DALLAS — Intraoperative ketamine in patients who underwent spinal anesthesia for primary total knee arthroplasty showed no significant differences postoperatively vs. patients who had a saline placebo in terms of pain, total morphine equivalents and side effects, according to an investigator.
Eric Levicoff, MD, of Philadelphia, and his colleagues studied the effect of sub-anesthetic dosing of ketamine, a glutamate receptor blocker, on post-TKA pain and narcotic consumption through a prospective, randomized trial conducted from January 2016 to April 2018 at a single institution.
The 90 patients enrolled in the study all underwent the same surgical approach and received the same surgical and multimodal pain management protocols, according to the abstract. The only difference was patients were randomized to either ketamine at incision of 6 mcg/kg/min for 75 minutes or to placebo.
“In our study, ketamine seemed to be a safe medication. We saw no increased side effects. We did not see with our infusion of ketamine a reduction in morphine consumption nor did it provide a significant reduction in pain, although this may be dose-related,” Levicoff said at the American Association of Hip and Knee Surgeons Annual Meeting.
Patients’ daily VAS pain scores showed average pain on postoperative day 0 for the ketamine and placebo groups was 35.1 and 32.5, respectively, and average pain was 47.4 and 55 on postoperative day 2, respectively.
Researchers reported a slight trend toward an increase in narcotic consumption in the ketamine group on postoperative day 2.
“Ketamine did not show much of a difference” in average maximum and minimum pain scores, Levicoff said. “Peak pain levels were realized within 24 to 48 hours after surgery in both groups and diminished steadily thereafter.” – by Susan M. Rapp
Tan TL, et al. Paper #6. Presented at: American Association of Hip and Knee Surgeons Annual Meeting; Nov. 1-4, 2018; Dallas.
Disclosure: Levicoff reports no relevant financial disclosures.