Cardio Vascular Accident CVA

Critical Care Situations in Neurological Nursing Increased Intracranial Pressure Delirium CVA

Increased Intracranial Pressure: Skull as a “closed box”
Brain tissue is 78%
Intravascular blood is 12%
Cerebrospinal fluid is 10 %
About 1900 mL in adults
Normally volume in = volume out

Normal ICP is 5-15 mmHg in pt. With HOB at 30 degrees.
If sustained pressure above 20 mmHg herniation of the brain is likely, compressing the brainstem
Body compensates for minor increases in ICP by increasing CSF absorption, decreased CSF production, as well as changing intracranial blood volume through increased venous outflow

Cerebral Perfusion Pressure: CPP
This is the pressure of the blood flow into the cerebrum, which must be above 30
CPP = MAP - ICP
Note the pressure-volume curve:

What are the factors that raise the ICP?
Increased arterial blood pressure (note: MAP is the mean arterial pressure)
Maximal constriction of vessels occurs at MAP of 150, maximal dilation at 50
Increased intra-abdominal and intrathoracic pressure (eg valsalva, cardiac)
Posture (how high head is in relation to heart)

More factors that influence ICP
Hyper and hypothermia
Brain injury = swelling
Low oxygen tension = cerebral vessel dilation
Increased PaCO2 = cerebral vessel dilation
Infection
Masses
Toxic substances in blood/brain tissue

Signs and Symptoms of Increased ICP
Change in LOC: orientation, restlessness, clouded sensorium. Subtle or dramatic
Change in Vital Signs: most important is watching for pattern.
Cushing’s Triad (late sign): widening pulse pressure, bradycardia with full bounding pulse, and irregular respirations

More Signs and Symptoms
Changes in pupil size, vision, symmetry, reactivity, as well as ocular and lid movement.
Hemiparesis, or other changes in motor function
Review decerebrate and decorticate posturing. Both serious, decerebrate is more ominous.
Vomiting, headache.

Brief overview of treatment of Increased ICP
Frequent assessment, with attention to subtle changes in LOC and neuro exam
Very important to ACT EARLY when symptoms emerge, by the time symptoms are overt, pressure may be hitting the dangerous part of the curve.
Maintain calm and non-stimulating environment (think: similar to “aneurysm precautions”)
PaO2 at 100%, some physicians will aim for hyperventilatory state, some not. Do avoid excess PaCO2

Increased ICP Care, continued
Team will want to address the cause, and treat it whenever possible (discuss)
Debate about use of sedation (discuss pros and cons, situational considerations)
Diuresis: osmotic and loop diuretics, watch I & O, note SIADH as serious problem
Corticosteroids

Even More ICP care
Maintain normothermia
Avoid skin breakdown
Maintain nutrition (discuss why)
Maintain adequate CPP with BP stable and fairly normo-tensive (physician may have specific boundaries in mind)
Maintain ICP as near normal as possible, moniter it.

CVA: Epidemiology
CVA affects over 730,000 people in US yearly
One of the top 3 causes of death in US
Costs us (in indirect and direct cost) about 41 billion yearly
Incidence doubles after age 55, CVA affects more men than women, and African Americans are at a higher risk as well.

More Epidemiology
About 50% Stroke victims in US die
About ½ Strokes in US are associated with hypertension
85% strokes occur at home
About 50% stroke victims travel to ED by ambulance

Risk Factors for CVA~Mostly Modifiable
Hypertension
Heart disease
Diabetes
High cholesterol
Smoking
Alcohol and other drug use, esp cocaine
Use of Oral Contraceptives
History of Migraine Headache
Elevated homocysteine
Obesity and physical inactivity
Diet

Cerebrovascular Disease that Predisposes to Stroke
Cerebral Vessel Abnormalities : arteriosclerosis, aneurysms, arteritis, hypertension*, vasoconstriction
Blood Flow Abnormalities : Stenosis, thrombi, emboli
Blood Property Abnormalities : coagulation problems, viscosity

CVA Symptoms
Sudden onset of focal neurological deficits, the deficits relate directly to the area of the brain that is affected: visual, motor, sensory, speech most common
Talk about stroke scales and their usefulness: NIH full and short scale, the LAPSS—why it matters

Mini NIHSS
Facial assessment : able to smile, grimace, show teeth equal bilaterally?
Extremity assessment : can hold affected arm up at 45 degrees for 10 seconds? Can hold affected leg up at 30 degrees for 5 seconds?
Language : Speak clearly and appropriately?

Pathophysiology of Stroke
Brain requires nearly constant supply of Oxygen and Glucose to function.
Brain is about 2% of body mass, but uses about 20% of the blood pumped by your heart.
Brain has little reserve Oxygen/glucose-therefore TIME IS BRAIN.

Ischemic Stroke (about 85%): Thrombus and Embolus (pictures)
Densely ischemic central core : neuronal tissue undergoes rapid infarction
Ischemic prenumbra : larger surrounding area that is compromised re circulation, but because of collateral circulation, tissue remains viable for a variable period of time (several hours)

Hemorrhagic Stroke: about 15%
Hypertension, Aneurysm, malformed vessel, drug use are implicated
Assessment findings alone are not definitive to differentiate.
May find “worst HA ever, blood in CSF

Parts of the Brain and Deficits in CVA (oversimplified)
Frontal Lobe: judgment, foresight, voluntary movement
Parietal Lobe: Language comprehension
Temporal Lobe: Hearing
Occipital Lobe: Primary visual area
Cerebellum: Coordination
Brain Stem: Swallowing, breathing, heart rate, wakefulness

A Few More
Broca’s Area: speech
Wernicke’s Area: speech comprehension
Sensory Cortex: pain, heat, and other sensations
Motor Cortex : movement

Diagnosis in Stroke: Essential to be correct~treatment differs
Physical Assessment
Labs: may see elevated Hgb and Hct if stroke is severe, EKG
Blood sugar and electrolytes
Stroke mimics hypoglycemia, migraine, seizure
CT scan is important
Evaluation needs to be rapid.
NURSE should be patient advocate and make sure things are going on time:Because time is brain.

Guidelines for Emergency Stroke Management
On arrival: EKG, blood sugar, Vital signs
Physician evaluation: 10 minutes
Stroke team notification: 15 minutes
CT scan : 25 minutes
CT interpreted: 45 minutes
Drug administration: 60 minutes
Monitored bed: 3 hours

Most Common Nursing Diagnoses (not all)
Self care deficits – all
Immobility
Situational Low Self Esteem
Injury, risk for
Aspiration, risk for & Impaired swallow
Body temp, risk for imbalanced
Communication, impaired
Unilateral Neglect

Thrombotic or Embolic Stroke
tPA Activase to dissolve clot. 3 hour time window and not for hemorrhagic stroke. 0.9 mg/kg up to 90 mg. First 10% as bolus, rest given over 60 minutes.
No ASA or heparin right now (discuss controversy)
Manage BP Goal: 140/80 to 150/90
If hypertensive labetrol used (20-40 mg over 2 min), or sodium nitroprusside

Other Medications: ASA, heparin, anticonvulsants
ASA, persantine:
Some studies find that ASA given early prevents early recurrence of th/emb.
Should be given if no clear diagnosis is possible (even at home before coming in)
Anticonvulsants to prevent seizure (which would compound injury
Heparin and low molecular weight heparin
Some controversy in research findings: the little decrease in thrombus or embolus may be canceled out by the increased risk of intracranial bleeding.
Review the use of these drugs, including appropriate lab values to monitor

Nursing Care Issues in Acute Treatment
Keep temperature normal (discuss why)
Prevent aspiration and choking while not starving the patient
Prevent and assess for thromboembolism
Prevent seizures, seizure precautions
Assess for depression (common)
Keep patient calm-avoid abrupt increases in ICP
Aim for good CPP and ICP as close to normal as possible (discuss)
Neuro assessment, report changes

Hemorrhagic Stroke Care
Once this type of stroke is diagnosed, there are a few key differences in medical care.
First, tPA, ASA, heparin, etc. are contraindicated (a main issue). Later, since 50% of hemorrhagic stroke victims go on to have a thrombotic or embolic stroke, they may be used with caution.
Second, depending on the case, surgery may be indicated
Third: a medication such as Amicar (an antifibrinolytic) may be used to facilitate a good clot at site of ruptured aneurysm

Nursing Care
Consider many of the same issues as for thrombotic or embolic stroke—temperature, aspiration, blood pressure, preventing DVT (but without heparin!), maintaining blood glucose.
Add aneurysm precautions
Research suggests that organized stroke teams/units do a better job with some of these nursing care issues, and have better patient outcomes.

Aneurysm precautions
HOB up
Bedrest
Quiet
Dark
No caffeine
Limit visitors
Limit TV
No very hot or cold liquids
No Valsalva maneuver
Patient may be sedated with medication
Rationale:

Prevention Issues
Primary Prevention: work with public to facilitate limiting the modifiable risk factors prior to any illness developing
Secondary Prevention: (early detection) Teach public that time is brain and symptoms of stroke to seek treatment for right away. Talk about ASA.

Tertiary Prevention
ASA up to 300 mg/day, or persantine. (discuss research)
Coumadin therapy esp if person has A fib. (not good if hemorrhagic stroke)
Antihypertensive therapy
Improve diet and exercise
Carotid endarterectomy especially useful if over 70% blockage
ACE inhibition
Pravastatin or Simvastatin to decrease hypercholesterol states
Stop smoking

Delirium: Basic Characteristics
Disturbance of consciousness or cognition
Usually reversible, with acute onset
Usually secondary to some other condition or problem, such as intoxication, withdrawl, medical condition, severe stressors

Delirium: Assessment concerns
Review MMS exam. In text.
Scrutinize for underlying causes
Orientation to time (1 st to go)
Orientation to place
Orientation to person (last to go)
Distractability
Ability to converse
Level of Consciousness (alert, drowsy, stuporous, etc)
Illusions, hallucinations (type, specific, timing)
Awareness of own deficits

Nursing Intervention: Delirium
Do what is appropriate to eliminate cause, includes careful assessment
Safety: falls, wandering, Ivs/ NGs pulled out easily, may strike out in fear
Meet physiologic needs: nutrition, hydration, sleep, appropriate level of stimulation, pain relief
Judicious use of antipsychotic,antianxiety meds

Communication with Confused Person
Short questions, instructions, with no “big” words. Be patient.
Check for comprehension, give instructions more than once, not in condescending manner
Face to face, normal tone, good light
No “honey” “dearie” etc

Reality Orientation with Confused Person
Clocks, calendars, cues placed prominently. Talk about it.
Names on doors, big.
Familiar routine, structure, staff
Verbal reorientation to PPT as a natural part of conversation
Read text for more interventions!!

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Cardio Vascular Accident CVA

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