Opioid-free Anesthesia as an Alternative to General Anesthesia in Abdominal Surgery

All consecutive patients undergoing elective urological surgery (laparoscopic or robotic nephrectomy, prostatectomy, or cystectomy) will be randomly divided into two groups: one under completely opioid-free anesthesia (infusion of ketamine, lidocaine and dexmedetomidine, with inhalation of sevoflurane) and the other under combined general anesthesia (using an infusion of remifentanil intraoperatively). In the postoperative period, all patients will receive oxycodone in a PCA pump or in the form of oral tablets [oxycodone hydrochloride + naloxone hydrochloride] and co-analgesics in the form of paracetamol and metamizole.

Opioid-free general anesthesia is a recognized method used during anesthesia. It allows participants to effectively control pain, reducing the number of complications associated with taking large doses of opioid drugs. It should be emphasized that it is approved for use in routine anesthetic practice, and whether such a technique is used in a given patient depends on the experience, knowledge and preferences of the anesthesiologist. It is used in everyday anesthetic practice, but there is no conclusive scientific data confirming its advantage in patients undergoing major urological surgery.

Mulier et al. proposed an OFA scheme including dexmedetomidine, ketamine and lidocaine for the induction of anesthesia, ensuring sedation, analgesia and sympatholytic therapy, followed by a maintenance infusion of lidocaine and dexmedetomidine. The protocol proposed by Mulier et al. is widely used and accepted worldwide. Initially used in patients undergoing bariatric procedures, it was subsequently extended to other types of surgical procedures.

In the postoperative period, pain will be assessed using the NRS scale at 1, 2, 6, 12, and 24 hours after the procedure. Serum creatinine and white blood cell (WBC) count will be measured preoperatively (baseline) and on postoperative day 1.

Inclusion criteria

• Adults aged 18-75 years scheduled for elective urological surgery under general anesthesia: laparoscopic or robotic nephrectomy, laparoscopic or robotic prostatectomy, or laparoscopic or robotic cystectomy.
• Ability to operate a patient-controlled analgesia (PCA) pump postoperatively.
• Ability to understand and use the Numeric Rating Scale (NRS) for pain assessment.
• Written informed consent.

Exclusion criteria

• Patient's refusal to participate.
• Inability to operate the PCA pump.
• Inability to understand the NRS pain scale.
• Known hypersensitivity to any of the study drugs (anesthetics, ketamine, dexmedetomidine, ropivacaine, oxycodone, metamizole, paracetamol, ibuprofen).
• Second- or third-degree atrioventricular block, or symptomatic bradycardia.
• Chronic opioid use.
• Contraindication to the planned regional anesthesia technique (e.g. coagulopathy or therapeutic anticoagulation, infection at the puncture site).