OFA vs OBA in Bariatric Surgery (OFA VS OBA1)

July 11, 2025 updated by: HIPÓLITO LABANDEYRA GONZALEZ, Hospital HM Nou Delfos

Comparison of Postoperative Morphine Requirements Between an Opioid-Based and an Opioid-Free Anesthesia Technique in Morbidly Obese Patients Undergoing Bariatric Surgery

This study compares two different anesthesia techniques in patients with obesity undergoing bariatric surgery: one that includes opioids (OBA), and one that avoids them completely (OFA). The main goal is to determine whether avoiding opioids during surgery leads to lower postoperative morphine requirements and fewer side effects. Researchers reviewed medical records of 70 patients who had bariatric surgery between June 2022 and December 2023 at a hospital in Spain. The study evaluates pain levels, sedation, complications, and total morphine use in the first 48 hours after surgery.

Study Overview

Status

Completed

Conditions

Detailed Description

This is a single-center, retrospective, observational cohort study conducted at Hospital HM Nou Delfos (Barcelona, Spain). The aim is to compare postoperative opioid requirements and outcomes in patients with morbid obesity undergoing laparoscopic bariatric surgery, according to the intraoperative anesthesia technique used.

Two anesthetic strategies were evaluated:

Opioid-Free Anesthesia (OFA): Total intravenous anesthesia (TIVA) without opioids, using agents such as propofol, ketamine, dexmedetomidine, lidocaine and magnesium.

Opioid-Based Anesthesia (OBA): TIVA including opioids, following institutional standards.

Medical records of 70 patients (35 in each group) who underwent surgery between June 2022 and December 2023 were analyzed. Key data extracted included demographics, surgical duration, anesthetic drugs used, intraoperative complications, pain scores (VAS at 1, 2, 4, 24, and 48 hours), sedation levels (RAMSAY scale), adverse effects (e.g., nausea, vomiting, ileus, hypotension), and morphine consumption.

The primary outcome is total morphine use within the first 48 hours postoperatively. Secondary outcomes include pain scores, adverse events, time to awakening, and hospital length of stay. Statistical analysis was performed using descriptive and inferential methods, including regression models adjusted for age, sex, BMI, and comorbidities.

This study provides real-world evidence on the clinical impact of opioid-free anesthesia in bariatric patients, aiming to improve perioperative safety and enhance postoperative recovery.

Study Type

Observational

Enrollment (Actual)

70

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Spain
      • Barcelona, Spain, 08023
        • Hospital HM Nou Delfos

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients (18-65 years) with obesity (BMI ≥ 30 kg/m²) classified as ASA II-III, who underwent laparoscopic bariatric surgery under general anesthesia at HM Nou Delfos between June 2022 and December 2023. Patients were retrospectively assigned to one of two groups based on the anesthetic technique used: opioid-free anesthesia (OFA) or opioid-based anesthesia (OBA).

Description

Inclusion Criteria Age between 18 and 65 years

Body Mass Index (BMI) ≥ 30 kg/m²

ASA physical status II or III

Underwent laparoscopic bariatric surgery under general anesthesia at HM Nou Delfos

Surgery performed between June 1, 2022 and December 31, 2023

Exclusion Criteria Pregnancy or breastfeeding

Chronic pain patients on high-dose opioids

Known allergy to any anesthetic drug used in the study

Severe hepatic (e.g., cirrhosis with portal hypertension) or renal insufficiency

Untreated coagulopathy

Active alcohol or drug abuse

Uncontrolled or severe psychiatric illness

Intraoperative complications requiring deviation from planned anesthetic technique

Postoperative morphine use exceeding institutional norms for bariatric surgery

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
OFA Group
Patients who received opioid-free total intravenous anesthesia (TIVA) for bariatric surgery, including propofol, lidocaine, ketamine, dexmedetomidine and magnesium, with no intraoperative opioids.
OBA Group
Patients who received opioid-based total intravenous anesthesia (TIVA) for bariatric surgery, including propofol and intraoperative opioids such as fentanyl, remifentanil and morphine, following standard practice.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total postoperative morphine consumption (mg)
Time Frame: From 0 to 48 hours after surgery
Cumulative amount of morphine (in milligrams) administered within the first 48 hours after surgery, as recorded in the post-anesthesia care unit and inpatient medical records.
From 0 to 48 hours after surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain intensity (VAS)
Time Frame: At 1, 2, 4, 24, and 48 hours postoperatively
Pain evaluated using the Visual Analog Scale (VAS) from 0 (no pain) to 10 (worst imaginable pain), both at rest and with movement.
At 1, 2, 4, 24, and 48 hours postoperatively
Sedation level (RAMSAY scale)
Time Frame: From 0 to 48 hours after surgery
Sedation assessed using the Ramsay Sedation Scale, ranging from 1 (anxious/agitated) to 6 (no response to stimuli).
From 0 to 48 hours after surgery
Incidence of adverse events
Time Frame: Up to 48 hours after surgery
Number of patients experiencing side effects such as nausea, vomiting, pruritus, hypotension, bradycardia, ileus, or urinary retention.
Up to 48 hours after surgery
Length of hospital stay
Time Frame: From surgery until discharge (up to 7 days)
Total duration of hospital stay in days, calculated from the day of surgery to discharge date.
From surgery until discharge (up to 7 days)
Time to awakening
Time Frame: Intraoperative period until recovery (measured at end of surgery)
Time in minutes from the end of surgery until patient opens eyes or responds to verbal commands.
Intraoperative period until recovery (measured at end of surgery)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hospital HM Nou Delfos

Investigators

  • Principal Investigator: Gregory Contreras-Pérez, Anesthesiologist, Hospital HM NouDelfos

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2022

Primary Completion (Actual)

December 31, 2023

Study Completion (Actual)

January 31, 2024

Study Registration Dates

First Submitted

July 11, 2025

First Submitted That Met QC Criteria

July 11, 2025

First Posted (Actual)

July 20, 2025

Study Record Updates

Last Update Posted (Actual)

July 20, 2025

Last Update Submitted That Met QC Criteria

July 11, 2025

Last Verified

July 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25.04.2517-GHM

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

This is a retrospective study involving patient health records. Due to ethical and privacy regulations, individual participant data cannot be shared publicly. Access is restricted to the research team as approved by the ethics committee.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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