A Prospective, Randomized Comparison Between Single- and Double-Injection, Ultrasound-Guided Supraclavicular Brachial Plexus Block
Bibliographic record
Abstract
BACKGROUND AND OBJECTIVES: This prospective, randomized, observer-blinded study compared single- and double-injection, ultrasound-guided supraclavicular brachial plexus block for upper extremity surgery. METHODS: Ninety-two patients were randomly allocated to receive a single-injection (n = 46) or double-injection (n = 46), ultrasound-guided supraclavicular block. Performance time (defined as the sum of imaging and needling times) and the number of needle passes were recorded during the performance of the block. Subsequently, a blinded observer recorded the onset time, block-related pain scores, success rate (surgical anesthesia), and the incidence of complications. The total anesthesia-related time was defined as the sum of the performance and onset times. The main outcome variable was the onset time. RESULTS: The onset time was shorter with the 2-injection technique (17.5 mins [SD, 8.4 mins] vs 21.7 mins [SD, 7.2 mins]; P = 0.021); however, performance time was also longer (7.2 mins [SD, 2.7 mins] vs 6.0 mins [SD, 2.4 mins]; P = 0.037). Thus, no differences were observed in terms of total anesthesia-related time (23.4-24.3 mins). Success rates (95.7%), block-related pain scores, and complication rates were also similar between the 2 groups. As expected, the 2-injection technique required a greater number of needle passes (3.5 [SD, 1.2] vs 1.9 [SD, 1.1]; P < 0.001). In return, it provided a faster onset for sensory and motor block of the musculocutaneous nerve and a faster sensory block of the radial nerve. However, at 30 mins, no differences were observed. CONCLUSION: The double-injection, ultrasound-guided supraclavicular block provides no significant advantages compared with its single-injection counterpart.
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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 | 0.007 | 0.013 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 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".