Opioid Use Unspecified

Being relatively new, the NOL monitor may offer interesting observations in perioperative nociception levels and appropriate analgesic consumption in diverse surgeries, including robot-assisted surgery. These observations may supplement the current efforts towards further advantages in rapid restitution. Therefore, the investigators planned a trial where intra-operative analgesics were guided using an NOL monitor to study if intra-operative NOL guidance influences peri-operative analgesic consumption, postoperative length of stay and quality of recovery of patients subjected for robot-assisted surgery.

The goal of this clinical trial is to compare Opioid Free and Opioid Based Anaesthesia in patients undergoing sleeve gastrectomy. The main questions it aims to answer are: * Will the total dose of intraoperative opioid be reduced? * Will there be difference in pain scores between groups? Participants will be managed with the Nociceptive Level Index algorithm to guide intraoperative analgesia. The Opioid Free Anaesthesia Group will be administered the Multimix infusion (Magnesium sulfate, dexmedetomidine, ketamine). The Opioid Based Anaesthesia Group will receive fentanyl as a bolus dose and remifentanil infusion. Rescue fentanyl bolused will be injected as appropriate according to nociceptive level (NOL) values.

The incidence and severity of postoperative pain after spine surgery are notably high, often requiring intensive management and potentially affecting the patient's recovery, satisfaction, and long-term outcomes. Post-operative pain is particularly difficult to manage in patients with substance use disorder likely due to a combination of withdrawal symptoms and molecular changes in the pain matrix. Opiates are the leading cause of overdose related fatalities, and carry a significant burden of substance related morbidity and mortality. As over 80% of patients undergoing low-risk surgery receive opioid prescriptions, the investigators aim to identify unique molecular characteristics of pain within current and previous opioid users, which have been understudied in this context. This study also seeks to understand the molecular mechanisms underlying worsened postoperative pain in patients with opioid use disorder (OUD). Flow cytometry analysis of human serum will be done, which will assess circulating immune cells that can contribute to exacerbated surgery site inflammation. Spatial profiling of gene expression will be done in the dermis using Visium slide sequencing, focusing on the interplay between nerve endings, resident immune cells, and supporting dermal cells, all of which collectively contribute to the sensation pain. Both the visual pain rating scale and McGill Pain Questionnaire will be used to comprehensively quantify pain outcomes during the participant's postoperative recovery stay after surgery in an effort to better understand postoperative pain management with biomarkers of worsened postoperative pain.

The objective of this study is to better understand the comprehensive integration of both clinical and genetic factors that will help to identify mothers who could be at an increased risk of poor response to opioid substitution and infants at risk of significant neonatal abstinence syndrome (NAS).

This study aims to evaluate esmolol's perfusion impact during induction and maintenance of general anesthesia, using Nociception-Level-guided control of nociception, in adult patients undergoing laparoscopic and lower abdominal surgery, on intraoperative remifentanil consumption and postoperative pain in the Post-Anesthesia Care Unit.