Intracranial Pressure Estimation Using B4C Device: A Systematic Review on the Validation Studies

Intracranial hypertension (IH) is a frequent and serious complication of acute brain injury, strongly influencing morbidity and mortality. While invasive intracranial pressure (ICP) monitoring is standard, it has limitations. Intracranial compliance (ICC) offers additional insight into the brain's ability to handle changes in volume. Noninvasive ICP waveform analysis, such as the peak 2 (P2)/peak 1 (P1) ratio and time to peak (TTP), shows promise in evaluating ICC and detecting IH. The brain4care (B4C) system provides continuous, noninvasive monitoring for neurocritical care. We systematically reviewed studies comparing B4C with invasive ICP monitoring, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. MEDLINE, Embase, and the Scientific Electronic Library Online were searched for clinical studies from 2016 to May 2025 reporting quantitative B4C parameters in patients undergoing invasive ICP monitoring. Two reviewers evaluated studies, extracted data, and assessed quality using the Newcastle-Ottawa Scale. Sixteen studies involving 826 patients with acute brain injury were reviewed. The P2/P1 ratio, frequently assessed, showed high sensitivity (26.8-100%) and variable specificity (45.5-96.5%) for IH, with moderate to good accuracy (area under the curve [AUC] 0.71-0.83). TTP was less consistent, although a 0.3 threshold gave 92% specificity in the largest study. All studies demonstrated qualitative morphological concordance between B4C-derived and invasive ICP waveforms. The overall methodological quality was moderate, with frequent limitations related to comparability, confounder adjustment, and follow-up. B4C noninvasive monitoring provides reliable reflections of ICC and shows strong correlation with IH, consistently aligning with invasive ICP waveform patterns. This approach is well tolerated as an adjunct for dynamic, physiology-driven neurocritical care. Further prospective, multicenter studies are necessary to clearly define its clinical utility and support safe integration into standard practice.