Comparison of relative oxycodone consumption in surgical pleth index-guided analgesia versus conventional analgesia during sevoflurane anesthesia: A randomized controlled trial

Abstract

Background: The surgical pleth index (SPI) is proposed for titration of analgesic drugs during general anesthesia. Several reports have investigated the effect of SPI on the consumption of opioids including remifentanil, fentanyl, and sufentanil during anesthesia, but there are no reports about oxycodone. We aimed to investigate intravenous oxycodone consumption between SPI-guided analgesia and conventional analgesia practices during sevoflurane anesthesia in patients undergoing thyroidectomy.

Methods: Forty-five patients undergoing elective thyroidectomy were randomly assigned to an SPI group (SPI-guided analgesia group, n = 23) or a control group (conventional analgesia group, n = 22). Anesthesia was maintained with sevoflurane to achieve bispectral index values between 40 and 60. In the SPI group, oxycodone 1 mg was administered intravenously at SPI values over 50; in the control group, oxycodone 1 mg was administered intravenously at the occurrence of tachycardia or hypertension event. Intraoperative oxycodone consumption and extubation time were recorded. The number of hemodynamic and somatic movement events was recorded, as were postoperative pain and recovery scores.

Results: Patients' characteristics were comparable between the groups. Intraoperative oxycodone consumption in the SPI group was significantly lower than the control group (3.5 ± 2.4 vs 5.1 ± 2.4 mg; P = 0.012). Extubation time was significantly shorter in the SPI group (10.6 ± 3.5 vs 13.4 ± 4.6 min; P = 0.026). Hemodynamic and somatic movement events during anesthesia were comparable between the groups, as were numeric rating scales for pain and modified Aldrete scores at postanesthesia care unit.

Conclusions: SPI-guided analgesia reduces intravenous oxycodone consumption and extubation time compared with conventional analgesia based on clinical parameters during sevoflurane anesthesia in patients undergoing thyroidectomy.

Conflict of interest statement

The authors have no funding and conflicts of interest to disclose.

Figures

Figure 1

A flowchart describing patient recruitment, randomization, and withdrawal. Initially, 48 patients were randomly assigned to 1 of 2 groups as follows: the surgical pleth index-guided analgesia group (SPI group) or the conventional analgesia group (control group). Finally, 45 patients (23 in the SPI group and 22 in the control group) completed this study. SPI = surgical pleth index.

Figure 2

Change of bispectral index (BIS) (A), surgical pleth index (SPI) values (B), and end-tidal sevoflurane concentrations (C) at major time points during general anesthesia in each group. The graphs show mean values ± standard deviation of each variable for every time points during general anesthesia. All data were collected at baseline, 1 minute after intubation (Intu+1 min), 5 minute after intubation (Intu+5 min), incision, 5 minute after incision (incision+5 min), 10 minute after incision (incision+10 min), 20 minute after incision (incision+20 min), 30 minute after incision (incision+30 min), 60 minute after incision (incision+60 min), end of surgery, and extubation. BIS values were well maintained between 40 and 60 during the surgery in both groups. For the SPI value and end-tidal sevoflurane concentration, there were no significant differences between the groups. SPI group: the surgical pleth index-guided analgesia group; control group: the conventional analgesia group. BIS = bispectral index, SPI = surgical pleth index.

Figure 3

Change of numeric rating scale (NRS) scores (A) and modified Aldrete scores (B) at postanesthesia care unit (PACU) in each group. The graphs show mean values ± standard deviation of each variable for every time points. For each score, there were no significant differences between the groups. SPI group: the surgical pleth index-guided analgesia group, control group: the conventional analgesia group. NRS = numeric rating scale, PACU = postanesthesia care unit, SPI = surgical pleth index.