water = first thing attempted
- Consult Speech Language Pathology (SLP) to determine appropriate diet & fluid texture
- Diet textures:
- Thickened fluids
- Go down slowly => allow pt more time to close epiglottis & to coordinate the muscles of their throat to swallow
- Minced diet
- More texture compared to pureed => easier to swallow
- sauce/gravy moistens foods -> easier to swallow
- May gradually be able to go back to regular diet/fluid
- Respiratory failur
pulmonary complications: respiratory failure
- Stroke can weaken or paralyze muscles
- Can cause atelectasis & pneumonia
- To detect: perform resp assessment & monitor temp closely for first 24 hrs after stroke
- Pneumonia = most common cause of an early temp in a pt w an acute stroke
- Associated w pt having a worse outcome
- May need intubation and mechanical ventilation
- Teach pt to perform deep breathing exercises
- Keep HOB elevated to 30 to promote lung expansion
pulmonary complications: airway obstruction
- d/t pocketing of food & inability to keep tongue from falling back
- Assess if pt needs an airway (OPA)
- For severe airway compromise, tracheostomy may be required
skin breakdown: what to asses and do
- Assess need for pressure-relieving equipment
- special mattresses
- wheelchair cushions
- Reposition pt frequently (esp limbs w decreased sensation or movement)
- Q2h throughout day & night
- Provide excellent skin care
- Cleansing
- Moisturizing
- Protection from moisture
- Use appropriate slider sheets & mech lifts to prevent friction & shear
nutrtion: asses
- Assess for malnutrition
- Up to 50% of ppl w severe strokes have been reported to be malnourished 3 weeks after stroke
promote good nutrition
- Sit pt fully upright during meals
- Ensure food/liquids are appropriate texture
- Check mouth for pocketing of food
- Perform oral hygiene after meals
- Feeding tube may be considered if unable to take in adequate nutrition
- Ensure adequate fluids
- 2000ml/day
- Increase fluids if prone to constipation
monitoring for GI blleds, labs, risk factors etc.
- Lab tests (RBC, hemoglobin)
- Thrombolytic therapy is not associated w increased risk
Risk factors: - Older age
- Severe stroke
- Liver cirrhosis
- Peptic ulcer disease
- Anti-ulcer med may be used if GI bleed occurs (ex: PPI or H2 receptor antagonist)
Secondary prevention strategies
prevention of strokes in ppl who have already experienced a stroke or TIA
- Since atherosclerosis = major risk factor for ischemic stroke, nurse should teach pts how to slow down its progression
Q: pt develops homonymous hemianopia after an acute ischemic storke. What knowledge will guide the nurse’s care?
- A: homonymous hemianopia = blindness in half of the visual field => pt will only see half of plate
- Eating only ½ of food results from inability to coordinate visual images & spatial relationships
atheroosclerotic plaques tx:
a. Transluminal angioplasty w a stent (to help hold carotid artery open)
- For significant atherosclerosis
b. Carotid endarterectomy
- Temporarily clamp off carotid artery & cut it open so that plaque can be removed
- Artery is sutured shut & clamp is removed
- How to reduce risk factors for atherosclerosis
- Smoking cessation
- Manage HTN
- <140/90 in normal
- <130/80 in DM
- <120 in high risk groups
- Manage BG levels in DM
- Fasting BG btw 4-7 mmol/L
- Monitor hemoglobin A1C regularly
- Most ppl: <7
- Ppl at high risk for diabetic nephropathy or retinopathy: <6.5
- Ppl who are frail, elderly, or high risk for asymptomatic hypoglycemia: 7-8.5
- Reduce serum cholesterol
- LDL <2mmol/L
- HDL >1,55
- Under 5.15 total
- Triglycerides: kep low (around 1mmol/L)
- Increase physical activity
- At least 150 min mod-vigorous physical activity/week
- Healthy diet & weight
- Reduce alcohol consumption
Atherosclerotic plaques : asses where and what
- Assess for plaques in carotid arteries w carotid duplex ultrasound
- Shows:
a. location & extent of atherosclerotic plaques
b. alterations in normal blood flow
- Assess for atrial fibrillation
- Afib results in more severe strokes than carotid disease
- Forms clots
- Most ppl w ongoing afib will receive oral anticoagulant therapy such as:
- Warfarin (target INR = 2-3)
- Factor Xa inhibitors (ex: rivaroxaban or apixaban)
- Becoming preferred tx bc it doesn’t require frequent blood testing & doesn’t have interactions w foods containing vit K
afib: assess for by monitoring:
- Irregular HR
- Tachycardia
- Weakness
- Dizziness or lightheadedness
- Not getting enough blood to brain
- Dyspnea
- ECG changes
afib characterstics
- Very irregular rhythm (distance btw each QRS complex = different)
- No P waves visible
- Bc atria aren’t firing together & depolarizing together
- Results in jagged baseline caused by hundreds of uncontrolled impulses originating in the atria
- Rate = very fast
- Bc as soon as ventricles depolarize, contract, and then repolarize, all electrical activity in the atria stimulates the ventricles to depolarize again w/o allowing a pause in-btw
- BUT since ventricles are still contracting normally, QRS complexes are narrow & normal looking
