Does ketamine have preemptive effects in women undergoing abdominal hysterectomy procedures?

Ketamine may produce "preemptive" analgesia when administered before surgically induced trauma. Therefore, we hypothesized that pre- versus postincisional administration of ketamine would improve pain control after abdominal hysterectomy procedures. Eighty-nine patients were randomly assigned to one of three treatment groups according to a placebo-controlled, double-blinded protocol: Group 1 (placebo) received saline 0.04 mL/kg IV immediately before and after surgery; Group 2 (preincision), received ketamine 0.4 mg/kg IV before skin incision and saline at the end of the operation; and Group 3 (postincision), received saline before skin incision, and ketamine 0.4 mg/kg IV was given after skin closure. The general anesthetic technique was standardized in all three treatment groups. During the first postoperative hour, Group 3 experienced significantly less pain than Groups 1 and 2, as assessed by using both visual analog and verbal rating scales. There were no significant differences between Groups 1 and 2 with respect to pain scores, postoperative opioid analgesic requirements, and incidence of postoperative nausea and vomiting. We conclude that a single dose of ketamine 0.4 mg/kg IV fails to produce preemptive analgesic effects. Implications: Even though ketamine 0.4 mg/kg IV has short-lasting acute analgesic effects, it failed to produce a preemptive effect when given before abdominal hysterectomy procedures.