Evidence map›Paper›PMID 40659917›Full record

Observational studyNeurocritical care2025

Exploring Cerebrospinal Compensatory Zones Using a Noninvasive Approach.

Sérgio Brasil, Marek Czosnyka, Wellingson S Paiva, Gustavo Frigieri

Erratum issued Registry-linked trialAbstract readObservational Study
PubMed Publisher
In one paragraph

Observational study in Neurocritical care, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. It is linked to trial NCT03144219 (A Novel Non-invasive Technique of Cerebral Compliance and Auto-regulation Assessment), which is not on this map. Cited by 7 papers.

0numbers the graph read from it
0cells of the map it votes in
7citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT03144219 unknown statusnot on this map

A Novel Non-invasive Technique of Cerebral Compliance and Auto-regulation Assessment

TypeobservationalSponsorUniversity of Sao PauloRan2017 to 2023Enrolled133ConditionsIntracranial HypertensionArmsTranscranial Doppler (TCD) ultrasound monitoring, Non invasive intracranial compliance monitoring
3 · Its place in the literature

Who cites it

7 citing papers in PubMed.

  1. Review
  2. Article
  3. Review
  4. Article
  5. Article
  6. Observational
  7. Article
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

4 authors.

Sérgio BrasilDivision of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil. sbrasil@alumni.usp.br.ORCID 0000-0003-2397-9947
Marek CzosnykaUniversity of Cambridge, Cambridge, UK.
Wellingson S PaivaDivision of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil.
Gustavo FrigieriMedical Investigation Laboratory 62, University of São Paulo Medical School, São Paulo, Brazil.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundIntracranial compliance (ICC) reflects the balance among intracranial volume components. Recent technological advances enable continuous, noninvasive assessment of ICC in neurocritical care settings. In this study, we aimed to correlate noninvasive ICC parameters derived from intracranial pressure (ICP) waveform morphology with the established amplitude-pressure index (RAP index), which is calculated using invasive ICP monitoring.

methodsPatients with traumatic brain injury underwent ventricular ICP monitoring. Simultaneously, ICP values and waveform characteristics were recorded using an external skull microdynamics sensor (brain4care) that provides surrogate waveform parameters, including the P2/P1 ratio and time-to-peak (TTP). The RAP index was calculated using dedicated software based on ICP values and pulse amplitude and was used to categorize patients into three groups: (1) adequate ICC, (2) compromised ICC, and (3) exhausted ICC. Noninvasive parameters (P2/P1 ratio and TTP) were then analyzed in relation to RAP index groupings.

resultsA total of 61 patients were included. Group 1 (adequate ICC) had a median ICP of 12.3 ± 5.4 mm Hg, a P2/P1 ratio of 1.06 ± 0.3, and a TTP of 0.18 ± 0.09 s. Group 2 (compromised ICC) had a median ICP of 13 ± 6.4 mm Hg, a P2/P1 ratio of 1.15 ± 0.32, and a TTP of 0.23 ± 0.07 s. Group 3 (exhausted ICC) had a median ICP of 19.45 ± 5.9 mm Hg, a P2/P1 ratio of 1.31 ± 0.26, and a TTP of 0.25 ± 0.05 s. Regression analysis revealed a statistically significant association between the noninvasive parameters and RAP index-based ICC classification (p < 0.0001).

conclusionsThis study demonstrates a significant correlation between the RAP index and noninvasive ICP waveform-derived parameters, such as the P2/P1 ratio and TTP. These findings suggest that such noninvasive measures may serve as reliable indicators of ICC status. The critical ICP cut-off per RAP was 19.45 mmHg, below the current threshold for therapy escalation according to TBI guidelines. Although further prospective validation is required, this approach has the potential to facilitate earlier intervention before ICC deterioration and enable noninvasive monitoring, possibly improving outcomes in neurocritical care.

trial registrationNCT03144219. Registered 15 June 2017, http://www. CLINICALTRIALS: gov/NCT03144219 . CLINICAL

trial registrationClinicalTrials.gov identifier: NCT03144219.

Indexed as

Brain Injuries, TraumaticIntracranial PressureNeurophysiological MonitoringAdultAgedFemaleHumansMaleMiddle AgedYoung AdultAcute brain injuryCerebral arterial blood volumeCerebrospinal complianceIntracranial pressureNoninvasive neuromonitoring

Identifiers

PMID40659917

What OpenQuestion holds

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.