Perioperative Lidocaine and Ketamine in Abdominal Surgery

Lidocaine and Ketamine in Abdominal Surgery

The investigators propose to test the hypothesis that perioperative infusions of lidocaine and/or ketamine reduce opioid consumption and pain scores in adults recovering from elective inpatient abdominal surgery.

The investigators propose a prospective, randomized, double-blind, placebo-controlled clinical trial (RCT) with a factorial design. Adults 18 to 80 years old having elective inpatient open or laparoscopic abdominal surgery with general anesthesia lasting 2 hours or longer will be included in this study.

Inclusion Criteria:

• Adults 18 to 80 years old
• Elective inpatient open or laparoscopic abdominal surgery
• General anesthesia lasting 2 hours or longer.

Exclusion Criteria:

• 1. Planned postoperative mechanical ventilation
• 2. Planned regional anesthesia/analgesia
• 3. Perioperative gabapentin, magnesium, or nitrous oxide use
• 4. Pregnancy or breastfeeding
• 5. Morbid obesity (BMI ≥ 35 kg/m2)
• 6. American Society of Anesthesiologists (ASA) physical status IV-V
• 7. Allergy to study medications
• 8. Contraindication to lidocaine (severe cardiac arrhythmia)
• 9. Contraindication to ketamine (psychiatric disorder, substance abuse, uncontrolled hypertension, pulmonary hypertension, increased intracranial or intraocular pressure, use of monoamine oxidase inhibitors)
• 10. Chronic preoperative opioid use (≥ 90 morphine mg equivalents per day for > 3 months)
• 11. Significant preoperative hepatic dysfunction (alanine aminotransferase or aspartate aminotransferase levels > 5 times normal) or planned liver transplantation
• 12. Preoperative cardiac failure (left ventricular ejection fraction ≤ 40%)
• 13. Unable to communicate or comprehend study instructions