Onset and duration of intradermal mixtures of bupivacaine and lidocaine with epinephrine
Bibliographic record
Abstract
BACKGROUND/OBJECTIVE: Bupivacaine and lidocaine are often used concurrently, in theory, to combine the more rapid onset of lidocaine and the longer duration of bupivacaine. The purpose of this study was to evaluate this concept. METHODS: Twenty-five subjects were enrolled in a double-blinded, randomized block design study to evaluate the onset and duration of four different mixtures of lidocaine and bupivacaine with epinephrine. The study was designed to achieve 80% power to detect an effect size of 0.37 at 5% overall significance. The four mixtures tested were: 0.25% bupivacaine with epinephrine (1:200,000); 1% lidocaine with epinephrine (1:100,000); 0.125% bupivacaine and 0.5% lidocaine with epinephrine (1:150,000); and 0.25% bupivacaine and 1% lidocaine with epinephrine (1:150,000). Four intradermal injections were made in the volar forearms of each participant. Time to effect and duration were measured by sensation of a sharp skin prick. RESULTS: Mean time to onset ranged from 12 s to 29 s without statistical significance across all tested solutions (P=0.891). Mean duration of effect ranged from 6 h 38 min to 7 h 25 min with a statistically significant difference across the tested solutions (P=0.036). CONCLUSIONS: No statistical benefit was measured when comparing lidocaine with epinephrine, bupivacaine with epinephrine, and mixtures of these local anesthetics with regard to onset of action. While a statistical difference was observed in duration of effect, the clinical benefit measured was narrow.
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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 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".