Nociception Level During Opioid-sparing Anaesthesia Versus Conventional Opioid-based Anaesthesia

Opioids have been an integral part of general anaesthesia. They are effective in preventing perception of noxious stimuli and ensure intraoperative haemodynamic stability. However, opioids are associated with a number of unwanted side effects (e.g. nausea and vomiting, sedation, ileus, respiratory depression, increased postoperative pain and morphine consumption and hyperalgesia). To minimise these side effects, there has been an interest in developing opioid-sparing anaesthesia protocols. Recently, analgesia nociception monitoring devices have become available. The aim of this double blind, randomised controlled non-inferiority trial is to compare the antinociceptive efficiency of an opioid-sparing and a conventional opioid-based anaesthesia protocol with the help of the CEcertificated Pain Monitoring Device (PMD-200). Patients scheduled to receive general surgical, gynaecological or urological laparoscopic surgery will be randomised into one of the two study groups. Study group A will be anaesthetised with an opioid-sparing protocol and study group B will be anaesthetised with a conventional opioid-based protocol. Intraoperative nociception will be evaluated with PMD-200. Postoperative visits will take place in recovery, 4-5h after surgery and then twice a day. In recovery, the amount of opioids and ketamine needed, pain, postoperative nausea and vomiting (PONV) and the time until the patient is fit for discharge according to the Aldrete score will be assessed. At the 4-5h postoperative visit, the amount of opioids and ketamine needed, maximum pain at rest and at mobilisation, incidence of PONV, mobilisation, micturition and sedation level will be assessed. At the twice daily follow up visits, amount of opioids and other analgesic drugs needed, pain at rest and at mobilisation, gastrointestinal function, quality of night's sleep, incidence of PONV, level of sedation and fitness for discharge home will be assessed. On day one after surgery, the perceived quality of recovery will be assessed with the QoR40 questionnaire.

Inclusion criteria

• Informed Consent as documented by signature
• Age older than 18 years
• Ability to give informed consent
• Undergoing scheduled general surgical, gynaecological or urological laparoscopic surgery
• American Society of Anesthesiology Score (ASA) status I, II, III

Exclusion criteria

• Inability to give informed consent
• ASA status IV and V
• Pregnant or breastfeeding women
• Allergy to one of the study drugs
• Urgent surgery
• Surgery with planned regional anaesthesia
• Outpatient surgery
• Atrioventricular block, intraventricular or sinoatrial block
• Atrial fibrillation
• Sinus bradycardia
• Cardiac insufficiency with a reduced left ventricular ejection fraction of below 40%
• Coronary artery disease
• Epilepsy
• Liver cirrhosis
• Chronic kidney disease (Clearance < 50ml/h)
• Chronic opioid therapy
• Chronic pain