Heart rate variability analysis as an index of emotion regulation processes: interest of the Analgesia Nociception Index (ANI)

End-of-life Comfort Evaluation, is Clinic Enough? A Retrospective Cohort Study of Combined Comfort Evaluation with Analgesia/Nociception Index and Clinic in non-Communicative Patients

Background: Comfort evaluation is one of the major challenges in the palliative care setting, particularly when it comes to non-communicative patients. For this specific population, validated tools for comfort evaluation are scarce and healthcare professionals have to rely on their clinical sense and experience. Objectives: To provide arguments for the use of Analgesia/Nociception Index (ANI) monitoring in order to improve clinical comfort evaluation. Methods: We conducted a retrospective cohort study of non-communicative patients at the end of their lives whose comfort was evaluated clinically and with ANI. We focused on the coherence or discordance of clinical and ANI evaluations and on pharmacological interventions driven by them. Results: 58 evaluations from 33 patients were analyzed. Clinical and demographic characteristics were highly variable. Simultaneous clinical and ANI evaluations were concordant in 45 measurements (77.58%), leading mostly to no treatment modification when indicating comfort and to increasing anxiolytic or pain-relief treatments when indicating discomfort. Thirteen (22.41%) evaluations were discordant, leading mostly to treatment incrementation. Conclusion: We suggest that the ANI monitor is a reliable tool in the palliative setting and may help provide patients with the best symptom relief and the most appropriate therapeutics.

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.

Prospective multicenter study of heart rate variability with ANI monitor as predictor of mortality in critically ill patients with COVID-19

The purpose of this study is to demonstrate that the most critically ill patients with COVID-19 have greater autonomic nervous system dysregulation and assessing the heart rate variability, allows us to predict severity and 30-day mortality. This was a multicentre, prospective, cohort study. Patients were divided into two groups depending on the 30-day mortality. The heart rate variability and more specifically the relative parasympathetic activity (ANIm), and the SDNN (Energy), were measured. To predict severity and mortality multivariate analyses of ANIm, Energy, SOFA score, and RASS scales were conducted. 112 patients were collected, the survival group (n = 55) and the deceased group (n = 57). The ANIm value was higher (p = 0.013) and the Energy was lower in the deceased group (p = 0.001); Higher Energy was correlated with higher survival days (p = 0.009), and a limit value of 0.31 s predicted mortalities with a sensitivity of 71.9% and a specificity of 74.5%. Autonomic nervous system and heart rate variability monitoring in critically ill patients with COVID-19 allows for predicting survival days and 30-day mortality through the Energy value. Those patients with greater severity and mortality showed higher sympathetic depletion with a predominance of relative parasympathetic activity.

Anterior plating technique for distal radius: comparing performance after learning through naive versus deliberate practice

BACKGROUND

Surgical teaching is most often carried out in the operating theatre through mentorship, and the performance of surgical procedures is rarely measured. The objective of this article is to compare the progression in learning curves of junior surgeons trained in the anterior plating technique for the distal radius on a nonbiological model according to three different methods.

METHODS

The materials comprised 12 junior surgeons of level 1 or 2 (as per Tang and Giddins) divided into three groups: control (G1), naive practice (G2), and deliberate practice (G3). The three groups watched a demonstration video of a level 5 expert. The four G1 surgeons (two level 1 and two level 2) saw the video only once, and each inserted five plates. The four G2 surgeons (two level 1 and two level 2) inserted five plates and watched the video before each time. The four G3 surgeons (two level 1 and two level 2) saw the video before the first plate insertion. Before posing the subsequent four plates, the four G3 surgeons watched their own video, and the expert indicated their errors and how to avoid them next time. A 12-criteria OSATS defined on the basis of the 60 videos, each graded from one (min.) to five (max.), was used to measure the objective surgical performance per plating (min. 12; max. 60) and per series of five plate fixations (min. 60, max. 300).

RESULTS

The total average objective performance of G1 was 44.73, of G2 was 50.57 and of G3 was 54.35. Change in objective performance was better for G3 (13.25) than G2 (5) or G1 (3.75). For all groups, the progression in objective performance was better amongst level 1 surgeons (9) than level 2 surgeons (5.6).

CONCLUSION

Surgical teaching is based on mentorship and experience. However, since "see one, practice many, do one" has started to replace "see one, do one, teach one", learning techniques have increasingly relied on procedure simulators. Against this background, few studies have looked at measuring the performance of surgical procedures and improved learning curves. Our results appear to suggest that deliberate practice, when used in addition to mentorship, is the best option for shortening the growth phase of the learning curve and improving performance. Deliberate practice is a learning technique for surgical procedures that is complementary to mentorship and experience, which allows the growth phase of the learning curve to be shortened and the objective performance of junior surgeons to be improved.

[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.

Is the heart rate variability monitoring using the analgesia nociception index a predictor of illness severity and mortality in critically ill patients with COVID-19? A pilot study

Introduction

The analysis of heart rate variability (HRV) has proven to be an important tool for the management of autonomous nerve system in both surgical and critically ill patients. We conducted this study to show the different spectral frequency and time domain parameters of HRV as a prospective predictor for critically ill patients, and in particular for COVID-19 patients who are on mechanical ventilation. The hypothesis is that most severely ill COVID-19 patients have a depletion of the sympathetic nervous system and a predominance of parasympathetic activity reflecting the remaining compensatory anti-inflammatory response.

Materials and methods

A single-center, prospective, observational pilot study which included COVID-19 patients admitted to the Surgical Intensive Care Unit was conducted. The normalized high-frequency component (HFnu), i.e. ANIm, and the standard deviation of RR intervals (SDNN), i.e. Energy, were recorded using the analgesia nociception index monitor (ANI). To estimate the severity and mortality we used the SOFA score and the date of discharge or date of death.

Results

A total of fourteen patients were finally included in the study. ANIm were higher in the non-survivor group (p = 0.003) and were correlated with higher IL-6 levels (p = 0.020). Energy was inversely correlated with SOFA (p = 0.039) and fewer survival days (p = 0.046). A limit value at 80 of ANIm, predicted mortalities with a sensitivity of 100% and specificity of 85.7%. In the case of Energy, a limit value of 0.41 ms predicted mortality with all predictive values of 71.4%.

Conclusion

A low autonomic nervous system activity, i.e. low SDNN or Energy, and a predominance of the parasympathetic system, i.e. low HFnu or ANIm, due to the sympathetic depletion in COVID-19 patients are associated with a worse prognosis, higher mortality, and higher IL-6 levels.

Conscious sedation for the management of dental anxiety in third molar extraction surgery: a systematic review

BACKGROUND

Dental anxiety is a condition associated with avoidance of dental treatment and increased medical and surgical risks. This systematic review aims to summarize available evidence on conscious sedation techniques used for the management of Dental anxiety in patients scheduled for third molar extraction surgery, to identify best approaches and knowledge gaps.

METHODS

A comprehensive search was conducted including MEDLINE/Pubmed, EMBASE, SCOPUS, clinicaltrials.gov and the Cochrane Database of Systematic Reviews through March 2019. Only randomized controlled trials were included. PRISMA guidelines were followed. Risk of bias was appraised as reported in the Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

Seventeen RCTs with a total of 1788 patients were included. Some aspects limited the feasibility of a meaningful meta-analysis, thus a narrative synthesis was conducted. Conscious sedation was associated with improvement in Dental anxiety in six studies. One study reported lower cortisol levels with midazolam vs. placebo, while another study found significant variation in perioperative renin levels with remifentanil vs. placebo.

CONCLUSIONS

This review found inconclusive and conflicting findings about the role of Conscious sedation in managing Dental anxiety during third molar extraction surgery. Relevant questions remain unanswered due to the lack of consistent, standardized outcome measures. Future research may benefit from addressing these limitations in study design.

Can postoperative pain be predicted? New parameter: analgesia nociception index

Background/aim

The Analgesia Nociception Index (ANI) is a new method of identifying nociception-analgesia balance. In this study, we investigate the correlation between the ANI and numeric rating scale (NRS) values immediately before and after extubation. The NRS values were recorded in the postanesthesia care unit, in a group of patients who underwent laparoscopic cholecystectomy, with the aim of evaluating the potential use of ANI values in the prediction of postoperative pain levels.

Materials and methods

The ANI and NRS values, heartbeat rate (HR), systolic and diastolic arterial pressure (SAP/DAP), and oxygen saturation (SpO2) values of the patients were recorded into three groups based on the initial NRS values recorded in the postanesthesia care unit (group I: NRS ≤ 3, group II: NRS 4–6, group III: NRS ≥ 7). Patients whose ANI values were lower than 47, considered as the pain threshold, and the groups to which these patients belonged were also recorded.

Results

Statistically significant increases were noted in HR, SAP, and DAP after extubation, while there was no significant change in ANI values. A weak correlation was identified between the ANI and NRS values of all patient groups.

Conclusion

We failed to identify a correlation between ANI and NRS values before and after extubation. Previous studies suggested that the ANI provides more valuable information in anesthetized patients, whereas our findings show that it is ineffective in the prediction of potential postoperative pain.

Effectiveness of the Analgesia Nociception Index Monitoring in Patients Who Undergo Colonoscopy with Sedo-Analgesia

Objective

The objective of this study was to improve the patient comfort and safety during procedures done under anaesthesia and sedation. The analgesia nociception index (ANI) noninvasively provides information on the nociception-antinociception balance, and it can be used to assess analgesia objectively. We aimed to compare the effects of analgesia management with conventional methods and with ANI monitoring on total opioid consumption, sedation and analgesia levels in patients who underwent colonoscopy using sedo-analgesia.

Methods

Adult patients (n=102), scheduled for procedural sedation, were prospectively analysed. After the induction with propofol and ketamine, infusions of propofol (2 mg kg⁻¹ h⁻¹) and remifentanil (0.05 mcg kg⁻¹ min⁻¹) were started. In Group A, remifentanil infusions were titrated to maintain the ANI value between 50 and 70, whereas in Group C, analgesic requirements were met according to the attending anaesthetist’s intention. The heart rate, blood pressure, respiratory rate, SpO₂, BIS, Numeric Rating Scale (NRS) and Ramsay Sedation Scale were monitored. Complications, analgesics consumption, duration of the procedure, demographic information, NRS and the Modified Aldrete Score were evaluated.

Results

A total remifentanil amount used in Group A was 66.51±47.87 mcg and 90.15±58.17 mcg in Group C (p=0.011); there was no difference in total amounts of ketamine and propofol given. There was a negative correlation between ANI and NRS scores of Group A patients at Minute 0 at the level of 0.402, which was significant statistically (p=0.003).

Conclusion

Opioid consumption was diminished when ANI monitoring was used, and thus the patient safety was improved. Further studies with longer procedure times and with a greater number of patients are required to demonstrate whether there is a difference in side effects and recovery times.

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.

EFFECTS OF CONVERSATIONAL HYPNOSIS ON RELATIVE PARASYMPATHETIC TONE AND PATIENT COMFORT DURING AXILLARY BRACHIAL PLEXUS BLOCKS FOR AMBULATORY UPPER LIMB SURGERY:A Quasiexperimental Pilot Study

This two-center quasiexperimental pilot study was to determine the effect of conversational hypnosis on patient comfort and parasympathetic tone, which may represent a quantitative measure of hypnotic depth, during regional anesthesia. The patients received conversational hypnosis in one center and oral premedication in the other. The patients' subjective comfort (0-10 rating scale) and objective parasympathetic tone, as assessed by the Analgesia/Nociception Index (ANI), were measured before and after regional anesthesia. The parasympathetic tone and comfort scores evidenced a significantly greater increase in the hypnosis patients than in controls. These findings suggest that using conversational hypnosis during regional anesthesia may be followed by a subjective increase in patient comfort and an objective increase in parasympathetic tone, monitored by ANI.

Effects of hypnosis on the relative parasympathetic tone assessed by ANI (Analgesia/Nociception Index) in healthy volunteers: a prospective observational study

Hypnosis has shown an effect on the regulation of the autonomic nervous system by increasing parasympathetic activity. The Analgesia/Nociception Index (ANI) is derived from heart rate variability and represents the relative parasympathetic tone. We investigated the effects of hypnosis on ANI in healthy volunteers. Participants to the 2016 International Hypnosis congress, Saint Malo, France were recruited in this prospective observational study. After comfortable positioning of the subject in the sitting position (T0), the hypnotic trance was induced (T1) then conducted with suggestions of comfort (T2) before return to normal consciousness (T3). The ANI, heart rate (HR) and respiratory rate (RR) were recorded at the different time-points. Forty subjects were enrolled (31 women, 9 men). The mean ± SD ANI at T2 (84 ± 12) was significantly greater than at T0 (60 ± 10), T1 (62 ± 9) and T3 (59 ± 11). The median [25th-75th percentile] ANI values at T2 were significantly greater in women (90 [83-95]) than in men (74 [68-83]). There were no significant variations of HR during time. The median [25th-75th percentile] RR at T1 (16 [14-18] breaths/min) and T2 (14 [12-16] breaths/min) were significantly smaller than at T0 (18 [16-20] breaths/min) and T3 (18 [16-20] breaths/min). This study shows that hypnosis induces an increase in the relative parasympathetic tone assessed by ANI in healthy volunteers, with greater ANI values observed in women. These results suggest that ANI monitoring may provide an objective tool for the measurement of the intensity of the hypnotic process, although this should be confirmed by further studies.

Analgesia nociception index (ani) monitoring in patients with thoracic paravertebral block: a randomized controlled study

The goal of the study was to evaluate the effectiveness of analgesia nociception index (ANI) monitoring during intraoperative period for patients with thoracic paravertebral block (TPVB) undergoing breast surgery under general anesthesia. This prospective randomized trial was performed after receiving ethics committee approval in 44 patients who were scheduled to undergo breast surgery under general anesthesia. TPVB was performed in the preoperative period using 20 mL of bupivacaine 0.25% at T4 level. Anesthesia maintenance was provided with sevoflurane in O₂: air mixture and remifentanil infusion. Intraoperative concentration of sevoflurane was adjusted according to BIS monitoring keeping the values between 40-60. In a randomized manner patients were divided into two groups. In Group control (n:22) intraoperative remifentanil infusion rate was regulated according to hemodynamic parameters, in Group ANI (n:22) remifentanil infusion rate was titrated to keep ANI monitoring values between 50-70. Total remifentanil consumption was recorded as micrograms. Demographic data, anesthesia and surgery time, intraoperative hemodynamic parameters, post-anesthesia recovery time and requirement of additional analgesic in the recovery drug were recorded. There were no significant difference in demographic data, intraoperative hemodynamic parameters, post-anesthesia recovery time and requirement of additional analgesic drug. There was a statistically significant difference between groups in total remifentanil consumption (Group ANI: 629.6 ± 422.4 mcg, Group control: 965.2 ± 543.6 mcg) (p = 0.027). In patients under general anesthesia ANI monitorisation can help optimisation of opioid consumption and provide data about nociception/antinociception intraoperatively but further experimental and clinical trials in a large scale are needed.

Physiological Signal-Based Method for Measurement of Pain Intensity

The standard method for prediction of the absence and presence of pain has long been self-report. However, for patients with major cognitive or communicative impairments, it would be better if clinicians could quantify pain without having to rely on the patient's self-description. Here, we present a newly pain intensity measurement method based on multiple physiological signals, including blood volume pulse (BVP), electrocardiogram (ECG), and skin conductance level (SCL), all of which are induced by external electrical stimulation. The proposed pain prediction system consists of signal acquisition and preprocessing, feature extraction, feature selection and feature reduction, and three types of pattern classifiers. Feature extraction phase is devised to extract pain-related characteristics from short-segment signals. A hybrid procedure of genetic algorithm-based feature selection and principal component analysis-based feature reduction was established to obtain high-quality features combination with significant discriminatory information. Three types of classification algorithms-linear discriminant analysis, k-nearest neighbor algorithm, and support vector machine-are adopted during various scenarios, including multi-signal scenario, multi-subject and between-subject scenario, and multi-day scenario. The classifiers gave correct classification ratios much higher than chance probability, with the overall average accuracy of 75% above for four pain intensity. Our experimental results demonstrate that the proposed method can provide an objective and quantitative evaluation of pain intensity. The method might be used to develop a wearable device that is suitable for daily use in clinical settings.

Comparison of pulse rate variability and heart rate variability for high frequency content estimation

Heart Rate Variability (HRV) analysis can be of precious help in most of clinical situations because it is able to quantify the Autonomic Nervous System (ANS) activity. The HRV high frequency (HF) content, related to the parasympathetic tone, reflects the ANS response to an external stimulus responsible of pain, stress or various emotions. We have previously developed the Analgesia Nociception Index (ANI), based on HRV high frequency content estimation, which quantifies continuously the vagal tone in order to guide analgesic drug administration during general anesthesia. This technology has been largely validated during the peri-operative period. Currently, ANI is obtained from a specific algorithm analyzing a time series representing successive heart periods measured on the electrocardiographic (ECG) signal. In the perspective of widening the application fields of this technology, in particular for homecare monitoring, it has become necessary to simplify signal acquisition by using e.g. a pulse plethysmographic (PPG) sensor. Even if Pulse Rate Variability (PRV) analysis issued from PPG sensors has been shown to be unreliable and a bad predictor of HRV analysis results, we have compared PRV and HRV both estimated by ANI as well as HF and HF/(HF+LF) spectral analysis on both signals.

A smartphone based cardiac coherence biofeedback system

Cardiac coherence biofeedback training consist on slowing one's breathing to 0.1 Hz in order to simulate the baroreflex sensitivity and increase the respiratory sinus arrhythmia efficiency. Several studies have shown that these breathing exercises can constitute an efficient therapy in many clinical contexts like cardiovascular diseases, asthma, fibromyalgia or post-traumatic stress. Such a non-intrusive therapeutic solution needs to be performed on an 8 to 10 weeks period. Even if some heart rate variability based solutions exist, they presented some mobility constrain rendering these cardiac / respiratory control technologies more difficult to perform on a daily used. In this paper, we present a new simplified smartphone based solution allowing people to process efficient cardiac coherence biofeedback exercises. Based on photo-plethysmographic imaging through the smartphone camera, this sensor-less technology allows controlling cardiac coherence biofeedback exercises through a simplified heart rate variability algorithm.

Maintenance of parasympathetic inhibition following emotional induction in patients with restrictive type anorexia nervosa

This study aimed to explore changes in heart rate variability (HRV), a proxy for parasympathetic activity characterizing emotion regulation processes before, during and after negative emotional induction in patients suffering from restrictive type anorexia nervosa (AN-RT). We compared two methods of HRV analysis, the Fast Fourier Transform high frequency (FFT-HF) and a specific HRV high frequency analysis technique, namely, the wavelet transform HRV (WT-HRV). A sample of 16 inpatients with AN-RT was compared to 24 control participants. Heart rate (HR) was continuously recorded for 5 min before the beginning of the video until 5 min after the video. The participants answered questionnaires concerning their eating behaviors, mood disorders and difficulties in emotion regulation. During the entire procedure, the FFT-HF in patients was lower than that in controls. Using the WT-HRV, the patients did not differ from the controls at baseline, and only the controls showed a decrease during emotional induction. After the video, the WT-HRV in patients began to decrease during the first 2 min of emotional recovery although the WT-HRV in controls was already increased. These results highlighted the disturbances in the physiological dynamics of emotion regulation processes in patients with AN-RT.

A multi sensing method for robust measurement of physiological parameters in wearable devices

The monitoring of physiological parameters such as heart rate, ventilatory rate, or oxygen saturation is a commonly used practice in the medical field. Many clinical solutions exist, based on the use of specific sensors, dedicated for bedside patient's vital functions monitoring at hospital. But the implementation of such sensors in ambulatory situations is rendered extremely difficult because of many artifacts induced by the movements of the subject that make the measures unusable. We have designed an original method for robust measurement of physiological parameters dedicated for wearable devices. The method is based on a multi sensing technique using, at least, two sensors of different nature or placed at different sites, for each parameter. In order to illustrate this method, we have developed a headset device including two heart rate (HR) sensors and two ventilatory rate (VR) sensors. This device has been evaluated on 6 healthy volunteers during exercises. This test showed the physiological values of HR and VR from the headset device stability and efficiency.