Ropivacaine Alone Versus Ropivacaine Plus Lidocaine With or Without Epinephrine for Supraclavicular Brachial Plexus Block in Upper Limb Orthopedic Surgery

Postoperative Pain, Upper Extremity Fracture, Anesthesia, Conduction

Brachial Plexus Block, Supraclavicular Block, Ropivacaine, Lidocaine, Epinephrine, Local Anesthetic Mixture, Regional Anesthesia, Postoperative Analgesia, Orthopedic Surgery

This randomized controlled trial compared three local anesthetic solutions for ultrasound-guided supraclavicular brachial plexus block in adults aged 18 to 59 years undergoing upper limb orthopedic and trauma surgery at a general hospital of the Mexican Social Security Institute (IMSS) in Aguascalientes, Mexico. Participants were randomly assigned to receive 30 mL of ropivacaine 0.375% alone, ropivacaine 0.375% plus lidocaine 1%, or ropivacaine 0.375% plus lidocaine 1% with epinephrine. The main question was whether adding lidocaine, with or without epinephrine, to ropivacaine improves postoperative analgesia. Pain intensity (0 to 10 Numeric Rating Scale) at 6 hours after surgery was the primary outcome. Secondary outcomes were pain at 0 and 12 hours, need for rescue analgesia, analgesic and opioid consumption, motor block (modified Bromage scale) and adverse events during the first 12 postoperative hours. Block onset time was also recorded.

Background. Mixing a fast-onset local anesthetic with a long-acting agent is common practice in peripheral nerve blocks to shorten block onset, but its effect on the quality and duration of analgesia is controversial, and no study had evaluated these mixtures in patients of the Mexican Social Security Institute. Design. Single-center, superiority, randomized controlled trial with three parallel groups (1:1:1 allocation) and blinded outcome assessment, conducted at Hospital General de Zona No. 3, IMSS, Aguascalientes, Mexico, from January 2 to April 16, 2026. The trial was approved by the local research and ethics committees (registration R-2026-101-005) and all participants gave written informed consent. This trial was registered retrospectively, after completion of enrollment. Interventions. All participants received an ultrasound-guided supraclavicular brachial plexus block with a total volume of 30 mL: group C, 15 mL of ropivacaine 0.75% plus 15 mL of sterile water (ropivacaine 0.375%); group L, 15 mL of ropivacaine 0.75% plus 15 mL of lidocaine 2% (ropivacaine 0.375% plus lidocaine 1%); group E, 15 mL of ropivacaine 0.75% plus 15 mL of lidocaine 2% with epinephrine (ropivacaine 0.375% plus lidocaine 1%, final epinephrine concentration 2.5 micrograms/mL, 1:400,000). No perineural adjuvants were used. Blocks were performed by attending anesthesiologists and anesthesiology residents assigned to each operating room according to the department's daily roster. All participants received the institution's standard intraoperative sedation and analgesia (a corticosteroid, a nonsteroidal anti-inflammatory drug, acetaminophen, midazolam and fentanyl), except when a drug was contraindicated. Randomization and blinding. The principal investigator generated the allocation sequence in Excel for folios 1 to 138. Allocation was concealed in sealed envelopes identified by folio number, kept by the thesis investigator together with the study syringes and opened immediately before the block. Outcomes were assessed by the attending anesthesiologists and residents in charge of each participant, who were unaware of group allocation. Outcomes. Pain intensity was measured with the 0 to 10 Numeric Rating Scale and motor block with the modified Bromage scale for the upper limb (0 = full movement, 3 = complete motor block) at 0, 6 and 12 hours after the end of surgery; rescue analgesics, opioid use and adverse events were recorded at the same time points. Block onset time was marked on the monitor from local anesthetic administration to onset of anesthesia and recorded in the anesthesia record. Withdrawal criteria. Withdrawal of consent, failed block (need for general anesthesia or additional intraoperative analgesia attributable to block failure), discharge before 6 postoperative hours, and block-related complications (puncture-site hematoma, pneumothorax, local anesthetic systemic toxicity, persistent neurological deficit or allergic reaction). Sample size and analysis. A sample of 138 participants (46 per group) was calculated with G\*Power (alpha 0.05, power 0.80, effect size d = 0.5). Analysis followed the intention-to-treat principle. Groups were compared with the Kruskal-Wallis test or one-way ANOVA with Bonferroni-corrected pairwise comparisons, and with the chi-square or Fisher-Freeman-Halton tests for categorical variables; effect estimates are reported with 95% confidence intervals. A p value below 0.05 was considered significant.

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