Effect of a single sub-dose of ketamine on postoperative fatigue syndrome in colorectal cancer patients undergoing radical laparoscopic surgery: A double-blind, pilot study

This study aimed at examining the effect of a single sub-anesthetic dose of ketamine on postoperative fatigue syndrome (POFS) in patients undergoing radical laparoscopic surgery for colorectal cancer (CRC).This prospective, double-blind, pilot study enrolled patients scheduled for radical laparoscopic surgery for CRC under general anesthesia. Eligible patients were randomized into the placebo and ketamine groups. The primary outcome was christensen score change at day 3. The secondary outcomes were the difference of Identity Consequence Fatigue Scale (ICFS) score between the placebo group and ketamine group at day 3 and level of serum tumor necrosis factor (TNF)-α, interleukin (IL)-6, S100β protein, and neuron-specific enolase (NSE).32 participants were assigned to the ketamine group and 31 to the placebo group. Compared with placebo group, the Christensen score was lower in ketamine group at day 3 (absolute difference, -1.13; 95 % confidence interval [CI], -2.02 to -0.24; P = 0.012). Ketamine group was superior to the placebo group with regard to the ICFS scores at day 3 (absolute difference, -6.4; 95 % CI, -11.4 to -1.4; P = 0.013). The plasma TNF-α, IL-6, S100β, and NSE levels were increased after operation compared with baseline in both groups and were significantly higher in placebo group than in ketamine group within 24 h after surgery (all P < 0.05). There was no significant difference of each safety evaluation indicator between the two groups (all P > 0.05).A single sub-anesthetic dose of ketamine may improve POFS in patients undergoing radical laparoscopic surgery for CRC, without postoperative adverse reactions.