This randomized, double-blind, placebo-controlled clinical trial evaluated whether intraoperative intravenous lidocaine infusion improves postoperative analgesia and recovery in patients undergoing laparoscopic appendectomy. The primary objective was to assess postoperative pain intensity and opioid consumption. Secondary outcomes included postoperative nausea and vomiting, time to bowel function recovery, length of hospital stay, plasma lidocaine concentrations, and adverse events.

Postoperative pain following laparoscopic appendectomy remains an important clinical concern despite advances in multimodal analgesia. Intravenous lidocaine has been proposed as an effective adjunct because of its analgesic, anti-inflammatory, and antihyperalgesic properties, but evidence in laparoscopic appendectomy remains limited.

This prospective, randomized, double-blind, placebo-controlled trial compared continuous intraoperative intravenous lidocaine infusion with placebo in patients undergoing laparoscopic appendectomy under standardized general anesthesia. Patients were randomly allocated to receive either lidocaine or placebo according to the study protocol.

The primary outcome was postoperative pain intensity measured using the Visual Analogue Scale (VAS). Secondary outcomes included opioid requirements, postoperative nausea and vomiting, return of bowel function, length of hospital stay, incidence of adverse events, and perioperative plasma lidocaine concentrations measured at predefined intraoperative and postoperative time points.

The study aimed to determine the clinical efficacy and safety of intravenous lidocaine infusion as part of multimodal perioperative analgesia for laparoscopic appendectomy and to correlate analgesic effects with measured plasma lidocaine concentrations.

Inclusion Criteria:

• Adults aged 18 to 45 years.
• ASA physical status I or II.
• Scheduled for laparoscopic appendectomy under general anesthesia.
• Able to provide written informed consent.

Exclusion Criteria:

• History of cardiac conduction disorders or documented arrhythmias.
• Hepatic insufficiency.
• Renal insufficiency.
• Chronic or long-term opioid therapy.
• Known or suspected hypersensitivity to amide-type local anesthetics.
• Hemodynamic instability at the time of admission to the operating room.
• Body mass index greater than 35 kg/m².

Individual participant data (IPD) will not be publicly shared. De-identified data may be made available by the corresponding author upon reasonable request and subject to institutional and ethical approval.

Participants, anesthesia providers, investigators, and outcome assessors were blinded to treatment allocation throughout the study. Intravenous lidocaine and placebo solutions were prepared in identical syringes by personnel not involved in patient management or outcome assessment.