Anaesthesia has three major components, analgesia, muscle relaxation and hypnosis.

For a long time, opioids have been covering the analgesia function. (1) When using opioids, an analgesic effect is obtained per-operatively, however, not without side-effects. Post-operative complications such as: respiratory depression, post-operative nausea and vomiting, pruritus, acute opioid tolerance and hyperalgesia, difficulty voiding and ileus, are well known.

Opioid usage is an important risk factor of postoperative desaturation. Postoperative desaturation can lead to severe hypoxemia and even tissue hypoxia, followed by obvious cardiologic and neurological complications.

Thus, in patients at risk, such as the obese patient, experts suggest reducing opioid usage.

Non-opiate protocols implemented on the obese patient have been published. Non-opiate protocols have been established using a combination of ketamine, lidocaine and an alpha-2 agonist.

The main purpose of this pilot study is to evaluate whether patients undergoing an opioid free anaesthesia regime experience less desaturation episodes during the first 24 h post-bariatric surgery than patients having received an opioid anaesthesia regime.

Anaesthesia has three major components, analgesia, muscle relaxation and hypnosis.

For a long time, opioids have been covering the analgesia function. When using opioids, an analgesic effect is obtained per-operatively, however, not without side-effects. Post-operative complications such as: respiratory depression, post-operative nausea and vomiting, pruritus, acute opioid tolerance and hyperalgesia, difficulty voiding and ileus, are well known. These complications may lead to a prolonged hospital stay.

Opioid usage is an important risk factor of postoperative desaturation. Postoperative desaturation can lead to severe hypoxemia and even tissue hypoxia, followed by obvious cardiologic and neurological complications.

Thus, in patients at risk, such as the obese patient, experts suggest reducing opioid usage.

Authors have indeed published non-opiate protocols implemented on the obese patient.

Non-opiate protocols have been established using a combination of ketamine, lidocaine and an alpha-2 agonist.

The main purpose of this pilot study is to evaluate whether patients undergoing an opioid free anaesthesia regime experience less desaturation episodes during the first 24 h post-bariatric surgery than patients having received an opioid anaesthesia regime.

Inclusion Criteria:

• All patients undergoing a gastric by-pass surgery will be screened.
• Patients with an ASA physical status of I-II-III (BMI >30) will be included.
• Knowledge of either French, English or Dutch will be required in order to be enrolled in this study.

Exclusion Criteria:

• allergy or contraindications to one of the study drugs
• renal failure
• hepatic failure
• hyperthyroidism
• AV block 2 or 3
• severe bradycardia
• left ventricular failure
• unstable blood pressure
• severe respiratory disease
• epilepsy
• psychiatric disturbance.