Abstract 131: Augmenting Cerebral Blood Flow using Military Anti-Shock Trousers: A Transcranial Doppler Study
Bibliographic record
Abstract
Background: Augmenting blood flow through iatrogenically raising blood pressure is one mechanism to augment cerebral blood flow (CBF) which confers benefits to ischemic brain tissue. CBF augmentation has potential applications in acute ischemic stroke to increase collateral flow. The MAST device has previosuly been used to in a cardiac setting to increase cardiac output and raise blood pressure which can increase systemic flow velocities. The aim of this study was to use the MAST device to augment CBF in healthy subjects. METHODS: In this study 11 healthy volunteers (22 vessels) were given MAST which was inflated while simultaneously measuring heart rate, systolic and diastolic blood pressure. Transcranial Doppler (TCD) was used to measure the flow velocities in the middle cerebral artery (MCA) including peak systolic velocity (PSV), end diastolic velocity (EDV), mean flow velocity (MSV) and to calculate pulsility index (PI) over a 4 minute inflation and 2 minute deflation protocol in the supine position. Results: After inflation of MAST there was an increase in both systolic and diastolic blood pressure and a slight decrease in PSV (74 vs. 72 cm/s), EDV (33 vs. 32 cm/s) and MFV (50 vs. 49 cm/s) and an increase in PI (0.83 vs. 0.85). After deflation of the MAST device, blood pressure decreased and there was a slight decrease in MFV (49 vs. 48 cm/s) and EDV (32 vs 31 cm/s). PSV was slightly increased (72 vs. 74 cm/s) while PI was greatly increased (0.82 vs. 0.86). Interestingly, two groups were identified based on early and late changes in PI after MAST inflation. Conclusion: This data suggests that an artificial increase in blood pressure can augment CBF parameters (PSV, EDV, and MFV) and this change is short lived after an increase in blood pressure. A drop in blood pressure will also change CBF parameters, and importantly increase PI as suggested by Doppler waveforms. Cerebrovascular motor reactivity occurs quickly after changes to blood pressure and works to maintain a constant CBF through the MCA.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".