Evidence Base for the Use of Ultrasound for Upper Extremity Blocks
Bibliographic record
Abstract
This article reviews and summarizes randomized, controlled studies that have assessed ultrasound (US) guidance for brachial plexus blocks in comparison with other nerve localization methods as well as those that have compared different US-guided brachial plexus block techniques. Both PubMed and EMBASE databases were searched using the MeSH terms anesthetic technique, brachial plexus, and ultrasound. Studies were included if they had randomized allocation comparing US with another conventional nerve localization technique or if they compared 2 different US-guided techniques, such as single versus multiple injections. Each study was classified as a categorical outcome as being supportive, unclear, or negative for the use of US. These were compared with χ analysis with the null hypothesis that US provides no benefit for brachial plexus blocks. Forty-seven studies met the inclusion criteria, and 29 compared US guidance to landmark or peripheral nerve stimulation techniques. Our analysis of the literature supports the use of US over other nerve localization techniques as being beneficial for several block performance outcomes including block performance time, reducing the number of needle passes and the incidence of vascular puncture, shortening sensory block onset time, and improving block success.
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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 | 0.007 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".