The effect of nicardipine on the surgical pleth index during thyroidectomy under general anesthesia: A prospective double-blind randomized controlled trial

Surgical pleth index monitoring in perioperative pain management: usefulness and limitations

Surgical pleth index (SPI) monitoring is a representative, objective nociception-monitoring device that measures nociception using photoplethysmographic signals. It is easy to apply to patients and the numerical calculation formula is intuitively easy to understand; therefore, its clinical interpretation is simple. Several studies have demonstrated its efficacy and utility. Compared with hemodynamic parameters, the SPI can detect the degree of nociception during surgery under general anesthesia with greater accuracy, and therefore can provide better guidance for the administration of various opioids, including remifentanil, fentanyl, and sufentanil. Indeed, SPI-guided analgesia is associated with lower intraoperative opioid consumption, faster patient recovery, and comparable or lower levels of postoperative pain and rates of adverse events compared with conventional analgesia. In addition, SPI monitoring allows for the degree of postoperative pain and analgesic requirements to be predicted through the SPI values immediately before patient arousal. However, because patient age, effective circulating volume, position, concomitant medication and anesthetic regimen and level of consciousness may be confounding factors in SPI monitoring, clinicians must be careful when interpreting SPI values. In addition, as SPI values can differ depending on anesthetic and analgesic regimens and the underlying disease, an awareness of the effects of these variables with an understanding of the advantages and disadvantages of SPI monitoring compared to other nociception monitoring devices is essential. Therefore, this review aimed to help clinicians perform optimal SPI-guided analgesia and to assist with the establishment of future research designs through clarifying current usefulness and limitations of SPI monitoring in perioperative pain management.

Effect of surgical pleth index-guided remifentanil administration on perioperative outcomes in elderly patients: a prospective randomized controlled trial

BACKGROUND

During general anesthesia, the surgical pleth index (SPI) monitors nociception. The evidence of SPI in the elderly remains scarce. We aimed to investigate whether there is a difference in perioperative outcomes following intraoperative opioid administration according to the surgical pleth index (SPI) value versus hemodynamic parameters (heart rate or blood pressure) in elderly patients.

METHODS

Patients aged 65-90 years who underwent laparoscopic colorectal cancer surgery under sevoflurane/remifentanil anesthesia were randomized to receive remifentanil guided by SPI (SPI group) or conventional clinical judgment based on hemodynamic parameters (conventional group). The primary endpoint was intraoperative remifentanil consumption. Secondary endpoints were intraoperative hemodynamic instability, pain score, fentanyl consumption and delirium in the post-anesthesia care unit (PACU), and perioperative changes in interleukin-6 and natural killer (NK) cell activity.

RESULTS

Seventy-five patients (38, SPI; 37, conventional) were included in the study. The SPI group consumed significantly more remifentanil intraoperatively than the conventional group (mean ± SD, 0.13 ± 0.05 vs. 0.06 ± 0.04 μg/kg/min, P < 0.001). Intraoperative hypertension and tachycardia were more common in the conventional group than in the SPI group. Pain score in the PACU (P = 0.013) and the incidence of delirium in the PACU were significantly lower in the SPI group than the conventional group (5.2% vs. 24.3%, P = 0.02). There was no significant difference in NK cell activity and interleukin-6 level.

CONCLUSIONS

In the elderly patients, SPI-guided analgesia provided appropriate analgesia with sufficient intraoperative remifentanil consumption, lower incidence of hypertension/ tachycardia events, and a lower incidence of delirium in the PACU than the conventional analgesia. However, SPI-guided analgesia may not prevent perioperative immune system deterioration.

TRIAL REGISTRATION

The randomized controlled trial was retrospectively registered in the UMIN Clinical Trials Registry (trial number: UMIN000048351; date of registration: 12/07/2022).

Elevated Surgical Pleth Index at the End of Surgery Is Associated with Postoperative Moderate-to-Severe Pain: A Systematic Review and Meta-Analysis

Despite acceptance of the surgical pleth index (SPI) for monitoring the intraoperative balance between noxious stimulation and anti-nociception under general anesthesia, its efficacy for predicting postoperative moderate-to-severe pain remains unclear. We searched electronic databases (e.g., Google Scholar, MEDLINE, Cochrane Library, and EMBASE) to identify articles focusing on associations of SPI at the end of surgery with immediate moderate-to-severe pain in the postanesthesia care unit from inception to 7 July 2022. A total of six observational studies involving 756 adults published between 2016 and 2020 were eligible for quantitative syntheses. Pooled results revealed higher values of SPI in patients with moderate-to-severe pain than those without (mean difference: 7.82, 95% CI: 3.69 to 11.95, p = 0.002, I2 = 46%). In addition, an elevated SPI at the end of surgery was able to predict moderate-to-severe pain with a sensitivity of 0.71 (95% confidence interval (CI): 0.65–0.77; I2 = 29.01%) and a specificity of 0.58 (95% CI: 0.39–0.74; I2 = 79.31%). The overall accuracy based on the summary receiver operating characteristic (sROC) curve was 0.72. In conclusion, this meta-analysis highlighted the feasibility of the surgical pleth index to predict postoperative moderate-to-severe pain immediately after surgery. Our results from a limited number of studies warrant further investigations for verification.

Effect of surgical pleth index-guided analgesia versus conventional analgesia techniques on fentanyl consumption under multimodal analgesia in laparoscopic cholecystectomy: a prospective, randomized and controlled study

BACKGROUND

The Surgical Pleth Index (SPI) is an objective tool that can reflect nociception-antinociception balance and guide the use of intraoperative analgesics. Multimodal analgesia has been neglected in many previous studies. The aim of this study was to compare fentanyl consumption using SPI-guided analgesia versus conventional analgesia techniques under multimodal analgesia in laparoscopic cholecystectomy.

METHODS

A total of 80 patients aged 18-65 years with American Society of Anaesthesiologists (ASA) grade I-II and a body mass index (BMI) of 18.5 to 30 kg/m2 who were scheduled for laparoscopic cholecystectomy under total intravenous anaesthesia from March 2020 to September 2020 were selected. Multimodal analgesia, including local infiltration of the surgical incision, nonsteroidal anti-inflammatory drugs and opioids, was adopted perioperatively. Fentanyl boluses of 1.0 µg/kg were administered to maintain the SPI value between 20 and 50 in the SPI group. By contrast, fentanyl boluses of 1.0 µg/kg were administered whenever the heart rate (HR) or mean arterial pressure (MAP) increased to 20 % above baseline or when the HR was greater than 90 beats per minute (bpm) in the control group. Preoperative and postoperative blood glucose, plasma cortisol and interleukin-6 (IL-6) levels were evaluated. Intraoperative haemodynamic events and propofol and fentanyl doses were noted. The extubation time, postoperative visual analogue scale (VAS) score, use of remedial analgesics and opioid-related adverse reactions were recorded.

RESULTS

In total, 18 of 80 patients withdrew for various reasons, and data from 62 patients were finally analysed. Intraoperative fentanyl consumption was significantly lower in the SPI group than in the control group (177.1 ± 65.9 vs. 213.5 ± 47.5, P = 0.016). The postoperative extubation time was shorter in the SPI group than in the control group (16.1 ± 5.2 vs. 22.1 ± 6.3, P < 0.001). Preoperative and postoperative blood glucose, plasma cortisol and IL-6 levels, intraoperative haemodynamic changes, postoperative VAS scores, remedial analgesic consumption and opioid-related adverse reactions were comparable in the two groups.

CONCLUSIONS

Lower doses of fentanyl are required intraoperatively with shorter extubation times when SPI is used to guide intraoperative analgesia compared to conventional analgesia techniques under multimodal analgesia in laparoscopic cholecystectomy.

TRIAL REGISTRATION

Chictr.org.cn ChiCTR2000030145 . Retrospectively Registered (Date of registration: February 24, 2020).

Comparison of Pupillometry With Surgical Pleth Index Monitoring on Perioperative Opioid Consumption and Nociception During Propofol-Remifentanil Anesthesia: A Prospective Randomized Controlled Trial

BACKGROUND

Intraoperative monitoring with pupillometry has shown promising results for nociception/antinociception balance monitoring. However, its benefits in clinical practice remain unproven. The aim of this study was to evaluate the efficacy of intraoperative pupillometry monitoring on intraoperative opioid consumption and postoperative pain compared to surgical pleth index (SPI), another widely investigated monitoring.

METHODS

American Society of Anesthesiologists (ASA) I-II patients scheduled for elective laparoscopic cholecystectomy were included. This prospective, parallel-arm, single-center study was conducted in 2 steps. First, we evaluated the feasibility of using pupillometry and SPI monitoring compared with conventional hemodynamic monitoring. Next, a parallel-arm, double-blind randomized study compared the peak postoperative pain measured with numerical rating scale (NRS) from 0 (no pain) to 10 (extreme pain) as a primary outcome between pupillometry (pupillometry group, n = 43) and SPI monitoring (SPI group, n = 43) using Mann-Whitney U test. Secondary outcomes included intraoperative remifentanil consumption, postoperative opioid responsiveness (a decrease in NRS by ≥1 after fentanyl administrations), number of analgesic administrations, and opioid-related complications.

RESULTS

In the preliminary study (n = 50), remifentanil consumption was less under pupillometry monitoring compared to SPI monitoring, and peak postoperative pain was lower under pupillometry compared to conventional monitoring. In the main study (n = 86), peak postoperative pain and intraoperative remifentanil consumption were lower in the pupillometry group (median [first to third quartile], 5 [4-6]; mean ± standard deviation [SD], 0.078 ± 0.019 μg·kg·minute) compared to the SPI group (7 [5-8] and 0.0130 ± 0.051 μg·kg·minute; P < .001), with the median difference in peak postoperative pain of -1 and its 95% confidence interval between -2 and -0.5. The pupillometry group had better responsiveness to fentanyl (84.6% vs 61.0%; P = .005) and lower number of analgesic administrations (2 [1-2] vs 2 [1-3]; P = .048) compared to the SPI group.

CONCLUSIONS

Intraoperative pupillometry monitoring reduced intraoperative remifentanil consumption and postoperative pain. It may be an alternative option for intraoperative opioid control under general anesthesia in adult patients.

Predictive value of the surgical pleth index for the hemodynamic responses to trachea intubation and skin incision

Surgical pleth index (SPI) has been widely investigated in assessing the nociceptive level. The aim of this study was to investigate the relationship between SPI level and patient responses to trachea intubation and skin incision. A total of 40 patients undergoing open abdominal general surgery were recruited for analyses. The patients were monitored with electrocardiogram, non-invasive blood pressure, SpO₂, invasive blood pressure and SPI before anesthesia induction. Anesthesia was induced with midazolam, propofol, sufentanil and rocuronium and maintained with sufentanil and sevoflurane. Blood pressure, heart rate and SPI were recorded for analyses during the peri-intubation and peri-incision periods. A receiver operating characteristic (ROC) curve analysis was performed to analyze the predictive value of blood pressure, heart rate (HR) and SPI for hemodynamic responses for trachea intubation and skin incision. SPI had a similar changing trend to systolic blood pressure (SBP) and diastolic blood pressure (DBP). The SPI level was linearly correlated with SBP, DBP and HR. SPI increased significantly after intubation and incision in patients with positive but not negative responses to intubation and incision. The ROC analysis showed that only SBP level is predictive of intubation responses. These data suggested that SPI elevated under the noxious stimulation by intubation and incision, but it was not predictive of the hemodynamic responses to intubation and incision.

The quantification and monitoring of intraoperative nociception levels in thoracic surgery: a review

Nociception is the unconscious perception of a stimulus applied by trauma or surgery and expressed through a response of the autonomous nervous system. Local anaesthetics (LAs), opioids and other modulating agents such as ketamine are usually utilised to blunt nociception as a component during general anaesthesia (GA) and surgery. The effectiveness of these measures, however, are still difficult to quantify and monitoring of anti-nociception has been confined to assess variation of heart rate (HR) or blood pressure (BP). Recently, various monitoring concepts have been introduced to quantify nociception more systematically and on the other hand guide anti-nociceptive interventions more appropriately. This review describes the various technologies, their performance in clinical studies and provides a critical appraisal with particular application to thoracic anaesthesia and surgery and their relevance in the context of chronic pain after surgery.

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.