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 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 | 0.004 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".