Morbid ObesityNCT07337135

Opioid-Free vs Opioid-Based Anesthesia in Bariatric Surgery

A study testing Opioid-Based Anesthesia (Remifentanil-Based Protocol) and Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol) in people with Morbid Obesity and Postoperative Pain, run by Hospital dos Lusíadas at 1 site in Portugal.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Who is it for?: Ages 18 years and older
Conditions the study is for: Morbid Obesity, Postoperative Pain, Opioid Free Anesthesia
What is being tested?: Opioid-Based Anesthesia (Remifentanil-Based Protocol) and Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol)
Type of treatment: Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 60 participants
Where: 1 sitePortugal
Study dates: 2 Oct 2023to 21 Apr 2024
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

Age ≥ 18 years;
Body mass index (BMI ≥ 35 kg/m² with associated comorbidities) or BMI ≥ 40 kg/m²;
Scheduled for elective laparoscopic bariatric surgery;
Ability to provide informed consent.

Who cannot join

Pregnancy;
History of substance abuse;
Severe psychiatric disease;
Contraindications to any of the drugs used in either anesthetic protocol (dexmedetomidine, ketamine, lidocaine, remifentanil, etc.);
Inability to comply with study procedures;
Refusal or inability to provide informed consent.

Trial locations and contacts

1 site in 1 country.

Portugal1 site

Hospital Lusíadas Amadora - Lusíadas Saúde, S.A.
Amadora, 2724-002

Other trials in Portugal

About this study

Official title: Opioid-free Anesthesia vs Opioid-based Anesthesia / A Heavyweight Showdown - Randomized Controlled Trial

This prospective randomized controlled trial aims to compare the clinical effectiveness and safety of opioid-free anesthesia (OFA) versus traditional opioid-based anesthesia (OBA) in adult patients undergoing laparoscopic bariatric surgery. The study evaluates postoperative pain, need for rescue analgesia, incidence of postoperative nausea and vomiting (PONV), intraoperative nociception monitoring (NOL index), and patient satisfaction. A total of 60 patients were randomized into two parallel groups receiving either OFA or OBA according to standardized anesthetic protocols.

Read the detailed description

Bariatric surgery is the most effective treatment for severe and morbid obesity, but perioperative pain management and PONV remain significant challenges. Traditional opioid-based anesthesia is associated with adverse effects such as respiratory depression, postoperative hyperalgesia, ileus, and delayed recovery.

Opioid-free anesthesia is an emerging strategy based on the use of multimodal, non-opioid agents-including dexmedetomidine, lidocaine, and ketamine-aimed at providing adequate analgesia while reducing opioid-related complications.

This randomized controlled trial evaluates whether OFA improves postoperative pain control, reduces the requirement for rescue analgesia, and promotes better perioperative outcomes compared to OBA in laparoscopic bariatric surgery. Outcomes include NRS pain scores at multiple time points, NOL monitoring during surgery, PONV occurrence, and patient satisfaction at discharge.

Conditions: Morbid Obesity, Postoperative Pain, Opioid Free Anesthesia, Bariatric Surgery
Being tested: Opioid-Based Anesthesia (Remifentanil-Based Protocol), Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol)
Keywords: Opioid-free anesthesia, Bariatric surgery, Morbid obesity, Nausea and Vomiting, Postoperative pain
Medical subject headings: Obesity, Morbid, Pain, Postoperative, Nausea, Vomiting

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Opioid-Based Anesthesia (Remifentanil-Based Protocol)Drug
Participants receive standard opioid-based general anesthesia consisting of:
- Continuous remifentanil infusion (2 mg diluted in 40 mL saline),
- Propofol for induction,
- Rocuronium for neuromuscular blockade,
- Desflurane for maintenance,
- Dexamethasone 4-8 mg for PONV prophylaxis,
- Cefazolin for antibiotic prophylaxis,
- Esomeprazole for stress-ulcer prevention.
Postoperative analgesia includes paracetamol + ketorolac/parecoxib + metamizole, with tramadol and/or morphine provided as rescue. NOL, BIS, TOF, and standard monitoring are used.
Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol)Drug
Participants receive opioid-free anesthesia consisting of:
- Dexmedetomidine bolus (15-20 μg),
- Continuous infusion of dexmedetomidine 50 μg + ketamine 50 mg + lidocaine 500 mg in 50 mL saline (rate: 1 mL/10 kg),
- Propofol for induction,
- Rocuronium for neuromuscular blockade,
- Desflurane for maintenance,
- Dexamethasone for PONV prophylaxis,
- Cefazolin and esomeprazole for prophylaxis.
- The analgesic infusion is reduced by half 30 min before end of surgery and continued for 1 hour in PACU.
Postoperative analgesia includes paracetamol + ketorolac/parecoxib + metamizole, with tramadol 100 mg as rescue. Monitoring includes NOL, BIS, TOF.

Study groups in NCT07337135
Study group	Role	What they receive
Opioid-Based Anesthesia (OBA)	Active comparator	Standard opioid-based anesthesia using remifentanil infusion plus propofol induction, desflurane maintenance, and conventional multimodal analgesia, with opioids permitted for rescue. Receives: Drug: Opioid-Based Anesthesia (Remifentanil-Based Protocol)
Opioid-Free Anesthesia (OFA)	Experimental	Opioid-free anesthesia using dexmedetomidine, ketamine, and lidocaine infusion, combined with propofol induction, desflurane maintenance, and opioid-free multimodal analgesia, continued into early recovery. Receives: Drug: Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol)

What is being measured

The primary outcome is the main question the study is designed to answer.

Postoperative Pain Intensity Measured by the Numerical Rating Scale for Pain (NRS)
Postoperative pain will be assessed using the Numerical Rating Scale for Pain (NRS), a validated 11-point scale ranging from 0 (no pain) to 10 (worst pain imaginable). Higher scores indicate a worse outcome, reflecting greater pain intensity.
Pain intensity will be compared between the opioid-free anesthesia group and the opioid-based anesthesia group at predefined postoperative time points.
Measured: Time Frame: - Within 30 minutes of arrival at the Post-Anesthesia Care Unit (PACU); - At PACU discharge (assessed up to 2 hours after PACU admission); - Within the first 24 postoperative hours; - 48 hours postoperatively (at hospital discharge).

Secondary outcomes (7)

Intraoperative Nociception (NOL Index)
Nociception will be assessed using the NOL (Nociception Level) Index, a multiparametric autonomic signal-based monitor. Lower values reflect better nociceptive control. Comparisons will be made between OFA and OBA groups at all recorded time points.
Measured: Multiple standardized time points during surgery (15 to 180 minutes)
Need for Rescue Analgesia
The proportion of patients requiring rescue analgesia (tramadol and/or morphine) will be compared between the opioid-free anesthesia group and the opioid-based anesthesia group.
Measured: - During PACU stay (assessed up to 2 hours after PACU admission).
Opioid Consumption
Need for opioid administration as rescue analgesia will be recorded and compared between groups.
Measured: - During PACU stay (assessed up to 2 hours after PACU admission).
Incidence of Postoperative Nausea and Vomiting (PONV)
PONV will be assessed using the Postoperative Nausea and Vomiting Impact Scale, comparing frequency and severity between groups. The total score ranges from 0 (no nausea or vomiting) to 6 (maximum impact). Higher scores indicate a worse outcome, reflecting greater severity and clinical impact of postoperative nausea and vomiting.
Measured: At 6 hours and 24 hours after surgery
Need for PONV Treatment
Proportion of patients requiring antiemetic treatment will be evaluated and compared.
Measured: First 24 postoperative hours
Patient Satisfaction
Patient satisfaction will be assessed using a Numerical Satisfaction Rating Scale and compared between groups. Total score ranges from 1 (minimum satisfaction) to 10 (maximum satisfaction). Higher scores indicate a better outcome, reflecting greater patient satisfaction.
Measured: 48 hours postoperatively (at hospital discharge).
Postoperative Complications
Occurrence of perioperative complications (respiratory, cardiovascular, surgical, or anesthesia-related) will be recorded.
Measured: Periprocedurally, up to 48 hours postoperatively.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

2 Oct 202321 Apr 2024

First posted13 Jan 2026
Study start2 Oct 2023
Primary completion19 Apr 2024
Study completion21 Apr 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Morbid ObesityStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Model description: Prospective, randomized, two-arm parallel-group clinical trial comparing opioid-free anesthesia versus opioid-based anesthesia in patients undergoing laparoscopic bariatric surgery.
Masking: None (open label)
Enrolment: 60 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT07337135
Sponsor's protocol ID: CESHLAM17072023
Status last verified: Feb 2026
First submitted: 10 Dec 2025
Last updated: 25 Feb 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No: Individual participant data will not be shared due to privacy restrictions and institutional regulations. Only aggregated results will be made available in publications.

Publications

Almeida E, Almeida F, Rossoni C, Ribeiro R. Opioid-free versus opioid-based anesthesia in laparoscopic bariatric surgery: an exploratory randomized pilot trial. BMC Anesthesiol. 2026 May 25. doi: 10.1186/s12871-026-03838-4. Online ahead of print.
PubMed 42185786

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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Study at a glance

From the registry record, last updated by the sponsor on 25 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Opioid-free Anesthesia vs Opioid-based Anesthesia / A Heavyweight Showdown - Randomized Controlled Trial
ClinicalTrials.gov ID: NCT07337135
Acronym / sponsor ID: CESHLAM17072023
Conditions: Morbid Obesity, Postoperative Pain, Opioid Free Anesthesia, Bariatric Surgery
Keywords: Opioid-free anesthesia, Bariatric surgery, Morbid obesity, Nausea and Vomiting, Postoperative pain
Study type: Interventional
Recruitment status: Completed
Enrolment: 60 participants (actual)
Lead sponsor: Hospital dos LusíadasUniversity, hospital or other
Study start: 2 Oct 2023 (actual)
Primary completion: 19 Apr 2024 (actual)
Study completion: 21 Apr 2024 (actual)
First posted: 13 Jan 2026 (actual)
Results: Posted 25 Feb 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 2
Model description: Prospective, randomized, two-arm parallel-group clinical trial comparing opioid-free anesthesia versus opioid-based anesthesia in patients undergoing laparoscopic bariatric surgery.

Arm	Type	Receives
Opioid-Based Anesthesia (OBA)	Active comparator	Drug: Opioid-Based Anesthesia (Remifentanil-Based Protocol)Standard opioid-based anesthesia using remifentanil infusion plus propofol induction, desflurane maintenance, and conventional multimodal analgesia, with opioids permitted for rescue.
Opioid-Free Anesthesia (OFA)	Experimental	Drug: Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol)Opioid-free anesthesia using dexmedetomidine, ketamine, and lidocaine infusion, combined with propofol induction, desflurane maintenance, and opioid-free multimodal analgesia, continued into early recovery.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (4 listed)

Age ≥ 18 years;
Body mass index (BMI ≥ 35 kg/m² with associated comorbidities) or BMI ≥ 40 kg/m²;
Scheduled for elective laparoscopic bariatric surgery;
Ability to provide informed consent.

Key exclusion criteria (6 listed)

Pregnancy;
History of substance abuse;
Severe psychiatric disease;
Contraindications to any of the drugs used in either anesthetic protocol (dexmedetomidine, ketamine, lidocaine, remifentanil, etc.);
Inability to comply with study procedures;

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Opioid-Based Anesthesia (Remifentanil-Based Protocol)Participants receive standard opioid-based general anesthesia consisting of: * Continuous remifentanil infusion (2 mg diluted in 40 mL saline), * Propofol for induction, * Rocuronium for neuromuscular blockade, * Desflurane for maintenance, * Dexamethasone 4-8 mg for PONV prophylaxis, * Cefazolin for antibiotic prophylaxis, * Esomeprazole for stress-ulcer prevention. Postoperative analgesia includes paracetamol + ketorolac/parecoxib + metamizole, with tramadol and/or morphine provided as rescue. NOL, BIS, TOF, and standard monitoring are used.	Drug	Opioid-Based Anesthesia (OBA)
Opioid-Free Anesthesia (Dexmedetomidine-Ketamine-Lidocaine Protocol)Participants receive opioid-free anesthesia consisting of: * Dexmedetomidine bolus (15-20 μg), * Continuous infusion of dexmedetomidine 50 μg + ketamine 50 mg + lidocaine 500 mg in 50 mL saline (rate: 1 mL/10 kg), * Propofol for induction, * Rocuronium for neuromuscular blockade, * Desflurane for maintenance, * Dexamethasone for PONV prophylaxis, * Cefazolin and esomeprazole for prophylaxis. * The analgesic infusion is reduced by half 30 min before end of surgery and continued for 1 hour in PACU. Postoperative analgesia includes paracetamol + ketorolac/parecoxib + metamizole, with tramadol 100 mg as rescue. Monitoring includes NOL, BIS, TOF.	Drug	Opioid-Free Anesthesia (OFA)

Primary outcome

Postoperative Pain Intensity Measured by the Numerical Rating Scale for Pain (NRS)
Time frame: Time Frame: - Within 30 minutes of arrival at the Post-Anesthesia Care Unit (PACU); - At PACU discharge (assessed up to 2 hours after PACU admission); - Within the first 24 postoperative hours; - 48 hours postoperatively (at hospital discharge).
Postoperative pain will be assessed using the Numerical Rating Scale for Pain (NRS), a validated 11-point scale ranging from 0 (no pain) to 10 (worst pain imaginable). Higher scores indicate a worse outcome, reflecting greater pain intensity. Pain intensity will be compared between the opioid-free anesthesia group and the opioid-based anesthesia group at predefined postoperative time points.

7 secondary outcomes

Intraoperative Nociception (NOL Index)
Time frame: Multiple standardized time points during surgery (15 to 180 minutes)
Need for Rescue Analgesia
Time frame: - During PACU stay (assessed up to 2 hours after PACU admission).
Opioid Consumption
Time frame: - During PACU stay (assessed up to 2 hours after PACU admission).
Incidence of Postoperative Nausea and Vomiting (PONV)
Time frame: At 6 hours and 24 hours after surgery
Need for PONV Treatment
Time frame: First 24 postoperative hours
Patient Satisfaction
Time frame: 48 hours postoperatively (at hospital discharge).
Postoperative Complications
Time frame: Periprocedurally, up to 48 hours postoperatively.

Results and safety

Results posted to the registry on 25 Feb 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Opioid-Free Anesthesia (OFA)	30	30
Opioid-Based Anesthesia (OBA)	30	30

Primary outcome: Postoperative Pain Intensity Measured by the Numerical Rating Scale for Pain (NRS)

Time frame: Time Frame: - Within 30 minutes of arrival at the Post-Anesthesia Care Unit (PACU); - At PACU discharge (assessed up to 2 hours after PACU admission); - Within the first 24 postoperative hours; - 48 hours postoperatively (at hospital discharge).. Median (Inter-Quartile Range). Unit: Score on a scale (0-10)

Measure	Opioid-Based Anesthesia (OBA) n = 30	Opioid-Free Anesthesia (OFA) n = 30
Within 30 minutes of arrival at the Post-Anesthesia Care Unit (PACU)	2.5 (0 to 5.5)	0 (0 to 2)
At PACU discharge (assessed up to 2 hours after PACU admission)	3 (1 to 5)	1 (0 to 3)
Within the first 24 postoperative hours;	3 (2 to 4)	1 (0 to 3)
48 hours postoperatively (at hospital discharge)	0 (0 to 2)	0 (0 to 0)

Population analysed: All randomized participants were included in the analysis of postoperative pain intensity. Pain assessments were available for all participants at the predefined time points, and no participants were excluded from this outcome analysis.

7 secondary outcomes are reported in the full results.

Adverse events

Time frame: Periprocedurally, up to 48 hours postoperatively.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Opioid-Free Anesthesia (OFA)	0 of 30 (0%)	0 of 30 (0%)	0 of 30
Opioid-Based Anesthesia (OBA)	0 of 30 (0%)	0 of 30 (0%)	0 of 30

Limitations and caveats (from the sponsor): This study was conducted at a single center with a relatively small sample size, which may limit the generalizability of the findings. The trial was retrospectively registered, and some intraoperative measurements (NOL index) were available only for a subset of participants, with the number of observations varying across time points due to differences in surgical duration. Differences in antiemetic prophylaxis between groups may also have influenced postoperative nausea and vomiting outcomes.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 25 Feb 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 42185786Almeida E, Almeida F, Rossoni C, Ribeiro R. Opioid-free versus opioid-based anesthesia in laparoscopic bariatric surgery: an exploratory randomized pilot trial. BMC Anesthesiol. 2026 May 25. doi: 10.1186/s12871-026-03838-4. Online ahead of print.
Individual participant dataSharing planned: No. Individual participant data will not be shared due to privacy restrictions and institutional regulations. Only aggregated results will be made available in publications.

Related trials for Morbid Obesity

Not yet recruitingObservational study
Pilot Study on the Effectiveness and Safety of OPTILENE® SILVER MESH ELASTIC in Prevention of Surgical Site Infection (SSI) and Incisional Hernia (IH)
Abdominal Aortic Aneurysm, Morbid Obesity
Not yet recruitingObservational study
Evaluating Metabolic Health in Individuals With Extreme Obesity
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Emanuel J Almeida, MD principal investigator

Hospital dos Lusíadas

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 25 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Portugal. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 25 Feb 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Postoperative Pain Intensity Measured by the Numerical Rating Scale for Pain (NRS) (time frame: Time Frame: - Within 30 minutes of arrival at the Post-Anesthesia Care Unit (PACU); - At PACU discharge (assessed up to 2 hours after PACU admission); - Within the first 24 postoperative hours; - 48 hours postoperatively (at hospital discharge).). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07337135, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Feb 2026.