Comparison of Opioid-Free versus Opioid-Based General Anesthesia for Reducing Nausea and Vomiting After Robotic Bariatric Surgery in Obese Patients (ANGELO Study)

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What is this study about?

This study focuses on obesity in patients undergoing robotic bariatric surgery (surgical procedures performed with robotic assistance to help reduce body weight). The purpose is to determine whether opioid-free general anesthesia reduces the frequency and intensity of postoperative nausea and vomiting compared to opioid-based general anesthesia. General anesthesia is medication that puts patients into a sleep-like state during surgery, while opioids are strong pain medications that can sometimes cause side effects like nausea and vomiting.

During the study, participants will be given either a type of general anesthesia that contains no opioid medications or the standard anesthesia that includes opioids. After surgery, researchers will monitor how much nausea and vomiting patients experience, along with their pain levels and need for additional pain medication during the first 24 hours following surgery.

1 Assignment to a study group

You will be randomly assigned to one of two anesthesia groups for your robotic bariatric (weight loss) surgery: either opioid-free general anesthesia or opioid-based general anesthesia.

This study aims to determine if opioid-free anesthesia reduces postoperative nausea and vomiting compared to traditional opioid-based anesthesia.

2 Receiving anesthesia during surgery

If you are in the opioid-free group, you will receive a combination of medications that may include magnesium sulfate, lidocaine hydrochloride, dexmedetomidine, and ketamine hydrochloride.

If you are in the opioid-based group, you will receive standard anesthesia medications which include opioid pain medications.

The anesthesiologist will administer these medications through an IV line while you are unconscious during your bariatric surgery.

3 Postoperative assessment period

After your surgery, you will be monitored for 24 hours to assess how you’re feeling.

You will be asked to rate your nausea using a Visual Analog Scale for Nausea (VAS-N), which is a simple line where you mark your level of nausea from none to severe.

You will also rate your pain using a similar Visual Analog Scale for Pain (VAS-P).

The medical team will record if and when you request any additional pain medication (opioids) during this 24-hour period.

4 Study completion

Your participation in the study will end after the 24-hour monitoring period following your surgery.

The information collected about your nausea, pain levels, and medication needs will be used to help determine which anesthesia approach might be better for future patients undergoing similar surgeries.

Who Can Join the Study?

You must be scheduled for bariatric surgery (weight loss surgery)
You must be between 18 and 75 years old
You must be voluntarily choosing to have the surgery (not emergency surgery)
You must be classified as ASA I-III (a health classification system where I means healthy, II means mild disease, and III means severe but not incapacitating disease)
You must be willing to sign an informed consent document
Both men and women can participate

Who Cannot Join the Study?

If you have a known hypersensitivity (severe allergic reaction) to any of the study medications
If you are under 18 years of age
If you are currently pregnant or breastfeeding
If you have severe heart problems that would make surgery risky
If you have severe liver disease that affects how your body processes medications
If you have severe kidney disease that affects how your body eliminates medications
If you have a history of chronic pain requiring regular opioid medication use
If you have uncontrolled high blood pressure that could increase surgical risks
If you have a history of adverse reactions to anesthesia in previous surgeries
If you are unable to provide informed consent due to cognitive issues or language barriers
If you are currently participating in another clinical trial that might interfere with this study

Where you can join this trial?

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Verified Sites

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Other Sites

Site Name	City	Country	Status
Hospital Universitari Arnau De Vilanova De La Gerencia Territorial De Lleida	Lleida	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	16.06.2025

Trial locations

Investigated drugs:

Opioid-Free General Anesthesia is a type of anesthesia technique that uses various non-opioid medications to keep patients comfortable and pain-free during surgery without using opioid painkillers. This approach aims to provide effective pain control while avoiding the side effects commonly associated with opioids, such as nausea and vomiting.

Opioid-Based General Anesthesia is the traditional approach to anesthesia that includes opioid medications (like fentanyl or morphine) as part of the pain management strategy during surgery. Opioids are powerful pain relievers commonly used during surgical procedures, but they can cause side effects such as postoperative nausea and vomiting.

Investigated diseases:

Obesity

Obesity – A chronic medical condition characterized by excessive accumulation of body fat to the extent that it may have negative effects on health. It occurs when a person’s body mass index (BMI) exceeds 30 kg/m². Obesity develops when energy intake consistently exceeds energy expenditure, leading to storage of excess calories as fat. This condition is associated with metabolic changes and can affect multiple body systems. Obesity increases the mechanical load on the body and alters normal physiology. Over time, it can lead to various complications including cardiovascular issues, insulin resistance, and joint problems.

Trial ID:

2025-521047-20-00

Protocol code:

ANGELO

Trial Phase:

Therapeutic confirmatory (Phase III)

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Comparison of Opioid-Free versus Opioid-Based General Anesthesia for Reducing Nausea and Vomiting After Robotic Bariatric Surgery in Obese Patients (ANGELO Study)

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?