The Safety of Ropivacaine TAP Block Combined With Intravenous Lidocaine in Patients Undergoing Colorectal Cancer Surgery

The Safety of Ropivacaine TAP Block Combined With Intravenous Lidocaine in Patients Undergoing Colorectal Cancer Surgery

The Safety of Ropivacaine Transversus Abdominis Plane Block Combined With Intravenous Lidocaine in Patients Undergoing Colorectal Cancer Surgery: a Single Center, Open Label Dose Escalation Study

Many studies have confirmed the analgesic effect of intravenous infusion of lidocaine in abdominal surgery. Transversus abdominis plane (TAP) block is also often recommended for abdominal surgery. Ropivacaine TAP block and intravenous lidocaine infusion are important components of multimodal analgesia for colorectal surgery. However, both of them are the local anesthetics and the safety of combination is unknown, so we design the study to explore the safety of the synergistic application of ropivacaine TAP block and intravenous lidocaine infusion in patients undergoing colorectal surgery.

Interventional Study Model: Sequential Assignment According to the principle of "the 3+3 design", 3 dose groups with 3 patients in each dose group will be set up. If no dose limited toxicity (DLT) is observed in three groups, a total of 9 patients will be included. If DLT is present in one dose group during dose escalation, 3 cases are amplified in this dose group; if no DLT is observed in 3 cases of amplification, proceed to the next dose group, and so on, up to 18 patients. DLT is defined as local anesthetic systemic toxicity. If blood samples cannot be obtained for any reasons, new patients will be recruited until there are at least 3 patients in each group with blood samples at every time point .

Patients will receive a TAP block using 1.5 mg/kg, 2.0 mg/kg or 2.5 mg/kg of ropivacaine. If there is no LAST (local anesthetic systemic toxicity) in the three subjects of 1.5 mg/kg group, the next three patients will receive 2.0 mg/kg of ropivacaine. Another three patients will receive 2.5 mg/kg of ropivacaine if there is no LAST in the three subjects of 2.0 mg/kg group. All subjects will be administered an i.v. bolus of lidocaine 2.0 mg/kg (given as an infusion for 10 min) after anaesthesia induction, then continuous infusion at 2 mg/kg/h until the end of surgery.

According to the specified dosage, dilute 1% ropivacaine to 0.2% and inject 1/2 of the total amount on each side.

To observe signs of LAST, such as dizziness, light-headedness, metallic taste, peri-oral numbness, seizure activity or tinnitus, new-onset ECG irregularities, or intraoperative spike wave of EEG, et al.

Blood samples will be drawn at 10min, 20min, 30min, 45min, 60min, 90min, 2h, 4h, 6h, 12h and 24h after the completion of bilateral TAP block to measure the plasma ropivacaine concentration. All data will be tested for normality, then we will show the central tendency of the blood concentration of ropivacaine for all patients at each time point by means (standard deviation) or median (interquartile interval), the peak time and peak concentration of the blood concentration of ropivacaine. We will also provide trends in the blood concentration of ropivacaine for each patient, and the concentration trend of blood drug concentration in each group of patients according to dose grouping.

Blood samples will be drawn at 10min, 20min, 30min, 45min, 60min, 90min, 2h, 4h, 6h, 12h and 24h after the initiation of IV lidocaine to measure the plasma lidocaine concentration. All data will be tested for normality, then we will show the central tendency of the blood concentration of lidocaine for all patients at each time point by means (standard deviation) or median (interquartile interval), and the peak time and peak concentration of the blood concentration of lidocaine. We will also provide trends in the blood concentration of lidocaine for each patient. and the concentration trend of blood drug concentration in each group of patients according to dose grouping.

Inclusion Criteria: Aged between 18 and 65 years; Patients who plan to undergo open/laparoscopic colorectal cancer resection surgery under general anesthesia; American society of Anesthesiologists (ASA) physical status classification system I~II; Exclusion Criteria: Weight less than 40kg or more than 100kg; Defects in the cardiac conduction system (II or III degree atrioventricular block) or cardiac dysfunction (LVEF<50%); Severe liver dysfunction (ALT, AST, bilirubin 2.5 times higher than normal), renal dysfunction (creatinine clearance rate<60ml/min); Allergies to experimental drugs; Patients who are unable to communicate; Participating in other clinical researchers.