Modulation of the Inflammatory Response in Bariatric Surgery

Recruiting

• Conditions: Obesity; Bariatric Surgery Candidate; Inflammation; Postoperative Pain; Opioid-Free Anesthesia; Heart Rate Variability

• Registration Number: NCT06915558
• Lead Sponsor: Hospital HM Nou Delfos

Brief Summary

This study will evaluate how different anesthesia techniques affect inflammation after bariatric surgery. Patients will be randomly assigned to receive one of three approaches: opioid-free anesthesia, intravenous anesthesia with opioids, or inhalational anesthesia with opioids.

The study will measure blood levels of inflammation-related substances (such as IL-6, CRP, cortisol, ESR , WBC and lactate) at several time points before and after surgery. Heart rate variability will also be monitored as an indicator of the body's stress response.

The results may help identify anesthesia strategies that reduce inflammation and improve recovery in patients undergoing bariatric surgery.

Detailed Description

This is a prospective, randomized, double-blind, comparative observational study designed to assess the perioperative inflammatory response in patients undergoing bariatric surgery under three anesthetic techniques: opioid-free anesthesia (OFA), opioid-based intravenous anesthesia (OBA-IV), and opioid-based inhalational anesthesia (OBA-Inh).

A total of 90 patients scheduled for elective laparoscopic bariatric surgery will be enrolled and randomized using computer-generated allocation into three equal groups (n=30 each). Allocation concealment will be maintained using sealed opaque envelopes. Blinding will involve both the patients and outcome assessors; anesthesiologists administering the interventions will not be blinded due to the nature of the techniques.

The study's primary focus is to evaluate the perioperative modulation of inflammation through quantification of biomarkers including interleukin-6 (IL-6), C-reactive protein (CRP), serum cortisol, leukocyte count (WBC), erythrocyte sedimentation rate (ESR) and lactate. Heart rate variability (HRV) will be continuously monitored as a surrogate marker for autonomic modulation of the inflammatory response.

Biomarkers will be sampled at three time points: preoperative baseline (T0), at the end of surgery (T1), and 24 hours postoperatively (T2). HRV data will be collected from induction to the end of surgical intervention using a non invasive monitoring system with time- and frequency-domain analysis.

Secondary outcomes include intraoperative and postoperative analgesic consumption, pain intensity assessed by visual analog scale (VAS), sedation scores using the Ramsay Agitation-Sedation Scale (RASS), incidence of opioid-related side effects (nausea, vomiting, respiratory depression), patient satisfaction (via validated questionnaire), and length of hospital stay.

Sample size was calculated based on preliminary data detecting a clinically significant difference in IL-6 levels, assuming an alpha of 0.05 and power of 0.8. Data will be analyzed using ANOVA or Kruskal-Wallis test for continuous variables, chi-square for categorical variables, and multivariate regression models to adjust for potential confounders.

This study aims to identify anesthetic strategies that minimize systemic inflammation and autonomic dysregulation in the bariatric surgical population, with potential applications in broader surgical settings.

Study Timeline

• Study Start: 2024-12-02
• Status Verified: 2025-03
• Study First Submitted: 2025-03-24
• Study First Submitted QC: 2025-04-04
• Last Update Submitted: 2025-04-04
• Study First Posted: 2025-04-08
• Last Update Posted: 2025-04-08
• Primary Completion: 2025-12-02
• Study Completion: 2025-12-02

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 90

Inclusion Criteria

• Patients scheduled for bariatric surgery.
• Age 18-65 years.
• BMI ≥ 30 kg/m².
• ASA physical status II-III.

Exclusion Criteria

• Pregnancy or breastfeeding.
• Chronic opioid use before surgery.
• Severe renal or hepatic failure.
• Uncontrolled psychiatric disorders.
• Significant intraoperative complications requiring protocol deviation.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Serum IL-6 Level	Preoperative (baseline), immediately after surgery, and 24 hours post-surgery.	Measurement of interleukin-6 (IL-6) concentration in pg/mL to evaluate inflammatory response.
C-reactive Protein (CRP) Level	Preoperative (baseline), immediately after surgery, and 24 hours post-surgery.	Measurement in mg/L to assess systemic inflammation.
Differential White blood Cell count (WBC).	Preoperative (baseline), immediately after surgery, and 24 hours post-surgery.	Measurement of total white blood cell count in peripheral blood, expressed in thousands of cells per microliter (10³/μL). Assessment of the percentage distribution of white blood cell subtypes, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, expressed as a percentage of total leukocytes.
Serum Cortisol Level	Preoperative (baseline), immediately after surgery, and 24 hours post-surgery.	Measurement in μg/dL.
Heart Rate Variability (HRV) as an Inflammatory Marker	Collected continuosly from the induction of the anesthesia until the end of surgery	Heart Rate Variability (HRV) as an Inflammatory Marker and its correlation with blood levels of inflammatory markers Heart Rate Variability (HRV) as an Indicator of Inflammatory Response
Serum Lactate Level	Preoperative (baseline), immediately after surgery, and 24 hours post-surgery.	Measurement in mmol/L as a marker of metabolic response.
Erythrocyte Sedimentation Rate (ESR)	Preoperative (baseline), immediately after surgery, and 24 hours post-surgery.	Measurement of ESR in mm/h to assess systemic inflammation.

Secondary Outcome Measures

Name	Time	Method
Patient Satisfaction with Anesthetic Technique	24 hours post-surgery.	Evaluation of patient satisfaction using a standardized 5-point Likert scale questionnaire (1 = very dissatisfied; 5 = very satisfied) regarding anesthesia and overall recovery experience.
Postoperative Pain Evaluation Using Visual Analog Scale (VAS)	hourly during the first 4 hours post surgery in the recovery area, and at 12 and 24 hours in the hospitalization ward	Assessment of pain intensity using the Visual Analog Scale (VAS), a 10 cm scale ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Postoperative Sedation Level Using Ramsay Sedation Scale	immediately after surgery, and hourly during the first 4 hours in the recovery area, and at 12 and 24 hours in the hospitalization ward	Evaluation of sedation using the Ramsay Sedation Scale, which ranges from 1 (anxious and agitated) to 6 (no response to stimulus). Higher scores indicate deeper levels of sedation.
Incidence of Postoperative Complications	24 hours post-surgery.	Measurement of total hospital stay (in days) after surgery.

Trial Locations

Locations (1)

Hospital HM Nou Delfos; 🇪🇸 Barcelona, Spain