Single- versus double-injection costoclavicular block: a randomized comparison
Bibliographic record
Abstract
BACKGROUND: The costoclavicular approach targets the brachial plexus in the proximal infraclavicular fossa, where the lateral, medial, and posterior cords are tightly bundled together. This randomized trial compared single- and double-injection ultrasound-guided costoclavicular blocks. We selected onset time as the primary outcome and hypothesized that, compared with its single-injection counterpart, the double-injection technique would result in a swifter onset. METHODS: Ninety patients undergoing upper limb surgery (at or below the elbow joint) were randomly allocated to receive a single- (n=45) or double-injection (n=45) ultrasound-guided costoclavicular block. The local anesthetic agent (35 mL of lidocaine 1%-bupivacaine 0.25%with epinephrine 5 µg/mL and 2 mg of preservative-free dexamethasone) was identical in all subjects. In the single-injection group, the entire volume of local anesthetic was injected between the three cords of the brachial plexus. In the double-injection group, the first half of the volume was administered in this location; the second half was deposited between the medial cord and the subclavian artery. After the performance of the block, a blinded observer recorded the onset time (defined as the time required to achieve a minimal sensorimotor composite score of 14 out of 16 points), success rate (surgical anesthesia) and block-related pain scores. Performance time and the number of needle passes were also recorded during the performance of the block. The total anesthesia-related time was defined as the sum of the performance and onset times. RESULTS: Compared with its single-injection counterpart, the double-injection technique displayed shorter onset time (16.6 (6.4) vs 23.4 (6.9) min; p<0.001; 95% CI for difference 3.9 to 9.7) and total anesthesia-related time (22.5 (6.7) vs 28.9 (7.6) min; p<0.001). No intergroup differences were found in terms of success and technical execution (ie, performance time/procedural pain). The double-injection group required more needle passes than the single-injection group (2 (1-4) vs 1 (1-3); p<0.001). CONCLUSION: Compared with its single-injection counterpart, double-injection costoclavicular block results in shorter onset and total anesthesia-related times. Further investigation is required to determine if a triple-injection technique (with targeted local anesthetic injection around each cord of the brachial plexus) could further decrease the onset time. TRIAL REGISTRATION NUMBER: NCT03595514.
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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 | 0.004 | 0.005 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.008 | 0.003 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.013 | 0.002 |
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".