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Background: The Surgical Pleth Index (SPI) is an objective tool that can reflect nociception-antinociception balance and guide the use of intraoperative analgesics. Multimodal analgesia has been neglected in many previous studies. The aim of this study was to compare fentanyl consumption using SPI-guided analgesia versus conventional analgesia techniques under multimodal analgesia in laparoscopic cholecystectomy. Methods: A total of 80 patients aged 18–65 years with American Society of Anaesthesiologists (ASA) grade I-II and a body mass index (BMI) of 18.5 to 30 kg/m2 who were scheduled for laparoscopic cholecystectomy under total intravenous anaesthesia from March 2020 to September 2020 were selected. Multimodal analgesia, including local infiltration of the surgical incision, nonsteroidal anti-inflammatory drugs and opioids, was adopted perioperatively. Fentanyl boluses of 1.0 µg/kg were administered to maintain the SPI value between 20 and 50 in the SPI group. By contrast, fentanyl boluses of 1.0 µg/kg were administered whenever the heart rate (HR) or mean arterial pressure (MAP) increased to 20 % above baseline or when the HR was greater than 90 beats per minute (bpm) in the control group. Preoperative and postoperative blood glucose, plasma cortisol and interleukin-6 (IL-6) levels were evaluated. Intraoperative haemodynamic events and propofol and fentanyl doses were noted. The extubation time, postoperative visual analogue scale (VAS) score, use of remedial analgesics and opioid-related adverse reactions were recorded. Results: In total, 18 of 80 patients withdrew for various reasons, and data from 62 patients were finally analysed. Intraoperative fentanyl consumption was significantly lower in the SPI group than in the control group (177.1 ± 65.9 vs. 213.5 ± 47.5, P = 0.016). The postoperative extubation time was shorter in the SPI group than in the control group (16.1 ± 5.2 vs. 22.1 ± 6.3, P < 0.001). Preoperative and postoperative blood glucose, plasma cortisol and IL-6 levels, intraoperative haemodynamic changes, postoperative VAS scores, remedial analgesic consumption and opioid-related adverse reactions were comparable in the two groups. Conclusions: Lower doses of fentanyl are required intraoperatively with shorter extubation times when SPI is used to guide intraoperative analgesia compared to conventional analgesia techniques under multimodal analgesia in laparoscopic cholecystectomy. Trial registration: Chictr.org.cn ChiCTR2000030145. Retrospectively Registered (Date of registration: February 24, 2020). [ABSTRACT FROM AUTHOR]

Background: Caudal epidural block (CEB) may be beneficial in anorectal surgery because its use may extend postoperative analgesia. This dose-finding study aimed to estimate the minimum effective anesthetic concentrations for 95% patients(MEC95) of 20 ml or 25 ml of ropivacaine in with CEB. Patients and methods: In this double-blind, prospective study, the concentration of ropivacaine administered in 20 ml and 25 ml for ultrasound-guided CEB were determined using the sample up-and-down sequential allocation study design of binary response variables. The first participant was given 0.5% ropivacaine. Depending on whether a block was successful or unsuccessful, the concentration of local anesthesia was decreased or increased by 0.025% in the next patient. Every five minutes for 30 min, the sensory blockade using a pin-prick sensation at S3 dermatome compared to at T6 dermatome were evaluated every 5 min within 30 min. An effective CEB was defined as a a reduction of sensation at S3 dermatome and the existence of flaccid anal sphincter. Anesthesia was considered successful if the surgeon could perform the surgery without additional anesthesia. We determined the MEC50 using the Dixon and Massey up-and-down method and estimated the MEC95 using probit regression. Results: The concentration of ropivacaine administered in 20 ml for CEB ranged from 0.2% to 0.5%. Probit regression with a bias-corrected Morris 95% CI derived by bootstrapping showed an MEC50 and MEC 50 of ropivacaine for anorectal surgical anesthesia were 0.27% (95% CI, 0.24 to 0.31) and 0.36%(95% CI, 0.32 to 0.61). The concentration of ropivacaine administered in 25 ml for CEB ranged from 0.175 to 0.5. Probit regression with a bias-corrected Morris 95% CI derived by bootstrapping showed an MEC50 and MEC95 for CEB were 0.24% (95% CI, 0.19 to 0.27) and 0.32% (95% CI, 0.28 to 0.54). Conclusion: With ultrasound-guided CEB, the MEC95 of 0.36% ropivacaine at 20 ml and 0.32% ropivacaine at 25 ml provide adequate surgical anesthesia/analgesia 95% of patients undergoing anorectoal surgery. Trial registration: Clinicaltrails.gov: Retrospectively registered (ChiCTR2100042954; Registration date:1/2, 2021). [ABSTRACT FROM AUTHOR]