Increased Intracranial Pressure (ICP) Overview

Study Notes

ICP is the total pressure exerted by the three components within the skull (brain tissue, blood, and cerebrospinal fluid).
The Monro-Kellie Hypothesis describes how the skull is a rigid structure, so if one component increases its volume, another component must decrease in volume, to maintain a constant intracranial volume.
Increased ICP can significantly decrease cerebral blood flow, leading to ischemia and cell death.
Increased CO2 causes cerebral vasodilatation, raising cerebral blood flow and consequently, ICP. Decreased CO2 has the opposite effect.
Cerebral edema, an abnormal accumulation of fluid within the brain, is a common cause of increased ICP. This fluid buildup puts pressure on brain tissue.
Three types of cerebral edema are: vasogenic, cytotoxic, and interstitial.
ICP is usually measured in the lateral ventricles. Normal ICP is 10-20 mm Hg.
Increased ICP can be caused by various factors, including head trauma, brain tumors, stroke, and certain medical conditions.
Cushing's triad is a clinical sign of increasing ICP, characterized by bradycardia, hypertension, and bradypnea.
ICP rises beyond compensatory mechanisms. Brain tissue is displaced, producing ischemia, infarction and ultimately, brain death.
Early signs of increasing ICP include changes in level of consciousness (LOC), slowing of speech, and delays in responses to verbal cues.
Severe cases may include a dilated, fixed pupil, hemiplegia/paresis, and Cushing's triad.

ICP is measured to monitor the pressure within the skull, to determine if an individual needs intervention.
Methods include intraventricular measures, epidural, subdural, or intraparenchymal.
Normal ICP is 5-15mm Hg/10-20 cm H₂O

Medical management, including mannitol infusions (osmotic diuretics), hyperventilation therapy, and reducing CSF volume, helps reduce ICP.
Surgical management (decompressive craniectomy), is an intervention option when other measures are not enough.

Infections, intracranial hemorrhages, CSF leaks, mechanical failure, or over-drainage of the CSF are potential complications of ICP monitoring.
Increased ICP can result in brain herniation, which is further complicated by ischemia and infarction, leading to permanent damage or death.

Nursing assessment involves history, neurologic examination, thorough pupil checks, frequent monitoring of vital signs, and use of the Glasgow Coma Scale.
Crucial nursing interventions include maintaining hemodynamic parameters, calculating and monitoring cerebral perfusion pressure (CPP), administering medications and oxygen, and maintaining input and output charts.
Additional nursing diagnoses and interventions include ineffective airway clearance, ineffective breathing pattern, fluid volume deficit, and risk of infection due to the ICP monitoring system.
These interventions focus on maintaining or stabilizing the patient's condition, to prevent further deterioration and promote recovery.