Terms in this set (50)
Cerebral Perfusion Pressure
"blood pressure in the brain"
MAP - ICP
Mean Arterial Pressure
1/3 of pulse pressure (difference between systolic and diastolic BP)
pressure inside the cranial vault
increase ICP =
and increased systolic blood pressure
ICP is dependent on three volumes...
& BLOOD IN CEREBRAL VESSELS
what causes increased ICP
increased brain volume
increased blood volume
increased CSF volume
what increases brain volume?
-Cerebral ischemia /infarction (Thrombotic Stroke)
-Brain bleeding (Hemorrhagic Stroke)
-Encephalitis (Swelling of the brain)
what increases blood volume?
-Cerebral Blood Volume (CBV) = The amount of blood in the vessels of the brain at a given time
-Increase in CBV caused by VASODILATION of cerebral vessels, caused by:
what increases CSF volume?
-Infection in Meninges
-Blood in Subarachnoid space (prevents re-absorption of CSF)
how do we recognize increased ICP early?
look for headache and altered LOC
Neurovascular assessment includes...
1. Glasgow Coma Scale (GCS)
2. Pupil Reaction
3. Motor Response Strength
Change in LOC is usually the
1st sign of a neruovascular problem
possible causes of altered LOC use...
A: Alcohol/Acid Base Disorders/Arrythmias
E: Epilepsy/Electrolyte Disorders
T: Trauma/Tumour/Thermal Insult (Hypothermia)
The 2 main types of stroke (CVA) are..
Hemorrhagic (10%): intracerebral (bleeding in the brain) & subarachnoid (bleeding in subarachnoid space)
-weakened blood vessel futures and blood leaks into brain tissue
Ischemic Stroke (90%): Thrombotic & Embolic
- blood clots stop the flow of blood to an area of the brain
transient ischemia attack
artery is temporarily blocked and resolves within 24hrs
Causes/Risk Factors for Ischemic Stroke
-Trauma to neck/head (resulting in a dissection of the artery)
-Atrial Fibrillation/Venous thromboembolism (VTE)
diagnosis of a stroke
S&S of a stroke
-time to call 911
Treatment specific for Ischemic Stroke
-Give a thrombolytic medication ("clot buster") to open up the artery
-Give medications to prevent further damage or reoccurrence (anticoagulants)
primary cause of subarachnoid hemorrhage is
ruptured berry embolism
Subarachnoid Hemorrhage (SAH) S & S...
Worst Headache EVER! (Thunder clap)
Nuchal Rigidity (neck stiffness)
Nausea & Vomiting
Treatment specific to Hemorrhagic stroke
Cerebral aneurysm clipping
Complications of Stroke?
-Increased Intracranial Pressure (ICP)
3 types of head injury...
-Skull Fractures (linear or depressed, simple or complicated)
-Mild Head Injury & Moderate Head Injury
-Severe Head Injury
Leakage of CSF through Nose
Leakage of CSF through Ears
Basilar Skull Fracture
# of bones that form base of skull causes otorrhea (leakage of CSF from ears) and rhinorrhea (leakage of CSF from nose) because of proximity of skull bones to ear and nose)
S & S of a concussion
Memory loss (retrograde amnesia - unable to remember events surrounding injury)
Mood and affect changes
My have transient LOC (loss of Consciousness)
Treatment includes reassurance, symptom relief and watching for worsening symptoms...
a contusion is...
Severe head injury!
-Large period of unconsciousness may be associated with hemiparesis, aphasia, cranial nerve palsy
-May have small hemmorhage, some brain swelling that is often seen on CT
Complications of Severe Head Injury =
BLEEDING in the BRAIN!
Epidural Bleeding : Between the Dura Mater & the Skull
(ABOVE = ARTERIES)
Subdural Bleeding: Between the Dura Mater and the Arachnoid (BELOW = VEINS)
epidural hematoma is
Usually (85%) caused by a head injury when skull is fractured and usually is an arterial bleed.
Often presents with a period of LOC followed by a period of consciousness, followed by LOC
subdural hematoma is...
between the dura mater and arachnoid mater, usually a result of a tear in veins.
-Most often occurs in elderly and alcoholics (at risk for falls/head injuries but don't remember event and therefore don't seek immediate medical attention)
-So bleeding is slower and may last for several days or weeks before being detected/showing overt S&S
-Acute Subdural: < 24 hours
-Subacute: 2-10 days
-Chronic: several weeks
Severe Head Injuries: treatment
Medications to decrease brain swelling
Pia Mater. Arachnoid Mater & Dura Mater (PAD)
CSF circulates in the
CSF is a
clear odourless solution which fills the ventricles of the brain, subarachnoid space and spinal cord
causes of meningitis..
Meningococcal or Pneumococcal are most common
Bacteria in nose/throat gets passed body's defense and invades cerebral spinal fluid
Highly contagious and DEADLY but not easily transferable
Virus in nose/throat gets passed body's defense and invades cerebral spinal fluid
Intestinal virus (wash your hands!!)
Contagious through direct contact like most viruses
S & S of meningitis
Fever & chills
Photophobia (TURN OFF THE LIGHTS!!!)
Stiff neck (nuchal rigidity)
Nausea & Vomiting
Irritability & drowsiness
meningitis treatment + complications...
Fluid, rest, analgesia
increased ICP = herniation
increased ICP occurs
normally throughout the day from sneezing, coughing, bending over, etc. but becomes a problem when it is sustained...
An increase in one volume can be compensated by a decrease in one or both other volumes...
brain herniation 4 types
Cingulate brain herniation
displacement of cingulated gyrus and hemisphere beneath the sharp edges of the falx cerebri to the opposite side of the brain
Central brain herniation
AKA Transtentorial = downward displacement of cerebral hemispheres, midbrain, etc thru tentorial incisura
Uncal brain herniation
occurs when a lateral mass pushes the brain tissue centrally and forces the medial aspect of the temporal lobe under edge of tentorial incisura into posterior fossa
brain stem is made of the
medulla is the
Coordinating centres for
Infratentorial brain herniation
-Brain Stem is compressed (Brain Stem is area of the brain that houses the Respiratory & Cardiovascular Centres)
-progresses rapidly can cause death, may occur upward or downward thru foramen magnum (large opening at most inferior/midline aspect of the posterior fossa where the brain stem passes in its descent to the spinal cord in the spinal canal)
hypertension with widening pulse pressure
Treatment for Increased ICP
Ensure adequate cerebral tissue perfusion & oxygenation:
-Maintain good oxygenation
-Maintain adequate BP
Reduce cellular metabolic demands:
-Avoid hyperglycemia or hypoglycemia
-Control temperature: Avoid shivering
-Mannitol (Osmotic diuretic)
-IV steroids (Decrease swelling of brain)
-Keep head of the bed at 30 degrees (promote venous drainage)
-Consider Hyperventilation (to decrease CO2)
Avoid increasing intracranial pressure:
-No coughing, straining, avoid hip flexion
-Space out nursing care
-Low stimuli (dim lights, quiet, calm, control pain)
-Don't bug them too much - anything you do will increase ICP!!!