Improvement of Pain Treatment After Major Abdominal Surgery by Intravenous S()-Ketamine

The use of intraoperative racemic ketamine for pain prevention after abdominal surgery is controversial. We compared one preincisional IV injection of S()ketamine with its preincisional and repeated intraoperative use in 45 patients undergoing surgery with epidural and general anesthesia. S()-ketamine is a new drug formulation that contains the more potent S()stereoisomer of ketamine. Patients were randomized to receive placebo, 0.5 mg/kg preincisional S()ketamine, or 0.5 mg/kg preincisional and 0.2 mg/kg intraoperative S()-ketamine repeated at 20-min intervals. In the postoperative period, epidural ropivacaine (2 mg/mL; 0.12 mL · kg 1 ·h 1 ) was infused for pain therapy. Pa