Opioid Free Anesthesia

Opioid-free anesthesia (OFA) is a multimodal analgesic approach designed to eliminate the intraoperative use of systemic, neuraxial, or intracavitary opioids. This technique employs a combination of antinociceptive agents targeting various pathways within the central and peripheral nervous systems to achieve effective analgesia. Dexmedetomidine (DEX), a highly selective α2-adrenoreceptor agonist, is a centrally acting non-opioid agent increasingly utilized in clinical practice for its antinociceptive and anxiolytic properties. Only a few prospective randomized controlled trials have specifically examined the postoperative analgesic efficacy of intraoperative dexmedetomidine infusion in patients undergoing spinal surgery, with limited data focusing on this as a primary endpoint. Importantly, no clinical studies have investigated its analgesic impact in patients undergoing spinal surgery under general anesthesia.

The introduction of synthetic opioids in 1960 to general anesthesia together with sedative hypnotics and muscle relaxants allowed the appearance of the concept of multimodal balanced anesthesia. Although they help in achieving hemodynamic stability during anesthesia of open heart surgeries, their administration consequences are neither scarce nor benign to the patient. Perioperative opioids are associated with increased incidence of respiratory depression, prolonged mechanical ventilation, nausea and vomiting, prolonged sedation, Postoperative ileus (POI), urine retention, Postoperative cognitive dysfunction (POCD), immune depression and hyperalgesia (Beloeil et al., 2018). Coronary artery bypass graft surgery with cardiopulmonary bypass (CPB) is particularly vulnerable to the above-mentioned complications. Indeed, some of the side effects of this surgery overlap with the adverse effects of opioids. Postoperative pulmonary complications are observed in up to 50% of patients (Fisscher et al., 2022) and POCD or delirium in 4-54% according to studies (Bhushan et al., 2021). Whereas major gastrointestinal complications are estimated to occur in around 3% of patients, essentially acute pancreatitis, postoperative ileus (Marsoner et al., 2019). Opioid-free anesthesia (OFA) strategies have emerged to avoid intraoperative opioid use. It is based on the fact that a sympathetic reaction evidenced by hemodynamic changes in an anesthetised patient does not systematically reflect pain. In addition, a sleeping patient will not recall pain, while hormonal stress and sympathetic and inflammatory reactions can be controlled by therapeutic classes

1. To evaluate the efficacy of a standardized multimodal Opioid Sparing (OS) protocol versus conventional opioid-based analgesia in reducing acute postoperative 2. To quantify opioid consumption reduction achievable through OS strategies 3. To assess the impact of OS on hemodynamic parameters during critical surgical phases 4. To compare recovery metrics (PONV, bowel function, ambulation) 5. To evaluate the safety profile of OS anesthesia

Adult patients aged 18-80 years old, American Society of Anesthesiologists physical status I-III, who were scheduled for elective colorectal cancer surgery under general anesthesia were recruited for this study. They were randomized to receive opioid-free anesthesia (OFA), opioid-sparing anesthesia (OSA) and opioid-based anesthesia (OA) group. Blood samples were collected pre-surgery and 24h post-surgery. As primary endpoint, serum neutrophil myeloperoxidase (MPO) and citrullinated histone3 (CitH3) was measured. The secondary endpoints included the effects of postoperative serum on colorectal cancer (CRC) cells malignancy, numerical rating scale (NRS) scores, postoperative adverse events and recovery profiles. For OA group, intraoperative remifentanil and sufentanil were used and postoperative patient controlled intravenous analgesia (PCIA) was performed with 0.5μg/ml of sufentanil and 0.75 mg/mL flurbiprofen, and the PCIA was stopped 48 h after surgery. For OSA group, remifentanil and sufentanil were used only for anesthetic induction and the patient received ultrasound-guided transversus abdominis plane (TAP) nerve blockwas performed. Patient controlled intravenous analgesia (PCIA) was performed with 1mg/mL of oxycodone and 0.75 mg/mL flurbiprofen after surgery, and the PCIA was stopped 48 hours after surgery. For OFA group, intraoperative epidural anesthesia combined with general anesthesia was used, and esketamine, lidocaine and dexmedetomidine for analgesia. Patient controlled epidural analgesia (PCEA) was used and terminated 48 hours after surgery.

Regional anesthesia is a technique in which a local anesthetic is injected near a nerve or spinal cord to block sensation, motor stimulation, and pain. In this study, an ultrasound-guided paravertebral block will be used, with careful consideration of all positive and negative factors and possible complications. A thoracic paravertebral block is performed by inserting a needle into the intercostal spaces on the back, approximately 4 cm lateral to the spine. Many studies support excellent pain control with this technique, during and after surgery in thoracic and abdominal surgery. Investigators aim to achieve faster patient mobility after surgery, rapid recovery of bowel function, reduced nausea and vomiting, and maximum pain control. The use of opioids, which can additionally cause respiratory suppression and drowsiness, is avoided. At any time in case of need to switch from laparoscopic to open surgery, equally adequate anesthesia and postoperative analgesia are ensured without the need to change the approach to the same. In this study, the basic scientific assumption (hypothesis) of the researchers is that non-opioid anesthesia with thoracic paravertebral block provides adequate pain control during and long-term after the surgical procedure, without the side effects of opioid anesthesia. The main goal of the study is to determine which type of anesthesia results in the best pain control and most significantly reduces complications of anesthesia and surgery in overweight patients who are scheduled for laparoscopic longitudinal gastrectomy and partial/total gastrectomy.

This study will evaluate how different anesthesia techniques affect inflammation after bariatric surgery. Patients will be randomly assigned to receive one of three approaches: opioid-free anesthesia, intravenous anesthesia with opioids, or inhalational anesthesia with opioids. The study will measure blood levels of inflammation-related substances (such as IL-6, CRP, cortisol, ESR , WBC and lactate) at several time points before and after surgery. Heart rate variability will also be monitored as an indicator of the body's stress response. The results may help identify anesthesia strategies that reduce inflammation and improve recovery in patients undergoing bariatric surgery.

This study aimed to evaluate the effect of an opioid-free anesthesia protocol on postoperative recovery quality in patients aged 65 years and older undergoing major surgery. Recovery quality was assessed using the Quality of Recovery-15 (QoR-15) questionnaire. Findings are expected to contribute to optimizing anesthesia practices in the elderly population by improving recovery quality and reducing opioid-related side effects.

This Study aims to evaluate the efficacy of opioid free general anesthesia in achieving enhanced recovery after surgery (ERAS) in laparoscopic bariatric surgery in terms of post-operative recovery time, cumulative pethidine consumption and number of episodes of postoperative nausea and vomiting(PONV).

Postoperative cognitive dysfunction (POCD)is a common well disorder of the central nervous system after surgery, mainly manifested by impaired memory, spirit, language ability or other aspects of brain function. POCD, which often occurs in elderly patients over 65 years, The recent phase is recommended to be changed to perioperative neurocognitive impairment ( PND), The PND is used to describe the cognitive function changes that occur before and within 1 year after surgery, Based on the time of disease onset, It can be divided into neurocognitive impairment existing before surgery, postoperative delusion (POD) occurring hours to days after surgery, neurocognitive recovery delay (DNR) within 30 days after surgery, and postoperative neurocognitive impairment occurring weeks to months after surgery (POND). With the acceleration of the aging process of Chinese social population, the frequency of surgical treatment for elderly inpatients has also increased, and the elderly patients have postoperative sleep disorders, and POCD is relatively common. Surgical patients after surgical trauma, the body inflammation, sympathetic excitation and endocrine disorders, make postoperative sleep structure or pattern change, often lead to postoperative sleep disorders (PSD) , the main performance for patients with postoperative complaint difficult to enter and maintain sleep, frequent nightmares, total sleep quantity and quality reduction, etc. PSD is not only the most common manifestation of postoperative brain dysfunction, but also an important risk factor for inducing postoperative fatigue, postoperative hyperalgesia, metabolic dysfunction, and cardiovascular and cerebrovascular diseases. Moreover, it is considered to promote the development of postoperative delusion. At present, the common mode of general anesthesia is still mainly opioids, and opioids are an important part of general anesthesia and perioperative analgesia. Perioperative use of opioids is not only associated with adverse effects such as postoperative nausea and vomiting, excessive sedation, and ileus, but also leads to the occurrence of postoperative hypoxemia, hyperalgesia and postoperative chronic pain, and cognitive impairment. Therefore, the Association of Accelerated Rehabilitation Surgery indicates that the use of a multimodal analgesic regimen during the perioperative period reduces pain and reduces opioid-related adverse effects, and that opioid-free anesthesia ( OFA) is used in clinical work. At present, most clinical studies of OFA focus on adults aged 18-65 or 18 years old, and few studies focus OFA solely on the elderly population to observe its application effect. Therefore, it is necessary to conduct clinical studies to observe postoperative recovery in elderly patients with different types of anesthetics, investigate the incidence and severity of POCD, and determine the efficacy and safety of each anesthetic agent.