Exam 3 - Neuro Flashcards by Ashley Burkhalter

3 essential components of the skull

brain tissue
blood
CSF

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factors that influence ICP

arterial pressure
venous pressure
intaabdominal, intrathoracic pressure
posture
temperature
blood gas (CO2 level)

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normal ICP is __ to __ mmHg

5-15 mmHg

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when is ICP considered elevated

sustained >20 mmHg

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cerebral blood flow is what

amount of blood in mL passing through 100 G of brain tissue in 1 minute

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what is the average cerebral brain flow

50 mL/100 G of brain tissue

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what occurs during auto-regulation of cerebral blood flow

adjusts diameter of blood vessels
ensures consistant CBF
only effective if MAP is 70-150 mmHg

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how to calculate cerebral perfusion pressure (CPP)

MAP - ICP = CPP

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what is considered a normal CPP

60-100 mmHg

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CPP < __ mmH is associated with ischemia and neuronal death

< 50 mmHg

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there are __ stages of increased ICP

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stage 1: increase ICP

total compensation

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stage 2: increased ICP

decrease compensation
RISK for increase ICP

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stage 3: increased ICP

failing compensation
clinical s/sx of increase ICP (Cushing’s Triad)

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stage 4: increased ICP

herniation imminent = death

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increase ICP can occur when there’s an increase of any of these 3 components

brain tissue
blood
CSF

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what is cerebral edema

increase extravascular fluid in the brain

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what are the 3 types of cerebral edema

vasogenic
cytotoxic
interstitial

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what is the most common type of cerebral edema

vasogenic

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where does vasogenic cerebral edema occur

mainly in white matter

what occurs during vasogenic cerebral edema

fluid leaks from intravascular to extravascular space

what is the cause of cytotoxic cerebral edema

secondary to destructive lesions or trauma to brain tissue

what occurs during cytotoxic cerebral edema

fluid shifts from extracellular to intracellular

what is the cause of interstitial cerebral edema

usually a result of hydrocephalus

how is interstitial cerebral edema treated

ventriculostomy or shunt

what is Cushing's Triad

increase SBP decrease HR decrease RR **remember CT s/sx are opposite of shock

s/sx of cerebral edema

change in LOC (flat affect, coma) Cushing's Triad diplopia, ptosis change in body temp inability to move eye upward unilateral pupil dilation vomiting (not preceded by nausea) HA (often worse in the AM) decrease motor function

decorticate vs. decerebrate vs. opisthotonic posturing

decort: flexion towards the core decere: hyperpronation away from the body opist: hyperflexion of the back

what are com complications of cerebral edema

inadequate cerebral perfusion cerebral herniation

how to dx cerebral edema

CT** MRI PET EEG angiography ICP, brain tissue oxygenation (LICOX catheter) doppler ABG CBC, Coag, CMP serum osmolality

what is NOT performed to dx cerebral edema

lumbar puncture

what must be assessed on a pt who needs sent for radiographic testing with suspected cerebral edema

airway

what is a normal serum osmolality

280-300

what will serum osmolality be with increased ICP

maintained >325

GSC measures which 3 areas

eye opening response verbal response motor response

what are some causes of inaccurate ICP readings

CSF leak obstruction/kink in cath bubbles, air in tubing* incorrect height of drainage system difference in height of bolt/transducer

what 2 things does LICOX catheter measure

brain oxygenation temperature

nursing interventions for increased ICP

keep CPP > 70 mmHg neurological exams HOB no more than 30 degrees neutral head positioning VS (HTN is common; CT is a LATE sign) GSC seizure precautions space activities assess pt response to family members

what are some things to avoid with increase ICP

coughing blowing nose straining for BM pushing against bedrail/footboard isometric muscle exercises

serum osmolarity is kept between __ to __

310-325 to draw extracellular fluid into the vascular system

what kind of IVF is preferred for increased ICP

1/2 NS NS

what kind of IVF should NOT be administered with increased ICP

NO hypertonic (3%) NO hypotonic (D5W)

decadron and solumedrol are only effective for ___ and ___; it is NOT effective if r/t ___

effective: meningitis, tumors not: trauma

HTN drug of choice with increased ICP

nicardipine

what must you turn off prior to assessing pupillary response

the room light

what occurs during oculocephalic reflex (dolls eye reflex)

eyes move when the head moves

what occurs during oculovestbular (caloric stimulation) test

cold water injected into ear, eyes should gaze towards that ear normal: both eyes asymmetrical: one eye negative: no eye movement

must know the cranial nerves