Does surgical plethysmographic index-guided analgesia affect opioid requirement and extubation time? A systematic review and meta-analysis.

Purpose: This meta-analysis of all relevant clinical trials investigated surgical plethysmographic index (SPI)-guided analgesia's efficacy under general anesthesia for perioperative opioid requirement and emergence time after anesthesia.

Methods: PubMed, Embase, Web of Science, and Cochrane Library were searched up to January 2022 to identify clinical trials comparing SPI-guided and conventional clinical practice for patients who underwent general anesthesia. With the random-effects model, we compared intraoperative opioid consumption, emergence time, postoperative pain, analgesia requirement, and incidence of postoperative nausea and vomiting (PONV).

Results: Thirteen randomized controlled trials (RCTs) (n = 1314) met our selection criteria. The overall pooled effect sizes of all RCTs indicated that SPI-guided analgesia could not significantly reduce opioid consumption during general anesthesia. SPI-guided analgesia accompanied with hypnosis monitoring could decrease intraoperative opioid consumption (standardized mean difference [SMD] - 0.31, 95% confidence interval [CI] - 0.63 to 0.00) more effectively than SPI without hypnosis monitoring (SMD 1.03, 95% CI 0.53-1.53), showing a significant difference (p < 0.001). SPI-guided analgesia could significantly shorten the emergence time, whether assessed by extubation time (SMD - 0.36, 95% CI - 0.70 to - 0.03, p < 0.05, I = 67%) or eye-opening time (SMD - 0.40, 95% CI - 0.63 to - 0.18, p < 0.001, I = 54%). SPI-guided analgesia did not affect the incidence of PONV, postoperative pain, and analgesia management.

Conclusion: SPI-guided analgesia under general anesthesia could enhance recovery after surgery without increasing the postoperative complication risk. However, it did not affect intraoperative opioid requirement. Notably, SPI-guided analgesia with hypnosis monitoring could effectively reduce intraoperative opioid requirement.