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• Intracranial pressure (ICP) and cerebral vascular disorders are the topics covered

Intracranial Pressure (ICP)

• ICP measures the pressure of brain tissue and cerebrospinal fluid (CSF)
• ICP measures pressure inside the skull
• Factors influencing ICP include:
• Arterial pressure
• Venous pressure
• Intraabdominal and intrathoracic pressure
• Posture
• Temperature
• Blood gasses (CO₂ levels)
• Transient activities such as coughing, sneezing, straining, or bending forward are not harmful to ICP
• Sustained ICP can cause tissue ischemia
• Conditions causing sustained ICP include cerebral edema, head trauma, tumors, stroke, inflammation, hemorrhage, CSF issues, birth trauma, and hydrocephalus
• The intracranial space is comprised of three compartments including:
• Brain substance (80%)
• Cerebrospinal fluid (10%)
• Blood (10%)
• Changes in any of the three compartments listed above can lead to altered ICP
• Under normal conditions, normal ICP is 0 to 15 mmHg mean pressure
• ICP is considered elevated if it is >22 mmHg
• Normal compensatory mechanisms include changes in CSF volume, increased absorption, changes in intracranial blood volume, and changes in tissue brain volume
• The ability to compensate will eventually fail
• If volume increases, ICP will rise and cause decompensation
• Herniation may occur

Autoregulation

• The brain has a complex capacity to maintain a sufficient cerebral blood flow (CBF) despite wide ranges in mean arterial pressure (MAP)
• Autoregulation is present when the brain is able to maintain cerebral blood flow
• A MAP of 50 to 150 mmHg will not alter CBF if autoregulation is present

Cerebral Perfusion Pressure (CPP)

• CPP determines the blood flow to the brain

• Blood pressure and intracranial pressure both affect CPP

• CPP is the difference between MAP and ICP

• Normal CPP is 60 to 100 mmHg

• Blood flow to the brain may be limited if blood pressure is low or ICP is high

• Cerebral hypoperfusion occurs when CPP drops to 40 to 60 mmHg

• Irreversible ischemia and infarction result when CPP is less than 40 mmHg

• CPP of 0 to 40 mmHg signifies brain death

• Factors that affect CBF include:

• Acidosis

• Alkalosis

• Changes in metabolic rate

• Hypoxia

• Ischemia

• Hypercapnia

• Hypocapnia

• Increases in intracranial volume are typically tolerated by the brain without large increases in ICP because of the volume pressure curve

• The amount of intracranial compliance is limited

• Once that limit is reached, decompensation will occur with increased ICP

• As ICP rises, volume and pressure will change drastically

• At this point, even small increases in volume may cause major elevations in ICP

• Mechanisms that can cause ICP elevation include disorders of CSF space, disorders of intracranial blood, and disorders of brain substance

• Disorders of CSF space:

• Overproduction of CSF

• Choroid plexus papilloma

• Rare type of benign brain tumor

• Hydrocephalus ("water on the brain")

• Interstitial edema

• Intracranial hemorrhage

• Vasospasm

• Vasodilatation

• Increased intracranial blood volume

• Disorders of brain substance:

• Expanding mass lesion with local vasogenic edema causing increased ICP

• Brain tumors

• Ischemic brain injury with cytotoxic edema increasing ICP

• Increased cerebral metabolic rate increasing cerebral blood flow and ICP

Glasgow Coma Scale (GCS)

• The Glasgow Coma Scale (GCS) is used to assess a patients level of consciousness
• GCS asses eye-opening, verbal and motor responses and awards points accordingly
• The best score is 15
• A score of less than 8 indicates the patient is in a coma
• A score of 3 indicates that the patient is unresponsive

Early Signs & Symptoms of Increased ICP

• Restlessness
• Irritability
• Personality changes
• Agitation
• Lower GCS
• Ptosis
• Delayed or sluggish reactivity
• Unilateral change in pupil size
• Slow or slurred speech
• Dysarthria
• Blurred vision
• Diplopia
• Decreased visual acuity
• Decreased grasp

Late Signs & Symptoms of Increased ICP

• Difficult to arouse
• Decreased GCS
• Unilateral pupil enlargement
• Bilateral fixed, dilated pupils (blown pupil)
• Dense weakness
• Decorticate or decerebrate posturing
• Rising systolic BP
• Widening pulse pressure
• Flaccidity
• Only posturing to painful stimulus
• Worsening headache with projectile vomiting
• Only groaning/moaning to painful stimulus
• Irregular respirations
• Cheyne-Stokes respirations
• Central neurogenic hyperventilation
• Respiratory arrest
• Temperature changes
• Tachycardia
• Cushing's response
• Rise in systolic blood pressure
• Widening pulse pressure
• Bradycardia
• Irregular breathing
• Sinus bradycardia
• Heart blocks
• Agonal rhythm leading to cardiac arrest
• Absent gag reflex
• Absent corneal reflex
• Babinski reflex

Stroke Statistics (American Stroke Association)

• Approximately 795,000 people in the United States suffer a new or recurrent stroke every year
• Stroke is the 5th leading cause of death in the United States
• Stroke is the leading cause of long term disability
• Transient Ischemic Attack (TIA)
• TIAs are also known as “warning strokes” or “mini strokes"
• Occurs when blood flow to a vessel in the brain is briefly blocked or reduced
• Symptoms resolve rapidly
• A person who experiences a TIA is 9.5 times more likely to have a major stroke
• TIAs are a Medical Emergency

Common Risk Factors for Stroke

• Age > 45 years
• History of TIA, previous stroke or myocardial infarction
• Atrial fibrillation (increases risk 5-fold)
• Sleep apnea
• Obesity
• Hypertension
• Heredity
• Ethnicity (Black, Hispanic)
• Smoking
• Sedentary style
• Substance abuse or alcoholism
• Women ages 55-75 have a slightly higher risk of stroke compared to men
• 80% of all strokes are preventable by:
• Eating Healthy
• Exercise
• Annual physicals
• Taking medications as prescribed
• Controlling and reducing stress
• Stop smoking
• Limiting alcohol use
• Knowing your risk factors

Brain Circulation

• Major arteries to the brain includemiddle cerebral artery, vertebral artery, common carotid artery and the arch of the aorta
• Strokes may affect parts of the brain that control leg, body, arm, hand, face, speech, reading, sight, and hearing

Effects of a Stroke

• A right brain stroke can cause paralysis on the left side, spatial-perceptual deficits, quick, impulsive behavioral style, and memory deficits
• A left brain stroke can cause paralysis on the right side, speech-language deficits, slow and cautious behavioral style, and memory deficits
• If someone is suspected to be having a stroke, remember act FAST
• Face: Ask the person to smile. Does one side of the face droop?
• Arms: Ask the person to raise both arms. Does one arm drift downward?
• Speech: Ask the person to repeat a simple phrase. Is their speech slurred or strange?
• Time: If you observe any of these signs, call 9-1-1 immediately
• During a stroke, about 2 million brain cells die every minute
• Every second, 32,000 die

Stroke Alert

• A stroke alert is activated when:
• EMS pre-notifies of in-coming stroke patient
• A patient has sudden neurological symptoms within 24 hours of last known well

Signs of a Stroke:

• Sudden numbness or weakness of the face, arm, or leg, especially on one side of the body.
• Sudden confusion, trouble speaking, or understanding.
• Sudden vision changes blindness or trouble seeing out of one or both eyes.
• Sudden trouble walking, dizziness, loss of balance, or coordination.
• Sudden severe headache with no known cause.

The AHA and American Stroke Association (ASA)

• Developed the 60 minute, or fewer, stroke protocol with the goal of intervention within 60 minutes upon arrival to the Emergency Department
• The “golden hour” in stroke care: 10 minutes after a stroke some brain regions(red) are already irreversibly lost, if the person gets treatment it could limit the disability.

Types of Stroke

• Ischemic stroke:
• A blood vessel in the brain is blocked by plaque or a blood clot
• This is the most common type of stroke
• Hemorrhagic stroke: (SAH and ICH)
• A blood vessel inside the brain bursts
• Blood in the brain takes up space meant for brain tissue

Stroke Treatments

• Patients whom are having a stroke should be treated with a medication that can break clots (clot buster), called tissue plasminogen activator (tPA)
• It may improve the chances of them getting better
• This medication is time-sensitive, meaning the person only has 4.5 hours from the time they get to the hospital to the time symptoms started
• The goal is to achieve a Door to Needle (DTN) time within 60 minutes on 75% of Ischemic stroke patients treated with IV tPA

Contraindications for receiving t-PA

• Recent history of CVA, intracranial neoplasm, aneurysm or AV malformation
• Recent trauma or surgery/procedure less than 2 months
• Active internal bleeding
• Prolonged or traumatic CPR
• Suspected aortic dissection
• Pregnancy
• Diabetic hemorrhagic retinopathy
• Severe uncontrolled hypertension greater than 185/110 mm/Hg
• Known bleeding diathesis

Steps when administering t-PA

• Check BP every 15 min for 2 hours and treat hypertension/hypotension as ordered.
• Monitor neuro status every 30 mins x4.
• Watch for bleeding from puncture sites, in urine, stool etc.
• Know signs/symptoms of Intracerebral Hemorrhage: any acute neurological deterioration, new HA, N/V, Sudden HTN.

Medical Management

• ABC's
• Surgical decompression if infarction is large
• Thrombolytic therapy
• Carotid endarterectomy
• Carotid angioplasty

Neuro-Intervention Services

• For Ischemic Strokes:
• Embolectomy is a procedure that can remove large clots in the brain
• Treatment is only available up to 24 hours from the time symptoms start

For Hemorrhagic Strokes

• Coiling, or stenting, and clipping through Neuro Surgery are other types of treatments available
• Penumbra is the tissue surrounding the infarct that is salvageable, but at risk, it is best visualized on MRI Rapid transfer to the stroke center will allow for protection of penumbra through emergency interventions and medical management

Types of Hemorrhagic Strokes

• Subarachnoid Hemorrhage
• Intracerebral Bleed
• Characteristics of subarachnoid hemorrhage (SAH)
• SAH is a common and devastating condition
• SAH is a common and devastating condition
• Cocaine related to SAH occurs in younger patients.
• 45% 30 day mortality rate after.

Risk Factors

• Hypertension, smoking, heavy alcohol use, and female gender
• Bleeding into the subarachnoid space
• Rupture of cerebral aneurysm
• Pathophysiology of SAH Cerebral Aneurysm
• Sac like or Berry like, it frequently occurs at the base of the circle of Willis
• Acute Evaluation-Diagnosis, “The worst headache of my life” or "Explosive Headache” is Described by 80% of the patients, Nausea/Vomiting, Stiff Neck, LOC, Focal Deficits Occur

Pathophysiology of SAH Arteriovenous Malformation

• AVM is fed by one or more Cerebral Arteries known as Feeders Enlargement over time which in turn increases the size of the AVM.
• Pressures in the venous portion increase, leading to vessel rupture.
• Cerebral Atrophy is common as the result of shunting of normal blood flow through the AVM and away from cerebral Circulat

Assessment and Diagnosis:

• Severe headache
• LOC
• Vomiting
• Focal neurological deficit
• Nuchal rigidity
• Stiff neck One or more previous incidents of headache accompanied by nausea and vomiting warning leaks.

Subarachnoid Hemorrhage:

• Medical emergency

• Preservation of neurological function is the goal

• ABCs

• Ventriculostomy to control ICP if the patient’s LOC is depressed

• Surgical Aneurysm clipping

• Cerebral Aneurysm coiling

• Surgical AVM excision

• Cerebral Aneurysm Coiling

• Gamma Knife embolization

• Oral Nimodipine

• Rebleeding incidence is 20 to 30% in the first month

• Mortality is 50 to 80%

• BP control essential to preen Reb bleeding

• Maintain systolic BP150mm HG

• Fluctuation in BP may be more significant then the absolute value

• Cerebral Vasospasm, Presence of absence of vasospasm significantly affect the outcome SAH

• 50% of all clients will develop some degree of vasospasm, can lead to ischemic events

• onset its usually 3 to 5 days alter initial hemorrhage and con last 3 to 4 weeks

• Intracerebral Hemorrhage (ICH)

• Bleeding directly into cerebral tissue, usually from a small artery.

• AVM Rupture, Aneurysm, Trauma, Hypertensive Hemorrhage, Blood dyscrasias, Anticoagulation Therapy, Brain Tumors

• Continued Elevated Bipeds to increased pressure on cerebral arteries causing rupture

• Sudden onset of severe headaches

• ICP rises quickly

• Unconsciousness common

• Cushing’s response

• Deep labord respirations

Nursing Care of Stroke Patients:

• Support Ariway breathing Circulation,provide Supplemental oxygen to maintain oxygen saturation -94% in Hypoxic patient,ventilator support for respiratory depression fatigued consciousness or a Compromised airway.
• Monitor Vital every 15 minutes neurologist assessment should be performed early or as needed monitored for signs of brain stem herniation intreacrainal pressure deceased strength increase in extremeties focal or global seizure activity or asymetrical pupile.
• Monitor for Seizure activity implementations procedure.
• Treat Hyper term with antipyretic medications e Treat hyperterm to keep blood glucose level between 140-180 mg/dL and treat hypouglycemia (blood glucose 40°C =94% In hypoxic Pt Ventilator support for respiratory depression, fatigue Decreased CON/ Compromize airway.
• Monitor VS Q 15min neurological assessment should be performed hour or AS needed Monitor sign /symptoms of brain step herniation Increrased inter cranial pressure.decreased strength in extremeitie focal or global Seize activity on assymmetricalpupile Monitor for Seisure activities procedure, treat hyperthermia with antipyretic medications, treat term to keep blood glucose level with is 140-180 MG 7 DL and treat hypoglcemia blled Glucose 60/ DL keep bed a minimum. screen for Dysphagia, monitors VS.