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

Abstract

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.

Keywords: Analgesia; analgesics; anesthesia; general; hemodynamics; opioid; photoplethysmography.

Figures

Figure 1.

Flow chart of the meta-analysis.

Figure 2.

Risk-of-bias summary: review of authors’ judgments about each risk-of-bias item for each included study. Green circle: low risk of bias; yellow circle: unclear risk of bias; red circle: high risk of bias.

Figure 3.

Intraoperative opioid requirement in five study groups (unit: µg/kg/minute). The experimental group is the surgical pleth index (SPI)-guided analgesia group, and the control group is the conventional analgesia group. CI = confidence interval, IV = inverse variance, SD = standard deviation.

Figure 4.

Extubation time (minutes). The experimental group is the surgical pleth index (SPI)-guided analgesia group, and the control group is the conventional analgesia group. CI = confidence interval, IV = inverse variance, SD = standard deviation.

Figure 5.

(a) Numerical rating scale (NRS) score for pain at postoperative 24 hours and incidences of (b) postoperative nausea and vomiting and (c) intraoperative unwanted somatic movement. The experimental group is the surgical pleth index (SPI)-guided analgesia group, and the control group is the conventional analgesia group. CI = confidence interval, IV = inverse variance, SD = standard deviation, M-H = Mantel–Haenszel method. Data of “Events” in panel (b) are given as the number of patients who had postoperative nausea and vomiting. Data of “Events” in panel (c) are given as the number of adverse events occurring in the patients in each group.

Figure 6.

Incidences of intraoperative hemodynamic adverse events. (a) Hypertension. (b) Tachycardia. The experimental group is the surgical pleth index (SPI)-guided analgesia group, and the control group is the conventional analgesia group. CI = confidence interval, M-H = Mantel–Haenszel method. Hypertension: an increase in arterial pressure to >120% of the initial value before anesthesia. Tachycardia: an increase in heart rate to >120% of the initial value before anesthesia. Data of “Events” in each figure are given as the number of events examined in all noninvasive blood pressure or heart rate measurements during anesthesia in the patients in each group.