Search Results (12)

Background and Objectives: The Analgesia Nociception Index (ANI), a surrogate marker derived from heart rate variability (HRV) analysis, has been validated for assessing the balance between antinociception and nociception during propofol anesthesia. The ANI continuously monitors this balance, with values above 50 indicating optimal analgesia. By adjusting analgesic administration based on ANI values, anesthesiologists can provide more personalized intraoperative pain control. Remimazolam, a novel benzodiazepine anesthetic lacking intrinsic analgesic properties, exhibits distinct HRV patterns compared to propofol. Considering these differences, the validity of the ANI during remimazolam anesthesia remains uncertain. We evaluated the validity of the ANI by assessing its ability to detect nociceptive stimuli during remimazolam anesthesia. Materials and Methods: In total, 28 patients were administered general anesthesia using remimazolam and remifentanil. We evaluated changes in the ANI before and after tetanic stimulation. In addition, we investigated the association between hemodynamic responses during surgical incisions and changes in the ANI. Results: Tetanic stimulation resulted in a significant (p < 0.001) reduction in the ANI, from 62.0 (interquartile range [IQR] 50.5–76.0) to 44.0 (IQR 37.0–55.5). Of the 13 patients who experienced hemodynamic responses during surgical incision, the ANI significantly decreased from 63.2 ± 13.6 to 36.9 ± 13.8 following noxious surgical stimulation (p < 0.001). Conclusions: The ANI reflects the dynamic equilibrium between antinociception and nociception during remimazolam-based general anesthesia. Full article

Background/Objectives: Transurethral resection of bladder tumor (TURBT) is commonly performed in elderly patients and often requires repeated procedures. A high proportion of non-procedural time in TURBT affects operating room utilization, highlighting the need for a safe and efficient anesthesia method. This study aimed to compare remimazolam-based monitored anesthesia care (MAC) guided by analgesia nociception index (ANI) monitoring to inhalation-based general anesthesia (GA) for TURBT, focusing on induction and emergence time (IAET). Methods: Forty-six patients who underwent TURBT were randomly assigned into either the MAC group or GA group. The primary outcome was the IAET. The secondary outcomes included hospital and anesthesia charges, safety (intraoperative hypotension and desaturation), and feasibility (surgeon and patient satisfaction) of both anesthetic methods. Results: The MAC group demonstrated a significantly shorter IAET (14 vs. 25 min, p < 0.001) and lower anesthesia cost (USD 152 vs. USD 195, p < 0.001). The MAC group showed better hemodynamic stability with a lower incidence of hypotension (29% vs. 73%, p = 0.004). Seven patients (33%) in the MAC group experienced intraoperative desaturation; all patients recovered without complications through the jaw-thrust maneuver. Patient satisfaction was equally high in both groups, and surgeon satisfaction, though slightly lower with MAC (71% vs. 100% rating “excellent”, p = 0.009), remained acceptable. Conclusions: Remimazolam-based MAC, guided by ANI monitoring, offers significant advantages including shorter IAET, reduced costs, and improved safety for TURBT, particularly in patients with small tumors. These findings support MAC as a promising alternative to GA for TURBT, as it enhances perioperative outcomes and operating room efficiency. Full article

Background and Objectives: The aim of our study is to determine the effects of analgesia nociception index (ANI) monitoring on intraoperative opioid consumption, postoperative analgesia, and the recovery unit length of stay in patients with a preoperative femoral nerve block (FNB) undergoing total knee arthroplasty (TKA) surgery under general anesthesia. Materials and Methods: Seventy-four patients in the American Society of Anesthesiologists Physical Status (ASA-PS) I-III scheduled for TKA under general anesthesia were included in this study. After FNB, the patients were divided into two groups (control group (n = 35)–ANI group (n = 35)). After standard anesthesia induction in both groups, maintenance was conducted using sevoflurane and remifentanil infusion with a bispectral index (BIS) between 40 and 60. In the control group, the intraoperative remifentanil infusion dose was adjusted using conventional methods, and in the ANI group, the dose was adjusted using ANI values of 50–70. The duration of operation, duration of surgery, extubation time, tourniquet duration and pressure, and the amount of remifentanil consumed intraoperatively were recorded. Results: Intraoperative remifentanil consumption was lower in the ANI group compared to the control group (p = 0.001). The time to reach a Modified Aldrete Scale score (MAS) ≥ 9 was shorter in the ANI group (p < 0.001). NRS scores in the recovery unit and 4, 8, 12, and 24 h postoperatively were lower in the ANI group compared to the control group (p = 0.006, p < 0.05). There was a weak significant inverse relationship between the last ANI values measured before extubation and NRS scores in the postoperative recovery unit (r: −0.070–0.079, p: 0.698–0.661). No difference was observed between the groups in other data. Conclusions: In patients undergoing TKA with FNB under general anesthesia, ANI monitoring decreased the amount of opioids consumed intraoperatively and postoperative pain scores and shortened the length of stay in the recovery unit. We suggest that ANI monitoring in intraoperative analgesia management may be helpful in determining the dose of opioid needed by the patient and individualized analgesia management. Full article

(1) Background and Objectives: Catheter-related bladder discomfort (CRBD), a common and distressing consequence of indwelling urinary catheters, can significantly impact postoperative recovery. This study aimed to determine the effectiveness of bladder irrigation with a 0.05% lidocaine normal saline solution for the prevention of CRBD following transurethral surgery. (2) Materials and Methods: In this randomized, double-blind, placebo-controlled trial, patients were assigned to either a control group receiving normal saline or a treatment group receiving 0.05% lidocaine (2% lidocaine 25 mL in 1000 mL saline) for bladder irrigation. Both groups were administered fentanyl (1 μg/kg) for analgesia at the end of the procedure. The primary endpoint was the assessment of the incidence and severity of CRBD upon awakening within the first 6 h postoperatively, using a four-grade scale based on the patients’ reports of discomfort. (3) Results: Out of 79 patients completing the study, the incidence of moderate to severe CRBD was significantly lower in the lidocaine group (5.1%, 2/39) compared to the control group (25%, 10/40) at 10 min after waking from anesthesia (p = 0.014). Furthermore, the lidocaine group experienced significantly less CRBD at 1 and 2 h postoperative (2.6% and 0%, respectively) compared to the control group (20% and 10%, respectively) (p = 0.015, p = 0.043), with no significant differences at 6 h (p = 0.317). (4) Conclusions: The results suggest that bladder irrigation with 0.05% lidocaine reduces the occurrence of moderate to severe CRBD by nearly 80% in the initial 2 h postoperative period after transurethral surgery. Full article

Hypnosis, a time-honored therapeutic approach, has gained widespread recognition for its effectiveness in addressing a range of psychological and somatic disorders. While its primary effects are mediated by central top–down mechanisms, hypnosis also exerts peripheral influence by modulating the autonomic nervous system (ANS). Psychophysiological measures, such as heart rate (HR) and its variability (HRV), electrodermal activity (EDA), respiratory rate (RR), and the analgesia nociceptive index (ANI), serve as reliable indicators of ANS activity. Studies have consistently demonstrated hypnosis’ ability to significantly impact ANS functions, lowering sympathetic activity and enhancing parasympathetic tone. This effect is particularly pronounced during relaxation procedures and is influenced by mediating factors like hypnotizability and task conditions. Despite methodological limitations, this review highlights the potential of enhanced ANS modulation through hypnosis, including its connections to the central nervous system (CNS), to optimize therapeutic outcomes in patients with psychosomatic disorders associated with ANS dysfunction. Full article

Background and Objectives: The analgesia/nociception index (ANI) potentially monitors nociceptive status during anesthesia, but its link to preoperative pain sensitivity is unclear. We investigated the relationship between pre-anesthetic ANI scores and propofol injection pain (PIP) in patients receiving remifentanil. Materials and Methods: This study included 124 male patients aged 19–60 undergoing general anesthesia (ASA class I or II). Patients were randomized to group R (n = 62, remifentanil 4 ng/mL) or group C (n = 62, saline). The primary outcome was the association between PIP and ANI. Secondary outcomes included the incidence and severity of PIP or rocuronium-induced withdrawal movement (RIWM) and their association with ANI. Results: PIP and RIWM incidence and severity were lower in group R than in group C. A weak negative correlation between PIP and ANI at pre-induction (r_pb = −0.21, p = 0.02, r_pb = −0.37, p < 0.01) and a moderate negative correlation during propofol injection (r_pb = −0.48, p = 0.02) were observed. A significant negative correlation was found between RIWM and ANI during rocuronium injection (τb = −0.61, p < 0.01). AUC, cut-off value, specificity, and sensitivity in ANI at pre-induction for predicting PIP were 0.67 (p = 0.02), 59, 76%, and 55%, respectively. AUC, cut-off value, specificity, and sensitivity in ANI during propofol injection for PIP were 0.77 (p < 0.01), 65, 81%, and 67%, respectively. Conclusions: ANI scores demonstrated significant differences between groups, suggesting potential predictive value for PIP despite the low pre-induction AUC value. This study highlights the potential of using ANI scores to predict and manage PIP in patients receiving remifentanil. Full article

Hypnoanalgesia is a promising non-pharmacologic adjunct technique in paediatric interventions. Its safety, efficiency, and impacts on paediatric cardiac catheterisation (CC) are unknown. Methods: In a prospective study, patients aged <16 years who underwent CC under hypnoanalgesia from January to December 2021 were included. Pain and anxiety were assessed using the analgesia nociception index (ANI) and the visual analogue scale (VAS). Results: Sixteen patients were included; the mean age was 10.5 years, and the mean weight was 37 kg. Catheterisations were interventional in 10 patients (62.5%). Hypnoanalgesia indications were general anaesthesia (GA) contraindication in four patients (25.0%), the need for accurate pressure measurements in three patients (18.7%), and interventionist/patient preferences in nine (56.3%). CC was accomplished in 15 patients (93.7%), even in complicated cases. In one case, pulmonary artery pressures were normalised compared to previous catheterisation under local anaesthesia alone. The VAS score was under 5/10 for all patients. The ANI remained above 50 (no painful zone) for all but one patient. There was no significant decrease in the ANI during the intervention compared to the baseline (p = 0.62). No complications were reported. Conclusion: Paediatric CC is feasible and safe under hypnoanalgesia, even in complicated cases. Hypnoanalgesia was efficient in managing pain and stress, and it ensures more reliable pressure measurements. Full article

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. Full article

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. Full article

Total intravenous anesthesia (TIVA) with remifentanil and propofol (RP) is considered to be an ideal type of general anesthesia (GA) for pediatric and adult patients undergoing medical procedures. However, delivery of an RP mixture by target-controlled infusion (TCI) for GA in surgical procedures has not been described. We investigated the merit of this approach for breast cancer surgery. Eighty-four patients (n = 42 per group) were randomly allocated to propofol and remifentanil either delivered by separate TCI pumps (S group) or in an RP mixture by a single TCI pump (M group). Dosages were adjusted based on the bispectral index (BIS) and the analgesia nociception index (ANI). The primary outcomes were adequate anesthesia (BIS 40–60 and ANI 50–70, respectively), acceptable hemodynamic fluctuations (<30% of baseline) with less frequent TCI pump adjustments, bolus injections of anesthetics, and total consumption of anesthetics during the procedure. The secondary endpoints included time of emergence from anesthesia, patient satisfaction, postoperative pain, rescue with opioids, and adverse events. The characteristics of patients, hemodynamic parameters, BIS and ANI scores, duration of surgery, anesthesia, and emergence were not significantly different between groups. The adjustment frequency of TCI was significantly higher in the S group (3 (range 0–6) vs. 2 (0–6) times; p = 0.005). The total dosage of anesthetics, pain rating, patient satisfaction, need for opioids postoperatively, and incidence of adverse events were not significantly different. We have demonstrated that this RP mixture provided adequate hypnotic and analgesic effects under BIS and ANI monitoring in patients undergoing breast cancer surgery within 1 h. Full article

There are many surgical operations performed daily in operation rooms worldwide. Adequate anesthesia is needed during an operation. Besides hypnosis, adequate analgesia is critical to prevent autonomic reactions. Clinical experience and vital signs are usually used to adjust the dosage of analgesics. Analgesia nociception index (ANI), which ranges from 0 to 100, is derived from heart rate variability (HRV) via electrocardiogram (ECG) signals, for pain evaluation in a non-invasive manner. It represents parasympathetic activity. In this study, we compared the performance of multilayer perceptron (MLP) and long short-term memory (LSTM) algorithms in predicting expert assessment of pain score (EAPS) based on patient′s HRV during surgery. The objective of this study was to analyze how deep learning models differed from the medical doctors′ predictions of EAPS. As the input and output features of the deep learning models, the opposites of ANI and EAPS were used. This study included 80 patients who underwent operations at National Taiwan University Hospital. Using MLP and LSTM, a holdout method was first applied to 60 training patients, 10 validation patients, and 10 testing patients. As compared to the LSTM model, which had a testing mean absolute error (MAE) of 2.633 ± 0.542, the MLP model had a testing MAE of 2.490 ± 0.522, with a more appropriate shape of its prediction curves. The model based on MLP was selected as the best. Using MLP, a seven-fold cross validation method was then applied. The first fold had the lowest testing MAE of 2.460 ± 0.634, while the overall MAE for the seven-fold cross validation method was 2.848 ± 0.308. In conclusion, HRV analysis using MLP algorithm had a good correlation with EAPS; therefore, it can play role as a continuous monitor to predict intraoperative pain levels, to assist physicians in adjusting analgesic agent dosage. Further studies may consider obtaining more input features, such as photoplethysmography (PPG) and other kinds of continuous variable, to improve the prediction performance. Full article

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. Full article