Evidence map›Paper›PMID 41814432›Full record

Observational studyCritical care (London, England)2026

A noninvasive method for assessing optimal cerebral perfusion pressure.

Sérgio Brasil, Gustavo Frigieri, Fabio Silvio Taccone, Diogo Dantas, Carlos Nassif, Marek Czosnyka, Pedro Kurtz, Salomon Soriano Ordinola Rojas, Wellingson Silva Paiva, Luiz Marcelo Sá Malbouisson

Abstract readObservational StudyMulticenter Study
In one paragraph

Observational study in Critical care (London, England), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing 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.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Sérgio BrasilDivision of Neurosurgery, Department of Neurology, University of São Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil. sbrasil@alumni.usp.br.ORCID http://orcid.org/0000-0003-2397-9947
Gustavo FrigieriMedical Investigation Laboratory 62, University of São Paulo Medical School, São Paulo, Brazil.
Fabio Silvio TacconeDepartment of Intensive Care, Hospital Erasme, Universitè Libre de Bruxelles, Brussels, Belgium.
Diogo DantasDepartment of Anesthesiology, University of São Paulo Medical School, São Paulo, Brazil.
Carlos NassifDepartment of Anesthesiology, University of São Paulo Medical School, São Paulo, Brazil.
Marek CzosnykaDepartment of Clinical Neurosciences, Division of Neurosurgery, University of Cambridge, Cambridge, UK.
Pedro KurtzIntensive Care Department, Instituto Estadual do Cérebro, Rio de Janeiro, Brazil.
Salomon Soriano Ordinola RojasIntensive Care Department coordinator, Hospital Beneficência Portuguesa de São Paulo, São Paulo, Brazil.
Wellingson Silva Paiva *Division of Neurosurgery, Department of Neurology, University of São Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil.
Luiz Marcelo Sá Malbouisson *Department of Anesthesiology, University of São Paulo Medical School, São Paulo, Brazil.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionAfter acute brain injuries, optimizing cerebral perfusion pressure (CPP) is critical for preventing secondary brain insults, yet current fixed CPP targets may not be ideal for all patients due to individual variability in cerebrovascular autoregulation (CA). The concept of"optimal CPP" (CPPopt) or "optimal mean arterial pressure" (MAPopt) identifies the specific pressure range where CA is most effective. The Pressure-Reactivity Index (PRx), derived from invasive intracranial pressure (ICP) and arterial blood pressure (ABP) monitoring, is a well-established means for assessing CA and MAPopt. This study aimed to investigate the ability of noninvasive surrogate ICP waveforms, specifically the P2/P1 ratio acquired using a cranial deformation sensor (B4C), to determine MAPopt in patients with acute brain injury, and to compare its efficacy with the established invasive PRx method.

methodsThis paper provides a retrospective analysis of data from a multicenter prospective observational study of intensive care patients with severe brain injuries requiring invasive ICP monitoring. Continuous invasive ABP and ICP data were collected alongside noninvasive ICP waveforms using the B4C sensor. MAPopt was determined for each monitoring session using two methods: (1) the nadir of a polynomial regression curve fitted to PRx values (correlation between ICP and ABP) stratified by 1 mmHg MAP intervals, and (2) the nadir of a polynomial regression curve fitted to the noninvasive P2/P1 ratio, also stratified by MAP intervals. Repeated measures correlation was used to analyze their correspondence and P2/P1 ratio ranges within MAPopt limits, whereas Bland-Altman analysis for the methods agreement.

resultsA total of 114 patients were included in the study, 68% severe traumatic brain injury and 15% spontaneous subarachnoid hemorrhage. Analysis of optimal MAP for each session revealed a strong linear relationship between the MAPopt derived from the invasive PRx and the noninvasive P2/P1 ratio (r = 0.905, p<0.0001). Bland-Altman analysis demonstrated good agreement between the two methods, with a mean difference of+2.00 mmHg and 95% limits of agreement ranging from −9.87 mmHg to +13.86 mmHg.

conclusionThe noninvasive P2/P1 ratio, serving as a marker of intracranial compliance, may effectively and accurately infer the optimal systemic mean arterial pressure. A noninvasive neuromonitoring tool may enable personalized, bedside-guided therapeutic management, significantly widening the assessment of cerebrovascular autoregulation in critical care settings.

Indexed as

Cerebrovascular CirculationIntracranial PressureAdultAgedArterial PressureBrain InjuriesFemaleHomeostasisHumansMaleMiddle AgedMonitoring, PhysiologicProspective StudiesRetrospective StudiesAcute brain injuryCerebrovascular autoregulationIntracranial pressureNnoninvasive neuromonitoring

Identifiers

PMID41814432
PMCPMC13094200

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Registered trials

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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.