Usefulness of surgical pleth index-guided analgesia during general anesthesia: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE: Previous studies comparing surgical pleth index (SPI)-guided and conventional analgesia have shown differing results. Therefore, we compared the intraoperative opioid requirement, extubation time, postoperative pain scores, and perioperative adverse events between these two modalities. METHODS: A comprehensive literature search was conducted to identify randomized controlled trials comparing the intraoperative opioid requirement and other outcomes between the two modalities. The mean difference (MD) or the pooled risk ratio and corresponding 95% confidence interval (CI) were used for analysis. A heterogeneity (I2) assessment was performed. RESULTS: Six randomized controlled trials comparing 463 patients were included. Intraoperative opioid consumption was significantly lower in the SPI-guided than conventional analgesia group (standardized MD, -0.41; 95% CI, -0.70 to -0.11; I2 = 53%). No significant intergroup difference was observed in the pain score on the first postoperative day or the incidence of perioperative adverse events. The extubation time was considerably shorter in the SPI-guided than conventional analgesia group (MD, -1.91; 95% CI, -3.33 to -0.49; I2 = 67%). CONCLUSIONS: Compared with conventional analgesia, SPI-guided analgesia can reduce intraoperative opioid consumption and facilitate extubation. Moreover, no intergroup difference was observed in the degree of postoperative pain or incidence of perioperative adverse events.