Intracranial probs

oculocephalic reflex

doll's-eye reflex turn the patient's head briskly to the left or right while holding the eyelids open. A normal response is movement of the eyes across the midline in the direction opposite that of the turning quickly flex and then extend the neck. *Eye movement should be opposite to the direction of head movement*: up when the neck is flexed and down when it is extended. Abnormal responses can help locate the intracranial lesion. This test should not be attempted if a cervical spine problem is suspected.

Elevation of the head of the bed promotes

drainage from the head and decreases the vascular congestion that can produce cerebral edema However, raising the head of the bed above 30 degrees may decrease the CPP by lowering systemic BP

oral airway

facilitates breathing and provides an easier suctioning route in the comatose patient

two important structures

falx cerebri tentorium cerebelli

ICP monitoring

for those admitted with a Glasgow Coma Scale of 8 or less or those with abnormal CT scans or MRI, to quantify the degree of elevation, initiate appropriate treatment, to provide access to CSF for sampling and drainage, and to evaluate the effectiveness of treatment.

cerebral herniation

force the cerebellum and brainstem downward through the foramen magnum If *compression of the brainstem* is unrelieved, *respiratory arrest* will occur as the result of compression of the respiratory control center in the medulla

Arterial blood gas (ABG) analysis

guides the oxygen therapy GOAL 1) PaO2 *MORE/= 100 *mm Hg 2) PaCO2 : *35 - 45* 3)

Confusion, agitation, and the possibility of seizures

increase the risk for injury Use restraints judiciously in the agitated patient

Decerebrate

indicate more serious damage and results from disruption of motor fibers in the midbrain and brainstem the arms are stiffly extended, adducted, and hyperpronated. There is also hyperextension of the legs with plantar flexion of the feet.

2 options for CSF drainage

intermittent continuous

Decorticate posture

internal rotation and adduction of the arms with flexion of the elbows, wrists, and fingers as a result of interruption of voluntary motor tracts in the cerebral cortex. Extension of the legs may also be seen

nasogastric tube

to aspirate the stomach contents can prevent distention, vomiting, and possible aspiration in patients with facial and skull fractures, a nasogastric tube is contraindicated unless a basal skull fracture has been ruled out, and oral insertion of a gastric tube is preferred

Nondepolarizing neuromuscular blocking agents

(e.g., vecuronium, cisatracurium besylate [Nimbex]) useful for achieving complete ventilatory control in the treatment of refractory intracranial hypertension Because these agents paralyze muscles without blocking pain or noxious stimuli, they are used in combination with sedatives, analgesics, or benzodiazepines although useful for sedation, are usually *AVOIDED*in the management of the patient with increased ICP because of the hypotensive effect and long half-life,

• Cerebral herniation

- Tentorial herniation - Uncal herniation - Cingulate herniation

Change in vital signs (Cushing's triad) *MEDICAL EMERGENCY*

*Cause* 1. increased presssure on Thalamus, Hypothalamus, pons and medulla *S&S* - HIGH SBP - WIDE PULSE PRESSURE - BRADYCARDIA w/bounding pulse -IRREGULAR RESPIRATION - may be high temp (hypothalamus affected) *this is a sign of* - brainstem compression - impending death

Evaluation of other cranial nerves

*Eye movements* controlled by cranial nerves *III, IV, and VI* can be examined in the patient who is *awake* and able to *follow commands* and can be used to assess the *function of the brainstem* *corneal reflex* gives information about the functioning of cranial nerves *V and VII*. If this reflex is absent, initiate routine eye care to prevent corneal abrasion.

Nursing Assessment

- Glasgow Coma Scale - Pupil checks - Assessment of selected cranial nerves - frequent VS - Subjective data - LOC

cerebral insult

*can cause* hypercapnia, cerebral acidosis, impaired autoregulation, *systemic hypertension* ---> formation and spread of edema ---> edema distorts brain tissue----> further increases the ICP----> more tissue hypoxia and acidosis

what happens if Cushing's response is not treated immidiately

- *Herniation of brain stem* : shifting of brain tissue from an area of high pressure to low pressure -------------- herniated tissue now puts pressure the new area it moved to ----> blood supply to the new area obstructed - occlusion of blood flow

what can cause Inaccurate ICP readings

- CSF leaks around the monitoring device, - obstruction of the intraventricular catheter or bolt (from tissue or blood clot), - kinks in the tubing, - difference between the height of the bolt and the transducer, - incorrect height of the drainage system relative to the patient's reference point. - Bubbles or air in the tubing can also dampen the waveform

Prevent hypoxia and hypercapnia

- Elevation of the head of the bed to *30 degrees* enhances respiratory exchange and aids in decreasing cerebral edema. - Remove accumulated secretions by *suctioning* as needed -

Cushing response

- cause : ischemia - cerebral blood flow decreases --> ischemia ---> increased ICP ---> vasomotor center increases arterial pressure *Late sign* - sympathetic response --> (1) increase SBP (2) increased pulse pressure (3) decreased HR must be treated immediately

What happens if CNIII (oculomotor) is compressed due to IICP?

- dialation of pupil on the same side= *ipsilateral* to the injuring event - slow/no response to light - cant move eye upward - *ptosis* (drooping of eyelid) - These signs can be the result of a *shifting of the brain from the midline, compressing the trunk of CN III and paralyzing the muscles controlling pupillary size and shape* -

Maintain the patient with increased ICP

- head-up position - prevent extreme neck flexion : can cause venous obstruction --> IICP - Adjust the body position to decrease the ICP & improve the CPP - turn pt with slow gentle movement - avoid increased intra abdominal pressure. - avoid hip flexion - minimize complications of immobility - protection from self-injury - anti seizure precautions -a quiet, nonstimulating environment - Touch and talk to the patient, even one who is in a coma

*Change in level of consciousness*

- indication of decreased CBF - derives *Cerebral Cortex* and *Reticular system* of O2 - may be dramatic (COMA )or subtle (flattening of affect, change in orientation, low attention span) -

cessation cerebral blood flow

- ischemia - infarction - brain death

Fluid and electrolyte disturbances

1) Closely monitor IV fluids with the use of an accurate IV infusion control device or pump 2) Intake and output, with insensible losses and daily weights taken into account . 3) Electrolyte determinations should be made daily, and any abnormal values should be discussed with the physician 4)monitor serum glucose, sodium, potassium, magnesium, and osmolality 5) urinary output to detect problems related to diabetes insipidus and syndrome of inappropriate antidiuretic hormone (SIADH)

ways to monitor monitor ICP

1) an intraventricular catheter (ventriculostomy), 2) a subarachnoid bolt, 3) an epidural or subdural catheter, or a 4) fiberoptic transducer The purpose of these is to be able to monitor if the brain is getting the perfusion it needs

prevent increasing ICP in

1) head in neutral position 2) of HOB 0 to 60 degrees to promote venous drainage 3) avoid - hip flexion - Valsalva maneuver - abdominal distention 4) calm, quiet atmosphere 5) Monitor fluid status carefully: checking I & O every hour during acute phase 6) aseptic technique for management of ICP monitoring system

2 major complications of uncontrolled increased ICP

1) inadequate cerebral perfusion 2)cerebral herniation. others: - cerebral insult

As the LOC decreases, the patient is at an increased risk of

Airway obstruction from the tongue dropping back and occluding the airway or from accumulation of secretion

vital signs

BP, pulse, respiratory rate, and temperature. Be aware of Cushing's triad because this indicates severely increased ICP

______________________ under pressure control is an effective method of treating intracranial hypertension

Continuous drainage of CSF

*↓ in motor function*

Hemiparesis/hemiplegia *Decerebrate* posturing (extensor), Indicates more serious damage, *Decorticate* posturing (flexor).

ICP Monitoring

ICP should be measured as a mean pressure If a CSF drainage device is in place, the drain must be *closed for at least 6 minutes* to ensure an accurate reading Intracranial pressure monitoring can be used to continuously measure ICP Immediately report to the health care provider any ICP elevation

craniectomy

In aggressive situations removal of part of skull reduce ICP and prevent herniation

Leveling a Ventriculostomy

It is important to make sure that the transducer of the ventriculostomy is level to the foramen of Monro (interventricular foramen) and that the ventriculostomy system is at the ideal height. ventriculostomy has to be leveled and zeroed. When ICP is monitored with a *fluid system* the transducer is calibrated at a particular reference point, usually *2.5 cm (1 in) above the ear* with the patient in the supine position. this point corresponds to the level of the *foramen of Monro*.). CSF pressure readings depend on the patient's position.For subsequent pressure readings, the head should be in the same position relative to the transducer *Fiberoptic catheters* calibrated before insertion and do not require further referencing; they do not require the head of the bed to be at a specific position to obtain an accurate reading.

a nonspecific sign associated with persistent increases in ICP

Papilledema (an edematous optic disc seen on retinal examination)

factors that can increase ICP

Valsalva maneuver, coughing, sneezing, suctioning, hypoxemia, and arousal from sleep

Subdural bleeding

Veins just below the dura may be torn and bleed. Occurs more slowly, sometimes over period of days.

The choice, dose, and combination of drugs may vary

depending on the patient's history, neurologic state, and overall clinical presentation

Uncal herniation

a dilated unilateral pupil

what sign indicates herniation of the brain

a fixed, unilateral, dilated pupil

tentorium cerebelli

a rigid fold of dura that separates the cerebral hemispheres from the cerebellum It is called the tentorium (meaning tent) because it forms a tentlike cover over the cerebellum

falx cerebri

a thin wall of dura that folds down between the cortex

It may be necessary to maintain the patient on a mechanical ventilator to ensure

adequate oxygenation

Dexmedetomidine (Precedex)

alpha-2 adrenergic agonist continuous IV sedation of intubated and mechanically ventilated patients in the ICU setting for up to 24 hours. It is another ideal agent for neurologic patients because of the ease in obtaining a neurologic assessment without altering the dose due to its anxiolytic properties

Cerebral edema

an abnormal accumulation of water or fluid in the intracellular space, extracellular space, or both, associated with an increase in the volume of brain tissue distorts brain tissue---> further increasing the ICP ---> more tissue hypoxia and acidosis

ventriculostomy

an intraventricular catheter a fine-bore catheter is inserted into a lateral ventricle, preferably in the nondominant hemisphere of the brain The catheter is connected by a fluid-filled system to a transducer , which records the pressure in the form of an electrical impulse. *WHAT ELSE CAN IT DO?* - besides monitoring ICP , it can *drain CSF* during acute IICP - *drain blood* from the ventricles - *access for the intraventricular administration of medication* - occasional*instillation of air or a contrast agent * for ventriculography DISADVANTAGES - infection, - meningitis, - ventricular collapse, - subdural hematoma - occlusion of the catheter by brain tissue or blood, - problems with the monitoring system

The Glasgow Coma Scale

and standardized system for assessing the level of consciousness 3 indicators (1) opening of the eyes, (2) the best verbal response, and (3) the best motor response. The subscale scores are particularly important if a patient is untestable in one area. For example, severe periorbital edema may make eye opening impossible.

LICOX Catheter System

another type of catheter that actually monitors *oxygenation of brain tissue* The LICOX brain tissue oxygen system involves a catheter inserted through an intracranial bolt (A). The system measures oxygen in the brain (Pbt02), brain tissue temperature, and intracranial pressure (ICP) (B).

motor strength

asking the awake and cooperative patient to squeeze your hands to compare strength in the hands - palmar drift test -Test all four extremities for strength and evaluate for any asymmetry in strength or movement - Resistance to movement during passive range-of-motion exercises is another measure of strength

What happens if CNII (optic) trochlear (CN IV), and abducens (CN VI) are compressed due to IICP?

blurred vision, diplopia, changes in extraocular eye movements.

*headache*

brain itself is insensitive to pain, BUT compression of other intracranial structures, such as the walls of arteries and veins and the cranial nerves, can produce headache *continuous* *worse in the morning* Straining, agitation, or movement may accentuate the pain

continuous ICP drainage

careful monitoring of the volume of CSF drained is essential, keeping in mind that normal CSF production is about 20 to 30 mL/hr, with a total CSF volume of 90 to 150 mL within the ventricles and subarachnoid space It is also recommended that a sign be posted above the patient's bed to notify anyone before turning, moving, or suctioning the patient to prevent the removal of too much CSF, which can result in other complications Strict aseptic technique during dressing changes or sampling of CSF is imperative to prevent infection

Suctioning and coughing

cause transient decreases in the PaO2 and increases in the ICP

SIADH

caused by an excess secretion of ADH. SIADH results in decreased urinary output and dilutional hyponatremia. It may result in cerebral edema, changes in LOC, seizures, and coma

Increased intrathoracic pressure

contributes to increased ICP by impeding the venous return Thus coughing, straining, and the Valsalva maneuver should be avoided

coma

deepest state of unconsciousness - pt does not response to painful stimuli - absent corneal & pupillary response - cant swallow/cough -incontinent of urine and feces - EEG : suppressed/ absent neuro activity

Epidural bleeding

is arterial from the middle meningeal artery Fracture near the temples may cause artery to bleed on top of the dura, resulting in pressure on the brain. Usually very rapid after injury

ICP monitoring

is used in combination with other physiologic parameters to guide the care of the patient and assess the patient's response to treatment

prevent abdominal distention

it can interfere with respiratory function

Uncal herniation

lateral and downward herniation. (1)

Cingulate herniation

lateral displacement of brain tissue beneath the falx cerebri

suctioning

less than 10 seconds in duration administration of 100% oxygen before and after to prevent decreases in the PaO2 AVOID IICP by: 1) limit suctioning to two passes per suction procedure

Position the bed so that it

lowers the ICP while optimizing the CPP and other indices of cerebral oxygenation

IV anesthetic sedative propofol (Diprivan)

management of anxiety and agitation in the ICU popular : because of its rapid onset and short half-life. An accurate neurologic assessment can be performed very soon after turning off the infusion of propofol. A side effect of this drug is hypotension

endotracheal tube or tracheostomy

may be necessary to maintain adequate ventilation

palmar drift test

measure of strength in the upper extremities. patient raises the arms in front of the body with the palmar surface facing upward. If there is any weakness in the upper extremity, the palmar surface turns downward, and the arm drifts downward Asking the patient to raise the foot from the bed or to bend the knees up in bed is a good assessment of lower extremity strength

*Vomiting*

not preceded by nausea unexpected vomiting and is related to pressure changes in the cranium

who needs intubation and mechanical ventilation

ny patient with a GCS less than or equal to 8 or an altered LOC who is unable to maintain a patent airway or effective ventilation

Tentorial herniation (central herniation)

occurs when a mass lesion in the cerebrum forces the brain to herniate downward through the opening created by the brainstem

fiberoptic transducer

tipped catheter placed in the subdural space or in the ventricle

Eye movements of the uncooperative or unconscious patient can be elicited by

reflex with the use of head movements (oculocephalic) and caloric stimulation (oculovestibular

With the ventricular catheter, it is possible to control ICP by

removing CSF The physician will typically order a specific level to initiate drainage (e.g., if ICP is greater than 20 mm Hg) as well as the frequency of drainage (intermittent or continuously). When the ICP is above the indicated level, the ventriculostomy system is opened by turning a stopcock and allowing the drainage of CSF, thus relieving the pressure inside the cranial vault.

brainstem edema

resulting in brainstem herniation As pressure is applied to the pituitary and hypothalamus the patient will develop Diabetes insipidus/SIADH.

Sustained increase in ICP

results in brainstem compression and herniation of brain from one compartment to another

turn the patient with

slow, gentle movements because rapid changes in position may increase the ICP Prevent discomfort in turning and positioning the patient because pain or agitation also increases pressure

Central herniation

sluggish but equal pupil response

minimize complications of immobility

such as atelectasis and contractures

Opioids,

such as morphine sulfate and fentanyl (Sublimaze), rapid-onset analgesics with minimal effect on CBF or oxygen metabolism

If increased ICP is caused by a mass lesion (e.g., tumor, hematoma)

surgical removal of the mass is the best treatment

any patient with increased ICP it is important to ensure

that adequate oxygenation is being maintained to support brain function

Vasogenic cerebral edema

• Associated with changes in the endothelial lining of cerebral capillaries result of a fluid and protein shift from the extracellular space directly into the cells. • This edema may produce a continuum of symptoms ranging from o headache to disturbances in consciousness, including coma (profound state of unconsciousness) and o focal neurologic deficits.

Clinical Manifestations

• Change in level of consciousness • Change in vital signs (Cushing's triad) • Ocular signs • Headache • Vomiting • ↓ In motor function

Interventions

• Maintain CPP • Regulating temperature • Improving gas exchange • Sensory deprivation • Enhancing self-image • Monitor I&O. • Preventing infections • Patient education

Cytotoxic cerebral edema

• develops from destructive lesions or trauma to brain tissue resulting in cerebral hypoxia or anoxia, sodium depletion, and syndrome of inappropriate antidiuretic hormone (SIADH) secretion. • In this type of edema, the blood-brain barrier remains intact, with cerebral edema occurring as a result of a fluid and protein shift from the extracellular space directly into the cells,

Interstitial cerebral edema

• is the result of rupture of CSF brain barrier; • usually a result of obstructive or uncontrolled hydrocephalus. • It can also be caused by enlargement of the extracellular space as a result of systemic water excess