Increased Intracranial Pressure (ICP)
Dr. Belal Hijji, RN, PhD
February 20 & 22, 2012
Learning Outcomes
By the end of this lecture, students will be able to:
1. Define ICP and recognise the causes of increased ICP and its
consequences
2. Discuss the pathophysiology of increased ICP and its clinical
manifestations
3. Describe the assessment and diagnostic findings of increased
ICP
4. Recognise the medical and nursing management of a patient
with increased ICP
2
Introduction
• The cranium contains brain tissue (1,400 g), blood (75 mL),
and CSF (75 mL). The volume and pressure of these three
components are usually in a state of equilibrium and produce
the ICP, which is 10 to 20 mm Hg and represents the pressure
within the rigid skull.
• Causes of increased ICP include a rise in cerebrospinal fluid
pressure, increased pressure within the brain matter, bleeding
into the brain or fluid around the brain, or swelling within the
brain matter itself.
• An increase in intracranial pressure is a serious medical
problem. The pressure itself can damage the brain or spinal
cord by pressing on important brain structures and by
restricting blood flow into the brain.
3
Subdural hematoma develops when blood vessels that are located between the
membranes covering the brain (the meninges) leak blood after an injury to the
head. This is a serious condition since the increase in intracranial pressure can
cause damage to brain tissue and loss of brain function.
4
Pathophysiology
• Increased ICP is a syndrome that affects many patients with
acute neurologic conditions. An elevated ICP is most
commonly associated with head injury, secondary effect in
other conditions, such as brain tumors, subarachnoid
hemorrhage, and toxic and viral encephalopathies.
• Increased ICP from any cause decreases cerebral perfusion,
stimulates further swelling (edema), and shifts brain tissue
through openings in the rigid dura, resulting in brain herniation
(next slide), a frequently fatal event.
5
6
Clinical Manifestations
• When ICP increases to the point at which the brain’s ability to
adjust has reached its limits, neural function is impaired; this
may be manifested by clinical changes first in LOC and later
by abnormal respiratory and vasomotor responses. Slowing of
speech and delay in response to verbal suggestions are other
early indicators.
• Restlessness (without apparent cause), confusion, or increasing
drowsiness, has neurologic significance.
• These signs may result from compression of the brain due to
swelling from hemorrhage or edema, an expanding intracranial
lesion (hematoma or tumor), or a combination of both.
Continued…..
7
• As ICP increases, the patient becomes stuporous, reacting only
to loud auditory or painful stimuli. At this stage, serious
impairment of brain circulation is probably taking place, and
immediate intervention is required.
• As neurologic function deteriorates further, the patient
becomes comatose and exhibits abnormal motor responses in
the form of decorticate or decerebrate posture (see next slide).
When the coma is profound, with the pupils dilated and fixed
and respirations impaired, death is usually inevitable.
8
9
Assessment and Diagnostic Findings
• The patient may undergo cerebral angiography, computed
tomography (CT) scanning, or magnetic resonance imaging
(MRI).
• Transcranial Doppler studies provide information about
cerebral blood flow. The patient with increased ICP may also
undergo electrophysiologic monitoring to monitor the pressure
(next slide).
• Lumbar puncture is avoided in patients with increased ICP
because the sudden release of pressure can cause the brain to
herniate.
10
Intracranial pressure monitoring is performed by inserting a catheter into the
head with a sensing device to monitor the pressure around the brain.
11
Medical Management
• Increased ICP is a true emergency and must be treated
immediately through:
– Invasive monitoring of ICP to identify increased pressure
early in its course (before cerebral damage occurs), to
quantify the degree of elevation, to initiate appropriate
treatment, to provide access to CSF for sampling and
drainage, and to evaluate the effectiveness of treatment.
– Decreasing cerebral edema: Osmotic diuretics (mannitol)
may be given to dehydrate the brain tissue and reduce
cerebral edema. They reduce the volume of brain and
extracellular fluid. Corticosteroids (eg, dexamethasone)
help reduce cerebral edema when a brain tumor is the cause
of increased ICP.
12
– Maintaining cerebral perfusion: The cardiac output may be
manipulated to provide adequate perfusion to the brain.
Inotropic agents such as dobutamine hydrochloride are used.
The effectiveness of the cardiac output is reflected in the
cerebral perfusion pressure, which is maintained at greater
than 70 mm Hg. A lower cerebral perfusion pressure
indicates that the cardiac output is insufficient to maintain
adequate cerebral perfusion.
• Cerebral perfusion pressure (CPP) is defined as the difference
between mean arterial and intracranial pressures. Mean arterial
pressure is the diastolic pressure plus one third of the pulse pressure
(difference between the systolic and diastolic). MAP is thus between
systolic and diastolic pressures.
• CPP = MAP - ICP
• Normal cerebral perfusion pressure is 80 mmHg, nearer diastolic.
13
– Lowering the volume of CSF and cerebral blood: CSF
drainage is frequently performed because the removal of CSF
with a ventriculostomy drain may dramatically reduce ICP and
restore cerebral perfusion pressure.
– Controlling fever: Preventing a temperature elevation is
critical because fever increases cerebral metabolism and the
rate at which cerebral edema forms.
– Maintaining oxygenation: Arterial blood gases must be
monitored to ensure that systemic oxygenation remains
optimal. Hemoglobin saturation can also be optimized to
provide oxygen more efficiently at the cellular level.
14
– Reducing metabolic demands: Cellular metabolic demands
may be reduced through the administration of high doses of
barbiturates when the patient is unresponsive to conventional
treatment. Another method is the administration of
pharmacologic paralyzing agents. Because the patient who
receives these agents cannot respond or report pain, sedation
and analgesia must be provided.
15
Nursing Process:
The Patient With Increased ICP
• Assessment:
– Obtain a history of events leading to the present illness; it may
be necessary to obtain this information from significant others.
– The neurologic examination should include an evaluation of
mental status, level of consciousness (LOC), cranial nerve
function, cerebellar function (balance and coordination),
reflexes, and motor and sensory function. Assessment of LOC
includes eye opening; verbal and motor responses; pupils (size,
equality, reaction to light).
– Because the patient is critically ill, ongoing assessment will be
more focused, including pupil checks, assessment of selected
cranial nerves, frequent measurements of vital signs and
intracranial pressure, and use of the Glasgow Coma Scale (next
slide), which is a tool for assessing a patient’s LOC. Scores range
from 3 (deep coma) to 15 (normal)..
16
Glasgow Coma Scale
Eye opening response
Best verbal response
Best motor response
Total
Spontaneous
To voice
To pain
None
Oriented
Confused
Inappropriate words
Incomprehensible sounds
None
Obeys command
Localizes pain
Withdraws
Flexion (decorticate)
Extension (decerebrate)
None
3 to 15
4
3
2
1
5
4
3
2
1
6
5
4
3
2
1
17
• Nursing diagnoses:
– Ineffective airway clearance related to diminished
protective reflexes (cough, gag)
– Ineffective breathing patterns related to neurologic
dysfunction (brain stem compression, structural
displacement)
– Ineffective cerebral tissue perfusion related to the effects of
increased ICP
18
• Planning and goals
– Maintenance of a patent airway
– Normalization of respiration
– Adequate cerebral tissue perfusion through reduction in
ICP
19
• Nursing Interventions:
– Maintaining patent airway.
• Assess the patency of the airway.
• Suction with care the secretions obstructing the airway,
because transient elevations of ICP occur with
suctioning.
• The patient is hyperoxygenated before and after
suctioning to maintain adequate oxygenation.
• Discourage coughing because it increases ICP.
• Auscultate the lung fields at least every 8 hours to
determine the presence of abnormal breath sounds.
• Elevate the head of the bed may aid in clearing
secretions as well as improving venous drainage of the
brain.
Continued….
20
– Achieving an adequate breathing pattern
• Monitor the patient constantly for respiratory
irregularities. This includes Cheyne-Stokes respirations
(alternating periods of hyperpnea and apnea) (See
picture below) and hyperventilation (increased rate and
depth of breathing) (Next slide).
Continued on Slide 23
21
Hyperventilation
22
• Monitor PaCO2 (normal range 35 to 45 mm Hg) if
hyperventilation therapy has been decided to reduce ICP
(by causing cerebral vasoconstriction and a decrease in
cerebral blood volume).
• Maintain a neurologic observation record. Repeated
assessments of the patient are made frequently to
immediately note improvement or deterioration.
• Prepare for surgical intervention in case of deterioration.
23
– Optimising cerebral tissue perfusion
• Maintain head alignment and elevate head of bed 30
degrees. The rationale is that hyperextension, rotation, or
hyperflexion of the neck causes decreased venous return.
• Avoid extreme hip flexion as this increases intraabdominal and intrathoracic pressures, leading to rise in
ICP.
• Avoid the Valsalva maneuver (straining at stool) as it
raises ICP. Administer stool softeners as prescribed. If
appropriate, provide high fiber diet.
• Note abdominal distention. Avoid enemas and cathartics
(sorbitol, magnesium citrate, sodium sulfate).
Continued……
24
• When moving or being turned in bed, instruct the patient
to exhale to avoid the Valsalva maneuver.
• If the patient is on mechanical ventilation, preoxygenate
and hyperventilate him, before suction, using 100%
oxygen on the ventilator. Suctioning should not last
longer than 15 seconds.
• Avoid activities that raise ICP if possible. Space nursing
interventions; this may prevent transient increases in ICP.
• During nursing interventions, the ICP should not rise
above 25 mm Hg and should return to baseline levels
within 5 minutes. Patients with
• Patients with the potential for a significant increase in
ICP should receive sedation or “paralyzation” before
initiation of many nursing activities.
25
• Avoid emotional stress, frequent arousal from sleep, and
environmental stimuli (noise, conversation).
• Isometric muscle contractions (Pushing against an
immovable wall) are also contraindicated because they
raise the systemic blood pressure and hence the ICP.
26