Choosing Intracranial Pressure Monitoring Devices for a Neuro-ICU

Types of ICP monitoring devices

The reference method is the external ventricular drain (EVD), a catheter placed in a lateral ventricle and connected to an external pressure transducer. Its advantage is that it can also drain cerebrospinal fluid and allow sampling. Its limitations are the infection risk that comes with any open fluid pathway and the need to keep the transducer levelled and the system patent.

Intraparenchymal probes are placed in brain tissue through a small burr hole, usually fixed with a bolt or a tunnelled lead. They measure pressure only and cannot drain CSF, but they are less affected by ventricular collapse. Subdural, subarachnoid and epidural sensors exist as well and are used in specific situations. Our comparison of bolt, EVD and intraparenchymal monitoring goes into the trade-offs.

• External ventricular drain: pressure plus CSF drainage and sampling
• Intraparenchymal fibre-optic or strain-gauge probe: pressure only, placed through a bolt
• Subdural, subarachnoid or epidural sensor: used for specific indications
• Non-invasive assessment: optic nerve sheath ultrasound, transcranial Doppler and others

What an intracranial pressure monitoring system includes

A complete intracranial pressure monitoring system has a sensor or catheter, a cable or fluid line, a monitor or module that displays the ICP value and waveform, and often an interface to the bedside patient monitor. Many hospitals prefer an ICP channel on their existing monitors, which keeps training and alarms uniform.

Check the display options: mean ICP, waveform, trends and cerebral perfusion pressure when arterial pressure is also available. Ask how zeroing is done, whether the probe can be re-zeroed in place and what the calibration interval is. For zeroing basics see transducer zeroing and calibration.

Non-invasive ICP monitor options

Non-invasive methods avoid placing a sensor through the skull. The best known approach measures the optic nerve sheath diameter with ultrasound, because the sheath around the optic nerve expands when intracranial pressure rises. Other methods include transcranial Doppler, pupillometry and tympanic membrane displacement, each with its own limitations.

Nisonic AS, a Norwegian company, has developed FAST-ICP, software that analyses transorbital ultrasound images of the optic nerve sheath. The Nisonic P-100 is a CE-marked ultrasound trolley system running this software. The manufacturer states that FAST-ICP is currently labelled for research use only, so it should be considered for investigator-led studies and not as a replacement for invasive monitoring. Read more in non-invasive ICP monitoring methods.

How to choose among intracranial pressure monitoring devices

The clinical team decides which technique suits the patient; the biomedical and purchasing side decides which platform and consumables the hospital can support. Compare the cost and availability of consumables over several years, compatibility with existing monitors, training needs and the supplier's service route.

Also check regulatory status. Every device should be registered for its intended use in the UAE, and research-use products must be handled as such. The article on invasive versus non-invasive ICP monitoring explains when each approach is appropriate.

Intracranial pressure monitoring device manufacturers and supply

When you evaluate intracranial pressure monitoring device manufacturers, ask for the instructions for use, the validated accuracy and drift data for each sensor, the shelf life of consumables and the number of installed units in comparable hospitals. A manufacturer should be able to explain these points without hesitation.

Beckfinity supplies neurosurgery equipment and the Nisonic non-invasive system in the UAE. To discuss your neuro-ICU requirements or request a quote, contact our specialists.