Pain monitoring in anesthetized children: first assessment of skin conductance and analgesia-nociception index at different infusion rates of remifentanil

Effects of goal-directed analgesia using the analgesia nociception index in children undergoing surgery for moyamoya disease: A randomised controlled trial

BACKGROUND

The potential benefits of Analgesia Nociception Index guided intra-operative analgesia on intra-operative opioid consumption remains to be demonstrated in paediatric anaesthesia.

OBJECTIVES

This study aimed to explore the effects of Analgesia Nociception Index guided analgesia on sufentanil consumption during anaesthesia and postoperative pain scores in paediatric patients with moyamoya disease.

DESIGN

A prospective randomised controlled study.

SETTING

Seoul National University Children's Hospital, Seoul, Republic of Korea.

PATIENTS

A total of 40 children scheduled for encephaloduroarteriosynangiosis.

MAIN OUTCOME MEASURES

The primary outcome was total intra-operative sufentanil consumption, and the secondary outcomes included postoperative pain scores and incidence of opioid-related adverse events.

RESULTS

The Analgesia Nociception Index group showed lower intra-operative sufentanil consumption (in μg kg-1 h-1) compared with the Standard group (0.30 ± 0.12 and 0.39 ± 0.17, respectively; mean difference, -0.09; 95% confidence interval, -0.19 to 0.00; P = 0.049). Postoperatively, compared with the Standard group, the Analgesia Nociception Index group reported lower median pain scores at 18 and 24 h and maximum pain within 24 h (1 [0 to 2] vs. 3 [2 to 5]; P = 0.004, 1 [0 to 2] vs. 3 [1 to 4]; P = 0.041, and 4 [3 to 5] vs. 5 [4 to 7]; P = 0.045, respectively), with fewer patients experiencing nausea (3 [15%] vs. 10 [50%], P = 0.043).

CONCLUSION

The Analgesia Nociception Index guided analgesic protocol can reduce intra-operative sufentanil consumption and postoperative pain within 24 h with fewer nausea symptoms in paediatric patients with moyamoya disease who undergo encephaloduroarteriosynangiosis.

TRIAL REGISTRATION NUMBER

NCT05672212 (registered at clinicaltrials, principal investigator: K.E.H., registration date: 2 January 2023).

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.

Analgesia nociception index is an indicator of laparoscopic trocar insertion-induced transient nociceptive stimuli

Objective

This study aimed to investigate whether analgesia nociception index (ANI) could be an indicator of perioperative pain during laparoscopic trocar insertion.

Methods

A total of 280 participants of anesthesia receiving laparoscopic surgery were enrolled. Anesthesia induction and maintenance were performed using the Marsh model for target propofol and the Minto model for remifentanil. Systolic blood pressure (SBP), heart rate (HR), and ANI were recorded at skin incision, the first-, second, the last-trocar insertion, and 5 min after the last trocar insertion.

Results

ANI was significantly different among the five groups in the last four time points (all P < 0.05). Pearson's correlation showed that ANI was negatively correlated with SBP (r = -0.114, P = 0.077) and HR (r = -0.247, P < 0.001). The area under the curve of ANI was positively correlated with those of SBP (r = 0.493, P < 0.001) and HR (r = -0.420, P < 0.001). Multivariate logistic regression showed that the ANI was an independent factor associated with intraoperative hemodynamic adverse events only at 5 min after the last trocar insertion.

Conclusions

Under general anesthesia, the change in ANI was consistent with changes in the balance between analgesia and nociceptive stimuli. The ANI can reflect the extent of transient pain but had a poor predictive performance for hemodynamic adverse events.

[New Approaches in Perioperative Algesimetry]

The measurement of anaesthetic depth and muscle relaxation have been routine procedures during general anaesthesia for years. Quantification of intraoperative nociception, on the other hand, is still largely impossible. Various methods have been tested and commercialised for more than 10 years. However, a real breakthrough has not yet been achieved and the routine application of all methods available so far is not without problems. This article explains methodological similarities, but also points to specific aspects of various commercial solutions for perioperative algesimetry.

Pain Assessment Using the Analgesia Nociception Index (ANI) in Patients Undergoing General Anesthesia: A Systematic Review and Meta-Analysis

The analgesia nociception index (ANI) has emerged as a potential measurement for objective pain assessment during general anesthesia. This systematic review and meta-analysis aimed to evaluate the accuracy and effectiveness of ANI in assessing intra- and post-operative pain in patients undergoing general anesthesia. We conducted a comprehensive search of Ovid-MEDLINE, Ovid-EMBASE, Cochrane Central Register of Controlled Trials, Google Scholar, public clinical trial databases (ClinicalTrials and Clinical Research Information Service), and OpenSIGLE to identify relevant studies published prior to May 2023 and included studies that evaluated the accuracy and effectiveness of ANI for intra- or post-operative pain assessment during general anesthesia. Among the 962 studies identified, 30 met the eligibility criteria and were included in the systematic review, and 17 were included in the meta-analysis. For predicting intra-operative pain, pooled sensitivity, specificity, diagnostic odds ratio (DOR), and area under curve of ANI were 0.81 (95% confidence interval [CI] = 0.79-0.83; I2 = 68.2%), 0.93 (95% CI = 0.92-0.93; I2 = 99.8%), 2.32 (95% CI = 1.33-3.30; I2 = 61.7%), and 0.77 (95% CI = 0.76-0.78; I2 = 87.4%), respectively. ANI values and changes in intra-operative hemodynamic variables showed statistically significant correlations. For predicting post-operative pain, pooled sensitivity, specificity, and DOR of ANI were 0.90 (95% CI = 0.87-0.93; I2 = 58.7%), 0.51 (95% CI = 0.49-0.52; I2 = 99.9%), and 3.38 (95% CI = 2.87-3.88; I2 = 81.2%), respectively. ANI monitoring in patients undergoing surgery under general anesthesia is a valuable measurement for predicting intra- and post-operative pain. It reduces the use of intra-operative opioids and aids in pain management throughout the perioperative period.

Nociception level response to calibrated stimulations in children: First assessment of the nociception level index in pediatric anesthesia

INTRODUCTION

Intraoperative monitoring of nociception has made great progress in adult anesthesia. However, pediatric data are scarce. The Nociception Level (NOL) is one of the most recent indexes of nociception. Its originality is that it provides a multiparametric assessment of nociception. In adults, NOL monitoring allowed lower perioperative opioid requirements, hemodynamic stability, and qualitative postoperative analgesia. So far, the NOL has never been used in children. Our objective was to validate the ability of NOL to provide a quantitative assessment of nociception in anesthetized children.

METHODS

In 5-12 years old children anesthetized with sevoflurane and alfentanil (10 µg kg^-1), before surgical incision, we performed three standardized tetanic stimulations (5 s, 100 Hz) of different intensities (10-30-60 mA) in a randomized order. NOL, heart rate, blood pressure and Analgesia-Nociception Index variations were assessed after each stimulation.

RESULTS

Thirty children were included. Data were analyzed with a covariance pattern linear mixed regression model. NOL increased after the stimulations (p < 0.05 at each intensity). NOL response was influenced by stimulation intensity (p < 0.001). Heart rate and blood pressure were barely modified by the stimulations. Analgesia-Nociception Index decreased after the stimulations (p < 0.001 at each intensity). Analgesia-Nociception index response was not influenced by stimulation intensity (p = 0.064). NOL and Analgesia-Nociception Index responses were significantly correlated (Pearson r = 0.47; p < 0.001).

CONCLUSIONS

NOL allows a quantitative assessment of nociception under anesthesia in 5-12 years-old children. This study provides a solid basis for all future investigations on NOL monitoring in pediatric anesthesia.

REGISTRATION

NCT05233449.

Analgesia nociception index and high frequency variability index: promising indicators of relative parasympathetic tone

At present, there is no objective and absolute measure of nociception, although various monitoring techniques have been developed. One such technique is the Analgesia Nociception Index (ANI), which is calculated from heart rate variability that reflects the relative parasympathetic tone. ANI is expressed on a non-unit scale of 0-100 (100 indicates maximal relative parasympathetic tone). Several studies indicated that ANI-guided anesthesia may help reduce intraoperative opioid use. The usefulness of ANI in the intensive care unit (ICU) and during surgery has also been reported. However, some limitations of ANI have also been reported; for example, ANI is affected by emotions and some drugs. In 2022, a high frequency variability index (HFVI), which was renamed from ANI and uses the same algorithm as ANI, was commercialized; therefore, ANI/HFVI are currently in the spotlight. Unlike ANI, HFVI can be displayed along with other biometric information on the Root® monitor. ANI/HFVI monitoring may affect the prognosis of not only patients in the perioperative period but those in ICU, those who receive home medical care, or outpatients. In this article, we present an updated review on ANI that has been published in the last decade, introduce HFVI, and discuss the outlooks of ANI/HFVI.

Evaluation of Nociception during Pediatric Surgery: A Topical Review

The association between intraoperative nociception and increased patient's morbidity is well established. However, hemodynamic parameters, such as heart rate and blood pressure, may result in an inadequate monitor of nociception during surgery. Over the last two decades, different devices have been marketed to "reliably" detect intraoperative nociception. Since the direct measure of nociception is impractical during surgery, these monitors measures nociception surrogates such as sympathetic and parasympathetic nervous systems responses (heart rate variability, pupillometry, skin conductance), electroencephalographic changes, and muscular reflex arc. Each monitor carries its own advantages and disadvantages. The manuscript aims to give an overview of the most up-to-date information available in the literature on current nociceptor monitors available in clinical practice, with particular focus on their applications in pediatrics.

Nociception associated with pain/distress in young children sedated for dental treatment: a clinical study with objective and subjective measures

PURPOSE

To evaluate the association between children's pain/distress levels and patient characteristics (age, sex, history of dental pain), sedation type (level of sedation, sedative regimen), nociception and pain intensity reported by the parents in sedated children undergoing minimally invasive dental treatment.

METHODS

This clinical study evaluated secondary outcomes of an RCT that evaluated the efficacy of dexmedetomidine sedation with or without ketamine. Only children who had nociception levels recorded using the Analgesia Nociception Index (ANI) were included (0-100; 0 = highest nociception). FLACC scale (Face, Legs, Activity, Cry and Consolability) was used to assess children's pain/distress (0-10; 0 = no pain/distress). Parental proxy report of the child's pain intensity during the treatment was performed using the Visual Analogue Scale (VAS; 0-100; 0 = no pain). The association between ANI, children's age and sex, dental pain history, sedation level, sedative regimen, and VAS with the FLACC was verified using the generalised estimation equation analysis (alpha 0.05).

RESULTS

Participants were 31 children (51.6% boys) and their parents (90.3% mothers). Median FLACC was 3.3 (25th-75th percentiles 1.7-8.2), ANI 80.9 (74.7-85.8), and VAS 10 (1-23). FLACC associated with ANI (OR 0.96; 95% CI 0.93-0.99; p = 0.02), moderate sedation (0.13; 0.03-0.50; p = 0.003), and VAS (1.05; 1.01-1.10; p = 0.01).

CONCLUSION

Pain/distress was generally low and more prominent with minimal (versus moderate) sedation and higher nociception.

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.

Quantitative assessment of a pediatric nociception monitor in children under sevoflurane anesthesia

INTRODUCTION

Intraoperative monitoring of nociception has recently made substantial progress in adult anesthesia. In contrast, pediatric data are scarce. Newborn-Infant Parasympathetic Evaluation (NIPE index, Mdoloris Medical Systems, Loos, France) is the first nociception index specifically designed for young children. It is a dimensionless index comprised between 0 and 100. Two previous studies suggested that NIPE could indeed 'detect' nociception in anesthetized children. The objective of our study was to investigate if NIPE allowed to detect and to provide a quantitative assessment of nociception in children.

METHODS

Children were anesthetized with sevoflurane, and received a bolus of alfentanil (10 µg/kg before intubation). Before surgical incision, each participant received three tetanic stimulations (5 s, 100 Hertz) with a 5 min interval, in a randomized order: 10, 30 and 60 milliamps. NIPE and heart rate variations were assessed after each stimulation.

RESULTS

Thirty children (2.4±1.6 years) were included. Mean delay between alfentanil and the first stimulation was 19±4 min. Mean baseline NIPE was 75±10. NIPE variation after the stimulations was significant at 10, 30 and 60 mA (linear mixed regression model, p<0.001). The intensity of stimulation significantly influenced the amplitude of NIPE variation (linear mixed regression model p<0.001), but had no statistically significant effect on heart rate variation (p=0.52).

DISCUSSION

NIPE might allow a quantitative assessment of nociception in young children in these anesthetic conditions. This study provides a basis for future research investigating the potential benefits of NIPE-guided intraoperative analgesia in pediatric anesthesia.

TRIAL REGISTRATION NUMBER

NCT04381637.

Monitoring of analgesia level during general anesthesia in children

PURPOSE OF REVIEW

Monitoring of intraoperative nociception has made substantial progress in adult anesthesia during the last 10 years. Several monitors have been validated and their use has been associated with intraoperative or postoperative benefits in the adult population. In pediatric anesthesia, less data are available. However, several recent publications have assessed the performance of nociception monitors in children, and investigated their potential benefits in this context. This review will describe the main validated intraoperative nociception monitors, summarize adult findings and describe the available pediatric data.

RECENT FINDINGS

Six intraoperative nociception indices were included in this review. Among them, four have shown promising results in children: Surgical Pleth Index (GE-Healthcare, Helsinki, Finland), Analgesia-Nociception Index (Mdoloris Medical Systems, Loos, France), Newborn-Infant Parasympathetic Evaluation (Mdoloris Medical Systems), and Pupillometry (IDMED, Marseille, France). The relevance of Skin Conductance (MedStorm innovations, AS, Oslo, Norway) under general anesthesia could not be established. Finally, the Nociception Level (Medasense, Ramat Gan, Israel) still requires to be investigated in children.

SUMMARY

To date, four monitors may provide a relevant assessment of intraoperative nociception in children. However, the potential clinical benefits associated with their use to guide analgesia remain to be demonstrated.

Analgesia Nociception Index-Guided Remifentanil versus Standard Care during Propofol Anesthesia: A Randomized Controlled Trial

The clinical benefits to be expected from intraoperative nociception monitors are currently under investigation. Among these devices, the Analgesia Nociception-Index (ANI) has shown promising results under sevoflurane anesthesia. Our study investigated ANI-guided remifentanil administration under propofol anesthesia. We hypothesized that ANI guidance would result in reduced remifentanil consumption compared with standard management. This prospective, randomized, controlled, single-blinded, bi-centric study included women undergoing elective gynecologic surgery under target-controlled infusion of propofol and remifentanil. Patients were randomly assigned to an ANI or Standard group. In the ANI group, remifentanil target concentration was adjusted by 0.5 ng mL⁻¹ steps every 5 min according to the ANI value. In the Standard group, remifentanil was managed according to standard practice. Our primary objective was to compare remifentanil consumption between the groups. Our secondary objectives were to compare the quality of anesthesia, postoperative analgesia and the incidence of chronic pain. Eighty patients were included. Remifentanil consumption was lower in the ANI group: 4.4 (3.3; 5.7) vs. 5.8 (4.9; 7.1) µg kg⁻¹ h⁻¹ (difference = −1.4 (95% CI, −2.6 to −0.2), p = 0.0026). Propofol consumption was not different between the groups. Postoperative pain scores were low in both groups. There was no difference in morphine consumption 24 h after surgery. The proportion of patients reporting pain 3 months after surgery was 18.8% in the ANI group and 30.8% in the Standard group (difference = −12.0 (95% CI, −32.2 to 9.2)). ANI guidance resulted in lower remifentanil consumption compared with standard practice under propofol anesthesia. There was no difference in short- or long-term postoperative analgesia.

Emergence agitation in paediatric day case surgery: A randomised, single-blinded study comparing narcotrend and heart rate variability with standard monitoring

BACKGROUND

Postoperative emergence agitation remains a significant challenge in paediatric anaesthesia. Although short-lived, it may cause harm to the patient and negative experiences for all. Differentiating agitation, delirium and pain is difficult. Electroencephalography allows precise titration of anaesthetic depth, and heart rate variability monitoring permits immediate intervention regarding nociception and pain. We examined if one of these measures could be used to reduce postoperative agitation in an unselected paediatric day surgical population.

OBJECTIVE

The primary outcome was postoperative agitation with a Richmond Agitation-Sedation Scale greater than 0. Secondary outcomes were: length of stay, postoperative nausea and vomiting, fentanyl and propofol consumption, pain scores and use of postoperative analgesics.

DESIGN

A randomised, single-blinded study constituting children aged 1 to 6 years, undergoing minor general day surgical procedures.

SETTING

Paediatric day surgical department 29th March 2019 to 12th June 2020.

PATIENTS

Ninety-eight children (ASA 1 or 2) were enrolled, and 93 children were included in the final analysis.

INTERVENTIONS

Children received standard monitoring (n=31), standard monitoring plus either Narcotrend (n=31), or Anaesthesia Nociception Index monitoring (n=31). Sevoflurane or fentanyl was titrated immediately according to monitor thresholds.

RESULTS

Kaplan-Meier analysis yielded a statistically significant difference between the groups (P = 0.016) with the lowest agitation levels in the Anaesthesia Nociception Index group, intermediate levels in the control group and the highest agitation levels in the Narcotrend monitored group. Intergroup pairwise comparison however, showed no difference. The Anaesthesia Nocioception Index group received slightly more fentanyl (P = 0.277). The control group patients had the highest pain scores despite receiving more caudal blocks and the Narcotrend group had more sevoflurane adjustments. Other secondary outcomes were comparable.

CONCLUSION

Children in the Anaesthesia Nociception Index group were the least agitated with the highest fentanyl doses, without increasing the length of stay in the PACU or postoperative nausea and vomiting.

CLINICAL REGISTRATION

The study was registered in RedCAP online trial database 1/11/2018 trial registration nr. OP720. https://open.rsyd.dk/OpenProjects/openProject.jsp?openNo=720&lang=da.

Available Instruments to Assess Pain in Infants

Pain assessment in newborns and infants is challenging for clinicians. Although behavioral and behavioral-physiological scales are validated pain assessment instruments, their use in this age group has significant limitations. In this review, we summarize the methods currently available for assessing pain in neonates and infants. It is possible that these pain detection methods are also useful for assessing the quality of anesthesia and analgosedation in these populations. Further research should be aimed at confirming the usefulness of these tools in infants and identifying additional pain assessment options for clinical practice.

Newborn Infant Parasympathetic Evaluation Index for the Assessment of Procedural Pain in Nonanesthetized Infants: A Multicenter Pilot Study

OBJECTIVE

The aim of this study is to evaluate the ability of the Newborn Infant Parasympathetic Evaluation (NIPE) index to detect the response to nociceptive stimuli in nonanesthetized infants and to compare these results to simultaneous scoring by behavioral scales.

STUDY DESIGN

Thirty-six nonanesthetized infants admitted to neonatal/pediatric intensive care unit (N/PICUs) were enrolled to the study. Due to faulty records of the data, three patients had to be excluded. To detect pain caused by noxious stimuli, the heart-rate-variability-derived NIPE index and behavioral pain scales designed for measuring procedural pain in nonverbal children were used.

RESULTS

Forty-one painful events were available for analysis. We observed in the whole group a statistically significant decrease in NIPE values at 1, 2, and 3 minutes after a painful stimulus, in comparison to the NIPE value at rest and the statistically significant differences between the minimum NIPE value within 3 minutes after the stimulus in comparison to NIPE value at rest in the whole group, as well as in the subgroups of moderate and severe pain. Receiver operating characteristic (ROC) analysis has shown the strong sensitivity and specificity of the NIPE in detecting the noxious stimuli (ROC AUC: 0.767). We also found that the stronger the sensation of pain was, the more rapidly NIPE reached its lowest value.

DISCUSSION

Our study indicates that the painful procedures are associated with a significant decrease in the NIPE value within 3 minutes after a noxious stimulus. Based on our observation, the minimum value within 3 minutes from the painful procedure seems to be the most distinctive value.

The newborn infant parasympathetic evaluation index for acute procedural pain assessment in preterm infants

BACKGROUND

Accurate assessments of pain in hospitalized preterm infants present a major challenge in improving the short- and long-term consequences associated with painful experiences. We evaluated the ability of the newborn infant parasympathetic evaluation (NIPE) index to detect acute procedural pain in preterm infants.

METHODS

Different painful and stressful interventions were prospectively observed in preterm infants born at 25 + 0 to 35 + 6 weeks gestation. Pain responses were measured using the composite Premature Infant Pain Profile Revised (PIPP-R) scale, the NIPE index, and skin conductance responses (SCR). Outcome measures were correlations between the NIPE index, the PIPP-R score, and the SCR. Sensitivity/specificity analyses tested the accuracy of the NIPE index and SCR.

RESULTS

Two hundred and fifty-four procedures were recorded in 90 preterm infants. No significant correlation was found between PIPP-R and the NIPE index. PIPP-R and SCR were positively correlated (r = 0.27, P < 0.001), with stronger correlations for painful procedures (r = 0.68, P < 0.001) and especially for skin-breaking procedures (r = 0.82, P < 0.001). The NIPE index and SCR had high sensitivity and high negative predictive values to predict PIPP-R > 10, especially for skin-breaking painful procedures.

CONCLUSIONS

We found no significant correlation between the NIPE index and PIPP-R during routine painful or stressful procedures in preterm infants.

IMPACT

Exposure to repetitive pain can lead to neurodevelopmental sequelae. Behavior-based pain scales have limited clinical utility, especially for preterm infants. New devices for monitoring physiological responses to pain have not been validated sufficiently in preterm infants. This study found that the NIPE index was not significantly correlated to the validated PIPP-R scale during acute procedural pain. Secondary analysis of this study showed that NIPE index and SCRs may help to exclude severe pain in preterm infants. In clinical practice, measurements of physiological parameters should be combined with behavior-based scales for multidimensional pain assessments.

Comparative study of analgesia nociception index (ANI) vs. standard pharmacokinetic pattern for guiding intraoperative fentanyl administration among mastectomy patients

Background

The Analgesia Nociception Index (ANI) has been suggested as a non-invasive guide for analgesia. Our objective was to compare the efficacy of ANI vs. standard pharmacokinetic pattern for guiding intraoperative fentanyl administration.

Methods

This was a prospective, randomized, controlled study of adult female patients undergoing elective mastectomy under general anesthesia. The patients were randomized to the ANI-guided group receiving a loading dose of 75 μg of fentanyl followed by 25 μg when the ANI score was under 50. The Control group received the same loading dose followed by 25 μg every 30 min with additional doses when there were signs of inadequate analgesia (viz., tachycardia or hypertension).

Results

Sixty patients—30 in each group—were recruited. Although the actual mean ANI score was higher in the ANI-guided than in the Control group (mean difference 2.2; 95% CI: 0.3 to 4.0, P = 0.022), there was no difference in the primary outcome—i.e., intraoperative fentanyl consumption (mean difference − 4.2 μg; 95% CI: − 24.7 to 16.4, P = 0.686 and − 0.14 μg·kg^− 1·h^− 1; 95% CI: − 0.31 to 0.03, P = 0.105). No difference between groups was shown for either intraoperative blood pressure and heart rate, or for postoperative outcomes (i.e., pain scores, morphine consumption, or sedation scores) in the postanesthesia care unit.

Conclusions

Intraoperative fentanyl administration guided by ANI was equivalent to that guided by a modified pharmacologic pattern. In a surgical model of mastectomy, the ANI-guided intraoperative administration of fentanyl had no impact on clinical outcomes.

Trial registration

The study was registered with ClinicalTrials.gov (NCT03716453) on 21/10/2018.

Procedural Pain Assessment in Infants Without Analgosedation: Comparison of Newborn Infant Parasympathetic Evaluation and Skin Conductance Activity - A Pilot Study

Objective: New technologies to measure pain responses, such as heart rate variability and skin conductance hold promise in the development of tools that can be reliable and quantifiable of detecting pain. The main objective of this study was to assess the capability of two monitors i.e., Newborn Infant Parasympathetic Evaluation (NIPE) and Skin Conductance Algesimeter for detecting procedural pain in non-anesthetized infants. Materials and Methods: Thirty-three non-anesthetized infants were enrolled to the study. To detect pain caused by heel stick, NIPE, and Skin Conductance monitors and behavioral pain scales were used. Three minutes before and just after heel stick, pain was evaluated by behavioral scales, and simultaneously over the whole period by NIPE and SCA. Results: A statistically significant decrease of NIPE Index and an increase of SCA values were found after the HS procedure. There were no statistically significant differences between the decrease in NIPEi values and the increase in PPS values between subgroups based on pain assessment by behavioral-scale scores. Conclusion: Both NIPE and SCA can be useful for detection of procedural pain and may constitue an additional valuable tool for better handling of pain among patients treated in NICUs. More studies on larger groups of patients are needed.

Advances in infrared thermography: Surgical aspects, vascular changes, and pain monitoring in veterinary medicine

One of the main functions of infrared thermography (IRT) consists in detecting temperature changes in organisms caused by variations in surface blood circulation. IRT is a useful tool that has been used mainly as a diagnostic method for various stress-causing pathologies, though recent suggestions indicate that it can be used to assess the block quality of certain body regions. In the field of anaesthesiology, IRT has been applied to brachial and epidural blocks, while in algology, changes in surface blood circulation associated with sympathetic activity have been investigated. Thermography has also been employed to complement pain level scales based on the facial expressions of patients in critical condition, or after surgery. In addition, it has been used as a tool in research designed to evaluate different surgical procedures in human medicine, as in the case of surgical burrs for placing dental implants, where IRT helps assess the degree of heating associated with bone devascularisation, reduction in vascular perfusion as a consequence of stroke, and changes in the autonomous nervous system, or the degree of vascular changes in flaps applied to burn patients. In veterinary medicine, thermography has brought several benefits for animals in terms of evaluating lesions, diseases, and surgical procedures. The aim of this review is to evaluate how IRT can be used as a tool in surgical procedures, cases of vascular change, and pain monitoring in veterinary medicine with an emphasis on small animals.

Nociception monitoring tools using autonomic tone changes for intraoperative analgesic guidance in pediatric patients

Nociception monitoring devices using changes in autonomic nervous system activity have been developed in numerous ways. Although there have been few studies conducted on children, compared to the relatively higher number of studies on adults, most of the nociception monitors in children, as in adults, appear to be more useful than the standard clinical practice that uses hemodynamic parameters in the evaluation and treatment of intraoperative nociception (pain) during general anesthesia. Particularly, when monitoring the surgical pleth index (SPI) in anesthetized children, the application of a new target range of SPI values (≤ 40) to the SPI monitoring criteria seems to be necessary for providing a more proper intraoperative analgesia. The analgesia nociception index (ANI) shows promising results in anesthetized adults, and recently, positive results along with cardiorespiratory coherence have been reported in pediatric patients. Newborn infant parasympathetic evaluation (NIPE) could be useful for providing adequate analgesia in newborns, infants, and children under 2 years of age in anesthetized or awake states. In cases of skin conductance and pupillometry, further studies are needed. Understanding the pros, cons, and limitations of these nociception monitoring tools will provide more effective and safe intraoperative analgesia to pediatric patients undergoing general anesthesia, and it may also help to plan and conduct promising research on the use of perioperative nociception monitoring in pediatric patients in the future.

Postoperative Pain Management in Pediatric Patients Undergoing Cardiac Surgery: Where Are We Heading?

OBJECTIVES

Adequate postoperative pain management is crucial in pediatric patients undergoing cardiac surgery because pain can lead to devastating short- and long-term consequences. This review discusses the limitations of current postoperative pain assessment and management in children after cardiac surgery, the obstacles to providing optimal treatment, and concepts to consider that may overcome these barriers.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSIONS

Effective pain management in infants and young children undergoing cardiac surgery continues to evolve with innovative methods of both assessment and therapy using newer drugs or novel routes of administration. Artificial intelligence- and machine learning-based pain assessment and patient-tailored management in both pain measurement and prevention are already being integrated into the routine of current practice.

Analgesia Nociception Index: assessment of acute postoperative pain

Background and objectives

Patient self-rating based scales such as Numerical Rating Scale, Visual Analog Scale that is used for postoperative pain assessment may be problematic in geriatric or critically ill patients with communication problems. A method capable of the assessment of pain in objective manner has been searched for years. Analgesia nociception index, which is based on electrocardiographic data reflecting parasympathetic activity, has been proposed for this. In this study we aimed to investigate the effectiveness of analgesia nociception index as a tool for acute postoperative pain assessment. Our hypothesis was that analgesia nociception index may have good correlation with Numerical Rating Scale values.

Methods

A total of 120 patients of American Society of Anesthesiologists (ASA) physical status I and II undergoing any surgical procedure under halogenated-based anesthesia with fentanyl or remifentanil were enrolled for the study. At the 15th minute of arrival to the Postoperative Care Unit the patients’ pain was rated on a 0–10 point Numerical Rating Scale. The patients’ heart rate, blood pressure, and analgesia nociception index scores were simultaneously measured at that time. The correlation between analgesia nociception index, heart rate, blood pressure and Numerical Rating Scale was examined.

Results

The study was completed with 107 patients, of which 46 were males (43%). Mean (SD) analgesia nociception index values were significantly higher in patients with initial Numerical Rating Scale ≤3, compared with Numerical Rating Scale >3 (69.1 [13.4] vs. 58.1 [12.9] respectively, p < 0.001). A significant negative linear relationship (r² = −0.312, p = 0.001) was observed between analgesia nociception index and Numerical Rating Scale.

Conclusion

Analgesia nociception index measurements at postoperative period after volatile agent and opioid-based anesthesia correlate well with subjective Numerical Rating Scale scores.

Objective monitoring of nociception: a review of current commercial solutions

Nociception, in contrast to pain, is not a subjective feeling, but the physiological encoding and processing of nociceptive stimuli. However, monitoring nociception remains a challenge in attempts to lower the incidence of acute postoperative pain and the move towards a more automated approach to analgesia and anaesthesia. To date, several commercialised devices promise a more accurate reflection of nociception than the traditionally used vital signs, blood pressure and heart rate. This narrative review presents an overview of existing technologies and commercially available devices, and offers a perspective for future research. Although firm conclusions about individual methods may be premature, none currently appears to offer a sufficiently broad applicability. Furthermore, there is currently no firm evidence for any clinically relevant influence of such devices on patient outcome. However, the available monitors have significantly aided the understanding of underlying mechanisms and identification of potential pitfalls.

Analgesia Nociception Index: Heart Rate Variability Analysis of Emotional Status

Background

Analgesia nociception index (ANI) has been developed for real-time pain measurement during a surgical procedure under general anesthesia. The index is based on heart rate variability and constitutes a measure of parasympathetic tone. In this paper, we hypothesized that this index could be used as a tool to investigate the process of emotional regulation of a human subject.

Materials and methods

Twenty adult volunteers were recruited for the study, wherein ANI response to the emotional stimulus was evaluated. An emotional stimulus was obtained through a 60-second music sound record from the song “Ala Gözlerini Sevdiğim Dilber,” performed by the Turkish rock band Badem. ANI measurements were obtained before the song presentation (T_pre), at the end of the record presentation (T0), and each minute thereafter until the end of the five-minute observation (T1-T5).

Results

Twenty participants were investigated; 10 males and 10 females. The mean age of the participants was 17.0 ± 0.9 (min: 16, max: 20). ANI measurements were significantly lower in T0 and T3 compared with T_pre (P = 0.009). The differences between other values were not statistically significant.

Conclusion

ANI can be used for assessment of parasympathetic changes related to the emotional state of conscious patients.

The heart rate variability-derived Newborn Infant Parasympathetic Evaluation (NIPE™) Index in pediatric surgical patients from 0 to 2 years under sevoflurane anesthesia-A prospective observational pilot study

BACKGROUND

The heart rate variability-derived Newborn Infant Parasympathetic Evaluation (NIPE™) Index is a continuous noninvasive tool to assess pain and discomfort in infants <2 years. Initial studies focused on pain monitoring in the neonatal intensive care unit environment.

AIMS

The aim of this study was to investigate the performance of the NIPE in infants under sevoflurane anesthesia. The primary objective of this study was to compare the NIPE and heart rate as tools to help recognize the need for additional opioid drugs. Secondary objectives were the course of the NIPE and heart rate around specific standardized noxious procedural mile-stones.

METHODS

NIPE and heart rate values recorded during a 120 seconds interval before the anesthetist's decision to administer additional opioid due to the perceived insufficient antinociception and during a 120 seconds interval after drug administration were analyzed by means of a repeated measures ANOVA. The same analyses were performed for datasets around per protocol administration of morphine for postoperative analgesia, performance of a caudal block and surgical incision.

RESULTS

In patients with a NIPE value <50, an additional opioid drug administration resulted in a rise of NIPE values, reaching a maximum increase of 5.1 (95% CI: 0.22-9.99) units 120 seconds after drug administration (P = 0.041). There was no evidence of a change in heart rate during these two 120 seconds periods. Per protocol administration of morphine, caudal block, and surgical incision did not result in changes of the NIPE, which was around 65 units on these occasions, and heart rate.

CONCLUSION

In infants anesthetized with sevoflurane, NIPE values <50 might be indicative of insufficient antinociception. The results of this observational pilot study might suggest that the NIPE could be a better measure of the nociception/antinociception balance than heart rate.

Development of a "Thermal-Associated Pain Index" score using infrared-thermography for objective pain assessment

Without any doubt, research in biomedical engineering and anesthesiology achieved diverse ground-breaking successes for the sake of patient safety and for optimization of medical treatment in the last decades. Particularly anesthesia has become increasingly comfortable and safer due to new monitoring devices and further techniques. However, assessment of pain still relies on self-reporting of the patient using a Numeric Rating Scale ranging from 0 to 10. Obviously, this method suffers from severe restraints when unconscious, anesthetized or uncooperative subjects or children are involved as patients. Furthermore, no continuous monitoring is available so that features like alerting telemetry are lacking. Several scientific groups and companies searched intensively for procedures to measure pain objectively. Skin conductance, heart rate variability and peripheral perfusion, among others, were used to develop new algorithms and devices. Up to date, none of these devices succeeded to enter in clinical routine. In this project, we used infrared thermography (IRT) to analyze facial expressions and further thermal-associated phenomena that are visible in recorded IRT sequences such as lacrimation and perspiration. By means of clinical observations, a number of IRT features were predefined that were expected to correlate with pain. The combination of those features led to the so-called "Thermal-Associated Pain Intensity" (TAPI) after normalization and transformation. The TAPI correlates significantly with the NRS and achieves a sensitivity of above 0.75 to detect pain.

Surgical pleth index in children younger than 24 months of age: a randomized double-blinded trial

BACKGROUND

The surgical pleth index (SPI) is a measurement of intraoperative nociception. Evidence of its usability in children is limited. Given that the autonomic nervous system is still developing during the first years of life, the performance of the SPI on small children cannot be concluded from studies carried out in older age groups.

METHODS

Thirty children aged <2 yr, planned for elective open inguinal hernia repair or open correction of undescended testicle, were recruited. The children were randomized into two groups; the saline group received ultrasound-guided saline injection in the ilioinguinal and iliohypogastric nerve region before surgery and ropivacaine after surgery, whereas the block group received the injections in the opposite order. The SPI was recorded blinded and was analysed at the time points of intubation, incision, and when signs of inadequate anti-nociception were observed.

RESULTS

There was a significant increase in the SPI after intubation (P=0.019) and after incision in the saline group (P=0.048), but not at the time of surgical incision in the block group (P=0.177). An increase in the SPI was also seen at times of clinically apparent inadequate anti-nociception (P=0.008). The between-patient variability of the SPI was large.

CONCLUSIONS

The SPI is reactive in small children after intubation and after surgical stimuli, but the reactivity of the SPI is rather small, and there is marked inter-individual variability in reactions. The reactivity is blunted by the use of ilioinguinal and iliohypogastric nerve block.

CLINICAL TRIAL REGISTRATION

NCT02045810.

Scope of physiological and behavioural pain assessment techniques in children - a review

Pain is an unpleasant subjective experience. At present, clinicians are using self-report or pain scales to recognise and monitor pain in children. However, these techniques are not efficient to observe the pain in children having cognitive disorder and also require highly skilled observers to measure pain. Using these techniques it is also difficult to choose the analgesic drug dosages to the patients after surgery. Thus, this conceptual work explains the demand for automatic coding techniques to evaluate pain and also it documents some evidence of techniques that act as an alternative approach for objectively determining pain in children. In this review, some good indicators of pain in children are explained in detail; they are facial expressions from an RGB image, thermal image and also feature from well proven physiological signals such as electrocardiogram, skin conductance, body temperature, surgical pleth index, pupillary reflex dilation, analgesia nociception index, photoplethysmography, perfusion index etc.

Heart rate variability: implications for perioperative anesthesia care

PURPOSE OF REVIEW

Heart rate variability (HRV) is a measure of the balance between both the parasympathetic and sympathetic nervous system and may provide useful information for anesthesia care providers. HRV may offer predictive information about critically ill and operative patients. Further, HRV collection provides real-time information of patient autonomic nervous system status and may allow tailoring of the analgesia for patients in the ICU and operating room.

RECENT FINDINGS

Reduced and abnormal resting HRV predict sudden and nonsudden cardiac death. Recent evidence shows that decreased HRV correlates with worsened outcomes in both trauma patients and patients with sepsis, as well as the risk of developing hypotension after induction of general anesthesia and placement of intrathecal local anesthesia. In addition, HRV appears to provide an accurate assessment of the nociception-analgesia balance in deeply sedated ICU patients and those under general anesthesia.

SUMMARY

No study has assessed the prognostic value of preoperative HRV in patients presenting for surgery. Use of HRV for patient risk stratification and intraoperative analgesia management may allow tailored perioperative care and improved outcomes. If intraoperative HRV data leads to decreased perioperative opioid use, opioid-related adverse events, a serious perioperative issue, may be decreased.

CLINICAL TRIALS REGISTRATION

Not applicable.

Evaluation of the analgesia nociception index for monitoring intraoperative analgesia in children

BACKGROUND

Intraoperative analgesia is still administered without guidance. Anaesthetists decide upon dosing on the basis of mean population opioid pharmacological studies and in response to variations in haemodynamic status. However, those techniques have been shown to be imprecise. We assessed the diagnostic value of monitoring the analgesia nociception index (ANI) to detect surgical stimulation in children.

METHODS

This was an observational study of 2- to 12-yr-old patients 5 min before and after surgical incision. Hypnosis was maintained with sevoflurane and guided by bispectral index. Intraoperative analgesia was administered as a remifentanil infusion titrated to variations in haemodynamic parameters, and ANI monitor values were recorded. ANI parameters assessed included instantaneous ANI (ANIi), mean ANI (ANIm), and the relative change of ANIi to ANIm (DeltaANI=ANIi-ANIm/ANIm). Statistical analyses were performed using receiver-operating-characteristic analysis with determination of the area under the receiver operating characteristic (AUROC) curve and the grey zone.

RESULTS

Overall, 49 subjects were included in this study. The AUROC was 0.755 (0.738-0.772), 0.771 (0.755-0.787), and 0.756 (0.738-0.774) for ANIi, ANIm, and DeltaANI, respectively. The threshold of ANI parameters indicating the presence of noxious surgical stimuli was ≤53%, ≤56%, and ≤-13.3% for ANIi, ANIm, and DeltaANI, respectively. The percentage of subjects in the inconclusive zone was 41%, 51%, and 33% for ANIi, ANIm, and DeltaANI, respectively.

CONCLUSIONS

ANI has diagnostic value for detecting surgical stimuli in children.

The predictive value of the heart rate variability-derived Analgesia Nociception Index in children anaesthetized with sevoflurane: An observational pilot study

Background

The heart rate variability (HRV)‐derived Analgesia Nociception Index (ANI™) is a continuous noninvasive tool to assess the nociception/antinociception balance in unconscious patients. It has been shown to be superior to haemodynamic variables in detecting insufficient antinociception in children, while little is known about its predictive value.

Methods

The primary objective of this prospective observational pilot study in paediatric surgical patients under sevoflurane anaesthesia was to compare the predictive value of the ANI and heart rate to help decide to give additional opioids. The paediatric anaesthesiologist in charge was blinded to ANI values.

Results

In patients with an ANI value <50 (indicating insufficient antinociception) at the moment of decision, ANI values dropped from ±55 (indicating sufficient antinociception) to ±35, starting 60 s before decision. Within 120 s after administration of fentanyl (1 μg/kg), ANI values returned to ±60. This phenomenon was only observed in the ANI values derived from HRV data averaged over 2 min. Heart rate remained unchanged. In patients with ANI values ≥50 at the time of decision, opioid administration had no effect on ANI or heart rate. The same accounts for morphine for postoperative analgesia and fentanyl in case of intraoperative movement.

Conclusions

This study provides evidence of a better predictive value of the ANI in detecting insufficient antinociception in paediatric surgical patients than heart rate. The same accounts for depicting re‐establishment of sufficient antinociception after opioid drug administration.

Significance

In paediatric surgical patients anaesthetized with sevoflurane, the heart rate variability‐derived Analgesia Nociception Index (ANI) appears to be a better predictor of insufficient antinociception than heart rate. The ANI also appears to depict re‐establishment of sufficient antinociception better than heart rate.

Electrodermal Activity during Blood Pooling for Arterial Blood Gases Analysis in Sedated Adult Intensive Care Unit Patients

Electrodermal activity (EDA) is considered a measure of autonomous nervous system activity. This study performed an exploratory analysis of the EDA changes during blood pooling for arterial blood gas analysis in sedated adult critical care patients and correlated the variations to other monitored parameters. EDA, along with other parameters, were monitored during 4 h routine daytime intensive care nursing and treatment in an adult ICU. 4 h measurements were divided into two groups based upon the sedation level. Selected recordings before and after blood pooling for arterial blood gases analysis (stress event) was performed. Nine stress events from Group A and 17 from Group B were included for further analysis. Patients’ demographics, laboratory exams, and severity scores were recorded. For both sedation levels, EDA changes are much greater than any other monitoring parameters used. The changes are noticed in both measurement (15 s and 60 s), even though in the 60 s measurement only selected EDA parameters are significantly changed after the start of the procedure. EDA measurements are more sensitive to a given stress event than cardiovascular or respiratory parameters. However, the present results could only be considered as a pilot study. More studies are needed in order to identify the real stress-load and clinical significance of such stimuli, which are considered otherwise painless in those patients.

Electrodermal Activity Responses for Quantitative Assessment of Felt Pain

Accurate assessment of experienced pain is a well-known problem in the clinical practices. Therefore, a proper method for pain detection is highly desirable. Electrodermal activity (EDA) is known as a measure of the sympathetic nervous system activity, which changes during various mental stresses. As pain causes mental stress, EDA measures may reflect the felt pain. This study aims to evaluate changes in skin conductance responses (SCRs), skin potential responses (SPRs), and skin susceptance responses (SSRs) simultaneously as a result of sequences of electrical (painful) stimuli with different intensities. EDA responses as results of painful stimuli were recorded from 40 healthy volunteers. The stimuli with three different intensities were produced by using an electrical stimulator. EDA responses significantly changed (increased) with respect to the intensity of the stimuli. Both SCRs and SSRs showed linear relationship with the painful stimuli. It was found that the EDA responses, particularly SCRs (p < 0.001) and SSRs (p = 0.001) were linearly affected by the intensity of the painful stimuli. EDA responses, in particular SCRs, may be used as a useful indicator for assessment of experienced pain in clinical settings.

Thermal camera as a pain monitor

Objectives

Today, many subjective methods are used to measure pain. Wong Baker and Hicks Facial Pain Scale is one of the most commonly used method. Clinicians grade pain according to the facial mimetic reaction of the patient. Unfortunately, there is no objective measure for monitoring pain. By using the same principle of the Wong Baker and Hicks Facial Pain Scale, in this study, we aimed to objectively measure pain by using a thermal camera to detect instant facial temperature changes.

Materials and methods

Thirty volunteers who attended blood collection unit were subjected to facial thermal monitoring and measurements were obtained 5 minutes before needle puncture (BNP), during needle puncture (DNP), and after needle puncture (ANP). Data were processed with TestoIRSoft 3.8 software program and mean temperatures of the whole face (FFM) and highest temperature points (HP), horizontal line (HOR) between two pupils and first glabellar wrinkle, and bilateral lines starting from the nasolabial sulcus to oral commissure (NLS-1 at right, NLS-2 at left) were evaluated. All data were statistically analyzed with paired sample t-test.

Results

Statistically, temperature measurements of HOR, NLS-1, NLS-2, HP, and FFM were significantly higher between BNP and DNP, significantly lower between ANP and DNP, and significantly higher between BNP and ANP (p<0.05). The most interesting result in our analysis was that the HP point was between the two eyebrows in 26 of the 30 volunteers.

Conclusion

Our results suggest that a thermal camera can be used to objectively monitor pain and in follow-up. However, further studies involving non-healthy volunteers (especially high-fever patients, children, immunosuppressive patients, and cancer and intensive care patients) should be performed.

[Pain in children with neurological impairment: A review from the French Pediatric Neurology Society]

Management of pain is one of the major expectations of children with neurological impairment and their families. The medical literature is poor on this topic accounting for approximately 0.15 % of the publications on pain in general. The objective of the French Pediatric Neurology Society was to review the current knowledge on this topic. Bibliographic research was conducted with PubMed and RefDoc for publications between 1994 and 2014 in French or English. A total of 925 articles were retrieved and 92 were selected for review. Pain is common in this population: a 2-week survey indicated that pain occurs in 50-75 % of children. Pain negatively impacts the quality of life of children and their parents. Children with neurological impairment express their pain with pain expression patterns and specific patterns common to children (change of tone, abnormal movements, spasticity, paradoxical reactions, such as laughter, self-injury or vasomotor dysfunction). Some children with neurological impairment are able to use self-report pain scales. If not, observational measures should be used. Behavioral rating scales specifically designed for this population are more sensitive than others. Scales must be selected according to children's communication skills, type of pain, and the context. Sometimes behavioral changes are the only expression of pain: any change in sleep, tone, feeding, or mood must suggest pain in this population. Management of pain remains difficult. There are no specific guidelines. Procedural pain management guidelines and the usual analgesic drugs can be used in children with neurological impairment with specific concerns regarding tolerance and side effects. These children are particularly at risk for neuropathic pain. A multidisciplinary approach is helpful, involving physicians, nurses, physiotherapists, psychologists and parents.

Closed-loop Administration of General Anaesthesia: From Sensor to Medical Device

Closed-loop administration devices for general anaesthesia have become a common subject of clinical research over the last decade and appear more and more acceptable in clinical practice. They encompass various therapeutic needs of the anesthetized patient, e. g. fluid administration, hypnotic and analgesic drug administration, myorelaxation. Multiple clinical trials involving closed-loop devices have underscored their safety, but data concerning their clinical benefit to the patient are still lacking. As the marketing of various devices increases, clinicians need to understand how comparisons between these devices can be made: the measure of performance error and wobble are technical but have also a clinical meaning, to which clinical outcomes can be added, such as drug consumption and maintenance of hemodynamic parameters (e. g. heart rate and blood pressure) within predefined ranges. Clinicians using closed-loop devices need especially to understand how various physiological signals lead to specific drug adaptations, which means that they switch from decision making to supervision of general anaesthesia.

Validation of Innovative Techniques for Monitoring Nociception during General Anesthesia

Background

This study compares the analgesic indices Analgesia Nociception Index (heart rate variability), Surgical Pleth Index (photoplethysmography), and pupillary dilatation, to heart rate, mean arterial pressure, and bispectral index, with regard to diagnostic accuracy and prediction probability for nociceptive response. The primary endpoint was the correlation between Δ values and the remifentanil dose administered.

Methods

We anesthetized 38 patients with propofol and increasing doses of remifentanil and applied standardized tetanic and intracutaneous electrical painful stimulations on each analgesic level. Baseline and Δ values of the Analgesia Nociception Index, the Surgical Pleth Index, pupillary dilatation, heart rate, mean arterial pressure, and bispectral index and their relation to remifentanil doses were analyzed by receiver operating characteristic curves, prediction probability (PK), and mixed-model analysis.

Results

Under propofol sedation, sensitivity and specificity of the Analgesia Nociception Index (PK = 0.98), the Surgical Pleth Index (PK = 0.87), and pupillary dilatation (PK = 0.98) for detecting both painful stimulations were high compared to heart rate (PK = 0.74), mean arterial pressure (PK = 0.75), and bispectral index (PK = 0.55). Baseline values had limited prediction probability toward the nociceptive response (Analgesia Nociception Index: PK = 0.7; Surgical Pleth Index: PK = 0.63; pupillary dilatation: PK = 0.67; and bispectral index: PK = 0.67). The remifentanil dose had an effect (P &lt; 0.001) on all parameters except for bispectral index (P = 0.216).

Conclusions

The Analgesia Nociception Index, the Surgical Pleth Index, and pupillary dilatation are superior in detecting painful stimulations compared to heart rate and mean arterial pressure but had limited predictive value. These effects are attenuated by increasing dosages of remifentanil. Our data confirm that bispectral index is not a marker of analgesia.

Impact of skin-to-skin contact on the autonomic nervous system in the preterm infant and his mother

Before, during and after mother-newborn skin-to-skin contact (SSC), parasympathetic activity was evaluated by heart rate variability (HRV) analysis. SSC had a favorable impact on maternal and premature infant parasympathetic activities with a more pronounced response for neonates when the basal HRV values were lower, without modifications of EDIN scores, temperatures or oxygen saturation.

Physiological Signal Processing for Individualized Anti-nociception Management During General Anesthesia: a Review

OBJECTIVE

The aim of this paper is to review existing technologies for the nociception / anti-nociception balance evaluation during surgery under general anesthesia.

METHODS

General anesthesia combines the use of analgesic, hypnotic and muscle-relaxant drugs in order to obtain a correct level of patient non-responsiveness during surgery. During the last decade, great efforts have been deployed in order to find adequate ways to measure how anesthetic drugs affect a patient's response to surgical nociception. Nowadays, though some monitoring devices allow obtaining information about hypnosis and muscle relaxation, no gold standard exists for the nociception / anti-nociception balance evaluation. Articles from the PubMed literature search engine were reviewed. As this paper focused on surgery under general anesthesia, articles about nociception monitoring on conscious patients, in post-anesthesia care unit or in intensive care unit were not considered.

RESULTS

In this article, we present a review of existing technologies for the nociception / anti-nociception balance evaluation, which is based in all cases on the analysis of the autonomous nervous system activity. Presented systems, based on sensors and physiological signals processing algorithms, allow studying the patients' reaction regarding anesthesia and surgery.

CONCLUSION

Some technological solutions for nociception / antinociception balance monitoring were described. Though presented devices could constitute efficient solutions for individualized anti-nociception management during general anesthesia, this review of current literature emphasizes the fact that the choice to use one or the other mainly relies on the clinical context and the general purpose of the monitoring.