Opioid-free Anesthesia in Thyroidectomies

Recovery Parameters and Nociception Levels in Opioid-free Versus Opioid Based Anesthesia for Thyroidectomy

The aim of this study will be to investigate the effect of an opioid-free anesthesia regimen with a mixture of dexmedetomidine-lidocaine-ketamine in the same syringe versus fentanyl analgesia in elective thyroidectomies. Recovery parameters and nociception levels throughout the operation will be evaluated

In the usual anesthetic practice opioids are often administered in the perioperative period for intraoperative analgesia to control the nociceptive pathway of pain and post-surgical pain management. However, in recent years, opioid Free Anesthesia (OFA) has become increasingly popular, in which opioid administration is avoided intraoperatively and minimized or avoided in the postoperative period. Opioid-free anesthesia (OFA) has been shown to decrease postoperative complications associated with opioids, include sedation, dizziness, nausea, vomiting, constipation, physical dependence, tolerance, and respiratory depression. Therefore, the investigators aim to perform this study to determine a goal-directed approach, which targets adequate antinociception (e.g., by measuring nociceptive/antinociceptive balance) that could reduce the negative effects of excessive drug infusion, prevent postoperative pain and improve patient outcomes.

Pain, Post Operative, Pain, Acute, Pain, Chronic, Pain, Neuropathic, Pain, Nociceptive, Ketamine, Dexmedetomidine, Lidocaine, Fentanyl, Analgesia, Analgesics, Analgesics Non-narcotic

patients will be administered 0.25 mcg/kg Dexmedetomidine in 100 mL of normal saline within 10 minutes. Followingly, they will receive 1 mL/10 kg of the solution containing ketamine, lidocaine and dexmedetomidine at predefined concentrations. As maintenance, they will be receiving 1mL/10kg/h of the aforementioned solution.

remifentanil infusion under the Minto model (target controlled infusion-TCI aiming at 4ng/ml blood concentration

The QoR-40 is used to measure functional recovery and has been validated in patients undergoing general surgical procedures. Five general quality-of-recovery dimensions are measured within the QoR-40: physical comfort (12 items), emotional state (9 items), physical independence (5 items), psychological support (7 items), and pain (7 items). Each item is graded on a five-point Likert scale, and the global scores range from 40 (extremely poor quality of recovery) to 200 (excellent quality of recovery)

pain score by the use of Numeric Rating Scale (NRS) on arrival to PACU, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) at discharge from PACU, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) 3 hours postoperatively, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) 6 hours postoperatively, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) 24 hours postoperatively, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

Nociception Level as measured via the NOL (Nociception Level) index, whose values vary from 0 to 100 (100 represents the maximum level of nociception and 0 represents total absence of nociception). The aim of the current study will be to record percentage of operative time during which NOL levels will be <25

rescue remifentanil required intraoperatively to maintain systolic arterial blood pressure and heart rate within the 20% of baseline value

sedation will be assessed with a 5-point sedation scale, where: 1, patient perfectly conscious; 2, patient feels a little drowsy; 3, patient seems to be sleeping but immediately reacts to verbal stimulation; 4, patient seems to be sleeping but slowly reacts to verbal stimulation and 5, patient seems to be sleeping and does not react to verbal stimulation but does react to a stimulus such as shaking or pain

sedation will be assessed with a 5-point sedation scale, where: 1, patient perfectly conscious; 2, patient feels a little drowsy; 3, patient seems to be sleeping but immediately reacts to verbal stimulation; 4, patient seems to be sleeping but slowly reacts to verbal stimulation and 5, patient seems to be sleeping and does not react to verbal stimulation but does react to a stimulus such as shaking or pain

subjective evaluation of sleep quality by patients, based on a sleep questionnaire (evaluation of sleep duration, number of nocturnal awakenings and marking of sleep quality)

satisfaction from postoperative analgesia on a six-point Likert scale with 1 marked as minimal satisfaction and 6 as maximal satisfaction

Inclusion Criteria: adult patients American Society of Anesthesiologists (ASA) classification I-II elective thyroidectomy Exclusion Criteria: body mass index (BMI) >35 kg/m2 contraindications to local anesthetic administration systematic use of analgesic agents preoperatively chronic pain syndromes preoperatively neurological or psychiatric disease on treatment pregnancy severe hepatic or renal disease history of cardiovascular diseases/ arrhythmias/ conduction abnormalities bradycardia(<55 beats/minute) drug or alcohol abuse language or communication barriers lack of informed consent

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