TBI/tumors

what are the 3 essential volume components in the skull?

brain tissue, blood, and cerebrospinal fluid

what happens when one or more of the components in the skull increases?

the others try to compensate, however this can only last for a little while and then causes increased intracranial pressure

what are the two phases of brain injury?

primary injury- occurs at the initial time of an injury

secondary injury- the resulting hypoxia, ischemia, hypotension, edema, or increased ICP that follows the primary injury

secondary injury can occur hours to days after the initial injury

what is normal intracranial pressure?

hydrostatic force measured in the brain CSF compartment

the monroe kelly doctrine states that the 3 compartments must stay at a relatively constant volume within the closed skull

normal ICP is 5-15 mmHg

compensatory mechanisms of increased ICP

CSF volume can be changed by altering CSF absorption or production, and by displacing CSF into the spinal subarachnoid space

changes in intracranial blood volume can occur through the collapse of cerebral veins and dural sinuses, regional cerebral vasoconstriction or dilation, and changes in the venous outflow

brain tissue volume compensates through distention of the dura or compression of the brain tissue

initially an increase in volume does not increase ICP due to these mechanisms, but there is a limited ability to compensate

what is cerebral blood flow?

the amount of blood in milliliters passing through 100g of brain tissue in 1 minute

the brain uses 20% of the body’s oxygen and 25% of its glucose

the brain regulates its own blood blow in response to its own metabolic needs despite wide fluctuations in systemic arterial pressure

MAP of 70 is the lower limit of system pressure at which autoregulation is effective

the global CBF is about 50mL/min/100g of brain tissue; maintaining blood flow to the brain is critical because the brain requires a constant supply of oxygen and glucose

what is cerebral perfusion pressure?

the pressure needed to ensure blood flow to the brain

MAP - ICP = CPP

a CPP of less than 50 is associated with ischemia and neuron death

a CPP of less than 30 results in ischemia and is not compatible with life

what are some factors that affect cerebral blood flow?

cardiac or respiratory arrest

systemic bleeding

trauma

tumors

cerebral bleeding

stroke

what is increased intracranial pressure?

a potentially life threatening situation that results from an increase in any or all the 3 components within the skull

decreases CPP and increases the risk for brain ischemia and infarction

causes could be a mass and cerebral edema

sustained increases in ICP results in brainstem compression and brain herniation

what is herniation?

occurs as the brain tissue is forcibly shifted from a compartment of greater pressure to a compartment of less pressure

can force the cerebellum and brainstem downward toward the foramen magnum; if compression is not relieved respiratory arrest will occur due to compression of the respiratory control center in the medulla

intense pressure is placed on the brain stem

brain death is imminent

what is cerebral edema?

increased accumulation of fluid in the extravascular spaces of brain tissue

results in an increase in tissue volume that can increase ICP

vasogenic- results from disruption of the blood brain barrier; h/a, decreased LOC, and neuro deficits; most common type

cytotoxic- results from the disruption of the integrity of the cell membrane, develops from destructive lesions or trauma to brain tissue which results in cerebral hypoxia and SIADH

interstitial- a result of hydrocephalus; manifested by ventricular enlargement

clinical manifestations of increased ICP

changes in LOC: most sensitive and reliable indicator of neuro status; result of impaired CBF which causes oxygen deprivation

EEG to check brain waves

changes in vital signs: cushing triad

ocular signs: a fixed, unilateral pupil is an emergency that indicates herniation

decrease in motor function: posturing

headache

vomiting: may not have nausea

what is cushing triad?

systolic HTN with a widening pulse pressure

bradycardia with a full and bounding pulse

irregular respirations

indicates that ICP has been increased for some time or it suddenly increased (trauma); it is an emergency and a sign of brainstem compression

may include a change in body temperature

what is decorticate posturing?

inward flexion of arms, elbows, hands, fingers

what is decerebrate posturing?

outward extension of arms and wrists

usually indicates a worse condition

complications and diagnostics of increased ICP

inadequate cerebral perfusion and cerebral herniation

CT and MRI, EEG, cerebral angiography, ICP measurement, PET scan

ICP monitoring

used to guide care when pt is at risk for or has ICP

should be monitored in pt admitted with GCS of 8 or less

also monitor CPP with ICP

can be done by: ventriculostomy with external transducer, fiberoptic catheter, or air pouch

infection is a serious complication

if draining CSF, the drain must be closed for at least 6 minutes to get an accurate ICP reading

ventriculostomy

the gold standard for ICP monitoring

directly measures pressure in the ventricles

can remove and sample CSF

allows for intraventricular drug administration

the external transducer must be level with the foramen of monro; must be at ideal height

reference point is the tragus of the ear

each position change requires it to be zeroed out and leveled

infection risk- keep clean

CSF fluid drainage

normal CSF production is about 20-30mL/hr

complications of rapid decompression: ventricular collapse, infection, and herniation or subdural hematoma formation

can be continuous or intermittent

cerebral oxygenation monitoring

measures oxygen in the brain

LICOX catheter, neurovent catheter, jugular venous bulb catheter

treatment for increased ICP

mannitol- osmotic diuretic given IV

hypertonic saline- pulls water out of tissues like mannitol; may use both

corticosteroids- not recommended for TBI, monitor for adverse effects

monitor glucose

H2 or PPI

reduce fever- fever increases metabolic demands and can lead to shivering

may need prophylactic seizure meds

due to hypermetabolic and hypercatabolic state pt needs adequate nutrition; may need EN or PN

what is the glasgow coma scale?

score from 3-15 to measure LOC and severity of brain injury; helps track pt progress and status

should be used in any neuro patients, including management of increased ICP

15 = fully alert

8 or less = generally indicates coma

eyes open, best verbal response, best motor response

increased ICP neuro assessment

pupillary reaction

eye movement

test all 4 extremities for strength- note any asymmetry

record vitals- BP, pulse, RR, temp

watch for cushing triad

test motor response- spontaneous (commands) or to pain

do not include hand squeezing since this is a reflex and can be misinterpreted

nursing management of increased ICP

GCS and neurological assessment

respiratory function: maintain patent airway, suction PRN but try to limit, monitor ABGs

sedation: may be needed for pain, agitation, seizures, etc; use caution because it could mask true neuro status

fluid and electrolyte balance: strict I&O, daily weights, monitor for SIADH or DI

maintain appropriate body position: keep head midline, HOB less than 30 degrees, turn pt slowly and gently every 2 hours

protect from injury: pt may be confused or agitated and need restraints, seizure precautions may be needed; keep in nonstimulating environment but touch and talk to pt even if in a coma

monitor ICP: no coughing, straining, or sneezing; do not use valsalva maneuver

traumatic brain injury

skull fractures often occur with head trauma

• linear or depressed

• simple, comminuted, or compound

• open or closed

manifestations: battle sign (behind ears), racoon eyes (black eyes), rhinorrhea or otorrhea (CSF leakage)

types of skull fractures

comminuted- multiple linear fractures with fragmentation of bone into many pieces; direct high momentum impact

compound- depressed skull fracture and scalp laceration with communicating pathway to intracranial cavity- severe head injury

depressed- inward indentation of skull; powerful blow

linear- break in continuity of bone without change of relationship of parts; low velocity injuries

simple- linear or depressed skull fracture without fragmentation or communicating lacerations; low to moderate impact

head trauma

classified as:

• minor- GCS 13-15

• moderate- GCS 9-12

• severe- GCS 3-8

diffuse or focal injury

what is a diffuse injury?

not localized to one area

concussion- sudden transient mechanical head injury with disruption of neural activity and a change in the LOC; brief disruption of LOC, amnesia, h/a

diffuse axonal injury- widespread axonal damage occurring after a mild, moderate or severe TBI; decreased LOC, increased ICP, decortication, decerebration, global cerebral edema

what is a focal injury?

localized injury to a specific area

can be minor or severe

lacerations- tearing of brain tissue

contusions- bruising of the brain tissue; coup-contrecoup injury

hematomas

CN injuries

complications of head injuries

epidural hematoma

subdural hematoma

intracerebral hematoma

what is an epidural hematoma?

bleeding between the dura and inner surface of the skull

neurologic emergency

initial period of unconsciousness at the scene, with a brief lucid interval followed by a decrease in LOC

need rapid surgical tx to evacuate the hematoma

what is a subdural hematoma?

bleeding between the dura mater and arachnoid layer of the meninges

usually venous in origin and develops slower

may be acute, subacute, or chronic

what is an intracerebral hematoma?

occurs from bleeding within the brain

more common in frontal or temporal lobes

head injury diagnostics and tx

CT, MRI, PET, cervical spine x-rays

may need surgery

prevent secondary injury

manage increased ICP

hematomas- surgical evacuation of blood

burr holes

emergency management of head injuries

unresponsive CAB; responsive ABC

assume neck injuries and stabilize

apply oxygen, establish IV access (2 large bore)

intubate if GCS is less than 8

control external bleeding with sterile pressure dressing

maintain normal temp

monitor vitals, GCS, LOC, pupils, gag reflex

assess for rhinorrhea, otorrhea, scalp wounds

give fluid carefully to prevent fluid overload and increasing ICP

nursing management of a head injury

management at the scene can have a significant impact on the outcome

monitor neuro status- assessment and GCS

eyes may need to be lubricated or taped; cold first then warm compress

fever may occur from injury or inflammation

CSF rhinorrhea or otorrhea- raise HOB to decrease pressure and no NG tube

meds for pain, n/v, h/a

may need rehab after stablized

seizures may develop

may have personality or memory changes

may have changes that inhibit returning to work

family may have unrealistic expectations and unrealistic timeline

brain tumors

can occur in any part of the brain or spinal cord

primary- arising from tissues within the brain

secondary- resulting from metastasis of cancer from elsewhere in the body

meningiomas are the most common primary brain tumor

gliomas are another common brain tumor

more than half are malignant

brain tumors rarely metastasize outside the CNS because they are contained by structural and physiologic barriers

clinical manifestations of brain tumors

depends on the location and size

headache- may worsen at night and wake pt up from sleep

seizures

n/v

increased ICP

cognitive dysfunction- memory problems, personality/mood changes

muscle weakness

sensory loss, aphasia, visual spatial dysfunction

brain tumor diagnostics

CT with contrast

MRI

PET

SPECT

EEF

cerebral angiography

brain tumor tx

surgical removal- preferred but not always possible

ventricular shunts- tx of hydrocephalus due to a tumor obstructing CSF flow

radiation and stereotactic radiosurgery- follow up measure after surgery, seeds can be implanted into the brain

chemo and targeted therapy- effectiveness of chemo is limited due to the blood brain barrier, can be implanted or delivered intrathecal

nursing management for brain tumors

families may need help understanding what is happening

frontal lobe tumors can cause behavioral and personality changes

protect from self harm

temporal lobe tumors can cause hallucinations

minimize environmental stimuli and keep daily routine

seizure precautions

language deficits

motor and sensory problems

encourage adequate nutrition

may need to help plan long term care or end of life care

cranial surgery

craniotomy- can be frontal, occipital, temporal, suboccipital, or a combination of these, drill burr holes and uses a saw to connect the holes to remove bone flap, after surgery the bone flap is secured with small plates or wired shut

stereotactic- uses precision apparatus to help HCP precisely target an area of the brain, drills burr holes or creates a bone flap

stereotactic radiosurgery- uses high dose radiation to destroy precisely target tumor cells and other abnormal growths

cranial surgery nursing management

similar to that of a pt with increased ICP

uncertainty about prognosis and outcome requires compassion

preoperative teaching can alleviate some fears

hair is usually removed in the OR

prevent increased ICP

monitor fluid and electrolyte status

provide meds for pain, n/v

HOB and turning will depend on surgical site

if bone flap was removed do not position pt on the operative side

monitor dressing and drains

prevent infection