Effect of Lidocaine on Postoperative Pain in Elderlypatients Undergoing Colorectal Cancer Surgery

Effect of Perioperative Continuous Intravenous Infusion of Lidocaine on Postoperative Pain in Elderly Patients Undergoing Colorectal Cancer Surgery: a Prospective, Randomized Controlled Trial

Patients who meet the enrollment criteria will be randomized 1:1 to the lidocaine group or placebo group.

Patients who meet the enrollment criteria will be randomized 1:1 to the lidocaine group or placebo group. In the lidocaine groups, 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. Blood samples will be collected from some patients in the lidocaine group for the measurement of lidocaine plasma concentration.In the placebo group, the same volume of normal saline will be administered during anesthesia. The postoperative PCIA device will contain sufentanil 2 μg/kg, granisetron 12 mg diluted to 200 mL in 0.9% normal saline solution with a total volume of 200 mL.

Patients were randomized in a 1:1 lidocaine group, placebo control group using a computer-generated random number table. After the randomization scheme is written, use the opaque envelope, hide each group envelope into an opaque envelope, the envelope outside the code, is sealed to the researcher, when the study, if the inclusion criteria, then open the corresponding numbered envelope, and intervene according to the group scheme in the envelope.

Blinding of research personnel and patients will be maintained throughout the observation period. On the day of surgery, nurses who did not participate in the perioperative management will assign the standard configuration of the trial drugs, including intraoperative medication and the configuration of the postoperative analgesic pump, to the researchers before the induction of anesthesia. Throughout the study, the patients and researchers should not be unblinded until the statistical analysis of the study data is completed. During the operation, an independent anesthesiologist will be responsible for the blood draw, and the postoperative blood samples will be collected together with the routine blood examination specimens. The investigators remained blinded throughout the observation period until the anesthesiologist or assessors observe significant adverse events of local general anesthesia toxicity.

Patients in the lidocaine groups, 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. Blood samples will be collected from some patients in the lidocaine group for the measurement of lidocaine plasma concentration.

In the placebo group, the same volume of normal saline will be administered during anesthesia. The postoperative PCIA device will contain sufentanil 2 μg/kg, granisetron 12 mg diluted to 200 mL in 0.9% normal saline solution with a total volume of 200 mL.

Patients in the lidocaine groups, 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. Blood samples will be collected from some patients in the lidocaine group for the measurement of lidocaine plasma concentration.

In the placebo group, the same volume of normal saline will be administered during anesthesia. The postoperative PCIA device will contain sufentanil 2 μg/kg, granisetron 12 mg diluted to 200 mL in 0.9% normal saline solution with a total volume of 200 mL.

The pain is evaluated using numerical rating scale（NRS). NRS scores range from 0 to 10 points, with 0 points representing no pain, and 10 points representing the strongest pain.

The pain is evaluated using numerical rating scale（NRS). NRS scores range from 0 to 10 points, with 0 points representing no pain, and 10 points representing the strongest pain.

The pain is evaluated using numerical rating scale（NRS). NRS scores range from 0 to 10 points, with 0 points representing no pain, and 10 points representing the strongest pain.

The pain is evaluated using numerical rating scale（NRS). NRS scores range from 0 to 10 points, with 0 points representing no pain, 1-3 points representing mild pain, 4-6 points representing moderate pain, 7-9 points representing severe pain and 10 points representing the strongest pain.

The pain is evaluated using numerical rating scale（NRS). NRS scores range from 0 to 10 points, with 0 points representing no pain, 1-3 points representing mild pain, 4-6 points representing moderate pain, 7-9 points representing severe pain and 10 points representing the strongest pain.

postoperative opioid use is reported as morphine milligram equivalents, calculated using the Practical Pain Management calculator

defined as the time to first defecation or time to first flatusdefined as the time to first defecation or time to first flatus defined as the time to first defecation or time to first flatus

The incidence of postoperative nausea and vomiting during the first 72 hours postoperatively (any nausea or vomiting);

The global QoR-15 score ranges from 0 to 150 and is categorized as five quality of recovery dimensions, including physical comfort (5 items), emotional state (4 items), psychological support (2 items), physical independence (2 items), and pain (2 items). Each piece is graded using an 11-point Likert scale. The QoR is classified according to the QoR-15 score as excellent (QoR-15 > 135), good (122 ≤ QoR-15 ≤ 135), moderate (90 ≤ QoR-15 ≤ 121) and poor (QoR-15 < 90).

such as new onset electrocardiogram (ECG) irregularities, drowsiness, light-headedness, metallic taste, peri-oral numbness, and tinnitus

Blood samples will be collected from some patients in the lidocaine group measurement of lidocaine plasma concentration.

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 alanine transaminase 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 third-degree heart block, ejection fraction <50%); Allergies to any of the trial drugs; chronic opioid use; Inability to comprehend numeric rating scale.