COMPARISON OF OPIOID-FREE AND OPIOID-BASED ANESTHESIA TECHNIQUES ON qNOX INDEX IN ABDOMINAL SURGERY UNDER GENERAL ANESTHESIA

Summary

This study is a randomized, double-blind controlled clinical trial designed to evaluate the effects of opioid-free anesthesia (OFA) compared with opioid-based anesthesia (OBA) in adult patients undergoing elective abdominal surgery under general anesthesia. Opioid-free anesthesia uses a multimodal combination of ketamine, lidocaine, and dexmedetomidine to provide analgesia and autonomic stability without intraoperative opioid administration. In contrast, the opioid-based approach utilizes fentanyl as the primary analgesic agent, which remains the conventional method in many surgical settings.

The primary objective of this study was to compare the nociceptive response between OFA and OBA techniques using the qNOX index, a quantitative parameter provided by the CONOX® monitor that reflects the probability of patient response to noxious stimuli. qNOX values were recorded at several key intraoperative time points: before induction, during intubation, before incision, during the surgical incision, and one hour after incision. Secondary outcomes included intraoperative hemodynamic stability and the incidence of postoperative nausea and vomiting (PONV).

A total of 42 patients were enrolled and randomly assigned into two equal groups. Both groups underwent surgery under standardized protocols to ensure comparable anesthetic depth and surgical conditions. The study found no significant differences in qNOX values between the OFA and OBA groups at any measured time point, suggesting that nociceptive control was equally effective in both techniques. Hemodynamic parameters remained stable and comparable across groups throughout the intraoperative period.

However, a notable difference was observed in the incidence of postoperative nausea and vomiting. The OFA group experienced a significantly lower rate of PONV compared to the OBA group, indicating a potential clinical benefit of avoiding intraoperative opioid exposure. These findings support the use of OFA as a safe and effective alternative to traditional opioid-based strategies, particularly in patients at risk for opioid-related adverse effects.

Overall, this study provides evidence that opioid-free anesthesia can offer equivalent intraoperative analgesic control while reducing postoperative opioid-associated complications.

Conditions

• Opioid-free Anesthesia

Interventions

DRUG

Non Opioid Analgesics

Participants in this arm will receive opioid-free anesthesia (OFA), an anesthetic approach that avoids the use of intraoperative opioids and utilizes a multimodal non-opioid regimen. The protocol includes dexmedetomidine for sedation and sympatholysis, low-dose ketamine for analgesia and prevention of central sensitization, intravenous lidocaine for systemic analgesic and anti-inflammatory effects, magnesium sulfate as an N-methyl-D-aspartate (NMDA) receptor antagonist to enhance analgesia, acetaminophen for central non-opioid analgesia, and nonsteroidal anti-inflammatory drugs (NSAIDs) for peripheral analgesic and anti-inflammatory effects. These agents are administered according to institutional protocols to provide adequate anesthesia and analgesia while minimizing opioid exposure.

Sponsors & Collaborators

• Muhammad Rahman Efendi Nasution

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-09-08

Primary Completion

2025-11-12

Completion

2025-12-01

Countries

• Indonesia

Study Locations