Increased Intracranial Pressure (ICP)

Learning Outcomes By the end of this lecture, students will be able to: Define ICP and recognise the causes of increased ICP and its consequences Discuss the pathophysiology of increased ICP and its clinical manifestations Describe the assessment and diagnostic findings of increased ICP Recognise the medical and nursing management of a patient with increased ICP

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.

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.

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),

Clinical Manifestations 1-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. 2-Restlessness ,confusion, or increasing drowsiness, has neurologic significance. 3-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. 4-As ICP increases, the patient becomes stuporous, reacting only to loud auditory or painful stimuli.

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. undergo electrophysiologic monitoring to monitor cerebral blood flow indirectly. measures the electrical potentials produced by nerve tissue in response to external stimulation (auditory, visual, or sensory)

Medical Management Increased ICP is a true emergency and must be treated immediately through: 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.

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,

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. 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. sedation and analgesia must be provided

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)..

Glasgow Coma Scale Eye opening response Spontaneous 4 To voice 3 To pain 2 None 1 Best verbal response Oriented 5 Confused 4 Inappropriate words 3 Incomprehensible sounds 2 Best motor response Obeys command 6 Localizes pain 5 Withdraws 4 Flexion 3 Extension 2 Total 3 to 15

Nursing diagnoses: Ineffective airway clearance related to diminished protective reflexes (cough, gag) Ineffective breathing patterns related to neurologic dysfunction) Ineffective cerebral tissue perfusion related to the effects of increased ICP

Planning and goals Maintenance of a patent airway Normalization of respiration Adequate cerebral tissue perfusion through reduction in ICP

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….

Achieving an adequate breathing pattern Monitor the patient constantly for respiratory irregularities. (alternating periods of hyperpnea and apnea)

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.

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 the (straining at stool) as it raises ICP. Administer stool softeners as prescribed. If appropriate, provide high fiber diet. Avoid activities that raise ICP if possible. Space nursing interventions; this may prevent transient increases in ICP. Patients with the potential for a significant increase in ICP should receive sedation or “paralyzation” before initiation of many nursing activities.

Avoid emotional stress, frequent arousal from sleep, and environmental stimuli (noise, conversation).