Tcu Abt - 1/19/10

Front 1

Monro-Kellie doctrine (DEFINE)

Back 1

if the volume of any one of the three components increases within the cranial vault and the volume from another component is displaced, the total intracranial volume will not change

Front 2

Normal intracranial ICP ranges

Back 2

0-15 mm Hg

Front 3

Autoregulation (DEFINE/PROVIDE RANGE)

Back 3

automatic adjustment in diameter of cerebral blood vessels by the brain to maintain a constant blood flow during changes in arterial blood pressure; functions between mean arterial pressure values of 50-150 mmHg

Front 4

CPP formula & Normal values

Back 4

CPP = Flow x Resistance – Normal values lie between 70-100 mHg

Front 5

Compliance (DEFINE & FORMULA)

Back 5

expandability of the brain = Volume/Pressure

Front 6

Cushing’s triad

Back 6

systolic hypertension with widening pulse pressure, bradycardia with bounding pulse, altered respirations, altered temperature

Front 7

PaCO2 is a potent vasoactive agent acting by...

Back 7

...relaxing smooth muscle, dilating cerebral vessels, decreasing cerebrovascular resistance, increasing CBF

Front 8

Vasogenic cerebral edema (DEFINE)

Back 8

MOST COMMON, occurs in the white matter d/t changes in endothelial lining of cerebral capillaries allowing leakage of macromolecules from capillaries into surrounding extracellular space -->osmotic gradient that favors flow of fluids from intravascular to extravascular

Front 9

Cytotoxic cerebral edema (DEFINE)

Back 9

local disruption of functional or morphologic integrity of cell membranes most often in the gray matter d/t destructive lesions or trauma to brain tissue --> cerebral hypoxia or anoxia

Front 10

Interestitial cerebral edema (DEFINE)

Back 10

result of pervientricular diffusion of ventricular CSF in patient with uncontrolled hydrocephalus d/t systemic water excess (water intoxication, hyponatremia) --> fluid moves into cells to equilibrate with hypoosmotic interstitial fluid

Front 11

Reticular activating system (RAS) DEFINE

Back 11

located in the brainstem, it may maintain a state of wakefulness even in the absence of a functioning cerebral cortex, once interrupted --> unconsciousness

Front 12

Compression of cranial nerve III Manifestations

Back 12

dilation of the pupil on the same side as the mass lesion (ipsilateral), sluggishness to light, inability to move the eye upward and ptosis of the eyelid are also common (indicates herniation of the brain)

Front 13

Hemiparesis/Hemiplagia Manifestations

Back 13

occurs contralateral (opposite side) to the mass lesion

Front 14

Tentorial herniation (DEFINE)

Back 14

a mass lesion in the cerebrum forces the brain to herniated downward through the opening created by the brainstem

Front 15

Uncal herniation (DEFINE)

Back 15

occurs when there is lateral and downward herniation

Front 16

Cingulate herniation

Back 16

occurs when there is lateral displacement of brain tissue beneath the falx cerebri

Front 17

Diagnostic tests to assess ICP

Back 17

gold standards include CT and MRI to differentiate the conditions causing ICP, lumbar puncture is NOT performed for fear of cerebral herniation from sudden release

Front 18

Monitoring ICP

Back 18

gold standard is ventriculostomy in which catheter is inserted into right lateral ventricle and coupled to external transducer; alternative is fiberoptic catheter using a sensor transducer within the catheter tip to provide a direct measurement of brain pressure (USE ANTIBIOTICS)

Front 19

CSF drainage

Back 19

foramen of Monroe is selected 15 cm above the ear canal and the system is raised to diminish drainage or lowered to increase volume – watch for ventricular collapse, infection or herniation

Front 20

Mannitol (classification and action)

Back 20

osmotic diuretic given IV which acts through plasma expansion and osmotic effect – monitor electrolyte levels

Front 21

Corticosteroids and their use in treating ICP

Back 21

Dexamethasone, may control vasogenic edema surrounding tumors and abscesses – watch for hyperglycemia, increased infections, GI bleeding and hyponatremia

Front 22

Barbiturates and their use in treating ICP

Back 22

reduce the metabolic rate to decrease CBF and therefore the ICP (pentobarbital, thiopental) and to reduce cerebral edema and production of more uniform blood supply to the brain

Front 23

Controversial/Unproven treatments for decreasing ICP

Back 23

hyperventilation to lower PaCO2 and lead to constriction of cerebral blood vessles to decrease ICP, early feeding to meet higher glucose needs and to fuel the metabolism of the injured brain, dehydration to reduce cerebral edema

Front 24

Glascow Coma Scale (DEFINE)

Back 24

assesses degree of impaired consciousness by assessing inability of patient to speak, obey commands or open eyes when verbal/painful stimulus is applied

Front 25

ICP Nursing goal: Maintain patient airway - Nursing measures to take

Back 25

lay patient on one side with frequent changes, removed secretions by suctioning as needed (O2 provided before AND after), elevate HOB to 30 degrees, insert NG tube to aspirate stomach contents and prevent distention, provided sedatives/paralytics to reduce pain/anxiety/fear

Front 26

Diabetes insipidus (DEFINE)

Back 26

increased urinary output related to a decrease in ADH secretion, may result in severe dehydration with treatment being fluid replacement, vasopressin or decompression acetate

Front 27

SIADH (DEFINE)

Back 27

syndrome of inappropriate antidiuretic hormone secretion  decreased urinary output