Comparison of adequacy of anaesthesia monitoring with standard clinical practice monitoring during routine general anaesthesia: An international, multicentre, single-blinded randomised controlled trial

Impact of age on the reliability of GE Entropy™ module indices for guidance of maintenance of anaesthesia in adult patients: a single-centre retrospective analysis

BACKGROUND

The GE Entropy™ module uses frontal EEG to compute the processed indices state entropy (SE), response entropy (RE), and burst suppression ratio (BSR) to guide maintenance of anaesthesia by supposedly minimising overly 'deep' or 'light' anaesthesia. It remains unclear whether the manufacturer-recommended index ranges accurately reflect anaesthesia levels or prevent complications such as burst suppression or arousal reactions.

METHODS

We retrospectively analysed 15 608 patient records, evaluating 14 770 adult patients (18-90 yr old) undergoing general anaesthesia. Age-dependent effects on processed index values were assessed using linear regression and Spearman's correlation coefficients (rho).

RESULTS

During steady-state anaesthesia (BSR=0), only 38.4% (32.5-42.4%) of SE values were within the recommended range, with most values below the target. Age was positively associated with an increase in age-adjusted minimal alveolar concentration for volatile anaesthetics (adjusted [adj.] R2=0.18, P<0.001, rho=0.47 [0.20-0.70]). Despite this, SE paradoxically increased with age (adj. R2=0.45, P<0.001, rho=0.67 [0.51-0.79]). This trend persisted even during periods with positive BSR despite supposedly adequate SE values (adj. R2=0.73, P<0.001, rho=0.90 [0.80-0.95]). Maintaining anaesthesia within the recommended index range did not prevent positive BSR. Additionally, both frequency (adj. R2=0.70, P<0.001, rho=0.92 [0.85-0.95]) and duration (adj. R2=0.73, P<0.001, rho=0.89 [0.82-0.93]) of ΔRE-SE≥10, indicating arousal, increased with age.

CONCLUSIONS

Despite their intuitive appeal, the processed EEG index values SE, RE, ΔRE-SE, and BSR showed limited reliability in guiding maintenance of anaesthesia, especially in older patients. Anaesthesiologists should not rely exclusively on the recommended index value range, as it is often unattainable and does not prevent burst suppression or arousal indicators.

Comparison of surgical pleth index-guided analgesia versus conventional analgesia technique in general anesthesia surgeries: A systematic review and meta-analysis

OBJECTIVE

The objective of this study is to investigate whether the use of surgical pleth index (SPI)-guided intraoperative analgesia can result in a reduction in opioid consumption, intraoperative circulatory fluctuations, and the incidence of postoperative adverse reactions when compared to conventional analgesia techniques.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, Web of Science, and the Cochrane Library from the inception of these databases to November 2024. The objective was to identify randomized controlled trials that compared the use of SPI-guided analgesia with conventional analgesia practices in adult patients who underwent general anesthesia. The primary outcome was the intraoperative consumption of opioids, while intraoperative circulatory fluctuations, postoperative opioid consumption, pain scores, and adverse events served as secondary outcomes. Standardized mean differences (SMDs), weighted mean differences (WMDs) or pooled risk ratios (RRs) along with the corresponding 95 % confidence intervals (CIs) were employed for analysis.

RESULTS

Fourteen studies were included in our meta-analysis. The pooled results indicated no significant difference in intraoperative opioid consumption between the SPI-guided analgesia group and the control group (SMD = 0.16, 95 % CI: -0.15 to 0.47, p = 0.33). However, SPI-guided analgesia was found to reduce intraoperative propofol dosage (SMD = -0.31, 95 % CI: -0.54 to -0.08, p = 0.008), prevent intraoperative tachycardia (RR = 0.50, 95 % CI: 0.30 to 0.85, p = 0.011), and significantly shorten the eye-opening time (WMD = -1.89, 95 % CI: -2.47 to -1.31, p < 0.001). No statistically significant differences were observed in extubation time, postoperative nausea and vomiting, pain scores, or postoperative opioid consumption.

CONCLUSIONS

Compared to the conventional analgesia group, SPI-guided analgesia does not reduce intraoperative opioid consumption in adult patients undergoing general anesthesia.

TRIAL REGISTRATION

The protocol for this meta-analysis has been registered in PROSPERO (CRD42024611690).

The use of the surgical pleth index to guide anaesthesia in gastroenterological surgery: a randomised controlled study

The measurement of nociception and the optimisation of intraoperative antinociceptive medication could potentially improve the conduct of anaesthesia, especially in the older population. The Surgical Pleth Index (SPI) is one of the monitoring methods presently used for the detection of nociceptive stimulus. Eighty patients aged 50 years and older who were scheduled to undergo major abdominal surgery were randomised and divided into a study group and a control group. In the study group, the SPI was used to guide the administration of remifentanil during surgery. In the control group, the SPI value was concealed, and remifentanil administration was based on the clinical evaluation of the attending anaesthesiologist. The primary endpoint of this study was intraoperative remifentanil consumption. In addition, we compared the durations of intraoperative hypotension and hypertension. No difference in intraoperative remifentanil consumption (4.5 µg kg- 1h- 1 vs. 5.6 µg kg- 1h- 1, p = 0.14) was found. Furthermore, there was no difference in the proportion of hypotensive time (mean arterial pressure, MAP < 65) (3.7% vs. 1.6%, p = 0.40). However, in the subgroup of patients who underwent operation with invasive blood pressure monitoring, there was less severe hypotension (MAP < 55) (0.3% vs. 0.0%, p = 0.02) and intermediate hypotension (MAP < 65) (10.2% vs. 2.6%, p = 0.07) in the treatment group, even though remifentanil consumption was higher (3.5 µg kg- 1h- 1 vs. 5.1 µg kg- 1h- 1p = 0.03). The use of SPI guidance for the administration of remifentanil during surgery did not help to reduce the remifentanil consumption. However, the results from invasively monitored study group suggest more timely administered opioid when SPI was used.

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.

Comparison of Adequacy of Anaesthesia (AoA) monitors with CONOX® monitor regarding sevoflurane consumption during routine general anaesthesia: A randomised clinical trial

Background and Aims

Adequacy of Anaesthesia (AoA) and CONOX® are combined monitors that assess levels of anaesthesia and analgesia and give a comprehensive score. No studies have measured and compared the total consumption of inhaled anaesthetic agents while using these monitors. We designed a study to compare AoA and CONOX in terms of sevoflurane usage, fentanyl usage and recovery from the effects of anaesthesia.

Methods

A randomised trial was conducted in 58 patients. Group A (n = 31) patients were monitored with AoA, and Group C (n = 27) patients were monitored with CONOX. Sevoflurane was titrated to maintain a state entropy value of 40-60 in AoA and a Quantium consciousness index (qCON) value of 40-60 in CONOX. Similarly, fentanyl was titrated with bolus doses of 0.5 μg/kg to maintain a surgical pleth index value of 40-60 in AoA and Quantium noxious index (qNOX) value of 40-60 in CONOX. Intraoperative awareness was assessed postoperatively using a modified Brice questionnaire. The t-test or Chi-square test was used to compare the parameters between the groups.

Results

Mean sevoflurane consumption was similar between AoA and CONOX groups [13.2 (standard deviation {SD}: 3.9) (95% confidence interval {CI}:11.8, 14.5) versus 14.4 (SD: 3.7) (95% CI: 13.0, 15.7) ml/h] (P = 0.236). Fentanyl usage was higher in the AoA group compared to the CONOX group [146.2 (SD: 34.28) (95% CI: 134.13, 158.26) versus 128.2 (SD: 26.7) (95% CI: 118.12, 138.27) μg] (P = 0.031). The emergence time and haemodynamic instability events were similar between AoA and CONOX.

Conclusion

Both AoA and CONOX measure anaesthetic depth similarly. However, interpreting qNOX values requires caution, as the patient's consciousness status influences them.

Evaluating the Efficacy of Pre-Emptive Peribulbar Blocks with Different Local Anesthetics or Paracetamol Using the Adequacy of Anesthesia Guidance for Vitreoretinal Surgeries: A Preliminary Report

BACKGROUND/OBJECTIVES

Precisely selected patients require vitreoretinal surgeries (VRS) performed under general anesthesia (GA) when intravenous rescue opioid analgesics (IROA) are administered intraoperatively, despite a risk of adverse events, to achieve hemodynamic stability and proper antinociception and avoid the possibility of intolerable postoperative pain perception (IPPP). Adequacy of anesthesia guidance (AoA) optimizes the titration of IROA. Preventive analgesia (PA) techniques and intravenous or preoperative peribulbar block (PBB) using different local anesthetics (LAs) are performed prior to GA to optimize IROA. The aim was to analyze the utility of PBBs compared with intravenous paracetamol added to AoA-guided GA on the incidence of IPPP and hemodynamic stability in patients undergoing VRS.

METHODS

A total of 185 patients undergoing vitreoretinal surgery (VRS) were randomly assigned to one of several anesthesia protocols: general anesthesia (GA) with analgesia optimized through AoA-guided intraoperative remifentanil opioid analgesia (IROA) combined with a preemptive single dose of 1 g of paracetamol (P group), or PBB using one of the following options: 7 mL of an equal mixture of 2% lidocaine and 0.5% bupivacaine (BL group), 7 mL of 0.5% bupivacaine (BPV group), or 7 mL of 0.75% ropivacaine (RPV group). According to the PA used, the primary outcome measure was postoperative pain perception assessed using the numeric pain rating scale (NPRS), whereas the secondary outcome measures were as follows: demand for IROA and values of hemodynamic parameters reflecting quality or analgesia and hemodynamic stability.

RESULTS

A total of 175 patients were finally analyzed. No studied PA technique proved superior in terms of rate of incidence of IPPP, when IROA under AoA was administered (p = 0.22). PBB using ropivacaine resulted in an intraoperative reduction in the number of patients requiring IROA (p = 0.002; p < 0.05) with no influence on the dose of IROA (p = 0.97), compared to paracetamol, and little influence on hemodynamic stability of no clinical relevance in patients undergoing VRS under AoA-guided GA.

CONCLUSIONS

PA using paracetamol or PBBs, regardless of LAs used, in patients undergoing VRS proved no advantage in terms of rate of incidence of IPPP and hemodynamic stability when AoA guidance for IROA administration during GA was utilized. Therefore, PA using them seems no longer justified due to the potential, although rare, side effects.

Continuity with caveats in anesthesia: state and response entropy of the EEG

The growing use of neuromonitoring in general anesthesia provides detailed insights into the effects of anesthetics on the brain. Our study focuses on the processed EEG indices State Entropy (SE), Response Entropy (RE), and Burst Suppression Ratio (BSR) of the GE EntropyTM Module, which serve as surrogate measures for estimating the level of anesthesia. While retrospectively analyzing SE and RE index values from patient records, we encountered a technical anomaly with a conspicuous distribution of index values. In this single-center, retrospective study, we analyzed processed intraoperative electroencephalographic (EEG) data from 15,608 patients who underwent general anesthesia. We employed various data visualization techniques, including histograms and heat maps, and fitted custom non-Gaussian curves. Individual patients' anesthetic periods were evaluated in detail. To compare distributions, we utilized the Kolmogorov-Smirnov test and Kullback-Leibler divergence. The analysis also included the influence of the BSR on the distribution of SE and RE values. We identified distinct pillar indices for both SE and RE, i.e., index values with a higher probability of occurrence than others. These pillar index values were not age-dependent and followed a non-equidistant distribution pattern. This phenomenon occurs independently of the BSR distribution. SE and RE index values do not adhere to a continuous distribution, instead displaying prominent pillar indices with a consistent pattern of occurrence across all age groups. The specific features of the underlying algorithm responsible for this pattern remain elusive.

Current perioperative nociception monitoring and potential directions

Perioperative nociception-antinociception balance is essential for the prevention of adverse postoperative events. Estimating the nociception level helps optimize intraoperative management. In the past two decades, various nociception monitoring devices have been developed for the identification of intraoperative nociception. However, each type of nociception monitoring device has advantages and disadvantages, limiting their clinical application in particular patients and settings. Therefore, this review aimed to summarize the information on nociceptor monitoring in current clinical settings, explore each technique's particularities, and possible future directions to provide a reference for clinicians and researchers.

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.

Schnider and Eleveld Models for Propofol Target-Controlled Infusion Anesthesia: A Clinical Comparison

BACKGROUND

Various pharmacokinetic/pharmacodynamic (PK/PD) models have been developed to accurately dose propofol administration during total intravenous anesthesia with target-controlled infusion (TIVA-TCI). We aim to clinically compare the performance of the Schnider model and the new and general-purpose Eleveld PK/PD model during TIVA-TCI.

METHODS

We conducted a prospective observational study at a single center, enrolling 78 female patients, including 37 adults (aged < 65 years) and 41 elderly patients (aged ≥ 65 years). These patients underwent breast surgery with propofol-remifentanil TIVA-TCI guided by the bispectral index (BIS) for depth of anesthesia monitoring (target value 40-60) and the surgical plethysmographic index (SPI) for antinociception monitoring (target value 20-50) without neuromuscular blockade. The concentration at the effect site of propofol (CeP) at loss of responsiveness (LoR) during anesthesia maintenance (MA) and at return of responsiveness (RoR), the duration of surgery and anesthesia (min), the time to RoR (min), the propofol total dose (mg), the deepening of anesthesia events (DAEs), burst suppression events (BSEs), light anesthesia events (LAEs) and unwanted spontaneous responsiveness events (USREs) were considered to compare the two PK/PD models.

RESULTS

Patients undergoing BIS-SPI-guided TIVA-TCI with the Eleveld PK/PD model showed a lower CeP at LoR (1.7 (1.36-2.25) vs. 3.60 (3.00-4.18) μg/mL, p < 0.001), higher CePMA (2.80 (2.55-3.40) vs. 2.30 (1.80-2.50) μg/mL, p < 0.001) and at RoR (1.48 (1.08-1.80) vs. 0.64 (0.55-0.81) μg/mL, p < 0.001) than with the Schnider PK/PD model. Anesthetic hysteresis was observed only in the Schnider PK/PD model group (p < 0.001). DAEs (69.2% vs. 30.8%, p = 0.001) and BSEs (28.2% vs. 5.1%, p = 0.013) were more frequent with the Eleveld PK/PD model than with the Schnider PK/PD model in the general patient population. DAEs (63.2% vs. 27.3%, p = 0.030) and BSEs (31.6% vs. 4.5%, p = 0.036) were more frequent with the Eleveld PK/PD model than with the Schnider PK/PD model in the elderly.

CONCLUSIONS

The Schnider and Eleveld PK/PD models impact CePs differently. A greater incidence of DAEs and BSEs in the elderly suggests more attention is necessary in this group of patients undergoing BIS-SPI-guided TIVA-TCI with the Eleveld PK/PD than with the Schnider model.

Unwanted spontaneous responsiveness and burst suppression in patients undergoing entropy-guided total intravenous anesthesia with target-controlled infusion: An observational prospective trial

STUDY OBJECTIVE

To estimate the incidence of unwanted spontaneous responsiveness and burst suppression (BSupp) in patients undergoing state entropy (SE) and surgical pleth index (SPI)-guided total intravenous anesthesia (TIVA) with target-controlled infusion (TCI).

DESIGN

Observational, prospective, single-center study.

SETTINGS

Operating room.

PATIENTS

107 adult (<65 years) and elderly (≥65 years) women undergoing breast surgery.

INTERVENTIONS

Propofol-remifentanil TIVA-TCI-guided by SE for depth of anesthesia monitoring (target value 40-60) and SPI for antinociception monitoring (target value 20-50) without neuromuscular blockade.

MEASUREMENTS

Age; body mass index; American Society of Anesthesiologists physical status classification; concentration at the effect site of propofol (CeP) and remifentanil (CeR) at loss of responsiveness (LoR), median during anesthesia maintenance (MdM), and at return of responsiveness (RoR); propofol infusion duration; incidence of postoperative delirium (POD) with Confusing Assessment Method for the Intensive Care Unit.

MAIN RESULTS

During SE-SPI-guided TIVA-TCI, 13.1% of patients showed unwanted spontaneous responsiveness, whereas 45.8% showed BSupp. Unwanted spontaneous responsiveness was observed mainly in adults (p < 0.05), and higher CeP RoR (p < 0.05) was registered. BSupp was observed mainly in patients showing a lower CeP MdM (p < 0.01) and CeP RoR (p < 0.05). Unwanted spontaneous responsiveness and BSupp were not associated with significant differences in CeRs. An age-related hysteresis effect was observed, resulting in higher CeP LoR than CeP RoR (p < 0.001). 12.2% of patients showed POD. Only preoperative serum albumin was associated with increased likelihood of POD (p = 0.046).

CONCLUSIONS

The SE-SPI-guided TIVA-TCI did not prevent unwanted spontaneous responsiveness and BSupp. CeP RoR may be used as a proxy for anesthetic sensitivity.

Effect of the using a pupillometer on recovery and early cognitive functions in anesthesia management for endoscopic retrograde cholangiopancreaticography in geriatric patients

Background/Aim: Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive procedure used for the diagnosis and treatment of pancreaticobiliary pathologies. Because it is an invasive procedure that is difficult to tolerate by the patient and takes a long time, it is preferable to use it under deep patient sedation and even under general anesthesia in some cases. This study aimed to evaluate the effects of using a pupillometer versus the Ramsey sedation scale (RSS) during anesthesia management for ERCP on recovery and return of cognitive functions in the geriatric patient population. Methods: A mini-mental test was applied to evaluate the pre-operative cognitive functions of the cases before the intervention. The included patients were divided into groups using the sealed-envelope method. Management of the depth of anesthesia was evaluated by Ramsey sedation scale; in group R and was evaluated by pupillometer in group P. The infusion dose of dexmedetomidine was changed to 0.1 µg/kg/h according to the results of the evaluation. Results: Sixty cases were included in the study. No difference between the groups in terms of age (P=0.246), gender (P=0.797), American Society of Anesthesiologists (ASA) score (P=0.197), comorbidity (P=0.748), anesthesia duration (P=0.397), midazolam doses (P=0.561), propofol doses (P=0.677), and intra-operative hemodynamic values (P=0.668) were found. Intra-operative dexmedetomidine dose was statistically significantly lower (P=0.004), and recovery was faster in group P (P<0.001). While no differences between the groups in the pre-operative mini-mental test scores (P=0.140) were found, the post-operative scores were statistically significantly lower in group R (P=0.025). Conclusion: In this study, it was observed that the pupillometer led to a reduction in the use of dexmedetomidine and cognitive functions were better during the post-operative recovery period. As a result, depth of anesthesia can be monitored with a pupillometer. Although the use of pupillometer in endoscopic interventions in the geriatric patient group does not make a hemodynamic difference when compared with the RSS, the pupillometer leads to accelerated recovery from anesthesia, improvement in the return of cognitive functions, and reduction in drug consumption.

Nociception monitors vs. standard practice for titration of opioid administration in general anesthesia: A meta-analysis of randomized controlled trials

Background

Nociception monitors are being increasingly used during surgery, but their effectiveness in guiding intraoperative opioid administration is still uncertain. This meta-analysis of randomized controlled trials (RCTs) aimed to compare the effectiveness of nociception monitors vs. standard practice for opioid administration titration during general anesthesia.

Methods

We searched the electronic databases of PubMed, EMBASE, Cochrane Library, Clinical Trial, and Web of Science from inception up to August 1, 2021, to identify relevant articles, and extracted the relevant data. Intraoperative opioid administration, extubation time, postoperative pain score, postoperative opioid consumption and postoperative nausea and vomiting (PONV) were compared between patients receiving nociception monitoring guidance and patients receiving standard management. The standardized mean difference (SMD), with 95% confidence interval (CI), was used to assess the significance of differences. The risk ratio (RR), with 95% CI, was used to assess the difference in incidence of PONV. Heterogeneity among the included trials was evaluated by the I² test. RevMan 5.3 software was used for statistical analysis.

Results

A total of 21 RCTs (with 1957 patients) were included in the meta-analysis. Intraoperative opioid administration was significantly lower in patients receiving nociception monitor-guided analgesia than in patients receiving standard management (SMD, −0.71; 95% CI, −1.07 to −0.36; P < 0.001). However, pain scores and postoperative opioid consumption were not significantly higher in the former group. Considerable heterogeneity was found among the studies (92%). Extubation time was significantly shorter (SMD, −0.22; 95% CI, −0.41 to −0.03; P = 0.02) and the incidence of PONV significantly lower (RR, 0.78; 95% CI, 0.61 to 1.00; P = 0.05) in patients receiving nociception monitoring guidance.

Conclusions

Intraoperative nociception monitoring guidance may reduce intraoperative opioid administration and appears to be a viable strategy for intraoperative titration of opioids.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=273619, identifier: CRD42019129776.

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, I² = 67%) or eye-opening time (SMD − 0.40, 95% CI − 0.63 to − 0.18, p < 0.001, I² = 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.

Spectral Entropy Monitoring Accelerates the Emergence from Sevoflurane Anesthesia in Thoracic Surgery: A Randomized Controlled Trial

The clinical efficacy of spectral entropy monitoring in improving postoperative recovery remains unclear. This trial aimed to investigate the impact of M-Entropy (GE Healthcare, Helsinki, Finland) guidance on emergence from anesthesia and postoperative delirium in thoracic surgery. Adult patients undergoing video-assisted thoracoscopic surgery for lung resection at a medical center were randomly allocated into the M-Entropy guidance group (n = 39) and the control group (n = 37). In the M-Entropy guidance group, sevoflurane anesthesia was titrated to maintain response and state entropy values between 40 and 60 intraoperatively. In the control group, the dosing of sevoflurane was adjusted based on clinical judgment and vital signs. The primary outcome was time to spontaneous eye opening. M-Entropy guidance significantly reduced the time proportion of deep anesthesia (entropy value <40) during surgery, mean difference: −21.5% (95% confidence interval (CI): −32.7 to −10.3) for response entropy and −24.2% (−36.3 to −12.2) for state entropy. M-Entropy guidance significantly shortened time to spontaneous eye opening compared to clinical signs, mean difference: −154 s (95% CI: −259 to −49). In addition, patients of the M-Entropy group had a lower rate of emergence agitation (absolute risk reduction: 0.166, 95% CI: 0.005−0.328) and delirium (0.245, 0.093−0.396) at the postanesthesia care unit. M-Entropy-guided anesthesia hastened awakening and potentially prevented emergence agitation and delirium after thoracic surgery. These results may provide an implication for facilitating postoperative recovery and reducing the complications associated with delayed emergence and delirium.

Adverse Events during Vitreoretinal Surgery under Adequacy of Anesthesia Guidance—Risk Factor Analysis

Vitreoretinal surgeries require the administration of general anesthesia (GA) in selected groups of patients. The administration of intraoperative rescue narcotic analgesia (IRNA) during GA poses the risk of postoperative nausea and vomiting (PONV). The surgical pleth index (SPI), a crucial component of the adequacy of anesthesia (AoA) guidance of GA, optimizes the intraoperative titration of IRNA. The current analysis evaluated the risk factors for the occurrence of PONV and the oculo-cardiac reflex (OCR) in patients undergoing pars plana vitrectomy (PPV) under AoA guidance. In total, 175 patients undergoing PPV were randomly allocated to receive either GA with SPI-guided IRNA administration using fentanyl alone or in addition to different preoperative analgesia techniques. Any incidence of PONV or OCR was recorded. Obesity, overweight, smoking status, motion sickness, postoperative intolerable pain perception, female gender, fluid challenge and arterial hypertension did not correlate with an increased incidence of PONV or OCR under AoA guidance. Diabetes mellitus, regardless of insulin dependence, was found to correlate with the increased incidence of PONV. The AoA regimen including SPI guidance of IRNA presumably created similar conditions for individual subjects, so no risk factors of the occurrence of PONV or OCR were found, except for diabetes mellitus. We recommend using AoA guidance for GA administration to reduce OCR and PONV rates.

Adverse Events during Vitrectomy under Adequacy of Anesthesia-An Additional Report

The intraprocedural immobilization of selected subsets of patients undergoing pars plana vitrectomy (PPV) requires the performance of general anesthesia (GA), which entails the intraoperative use of hypnotics and titration of opioids. The Adequacy of Anesthesia (AoA) concept of GA guidance optimizes the intraoperative dosage of hypnotics and opioids. Pre-emptive analgesia (PA) is added to GA to minimize intraoperative opioid (IO) usage. The current additional analysis evaluated the advantages of PA using either COX-3 inhibitors or regional techniques when added to AoA-guided GA on the rate of presence of postoperative nausea and vomiting (PONV), oculo-emetic (OER), and oculo-cardiac reflex (OCR) in patients undergoing PPV. A total of 176 patients undergoing PPV were randomly allocated into 5 groups: (1) Group GA, including patients who received general anesthesia alone; (2) Group T, including patients who received preventive topical analgesia by triple instillation of 2% proparacaine 15 min before induction of GA; (3) Group PBB, including patients who received PBB; (4) Group M, including patients who received PA using a single dose of 1 g of metamizole; (5) Group P, including patients who received PA using a single dose of 1 g of acetaminophen. The incidence rates of PONV, OCR, and OER were studied as a secondary outcome. Despite the group allocation, intraoperative AoA-guided GA resulted in an overall incidence of PONV in 9%, OCR in 12%, and OER in none of the patients. No statistically significant differences were found between groups regarding the incidence of OCR. PA using COX-3 inhibitors, as compared to that of the T group, resulted in less overall PONV (p < 0.05). Conclusions: PA using regional techniques in patients undergoing PPV proved to have no advantage when AoA-guided GA was utilised. We recommend using intraoperative AoA-guided GA to reduce the presence of OCR, and the addition of PA using COX-3 inhibitors to reduce the rate of PONV.

[Nociception monitoring : Method for intraoperative opioid control?]

The intraoperative dosing of opioids is a challenge in routine anesthesia as the potential effects of intraoperative overdosing and underdosing are not completely understood. In recent years an increasing number of monitors were approved, which were developed for the detection of intraoperative nociception and therefore should enable a better control of opioid titration. The nociception monitoring devices use either continuous hemodynamic, galvanic or thermal biosignals reflecting the balance between parasympathetic and sympathetic activity, measure the pupil dilatation reflex or the nociceptive flexor reflex as a reflexive response to application of standardized nociceptive stimulation. This review article presents the currently available nociception monitors. Most of these monitoring devices detect nociceptive stimulations with higher sensitivity and specificity than changes in heart rate, blood pressure or sedation depth monitoring devices. There are only few studies on the effect of opioid titration guided by nociception monitoring and the possible postoperative benefits of these devices. All nociception monitoring techniques are subject to specific limitations either due to perioperative confounders (e.g. hypovolemia) or special accompanying medical conditions (e.g. muscle relaxation). There is an ongoing discussion about the clinical relevance of nociceptive stimulation in general anesthesia and the effect on patient outcome. Initial results for individual monitor systems show a reduction in opioid consumption and in postoperative pain level. Nevertheless, current evidence does not enable the routine use of nociception monitoring devices to be recommended as a clear beneficial effect on long-term outcome has not yet been proven.

Adequacy of Anesthesia Guidance for Colonoscopy Procedures

In patients undergoing colonoscopy procedures (CPs), inadequate dosing of hypnotic drugs (HD) and opioid analgesics (OA) during intravenous sedoanalgesia (ISA) may lead to intraprocedural awareness with recall (IAwR), intraprocedural (IPP) and postprocedural pain (PPP), as well as postoperative nausea and vomiting (PONV). The aim of this study was to evaluate whether the titration of HD and OA based on the observance of changing values of state entropy (SE) and surgical pleth index (SPI) (adequacy of anesthesia-AoA), state entropy alone, or standard practice may reduce the number of adverse events. One hundred and fifty-eight patients were included in the final analysis. The rate of IAwR and IPP was statistically more frequent in patients from the C group in comparison with the AoA and SE groups (p < 0.01 and p < 0.05, respectively). In turn, the rate of PPP, PONV, and patients' and operators' satisfaction with ISA between groups was not statistically significant (p > 0.05). Changes in hemodynamic parameters, demand for HD, and OA were statistically significant, but of no clinical value. In patients undergoing CPs under ISA using propofol and FNT, as compared to standard practice, intraprocedural SE monitoring reduced the rate of IAwR and IPP, with no influence on the rate of PPP, PONV, or patients' and endoscopists' satisfaction. AoA guidance on propofol and FNT titration, as compared to SE monitoring only, did not reduce the occurrence of the aforementioned studied parameters, imposing an unnecessary extra cost.