L3_Cerebral Vascular Problems (2)_Cerebral Aneurysm AV Malformations_Moodle Flashcards
what is three components of Monro-Kellie hypothesis
caerebrospinal fluid 10%
intravascualr blood 12%
brain tissue 78%
what is suggested by Monro-Kellie hypothesis
3 components must remain at a relatively constant volume within the closed skull.
what if If the volume of any one of the 3 components increases within the cranial vault under Monro-Kellie hypothesis?
vault & the volume from another
component is displaced, the total volume will not changed.
how can CSF volume be changed?
can be changed by altering CSF absorption or production, displacing
CSF into spinal subarachnoid space.
how can intracranial blood volume be chnaged?
Changes in intracranial blood volume can occur through the collapse of cerebral veins & dural sinuses, regional cerebral vasoconstriction of dilation, changes in venous outflow.
how can brain tissue volume be changed?
Brain tissue volume compensates through distention of the dura or
compression of brain tissue
what is the range of MAP under normal function of autoregulation of cerebral blood flow?
MAP 70-150 mmHg
what if MAP< 70 mmHg
CBF decreases and symptoms of cerebral ischemia, such as syncope and blurred vision occurs.
what if MAP>150 mmHg
If MAP >150mmgHg, when this pressure exceeded, the vessels are maximally
constricted, & further vasoconstrictor response is lost.
what is the normal range of ICP
5-15 mmHg
what is the normal range of CPP
60-100 mmHg
what is the relationship between CPP, MAP and ICP
CPP= MAP-ICP
what is the relationship between MAP, DBP and SBP?
MAP= DBP+ 1/3 (SBP-DBP)
what are associated with CPP< 50 mmHg (2)
CPP < 50 mmHg is associated with ischemia and neuronal death.
what are associated with CPP< 30 mmHg?
ischemia and is incompatible with life
complications of increased ICP (3)
- brain herniation (occurs late in the course of ↑ICP) and
- Compression of the brainstem lead to respiratory arrest
- brain death (occurs when cerebral blood
flow stops)
LOC under increased ICP
decreased, progresses to coma and no response to painful stimuli
motor function under increased motor function
Weakness in one
extremity or side
progressing to
hemiplegia opposite the brain injury side
–> Decorticate or
decerebrate posturing
3 components of Cushing’s traid
increased systolic BP
widening pulse pressure
bradycardia
why have bradycardia and increased SBP under increased ICP
if patient have increased ICP because of hematoma, we want CPP to be constant. Therefore, MAP increases. therefore we have hypertension. we also have parasympathetic nervous system. it notices high BP and reduces HR, leading to bradycardia
other symptoms under increased ICP
headache worse on rising in the morning and with position changes, projectile vomiting
unilateral fixed dilated pupil
pressure on ipsilateral cranial nerve III (oculomotor nerve)
bilateral fixed and dilated pupils
severe brain anoxia and ischemia, bilateral CNIII compression
pinpoint pupils
brain stem hemorrhage
pinpoint, nonreactive pupils
pons damage
bilateral fixed dilated pupils
brain herniation
small, equal, reactive pupils
bilateral diencephalic damage affecting sympathetic innervation originating from hypothalamus
nonreactive, midpositioned pupils
midbrain damage
instillation of mydriatics (atropine, scopolamine) and orbital injuries may cause
unilateral fixed and dilated pupil
medication such as dopamine, amphetamine and atropine may cause
bilateral fixed and dilated pupils
miotic agents and opiates overdose may lead to
pinpoint, nonreactive pupils
metabolic dysfunction may lead to
small, equal, reactive pupils
describe cheyne-stokes respirations
Regular cycles of respirations that gradually increase in depth to hyperpnea and then decrease in depth to periods of apnea
what does cheyne-stokes respirations indicate
Usually bilateral lesions deep within cerebral hemispheres,
diencephalon, and basal ganglia
describe central neurogenic hyperventilation
deep, rapid respiration
where is affected if central neurogenic hyperventilation
midbrain, upper pons
describe apneustic respirations
Prolonged inspirations followed by a 2 to 3 second pause;
occasionally may alternate with an expiratory pause
where is affected if apneustic respirations
lower pons
describe cluster respirations
Clusters of irregular breaths followed by an apneic period lasting a variable amount of time
where is affected if cluster respirations
lower pons and upper medulla
describe ataxic respirations
Irregular, unpredictable pattern of shallow and deep respirations
and pauses
where is affected if ataxic respirations
medulla
what is intracerebral hemorrhage
rupture of a vessel, usually in the basal ganglia
what is the range of rate of 30 day mortality for intracerebral hemorrhage?
40-80%
what is the portion of patients with intracerebral hemorrhage die within 48 hrs
half
what is the most common cause of intracerebral hemorrhage
hypertension
other cause of intracerebal hemorrhage (6)
- vascular malformations
- coagulation
disorders - anticoagulant and thrombolytic drugs
- trauma
- brain tumors
- ruptured aneurysms.
what is subarachnoid hemorrhage
bleeding into the subarachnoid space
cause of subarachnoid hemorrhage
caused by rupture of a cerebral aneurysm or arteriovenous malformation
range of mortality rate of subarachnoid hemorrhage
25-50%, most patient die on first day
posttest of femoral artery site care after cerebral angiogram (5)
- After the diagnostic catheters are removed from the femoral artery, pressure is applied to the femoral vessels until bleeding has stopped.
- The patient remains flat for up to 6 hours to allow the femoral arterial puncture site to form a stable clot.
- Check the groin area for bleeding or hematoma.
- Monitor dorsal pedal and posterior tibial pulses hourly of affected limb.
- Check the color, temperature, pain or paresthesia to detect early evidence of acute arterial occlusion.
what is endovascular coiling
- a percutaneous transfemoral approach
- the catheter is threaded up to the internal carotid artery.
- Specially microcatheters are then manipulated into the area of the vascular anomaly, and embolic
materials are placed endovascularly.
what is surgical clipping
- Craniotomy to expose and isolate the area of aneurysm or AVM.
- A clip is placed over the neck of the aneurysm to eliminate the area of weakness.
how to monitor respiratory status (5)
- High priority to maintain patent airway for patient with stroke !
- Monitor RR
- SpO2, keep > 90 -92% (to prevent hypoxia and worsening the brain injury)
- Administer oxygen as ordered (no routine oxygen administration)
- Seizure precaution by Positioning to side lying/recovery position
- +/ -assist in intubation if severe pre pre-existing or acute pulmonary disease/acute aspiration/LOC with risk of aspiration
how to monitor neurological status (5)
- Ensure prompt assessment of patient at least q1-2h for first 24 hr
- Monitoring neurological signs (e.g. GCS/NIHSS)
- detect any early S/S of new neurological deficits caused by cerebral edema or ↑ICP,
decrease in limb powers, unequal pupil sizes- Observes for signs of increased ICP e.g. decreased LOC, headache ( more common with SAH), nausea, vomiting (more common with ICH), slurred speech, and Cushing’s triad.
- Elevate the head of the bed
- Prepare for neurosurgery to evacuate intracerebral bleed or to repair vascular defect, as indicated.
how to monitor BP
- antihypertensive medications should be restarted at approximately 24 hours after stroke onset in patients with preexisting hypertension who are neurologically stable
- intravenous labetalol and nicardipine as first first-line antihypertensive agents if pharmacologic therapy is necessary in the acute phase
why we cannot drop BP rapidly
gradual BP reduction (5-15%) with 24 hrs. rapid BP lowering may lead to cerebral infarction (caused by sudden inadequate blood supply to brain due to sudden change in BP
ischemic stroke BP management
allow Bp < SBP 220 mmHg and DBP < 120 mmHg UNLESS patient was treated with thrombolytic therapy
hemorrhagic stroke
Bp < SBP 180 mmHg and DBP < 105 mmHg
how to reduce risk of aspiration
- Monitor level of consciousness, cough reflex.
- A swallowing assessment should be performed as soon as possible after admission within first 24 hrs and before any oral intake.
- Consult speech therapist if necessary and follow prescription if any, e.g.
- Take smaller boluses of food
- Puree diet
- Use thickener as prescribed for liquid (water, juice)
- Inform doctor if patient cannot tolerate oral feeding with choking and NG feeding may prescribed to ensure adequate nutrition
3 teaspoons or table spoons thicken up in 100ml H20?
teaspoons
how to manage impaired physical mobility
- Collaborate with physiotherapist and occupational therapist in developing exercise program.
- Encourage passive and active exercise
- Apply splints to achieve stability of proximal joints involved with fine motor skills to prevent contractures.
- Provide restful environment for patient after periods of exercise to facilitate recuperation.
how to manage impaired verbal communication
- Listen attentively to convey the importance of patient’s thoughts and promote a
positive environment for learning. - Use simple words and short sentences to avoid overwhelming patient with verbal
stmuli - Provide verbal prompts and reminders to help patient to express self (e.g. picture)
unilateral neglect management
- Monitor for abnormal responses
- Inability to see objects on affected side
- Leaving food on plate that correspond to affected side
- Lack of sensation on affected side.
- Instruct patient to scan from Lt to Rt to visualize the entire environment.
- Rearrange the personal items within view on unaffected side to compensate for
visual field deficits.
how to maintain bladder function
- Encourage fluid intake, acidification of the urine to avoid urinary tract infection (UTI)
- Bladder training Q2H –> possibility of establishing normal bladder function
- Monitor I/O
- Do not suggest insertion of an indwelling catheter in the rehabilitation period unless for
those with skin complications!
maintain bowel function
- Constipation is the most common problem!
- Developed a bowel training program
- Provide food that stimulates defecation (e.g.
high fiber diet, roughage, prune juice) - Encourage fluid intake & exercise
how to reduce risk for impaired skin integrity
- Assess patient’s skin regularly especially on bony areas and dependent parts of
the body. - The patient’s skin keep clean and dry.
- Maintain a regular turning schedule with minimize shear and fiction forces
- Apply pressure relieving devices (e.g. low air loss mattress, heel protector)
- Maintain adequate nutrition.
how to maintain motor function and prevent complications
- Frequent turning
- Maintain good body alignment: correct positioning
- provide appropriate support with pillows or cushions
what is the correct positioning
- avoid pressure on shoulders, ulnar and peroneal nerve when turning
and positioning - prevent shoulder adduction by placing a pillow in the axilla to keep
arm away from chest when turning.
eating devices
- Nonskid mates to stabilize plates
- Plate guards to prevent food from being pushed off plate
- Wide -grip utensils to accommodate a weak grasp
bathing and grooming devices
- Long handled bath sponge
- Grab bars, nonskid mats, handheld shower heads
- Shower & tub seats, or on wheels
toileting aids
- Raised toilet seat
- Grab bars next to toilet
dressing aids
- Long handled shoe horn
- Velcro closures
mobility aids
- canes
- walkers
- wheelchairs
how to deal with low self-esteem of patient
- Assess patient’s emotional state
- Assist in setting realistic goals to achieve higher self self-esteem
- Reward or praise patient’s progress toward reaching goals
- Introduce relevant social resources (e.g. MSW, support group, respite service)
- Introduce coping skill to patient and caregivers for managing stress, emotion and loss.
what are the purpose of home visit before discharge
- Home modifications to help patient more independent
- Ensure a safe home environment
what community support can we give
- geriatric day center, meals on wheels
- Respite care (relieve family from continuous 24 hours care)
