Effect of single injection of a sub-anesthetic dose of ketamine on postoperative fatigue syndrome in patients undergoing laparoscopic radical resection of colorectal cancer

Objective To investigate the effect of single injection of a sub-anesthetic dose of ketamine on postoperative fatigue syndrome in patients undergoing laparoscopic radical resection of colorectal cancer. Methods A total of 90 elderly patients who underwent laparoscopic radical resection of colorectal cancer in Zhangjiagang Hospital Affiliated to Soochow University from January 2020 to September 2022 were selected. Inclusion criteria: aging 60-75 years old, ASA Ⅱ—Ⅲ, body mass index (BMI) 18.5-27.9 kg/m², Christensen fatigue score≤4 points 1 day before surgery, expected operation time less than 6 h, and expected blood loss less than 800 mL. The patients were randomly divided into two groups (n=45): a ketamine group (group K) and a placebo group (group P). Their Christensen fatigue score and ICFS-10 were assessed 1 day before surgery, 3 days after surgery, 5 days after surgery, and 7 days after surgery. Peripheral venous blood samples were collected 10 min before anesthesia induction (T0), immediately after surgery (T1), 6 h after surgery (T2), 12 h after surgery (T3), and 24 h after surgery (T4). The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured. The extubation time, the length of PACU stay, and the incidences of delayed recovery, agitation, nausea and vomiting, and diplopia were recorded. Results There was no statistical difference in the extubation time and the length of PACU stay between the two groups (P＞0.05). There was no statistical difference in the incidences of delayed recovery, agitation, nausea and vomiting and diplopia between the two groups (P＞0.05). Group K showed remarkable decreases in Christensen fatigue score and ICFS-10 on 3, 5 and 7 days after surgery, compared with group P (P＜0.05). Christensen fatigue score and ICFS-10 in both groups 3 days after surgery were significantly higher than those at other time points (P＜0.05). The levels of IL-6 and TNF-α in group K were significantly lower than those in group P at T1 to T4 (P＜0.05). The levels of IL-6 and TNF-α in both groups at T1 were significantly higher than those at other time points (P＜0.05). Conclusions A single injection of sub-anesthetic dose of ketamine can improve postoperative fatigue syndrome in patients undergoing laparoscopic radical resection of colorectal cancer, without obvious adverse effect on the quality of recovery.