What are the recommended devices for measuring intracranial pressure (ICP)?

Recommended Devices for Measuring Intracranial Pressure (ICP)

Parenchymal ICP monitors and external ventricular catheters (EVD) are the recommended devices for measuring ICP, with EVDs being preferred in cases of hydrocephalus when safe and practical to place. 1

Gold Standard Devices

• External ventricular catheters (EVD) are considered the gold standard for ICP monitoring and provide the most reliable and accurate measurements. They have the added benefit of allowing therapeutic CSF drainage for ICP management. 1

• Parenchymal ICP monitors (intraparenchymal devices) are equally accurate for pressure measurement but do not allow for CSF drainage. These are preferred when ventricular access is difficult or contraindicated. 1, 2

Device Selection Considerations

When to Choose EVD:

• Patients with hydrocephalus or significant intraventricular hemorrhage 1
• When CSF drainage may be needed as part of treatment 1
• When continuous ICP monitoring and therapeutic intervention are required simultaneously 1

When to Choose Parenchymal Monitors:

• When ventricular access is difficult (e.g., compressed or displaced ventricles) 1
• When CSF drainage is not anticipated 2
• When only monitoring (not drainage) is required 1

Safety and Implementation

• Standard insertion and maintenance protocols should be used to ensure safety and reliability of ICP monitoring procedures. 1
• Before insertion of any monitoring device, the patient's coagulation status should be evaluated. Prior use of antiplatelet agents may justify platelet transfusion, and warfarin use may require reversal of coagulopathy. 1
• Continuous assessment of ICP and cerebral perfusion pressure (CPP) should include waveform quality evaluation using a structured protocol. 1
• Instantaneous ICP values should be interpreted in the context of monitoring trends, CPP, and clinical evaluation rather than as isolated readings. 1

Risks and Complications

• Invasive ICP monitoring carries risks including infection and intracranial hemorrhage. 1, 2
• The risk of hemorrhage or infection is generally higher with ventricular catheters than with parenchymal devices, although these rates are primarily derived from traumatic brain injury or subarachnoid hemorrhage data. 1
• In one series of 108 intraparenchymal devices, infection rate was 2.9% and intracranial hemorrhage rate was 2.1% (increasing to 15.3% in patients with coagulopathies). 1

Non-Invasive Alternatives

• Despite advances in technology, current non-invasive ICP monitoring methods lack sufficient accuracy to replace invasive techniques in clinical practice. 2, 3, 4
• The most promising non-invasive techniques include optic nerve sheath diameter assessment and transcranial Doppler, but these cannot substitute for invasive measurements when accurate readings are required. 2
• Non-invasive methods may be useful as screening tools in select patients when invasive monitoring is contraindicated or unavailable. 5

Emerging Technologies

• Implantable passive sensors that can be used for continuous intraparenchymal and intraventricular ICP monitoring are being developed. 6
• These newer devices may eventually allow for long-term monitoring with fewer complications, but they require further validation before clinical implementation. 6

Clinical Context

• ICP monitoring should be tailored to the specific diagnosis (e.g., subarachnoid hemorrhage, traumatic brain injury, encephalitis). 1
• While refractory ICP elevation strongly predicts mortality, ICP measurements should not be used in isolation as a prognostic marker for functional outcomes. 1
• ICP monitoring is a mandatory prerequisite when other intracranial monitors are used, providing a framework for optimal interpretation of additional monitoring data. 1