Noninvasive Intracranial Pressure Monitoring: Are We There Yet?

Area of Science:

• Neuroscience
• Medical Technology
• Critical Care Medicine

Background:

• Intracranial pressure (ICP) monitoring is crucial but invasive methods are often unavailable or risky.
• A significant unmet need exists for reliable, noninvasive ICP detection tools.

Purpose of the Study:

• To review the clinical utility of extensively evaluated noninvasive techniques for detecting elevated ICP.
• To assess the potential of ultrasound-measured optic nerve sheath diameter (ONSD), transcranial Doppler (TCD), and quantitative pupillometry.

Main Methods:

• Review of existing literature on noninvasive ICP monitoring techniques.
• Evaluation of ultrasound for ONSD measurement.
• Analysis of transcranial Doppler indices (pulsatility index, Czosnyka method).
• Assessment of quantitative pupillometry for pupillary light response.

Main Results:

• Ultrasound ONSD shows potential but suffers from bias and inconsistent thresholds, precluding routine use.
• TCD-based estimated ICP has high negative predictive value (>95%) but low positive predictive value (≤30%).
• Quantitative pupillometry shows promise for early ICP elevation detection, but data are limited.

Conclusions:

• No current noninvasive technique reliably replaces invasive ICP monitoring.
• Multimodal noninvasive assessment may be beneficial when invasive monitoring is unavailable.
• Further research and innovation are essential for developing a reliable, continuous noninvasive ICP monitoring tool.