Effect of Lidocaine on Postoperative Pain and Long-term Survival in Elderly Patients Undergoing Colorectal Surgery

This study is a further observation and follow-up of the patients enrolled in the registration number NCT05920980 to further evaluate the effect of long-term infusion of lidocaine on postoperative chronic pain, long-term quality of life and survival rate in patients undergoing colorectal cancer surgery. Patients who meet the enrollment criteria will be randomized 1:1 to the lidocaine group or placebo group. In the lidocaine group, lidocaine 1.5mg/kg/h was continuously infused (using ideal body weight) during the whole procedure. Postoperative analgesia pump with lidocaine (lidocaine 50mg/kg, sufentanil 2ug/kg, glassetron 12mg) diluted to 200ml with saline until 72h after surgery. In the placebo group, the same volume of normal saline will be administered during anesthesia. The postoperative PCIA device will contain sufentanil 2μg/kg, granisetron 12mg diluted to 200mL in 0.9% normal saline solution with a total volume of 200mL.Follow-up after discharge includes chronic pain, the impact of chronic pain on quality of life, the relapse-free survival and overall survival from postoperative 3 months to 5 years.

Inclusion criteria

• Participants were at least 60 years old;
• American Society of Anesthesiologists (ASA) physical status I to III;
• Body-mass index of 18-30 kg/m2;
• Scheduled for elective colorectal surgery.

Exclusion criteria

• Metastases occurring in other distant organs;
• Severe hepatic insufficiency (aspartate aminotransferase or alaninetransaminase or bilirubin >2.5 times the upper limit of normal);
• Renal impairment (creatinine clearance <60 mL/min);
• Cardiac rhythm disorders or systolic heart failure (second-and thirddegree heart block, ejection fraction <50%);
• Allergies to any of the trial drugs; chronic opioid use;
• Inability to comprehend numeric rating scale.