Effects of pupillary reflex dilation-guided opioid administration on remifentanil and morphine consumption during laparoscopic surgery: A randomised controlled trial

Comparison of different monitors for measurement of nociception during general anaesthesia: a network meta-analysis of randomised controlled trials

BACKGROUND

To avoid underdosing or overdosing of analgesic medications, a variety of nociception monitors that use distinct techniques have been developed to quantify nociception during general anaesthesia. Although prior meta-analyses have examined the behaviour of nociception monitors vs standard care protocols, they did not include the potentially valuable data for monitor-to-monitor comparisons. In order to capture these data fully and compare the behaviour of these monitors, we conducted a systematic search and network meta-analysis.

METHODS

We performed a Bayesian network meta-analysis on data obtained from a systematic search within PubMed, Embase, Web of Science, Cochrane Library, and EmCare databases. The search was aimed to detect relevant RCTs on the use of nociception monitoring versus standard care or versus other nociception devices(s) during general anaesthesia in adult patients. The primary endpoint was intraoperative opioid consumption, for which we calculated the standardised mean difference (SMD) of morphine equivalents (MEs). Secondary endpoints included postoperative opioid consumption and nausea or vomiting, extubation time, postoperative pain score, and time to discharge readiness. The risk of bias was assessed using the revised Cochrane Risk of Bias tool for randomised trials (RoB 2.0).

RESULTS

Thirty-eight RCTs, including 3412 patients and studying five different types of nociception monitors, were included in the analyses: Nociception Level Monitor (NOL), Analgesia Nociception Index (ANI), Surgical Plethysmographic Index (SPI), Pupillometry (pupillary pain index [PPI] or pupil dilation reflex [PDR]), and the beat-by-beat cardiovascular depth of anaesthesia index (CARDEAN). Pupillometry showed a significant reduction in intraoperative opioid consumption compared with standard care (SMD -2.44 ME; 95% credible interval [CrI] -4.35 to -0.52), and compared with SPI (SMD -2.99 ME; 95% CrI -5.15 to -0.81). With respect to monitors other than pupillometry, no significant differences in opioid consumption were detected in comparison with standard care or other monitors. Pupillometry was associated with a longer time to discharge readiness from the PACU, whereas NOL was associated with shorter extubation times. No relevant differences in other secondary outcomes were found.

CONCLUSIONS

Apart from pupillometry, no monitors demonstrated a significant effect on intraoperative opioid consumption. Secondary outcomes indicate limited clinical benefit for patients when using these monitors.

Postoperative Nausea and Vomiting following Endoscopic Sinus Surgery under the Guidance of Adequacy of Anesthesia or Pupillometry with Intravenous Propofol/Remifentanil

Postoperative nausea and vomiting (PONV) constitutes an adverse event after endoscopic sinus surgery (ESS) under general anesthesia (GA) with intravenous opioids, such as remifentanil (RMF). Monitoring the nociception/antinociception balance using the surgical pleth index (SPI) or pupillary dilatation reflex (PRD) helps guide intravenous RMF infusion. We aimed to investigate whether their employment could help reduce the incidence of PONV in patients undergoing ESS. The data of 30 patients from the GA group, 31 from the SPI group, and 28 from the PRD group were analyzed. The initial RMF infusion rate of 0.25 µg/kg body weight/minute was increased by 50% when the SPI, PRD, or Boezaart Bleeding Scale (BBS) were elevated by >15, >5%, or >2 points, respectively, until they normalized. PONV was present in 7/89 patients (7.9%): 2/31 patients (6.5%) of the SPI group, 1/30 patients (3.3%) of the GA group, and 4/28 patients (14.3%) of the PRD group. Neither PRD nor SPI guidance for RMF administration reduced the incidence of PONV compared to standard practice. Further studies are required in order to investigate the possibility of PONV eradication in patients undergoing ESS under GA when it is possibly combined with paracetamol/metamizole preventive analgesia, as well as those using antiemetic prophylaxis based on the Apfel Score and premedication with midazolam.

EEG-derived pain threshold index-guided versus standard care during propofol-remifentanil anesthesia: A randomized controlled trial

Purpose

The pain threshold index (PTI), a novel index of nociception based on spontaneous EEG wavelet analysis, has been reported to provide reliable accuracy for predicting postoperative pain and hemodynamic reactivity. The present study is aimed to investigate whether PTI-guided analgesia reduces the pain intensity and rate of remedial analgesia in the post-anesthesia care unit (PACU).

Methods

A total of 122 females undergoing elective gynecologic surgeries had been randomized to receive either PTI-guided analgesia (PTI group) or standard clinical care (control group). Remifentanil administration in the PTI group was guided by PTI to maintain the value between 40 and 65, while that in the control group was guided by hemodynamic changes. The primary outcome was remedial analgesia rate in the PACU. The postoperative pain scores, intraoperative remifentanil requirements, opioid-related adverse events and perioperative serum stress hormone concentrations between the two groups were also compared.

Findings

It was found that 23 of 58 patients (40%) in the control group and 8 of 58 patients (14%) in the PTI group needed remedial analgesia. The relative risk of receiving remedial analgesia was 2.88 (95% CI, 1.40-5.89, P = 0.002) in the control group. Sufentanil consumption in the PACU (μg) was lower in the PTI group (P = 0.002) than in the control group. Remifentanil and propofol consumption, opioid-related adverse events between these two groups were comparable.

Implications

PTI-guided analgesia during gynaecologic operations resulted in 25.87% less remedial analgesia. However, studies with different PTI thresholds and larger, more diverse populations should be conducted to further demonstrate the clinical effectiveness of PTI.