Influence of Surgical Pleth Index-Guided Versus Conventional Analgesia on Opioid Consumption During Gastric Sleeve Surgery: A Pilot Study

Recent advances in intraoperative nociception monitoring, such as the Surgical pleth index (SPI, GE Healthcare, Helsinki, Finland), may help optimize opioid use. Obese patients are particularly susceptible to opioid-related side effects, making this approach of interest in bariatric surgery. In this randomized pilot study, we investigated whether SPI-guided fentanyl administration would influence intraoperative opioid use and postoperative pain. We enrolled 49 patients undergoing laparoscopic gastric sleeve surgery under sevoflurane-based general anesthesia with multimodal perioperative analgesia, randomized to conventional fentanyl dosing at the anesthetist's discretion (<i>n</i> = 25) or SPI-guided dosing (<i>n</i> = 24). The primary endpoint was intraoperative fentanyl consumption. Secondary outcomes included time to extubation, hemodynamic events, pain scores in the first 90 min postoperatively and rescue analgesia. Fentanyl use did not differ significantly between groups (SPI: 400 ± 101 mcg vs. control: 450 ± 56 mcg, <i>p</i> = 0.100). Extubation was faster with SPI guidance (8.1 ± 1.6 vs. 9.6 ± 1.3 min, <i>p</i> < 0.001). Hemodynamic events and rescue analgesia were less frequent in the SPI group, though not statistically significant. Pain scores were comparable, and no opioid-related adverse effects occurred. In our study, SPI-guided opioid administration did not reduce overall intraoperative fentanyl requirements compared with conventional practice but was associated with a modestly shorter time to extubation.