A wireless ultrasound patch detects mild-to-moderate central hypovolemia during lower body negative pressure
Bibliographic record
Abstract
BACKGROUND: We have developed a wireless, wearable Doppler ultrasound system that continuously measures the common carotid artery Doppler pulse. A novel measure from this device, the Doppler shock index, accurately detected moderate-to-severe central blood volume loss in a human hemorrhage model generated by lower body negative pressure. In this analysis, we tested whether the wearable Doppler could identify only mild-to-moderate central blood volume loss. METHODS: Eleven healthy volunteers were recruited and studied in a physiology laboratory at the Mayo Clinic. Each participant underwent a lower body negative protocol in duplicate. Carotid Doppler measures including Doppler shock indices were compared with blood pressure and the shock index for their ability to detect both 10% and 20% reductions in stroke volume. RESULTS: All carotid Doppler measures were better able to detect diminishing stroke volume than either systolic or mean arterial pressure. Falling carotid artery corrected flow time and rising heart rate/corrected flow time (DSI FTc ) were the most sensitive measures for detecting 10% and 20% stroke volume reductions, respectively. The area under the receiver operator curves (AUROCs) for all shock indices was at least 0.86; however, the denominators of the two Doppler shock indices (i.e., the corrected flow time and velocity time integral) had AUROCs ranging between 0.81 and 0.9, while the denominator of the traditional shock index (i.e., systolic blood pressure) had AUROCs between 0.54 and 0.7. CONCLUSION: The wearable Doppler ultrasound was able to continuously measure the common carotid artery Doppler pulse. Carotid Doppler measures were highly sensitive at detecting both 10% and 20% stroke volume reduction. All shock indices performed well in their diagnostic ability to measure mild-to-moderate central volume loss, although the denominators of both Doppler shock indices individually outperformed the denominator of the traditional shock index. LEVEL OF EVIDENCE: Diagnostic test or criteria; Level III.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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.
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 teacher head, 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".