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Static autoregulation in humans: a review and reanalysis

2014· review· en· W1999903381 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueMedical Engineering & Physics · 2014
Typereview
Languageen
FieldMedicine
TopicTraumatic Brain Injury and Neurovascular Disturbances
Canadian institutionsUniversity of British Columbia, Okanagan CampusUniversity of British Columbia
Fundersnot available
KeywordsCerebral blood flowMean arterial pressureCerebral autoregulationAutoregulationHypercapniaHemodynamicsCardiologyLinear regressionMedicineBlood pressureMathematicsAnesthesiaInternal medicineHeart rateStatisticsRespiratory system

Abstract

fetched live from OpenAlex

INTRODUCTION: Cerebral autoregulation (CA) is a theoretical construct characterized by the relationship between mean arterial pressure (MAP) and cerebral blood flow (CBF). We performed a comprehensive literature search to provide an up-to-date review on the static relationship between MAP and CBF. METHODS: The results are based on 40 studies (49 individual experimental protocols) in healthy subjects between 18 and 65 years. Exclusion criteria were: a ΔMAP <5%, hypoxia/hyperoxia or hypo/hypercapnia, and unstable levels (<2 min stages). The partial pressure of arterial CO2 (PaCO2) was measured in a subset of the included studies (n=28); therefore, CBF was also adjusted to account for small changes in PaCO2. RESULTS: The linear regression coefficient between MAP and CBF (or velocity) of 0.82±0.77%ΔCBF/%ΔMAP during decreases in MAP (n=23 experiments) was significantly different than the relationship of 0.21±0.47%ΔCBF/%ΔMAP during increases (n=26 experiments; p<0.001). After correction for increases/decreases in PaCO2, the slopes were not significantly different: 0.64±1.16%ΔCBF/%ΔMAP (n=16) and 0.39±0.30%ΔCBF/%ΔMAP (n=12) for increased vs. decreased MAP changes, respectively (p=0.60). CONCLUSION: The autoregulatory ability of the cerebral circulation appears to be more active in buffering increases in MAP as compared to reductions in MAP. However, the statistical finding of hysteresis is lost following an attempt to correct for PaCO2.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.001
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Review · Consensus signal: Review
Teacher disagreement score0.858
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0020.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.025
GPT teacher head0.317
Teacher spread0.292 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it