Abstract:Abstract: Objective To test whether the analgesia nociception index (ANI) was coherent with events related with changes in the antinociception/nociception balance during anaesthesia, especially in comparison with usual haemodynamic parameters such as HR and systolic blood pressure (SBP). Methods 53 adult patients who underwent laparoscopic appendectomy and cholecystectomy under general anesthesia in our hospital were included in this study. Analgesia nociception index (ANI), heart rate (HR) and systolic blood pressure (SBP) in patients under general anesthesia were compared during noxious stimuli. The induction of anesthesia adopted the dual-channel target-controlled infusion (TCI) of Propofol and Remifentanil based on the multimode intravenous anesthesia workstation. The plasma Propofol concentration (ProCp) was set to 2 μg/ml and the dose of Propofol would be adjusted if hemodynamic responses (Hemod Resp) occurred. Hemodynamic response referred to the condition that HR or SBP increased by more than 20 percent. Patients’ ANI and hemodynamic data were collected at 7 preset time points. Results During the induction of anesthesia, HR and SBP decreased while the ANI value was high (81.6 ± 11.2), suggesting the parasympathetic predominance. Patients received preoperative tetanic stimulation. In the 5 minutes of tetanic stimulation, the patients ANI value decreased from (81.6 ± 11.2) to (58.6 ± 11.7), while HR and SBP did not change. After the establishment of pneumoperitoneum, the ANI further decreased to (50.2 ± 15.8) while HR and SBP had obvious increase. After the completion of the operation, the ANI returned to (90.1 ± 3.4). No difference was observed between the values before and after operation. Conclusion The ANI values of patients receiving Propofol anesthesia had higher sensitivity to moderate pain stimuli than to HR and SBP. The ANI monitoring is effective in assisting the laparoscopic abdominal surgery for Adult patients under general anesthesia with Propofol and Remifentanil.