Transport and Cerebral Perfusion (Week 5) Flashcards
1
Q
Causes of a stroke
A
Ischemia in a brain area; 80% of strokes
Hemmorhage of a brain blood vessel; 20%
2
Q
Stroked can result in loss or impaired:
A
Movement, sensation or emotions.
3
Q
Hemiparesis
A
1- sided weakness (partial parylysis)
4
Q
After effects of a stroke
A
- Hemiparesis
- Inability to walk
- Partial or complete loss of independence in performing 4.ADL’s
- Aphasia
- Depression
5
Q
Unmodifiable risk factors of stroke
A
- Age
- Sex
- Race
- Genetics
6
Q
Modifiable risk factors of a stroke
A
- Hypertension
- Heart disease
- Diabetes
- Hypercholesterolemia
- Smoking
- Alcohol <2good, >2bad
- Obesity
- Physical inactivity
- Poor Diet
- Cocaine
- Birthcontrol
- Migrane headaches
- Hypercoaguability
- Chronic Inflammation
- Hyperhomocystenimia
- Sickle cell anemia
7
Q
Primary blood vessels that supply the brain with blood
A
Carotid Arteries
Vertebral arteries
8
Q
Where does the greatest risk of stroke development occur?
A
Circle of Willis
9
Q
How much blood supply does the brain require
A
20% of the bodys cardiac output, 750-1000 mL/min.
10
Q
How fast do CNS changes occur after complete loss of bloodflow to the brain?
A
30 sec Permanent damage (cell necrosis) within 5 mins
11
Q
What are the factors that contribute to the severity of stroke damage?
A
- Rate of onset
- Size of lesion
- Presence of collateral circulation
12
Q
Cerebral Autoregulation
A
Refers to the ability of the brains bloodvessels to adapt to systemic blood pressure changes. Adjusts mean systemic blood pressures of 50-100 mmHg.
13
Q
How does increased CO2 levels effect brain blood supply?
A
Increases blood flow (it is a potent vasodilator)
14
Q
How does atherosclerosis contribute to a stroke?
A
- Plaque depositions narrow the blood vessels creating areas for the clots to become lodged.
- Bits of plaque break off and become lodged in smaller vessels.
- Weakening of blood vessels from atherosclerosis increase risk of hemorrhage.
15
Q
3 Types of Ischemic strokes
A
- Thrombotic
- Embolic
- Lacunar
16
Q
Thrombotic Stroke
A
Occur when a clot or plaques form and occlude vascular blood flow.
17
Q
Embolic strokes
A
Occur when a circulating clot or piece of broken off plaque becomes lodged in a narrow vessel. Most clots originate in the heart (endocardial) from AFib or Valvular disease.
18
Q
Lacunar Strokes
A
When a vessel supplying blood to the deeper structures of the brain becomes blocked. Can be asymptomatic b/c of collateral circulation.
When symptoms do occur they are severe including hemiplegia, or total collateral sensory loss.
19
Q
What kind of stroke has much more sudden effects and severe symptoms.
A
Embolic
20
Q
Cerebral Infarction
A
Death of brain cells from cerebral ischemia.
21
Q
Classifications of Hemorrhagic strokes
A
Intracerebral, intraparenchymal, subarachnoid, or intraventricular.
22
Q
Transient ischemic attack (TIA)
A
Essentially a “temporary stroke”. When an area become ischemic but blood flow is restored after a period of time.
23
Q
Intracerebral hemorrhages
A
Bleeding in the brain caused by a ruptured blood vessel. HTN is the greatest cause. 50% death rate.
24
Q
Subarachnoid Hemorrhage
A
When there is bleeding into the CSF space between the pia matter and the arachnoid membranes covering the brain. Usually occurs due to the rupture of a cerebral aneurysm.
25
Clinical Manifestations of stroke
1. Changes in motor function.
2. Changes in intellectual function.
3. Spatial-perceptual alterations.
4. Communication changes.
5. Changes in affect.
6. Changes in elimination function.
26
Motor function symptoms of stroke
Motor deficits are the most apparent symptoms of a stroke and are seen as a loss of function in mobility, rep function, swallowing and speech, gag reflex, and ability to perform ADL's.
27
Akenesia
Loss of skilled voluntary movement.
28
A stroke on which side of the brain causes aphasia?
Left
29
Expressive aphasia is known as what?
Broca's aphasia
30
Receptive aphasia is known as what?
Wernike's aphasia
31
Amnesic Aphasia
"loss of words"
32
Global Aphasia
Loss of receptive and expressive function.
33
Dysarthria
Disturbances in the muscular components of speech.
34
Intellectual function
Changes in memory and judgement from stroke. Left sided stroke pt's become more cautious. Right- more impulsive
35
Perceptual alterations
Four primary types:
1. Anosognosia - Inability to recognize objects
2. Erroneous perception of self in space - Sensory input from one side of body.
3. Homonymous hemianopsia- is when blindness occurs on one half of the visual field of both eyes)
4. Apraxia- The inability to carry out learned sequences of movement.
36
Affect post stroke
After a stroke the individual may express exaggerated or uncontrollable emotions of any type. Often depression will become evident.
37
Elimination function post stroke
Because of loss of sensory and muscle function, constipation and urinary retention commonly occur. These are most often resolved after time.
38
Diagnostic studies re: stroke
MRI/CT, they can determine it was in-fact a stroke as well as determine the cause of the stroke.
39
Stroke prevention (collaborative care)
1. Blood pressure control
2. Blood glucose control
3. Diet and exercise
4. Smoking cessation
5. Limiting alcohol consumption
6. Routine health assessments
40
Drug therapy for strokes
Hypertensives, aspirin ( or other antiplatelets like clopiodril). Patients with Afib are also prescribed prophylaxis such as warfarin.
41
Carotid Endarterectomy
Surgical removal of artheromatous areas from the carotid artery.
42
Transluminal angioplasty
The insertion and inflation of a baloon device to open stenosed vessels.
43
Stenting for stroke
May be used to maintain the patency of cerebral artery.
44
Acute care for a stroke is focused on (general)
Preserving life
Preventing further brain damage
Reducing disability
45
Why would stroke patient have difficulty keeping their airway patent?
Compromised LOC. Ensuring adequate O2 is critical to prevent further damage. In severe cases intubation and mechanical ventilation are required.
46
What does the body often do to maintain cerebral perfusion following a stroke?
Elevate its BP (>220 systolic). Antihypertensives will be administered.
47
What happens with fluid and electrolytes for stroke patients?
Possible hypovolemia.
48
ICP's
Increased intracranial pressures. Most often with hemorrhagic but also with ischemic.
49
Cerebral edema during stroke can cause
Brain herniation
50
Prevention and reduction of intracranial pressures
Elevate the head, use antidiuretics, drain CSF (possibly with boneflap).
51
Acute surgical therapy for stroke
Larger hematomas >3cm must be evacuated surgically. (sucked off)
52
Aneurisms can be surgically treated with what procedures?
Clipping
Wrapping
Coiling
53
Clipping
Insertion of metal clip to separate aneurism from the rest of the vessel.
54
Wrapping
Application of "band aid" to recompress ballooned aneurism.
55
Coiling
Insertion of platinum threads into the aneurism balloon space to prevent circulated blood from entering it.
56
What is administered during surgical aneurism treatment and why?
Calcium channel blockers, to prevent vasospasm and further ischemia.
57
Nursing data gathering right after a stroke:
```
Current illnesses.
Hx of similar symptoms.
Current meds
Hx of risk factors
Family Hx
```
58
Nursing neurological assessment after a stroke:
```
LOC
Cognitive status
Motor abilities
Cranial nerve function
Sensation
Proprioception
Cerebellar Function
Deep tendon reflexes
```
59
Care planning categories after a stroke
Cognition stabilization
Mood stabilization
Promoting independence
Avoiding complications
60
Nursing health promotion after a stroke
```
Prevention
Hypertension reduction
Reducing diabetes effects
Smoking cessation
Anticoagulant meds
```
61
Resp. nursing intervention for stroke
Assess airway patency and function, oxygenation, suctioning, client mobility.
62
Neuro. nursing intervention for stroke
Monitor neurological changes, they may indicate advancement of stroke symptoms, complications or recovery of the stroke.
GLASGOW may be used.
63
Cardiovasc. nursing intervention for stroke
Monitor for DVT development. Possibly administer blood thinners.
64
Musculoskeletalnursing intervention for stroke
MAINTAIN function after stroke.
Prevent contractures or atrophy.
Place joints high to prevent edema.
65
Integument. nursing intervention for stroke
Prevent skin breakdown. Immobility is common with stroke.
66
Urinary intervention for stroke
Maintaining regular bladder function. Retention and incontinence is often present.
67
GI system nursing intervention for stroke
Maintain GI function with the assistance of medications.
68
Nutrition intervention for stroke
Dysphagia assessment
Dysphagia treatment
Oral hygiene
69
Communication interventions after stroke
Asses ability to speak and understand. Can resort to gesturing if needed.
70
Vision alterations from stroke
Homonymous hemianopsia- (blindness) same half visual field for both eyes
Diplopia- Double vision, can be treated with eyepatch.
Ptosis- Eyelid drooping. Usually doesn't affect vision and doesn't necessate treatment.
71
Coping after stroke
Help arrange care for patient.
| Help patient and family cope with occurence of stroke.
72
Ambulatory and home care for stroke
Must be able or have the ability otherwise to complete ADL's
Must be completely educated on disease and changes that may occur in their lives
Must see many members of the healthcare team and be approved for discharge.
73
Rehabilitation Categories for stroke
```
Musculoskeletal Function
Nutritional Therapy
Bowel function
Bladdar function
Sensory-perceptual alterations
Affect (emotional state)
Coping
Sexual Funcion
Communication
Community reintergration
```
74
Volume of brain consists of
1. Brain tissue (78%)
2. Blood (12%)
3. CSF (10%)
75
Factors that ICP (inter cranial pressure)
```
Blood pressure
Cardiac Function
Intra-Abdominal and Intra-Thoracic Pressures.
Body Position
Temp
Blood gasses (esp. CO2)
```
76
Normal Intercranial pressure
Pressure exerted on the skull from blood, csf and brainmatter that is self regulated to some degree. 0-15 mmHg, any elevation above for over 5 mins is considered abnormal.
77
Where can a pressure transducer be inserted?
```
Ventricles
Subdural Space
Subarachnoid Space
Epidural space
Parenchyma (RIght into the actual white or grey matter :O )
```
78
Causes of increased ICP
```
Head Trauma
Stroke
Subarachnoid Hemorrhage
Brain Tumour
Inflammation
Hydrocephalus
```
79
What is expected when a client suddenly loses consiousnesS?
ICP (Increased cranial pressure)
80
Nursing interventions for increased ICP
Preservation of cerebral oxygenation and perfusion
Early identification of neurological changes
Prevention of complications secondary to increased ICP
81
Cerebral blood flow normal rate
50mL per minute per 100g of brain tissue.
| ex. 1.5kg= average 750 mL per min.
82
Why is ongoing blood flow critical to the brain?
Because it does not store O2 or glucose.
83
Autoregulation
Vasoconstriction or dilation of cerebral blood vessels in response to changing systemic pressures.
84
Cerebral perfusion pressure
Pressure that pushes through brain tissues
85
What pressure changes make the CPP change?
Mean Arterial Pressure (MAP)
Intracranial Pressure (ICP)
86
MAP-ICP=
CPP
| ex. 93.33mmHg -10mmHg =83.33mmHg
87
Summary of CPP's
Average human norm: 70-100mmHg
Borderline Damaging to cerebral tissues: 50-60mmHg
Catastrophic brain damage and death: <30 mmHg
88
Cerebral edema
Increased fluid in the vascular spaces in the brain. Causes damage. Three types:
Vasogenic
Cytotoxic
Interstitial
89
Vasogenic Cerebral Edema
MOST COMMON
Occurs due to changes in the endothelial lining of cerebral capillaries. Pores in capillaries enlarge enough to allow molecules to escape into the extravascular space. These macromolecules create and osmotic gradient that pulls water our of serum into the interstitial regions of white matter in the brain.
90
Cytotoxic cerebral edema
Cellular edema.
| Water and proteins shift from interstitial compartment into the cells causing cellular swelling and loss of function.
91
Interstitial cerebral edema
Caused by blocked CSF return (hydrocephalus) causing increased hydrostatic pressures in cerebral capillaries forcing serum into the interstitial spaces or changes in electrolyte levels such as hyponatremia. When interstitial osmolality exceeds vascular osmolality, water is pulled into the interstitial space.
92
Clinical manifestations of increased ICP
```
Changes in LOC
Changes in vital signs
Ocular signs
Decrease in motor function
Headache
Vomiting
```
93
Ocular signs of increased ICP
Compression of the oculomotor nerve results in dilation of the pupil on the same side.
94
Complications of increased ICP
Cerebral herniation
| Decreased cerebral perfusion
95
Diagnostics for ICP
CT and MRI
96
Neuromonitoring: measurement of ICP
Transducer (pressure sensor) inserted into brain via catheter.
97
CSF Drainage
Dangerously elevated ICP's deteted, CSF may be removed to make room for swelling.
98
Multimodal Monitoring
Measurement of the brains level of O2.
99
Collaborative care for ICP
Identify and treat underlying cause
Support brain function
Oxygenation
100
Drugs used for ICP
```
Mannitol
Corticosteriods
Dexamethasone
Benzos
Anticonvulsants
Phenytoin (dilantin)
```
101
Hyperventilation therapy for ICP
THis is a good therapy for primary intervention to reduce ICP. BUT research has shown that this method increased the risk of cerebral ischemia.
102
Nursing management for ICP includes
Pupillary assessment
| Motor function assessment
103
Care planning for client with ICP
Airway clearance
Ensuring ICP and CPP stay within normal limits
Maintain fluid and electrolytes
Avoid complications secondary to decreased LOC and immobility.
104
Acute interventions for ICP
```
Resp function
Fluid and electrolyte balances
Monitoring of intracranial pressure
Body positioning
Protection from injury
Psychological Considerations
```
