A randomized, double blind, placebo controlled clinical trial of the preoperative use of ketamine for reducing inflammation and pain after thoracic surgery

Purpose: We hypothesized that patients who received ketamine during thoracic surgery would benefit from suppression of the inflammatory cascade, represented by lower interleukin (IL)-6 and C-reactive protein (CRP) plasma levels. Methods: This study was a randomized, double blind, placebo controlled clinical trial of ketamine in patients undergoing thoracic surgery. The setting was a single university teaching hospital. Forty patients who presented to the preoperative clinic prior to thoracic surgery (20 control, 20 treatment) were randomized to receive either a 0.5 mg/kg ketamine bolus or an equivalent volume of normal saline intravenously prior to chest wall incision. Plasma samples taken prior to induction of anesthesia and at 24 h following surgery were assayed for IL-6 and CRP levels. Verbal pain scores were reported at 4 and 24 h following surgery and at discharge. Results IL-6 plasma levels did not differ significantly at 24 h for patients receiving ketamine (245 ± 287 pg/ml, mean ± SD) compared to patients who received placebo (269 ± 210 pg/ml), p = 0.39. Additionally, CRP levels at 24 h were not significantly different (8.8 ± 4.5 mg/dl for ketamine, 9.3 ± 5.6 mg/dl for placebo patients), p = 0.37. Finally, verbal pain scores were not significantly different between patient groups at 4 or 24 h, or at discharge. Conclusions These findings suggest that the routine use of a single dose of ketamine prior to chest wall incision is not effective at reducing pain or inflammation in thoracic surgery patients at 24 h postoperatively.