NURS 418 - Increased Intracranial Pressure

1. brain tissue

2. blood

3. cerebrospinal fluid (CSF)

the skull is an enclosed space with what three essential volume components?

primary injury

phase of brain injury: occurs immediately at the initial time of injury (e.g., impact of car accident, blunt-force trauma)

primary injury

phase of brain injury: results in displacement, bruising, or damage to the brain or any of its components (e.g., fibers, nerves, vessels)

secondary injury

phase of brain injury: the resulting hypoxia, ischemia, hypotension, edema, or increased ICP that follows the primary injury

secondary injury

phase of brain injury: related to the metabolic and physiologic process initiated by ischemia

intracranial pressure (ICP)

the hydrostatic force measured in the brain CSF compartment

1. arterial pressure

2. venous pressure

3. intraabdominal and intrathoracic pressure

4. posture

5. temperature

6. blood gasses, especially CO2

factors that influence ICP under normal conditions (6)

CO2

blood gasses influence ICP under normal conditions, especially _____

vasodilation occurs in the presence of fever, which causes an increase in blood flow to the brain, therefore increasing ICP

why can an increase in temperature increase ICP?

CO2 is a powerful vasodilator which causes an increase in blood flow to the brain, therefore increasing ICP

why can an increase in CO2 increase ICP?

5-15 mmHg

normal ICP

20 mmHg

an ICP sustained above _____ diminishes cerebral perfusion pressure (CPP)

ventriculostomy

a _____ is the gold standard for measuring ICP because it allows for the measurement of ICP and drainage of CSF

≤ 8

a ventriculostomy is indicated for use in patients with a GCS _____

Monro-Kellie doctrine

states that the three components of the brain must stay at a relatively constant volume within the skull. if the volume of any one of the three components increases within the skull and the volume from another component is displaced, the total intracranial pressure will not change

1. altering CSF production

2. displacing CSF into the subarachnoid space

3. vasoconstricting/vasodilating to alter blood flow

according to the Monro-Kellie doctrine, the body can adapt to volume changes within the skull by _____ (3)

cerebral perfusion pressure (CPP)

the pressure needed to ensure adequate blood flow to the brain

CPP = MAP - ICP

CPP equation

60-100 mmHg

normal CPP

< 50 mmHg

a CPP _____ is associated with ischemia and neuron death

< 30 mmHg

a CPP _____ is incompatible with life

< 70 or > 150

with a MAP _____, cerebral autoregulation fails, which is the automatic adjustment in the diameter of the cerebral blood vessels by the brain to maintain a constant blood flow with changes in arterial BP

cerebral autoregulation

the automatic adjustment in the diameter of the cerebral blood vessels by the brain to maintain a constant blood flow with changes in arterial BP

elastance

refers to the brain's stiffness or resistance to volume changes

compliance

refers to the brain's ability to accommodate increases in volume without a significant rise in ICP

stage 1

stage of brain compliance: high compliance

stage 1

stage of brain compliance: compensatory. the brain's compensatory system and CSF absorb any increase in volume, so there is little increase in ICP

stage 2

stage of brain compliance: reduced compliance

stage 2

stage of brain compliance: beginning decompensation. the compensatory system starts to fail, and CSF and veins become overloaded

stage 3

stage of brain compliance: low compliance

stage 3

stage of brain compliance: decompensation. small additions of volume causes a great increase in ICP

stage 4

stage of brain compliance: critical compliance

1. headache

2. vomiting

3. drowsiness

4. changes in LOC

5. changes in pupil responsiveness

clinical manifestations of low brain compliance (stage 3) (5)

stage 4

stage of brain compliance: failure and herniation. leads to respiratory arrest, cardiac collapse, and death

1. coma

3. fixed and dilated pupils

3. posturing

clinical manifestations of critical brain compliance (stage 4) (3)

increased ICP

cushing's triad indicates _____

1. widening pulse pressure (increasing systolic, decreasing diastolic)

2. bradycardia

3. altered respirations

components of cushing's triad

ventriculostomy

the gold standard for monitoring ICP is the _____, in which a specialized catheter is inserted into the lateral ventricle and coupled to an external transducer

ventriculostomy

the most invasive, but most accurate means of ICP monitoring

ventriculostomy

directly measures the pressure within the ventricles, facilitates removal and/or sampling of CSF, and allows for intraventricular drug administration

the tragus of the ear

the transducer of a ventriculostomy must be leveled at _____

6 minutes

a ventriculostomy drain must be turned off _____ prior to ICP measurement

1. ventricular collapse

2. infection

3. herniation

4. subdural hematoma formation

complications of a ventriculostomy (4)

1. head trauma

2. stroke

3. subarachnoid/intracerebral hemorrhage

4. brain tumor

5. inflammation

6. hydrocephalus

7. brain tissue damage

disease processes related to increased ICP (7)

1. coughing

2. suctioning/oral care

3. vomiting

4. defecating

5. PEEP

6. repositioning/turning

7. stress

8. pain

physical processes related to increased ICP (8)

an increase in PEEP decreases venous return to the heart, therefore increasing ICP due to impeded cerebral venous drainage

why does an increase in PEEP increase ICP?

1. preservation of cerebral perfusion

2. early identification of neurological changes

3. prevention of complications

4. maintain normal CPP

goals for interprofessional management for increased ICP (4)

oxygen and glucose

without adequate cerebral perfusion, the delivery _____ to the brain is impaired, leading to impaired cognitive abilities and potential brain damage if not addressed promptly

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 edema

type of cerebral edema: results from a disruption of the blood-brain barrier, which allows fluid and large molecules (e.g., protein, blood products) from the intravascular space to enter the brain tissue

vasogenic edema

type of cerebral edema: the most common type

1. vasogenic edema

2. interstitial edema

type of cerebral edema: occurs mainly in the white matter of the brain (2)

vasogenic edema

type of cerebral edema: associated with tumors, trauma, infection, and inflammation

vasogenic edema

type of cerebral edema: corticosteroids (dexamethasone) are extremely effective when associated with brain tumors

corticosteroids (dexamethasone)

what drug is extremely effective for vasogenic edema associated with brain tumors?

cytotoxic edema

type of cerebral edema: results from the disruption of the integrity of the cell membranes (i.e., cellular injury), leading to the accumulation of fluid within the brain cells (e.g., neurons, glial cells, endothelial cells)

cytotoxic edema

type of cerebral edema: involves intracellular swelling that leads to diffuse brain swelling

cytotoxic edema

type of cerebral edema: occurs in the gray matter of the brain

cytotoxic edema

type of cerebral edema: may occur concurrently with vasogenic edema

seizures

one of the earliest effects seen with cytotoxic edema is _____ following brain insult

1. cytotoxic edema

2. interstitial edema

type of cerebral edema: corticosteroids are NOT effective (2)

to restore perfusion and ensure adequate oxygenation to neurons

the goal of treatment of cytotoxic edema

interstitial edema

type of cerebral edema: results from the movement of CSF into the brain's extracellular space

interstitial edema

type of cerebral edema: also known as hydrostatic edema or hydrocephalic edema

interstitial edema

type of cerebral edema: associated with conditions that lead to increased ICP due to the buildup of CSF, such as hydrocephalus

interstitial edema

type of cerebral edema: treatment options include temporary drainage of CSF (e.g., ventriculostomy) until the condition corrects itself, or requires permanent placement of a shunt

interstitial edema

type of cerebral edema: osmotic diuretics are NOT effective

1. change in LOC

2. headache (worse in AM)

3. projectile vomiting without nausea

4. pupillary changes, especially unilateral dilation

5. blurred or double vision

clinical manifestations of increased ICP (5)

change in LOC

usually the earliest sign of increased ICP, but may be subtle

vague and subjective

when trying to describe a patient's neurological state, avoid terminology that is _____

AM

when is the headache typically worse in patients with increased ICP?

1. ipsilateral pupillary dilation

2. sluggish or no pupillary response to light

3. inability to move the eye upward

4. ptosis of the eyelid

compression of cranial nerve III (the oculomotor nerve) results in _____ (4)

oculomotor nerve

cranial nerve III

diplopia

associated with paresis or paralysis of one or more extraocular muscles

1. deterioration in LOC (e.g., increased lethargy, obtundation, somnolence, stupor, coma)

2. deterioration in motor/sensory signs

3. alterations in vital signs

4. cushing's triad

late signs of increased ICP (4)

pons

decorticate and decerebrate posturing indicates that the pressure has now progressed lower to the level of the _____

cushing's triad

systolic hypertension with a widening pulse pressure, bradycardia with a full and bounding pulse, and irregular respirations

1. hemiparesis or hemiplegia

2. exaggerated reflexes, presence of the babinski reflex

3. seizures

4. diminished motor responses and impaired response to noxious stimuli (e.g., sternal rub)

5. posturing

motor signs of increased ICP (5)

decorticate (flexor) posturing

type of posturing: consists of internal rotation and adduction of the arms with flexion of the elbows, wrists, and fingers

decerebrate (extensor) posturing

type of posturing: consists of stiff extension and adduction of the arms with hyperpronation

decorticate (flexor) posturing

this picture indicates:

decerebrate (extensor) posturing

this picture indicates:

1. CT scan

2. MRI

3. magnetic resonance angiogram (MRA)

4. electroencephalography (EEG)

5. transcranial doppler (TCD)

diagnostic studies for increased ICP (5)

magnetic resonance angiogram (MRA)

diagnostic study for increased ICP: a non-invasive imaging test that creates detailed pictures of the brain's blood vessels

electroencephalography (EEG)

diagnostic study for increased ICP: measures the electrical activity of the brain

transcranial doppler (TCD)

diagnostic study for increased ICP: a non-invasive ultrasound that measures blood flow in the brain's blood vessels. can detect the presence of cerebral vasospasms

1. elevate the HOB > 30 degrees, unless contraindicated

2. maintain oxygen and ventilation

3. maintain CPP > 60 mmHg

4. maintain SBP between 100-160 mmHg

5. monitor fluid balance

6. reduce metabolic demands (e.g., fever, shivering, seizures)

7. protect from injury

8. prepare for psychological issues

9. early feeding

interprofessional management for increased ICP (9)

> 30

for patients with increased ICP, elevate the HOB _____ degrees, unless contraindicated

> 60

for patients with increased ICP, maintain CPP _____ mmHg

100-160

for patients with increased ICP, maintain SBP between _____ mmHg

≥ 100

for patients with increased ICP, keep PaO2 _____ mmHg

35-45

for patients with increased ICP, keep PaCO2 between _____ mmHg

1. diabetes insipidus

2. SIADH

fluid balance should be monitored in patients with increased ICP because patients are at high risk for _____ (2)

1. mannitol (Osmitrol) and hypertonic saline

2. corticosteroids (dexamethasone) with peptic ulcer prophylaxis

3. antipyretics for fever

4. nimodipine (Nimotop)

5. anti-seizure medications

6. sedatives/analgesics

7. high-dose barbiturates (pentobarbital)

drug therapy for increased ICP (7)

mannitol (Osmitrol) and hypertonic saline

drug for increased ICP: pulls fluid out of the brain tissue and into the intravascular space to reduce swelling

corticosteroids

drug for increased ICP: indicated for vasogenic edema. are harsh on the GI system, so patients should also receive an H2 receptor blocker or proton pump inhibitor to prevent GI ulcers and bleeding

nimodipine (Nimotop)

drug for increased ICP: indicated to prevent cerebral vasospasm

an H2 receptor blocker or proton pump inhibitor to prevent GI ulcers and bleeding

what should be administered with corticosteroids in patients with vasogenic edema?

metabolic demand

fever increases _____, which can exacerbate ICP

high-dose barbiturates (pentobarbital)

drug for increased ICP: indicated in patients with increased ICP refractory to other treatments