Narcotrend Index Research Articles

The NARCOguide index – a novel parameter for monitoring depth of hypnosis during anaesthesia/sedation with propofol

BACKGROUND The NARCOguide algorithm calculates an EEG-derived index to monitor the hypnotic component of anaesthesia. OBJECTIVE This study evaluates the accuracy of the index calculated by NARCOguide against the Narcotrend index as a reference. Secondly, the automatic detection of burst-suppression patterns as represented by the burst suppression ratio was compared. DESIGN Comparative study to assess the agreement between two medical devices. SETTING At two study centres, patient data were collected from a total of 40 adults receiving general anaesthesia or sedation with propofol. INTERVENTIONS Patients underwent either general anaesthesia for oral surgery with propofol/remifentanil/rocuronium (study centre 1) or light general anaesthesia/deep sedation with propofol alone for laryngoscopic upper airway exploration (study centre 2). MAIN OUTCOME MEASURES In a posthoc analysis, the NARCOguide index was compared with the Narcotrend index. Comparison was made after averaging over 1 min at defined clinical markers using classic linear least squares regression and Bland–Altman plots. Precision and recall for the detection of burst suppression were determined using human scoring as a reference. RESULTS Data analysis showed good agreement [Bland–Altman mean difference (MD) = −2.3; limits of agreement = −27.1, to +22.4; n = 1209] and high correlation (r 2 = 0.76) between the depth of anaesthesia index calculated by NARCOguide and Narcotrend. The precision and recall of NARCOguide and Narcotrend for the detection of burst suppression were in a similar range. Over the entire dataset, the NARCOguide algorithm showed higher precision and recall than the Narcotrend algorithm (56% vs. 36% and 68% vs. 58%, respectively). CONCLUSION The NARCOguide index can be used to monitor the hypnotic component of anaesthesia in patients undergoing general anaesthesia or sedation with propofol, with a performance similar to that of the Narcotrend index. TRIAL REGISTRATION Trial registration number: 18020, regulatory authority: Ethikkommission der bayerischen Landesärztekammer, chairman: Dr med. Gerald Quitterer, applicant: Dr Gert Küchler, date of approval: 12. Jun 2018, completion of data collection: 12 December 2018, study completion: 31 March 2022.

Comparative analysis of the consistency of anesthesia depth between anesthesia index and Narcotrend index in monitoring pediatric tonsillectomy/adenoidectomy surgery

Objective: To analyze the consistency of the anesthesia index (AI) and Narcotrend index (NI) in monitoring the depth of anesthesia in pediatric tonsil/adenoidectomy. Methods: A total of 129 children who underwent elective tonsil/adenoidectomy at Xijing Hospital Affiliated to Air Force Medical University from July 2022 to October 2023 were prospectively enrolled. Both AI monitoring by ConView monitor and NI monitoring by Narcotrend monitor were conducted for children after they were admitted to the operating room, while Propofol-remifentanil combined with total intravenous anesthesia was used during the operation and the anesthetic dose was adjusted to maintain the NI value at 40-60. In addition, the AI and NI values were recorded at following time points: quiet eyes closing (T1), the beginning of induction (T2), loss of consciousness (T3), tracheal intubation (T4), the beginning of surgery (T5), during tonsil excision (T6), adenoidectomy (T7), the end of surgery (T8), consciousness recovery (T9) and tracheal extubation (T10). Bland-Altman consistency analysis was used to evaluate the consistency of the results of the two types of anesthesia depth monitoring, AI value and NI value. Receiver operator characteristic (ROC) curve and area under curve (AUC) were used to analyze the predictive efficacy of AI and NI values for the state of consciousness of children. The intraoperative awareness was followed up at 24 hours, 1 week and 1 month after surgery. Results: In 129 cases, there were 78 boys and 51 girls, with an average age of (7.2±3.2) years and an operation time of (72.8±14.0) min. No AI data were missing, but 13 NI data were missing, with a missing rate of 10.1% (13/129). At time points T1-T10, the AI values were 67.5±19.2 and the NI values were 67.2±19.2. Bland-Altman consistency analysis showed that the difference in value between AI and NI was 0.3 (95%CI:-0.1-0.6, P=0.120), with an out-of-consistency range of 4.0% (51/1 290). Before anesthesia induction, AI and NI values were maintained at a high level; with the beginning of anesthesia induction and the disappearance of the children's consciousness, both AI and NI values gradually decreased; after discontinuing the infusion of anesthetics, the values of AI and NI gradually increased, and the change trend of AI and NI in each stage of the perioperative period was consistent, and there was no significant difference between the two groups at each time point (all P>0.05). ROC curve analysis showed that the cut-off value for predicting the state of consciousness using AI was 72.5, with an AUC of 0.73 (95%CI: 0.70-0.75), and the cut-off value of NI was 79.5 and the AUC was 0.74 (95%CI: 0.72-0.77). There was no significant difference in AUC between the two indices (P=0.310). None of the children had intraoperative awareness. Conclusion: Both AI and NI can be used to monitor the depth of anesthesia in pediatric tonsil/adenoidectomy with high accuracy.

Heart rate variability as a predictor of intraoperative autonomic nervous system homeostasis.

The aim of the proof-of-concept study is to investigate the level of concordance between the heart rate variability (HRV), the EEG-based Narcotrend Index as a surrogate marker for the depth of hypnosis, and the minimal alveolar concentration (MAC) of the inhalation anesthetic sevoflurane across the entire course of a surgical procedure. This non-blinded cross-sectional study recorded intraoperative HRV, Narcotrend Index, and MAC in 31 male patients during radical prostatectomy using the Da-Vinci robotic-assisted surgical system at Mannheim University Medical Center. The degree of concordance was calculated using repeated measures correlation with the R package (rmcorr) and presented using the rmcorr coefficient (rrm). The Narcotrend Index correlates significantly across all measures with the time-dependent parameter of HRV, the standard deviation of the means of RR intervals (SDNN) (rrm = 0.2; p < 0.001), the frequency-dependent parameters low frequency (LF) (rrm = 0.09; p = 0.04) and the low frequency/high frequency ratio (LF/HF ratio) (rrm = 0.11; p = 0.002). MAC correlated significantly negatively with the time-dependent parameter of heart rate variability, SDNN (rrm = -0.28; p < 0.001), the frequency-dependent parameter LF (rrm = -0.06; p < 0.001) and the LF/HF ratio (rrm = -0.18; p < 0.001) and the Narcotrend Index (rrm = -0.49; p < 0.001) across all measures. HRV mirrors the trend of the Narcotrend Index used to monitor depth of hypnosis and the inhibitory influence of the anesthetic sevoflurane on the autonomic nervous system. Therefore, HRV can provide essential information about the homeostasis of the autonomic nervous system during general anesthesia. DRKS00024696, March 9th, 2021.

The Effect of Different Anesthesia Depths on Postoperative Cognitive Function of Tumor Patients Monitored by Narcotrend

Abstract Objectives The study aimed to examine the influence of different anesthesia depths monitored by Narcotrend on postoperative cognitive dysfunction (POCD) in elderly patients undergoing radical resection of gastrointestinal malignancies. Methods Individuals in the control group (n = 40) maintained the Narcotrend index (NTI) at 50 to 59 monitored by Narcotrend, whereas the experimental group at 30 to 39. The mini-mental state examination (MMSE) scale and serum S100β concentration were used to evaluate the cognitive function. Cerebral oxygen metabolism and inflammation were evaluated, presenting as regional oxygen saturations of brain (rSO2) and cerebral oxygen uptake rate (CERO2), serum tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). Results Experimental group presented prominently high levels of rSO2 and low levels of CERO2 relative to controls, meanwhile with reduced serum TNF-α and IL-6. Individuals receiving deep anesthesia owned low levels of S100β and enhanced MMSE score, which showed negative correlation. Low incidence rate of POCD was detected in the experimental group. Both age (hazard ratio = 5.219, 95% confidence interval = 1.813–15.025) and NTI score (hazard ratio = 3.707, 95% confidence interval = 1.292–10.633) were independent influence factors for the onset of POCD. Conclusion NTI maintained at 30 to 39 can reduce the incidence of POCD in the early postoperative period for elderly patients receiving gastrointestinal tumors surgery, the contribution might be attributed to the improvement of perioperative cerebral oxygen metabolism and inflammatory stress response.

Correlation of Comfort Score and Narcotrend Index during Procedural Sedation with Midazolam and Propofol in Children.

Background/Objectives: Precise assessment of hypnotic depth in children during procedural sedation with preserved spontaneous breathing is challenging. The Narcotrendindex (NI) offers uninterrupted information by continuous electrocortical monitoring without the need to apply a stimulus with the risk of assessment-induced arousal. This study aimed to explore the correlation between NI and the Comfort Scale (CS) during procedural sedation with midazolam and propofol and to identify an NI target range for deep sedation. Methods: A prospective observational study was conducted on 176 children (6 months to 17.9 years) undergoing procedural sedation with midazolam premedication and continuous propofol infusion. Statistical analyses included Pearson correlation of NI and CS values, logistic regression, and receiver operating curves. Results: Median NI values varied with CS and age. The correlation coefficient between CS and NI was 0.50 and slightly higher in procedure-specific subgroup analyses. The optimal NI cut-off for deep sedation was between 50 and 60 depending on the analyzed subgroup and displayed high positive predictive values for sufficient sedation throughout. Conclusion: Our study found a moderate correlation between NI and CS, demonstrating reliable identification of adequately sedated patients.

Remimazolam besylate versus propofol for deep sedation in critically ill patients: a randomized pilot study

ObjectiveTo compare the efficacy and safety of remimazolam besylate and propofol for deep sedation in critically ill patients.MethodsIn this single-center, prospective, randomized, controlled pilot study, patients in the intensive care unit (ICU) requiring deep sedation were randomized to receive remimazolam besylate or propofol intravenously. Deep sedation was defined as a Richmond Agitation and Sedation Scale (RASS) score of − 4 or − 5. Sedation depth was monitored using RASS and Narcotrend Index (NI). The primary outcome was the percentage of time within the target sedation range without rescue sedation. The secondary outcomes included ventilator-free hours within 7 days, successful extubation, length of ICU stay, and 28-day mortality. Adverse events during the interventional period were also recorded.ResultsThirty patients were assigned to each group. The median (IQR) RASS score was − 5.0 (− 5.0, − 4.0), and the median (IQR) NI value was 29.0 (21.0, 37.0) during the intervention period. Target RASS was reached a median of 100% of the sedation time in the two groups. No significant differences were observed in ventilator-free hours within 7 days, successful extubation, length of ICU stay, or 28-day mortality among groups. Hypotension occurred in 16 (53.3%) patients of remimazolam group and 18 (60.0%) patients of propofol group (p > 0.05). No patient experienced bradycardia.ConclusionsRemimazolam besylate appears to be an effective and safe agent for short-term deep sedation in critically ill patients. Our findings warrant large sample-sized randomized clinical trials.

Genetic polymorphisms are associated with individual susceptibility to dexmedetomidine.

Introduction: Dexmedetomidine (DXM) is widely used as an adjuvant to anesthesia or a sedative medicine, and differences in individual sensitivity to the drug exist. This study aimed to investigate the effect of genetic polymorphisms on these differences. Methods: A total of 112 patients undergoing hand surgery were recruited. DXM 0.5μg/kg was administered within 10min and then continuously injected (0.4μg/kg/h). Narcotrend index, effective dose and onset time of sedation, MAP, and HR were measured. Forty-five single nucleotide polymorphisms (SNPs) were selected for genotype. Results: We observed individual differences in the sedation and hemodynamics induced by DXM. ABCG2 rs2231142, CYP2D6 rs16947, WBP2NL rs5758550, KATP rs141294036, KCNMB1 rs11739136, KCNMA1 rs16934182, ABCC9 rs11046209, ADRA2A rs1800544, and ADRB2 rs1042713 were shown to cause statistically significant (p < 0.05) influence on the individual variation of DXM on sedation and hemodynamics. Moreover, the multiple linear regression analysis indicated sex, BMI, and ADRA2A rs1800544 are statistically related to the effective dose of DXM sedation. Discussion: The evidence suggests that the nine SNPs involved in transport proteins, metabolic enzymes, and target proteins of DXM could explain the individual variability in the sedative and hemodynamic effects of DXM. Therefore, with SNP genotyping, these results could guide personalized medication and promote clinical and surgical management.

Depth of anesthesia, temperature, and postoperative delirium in children and adolescents undergoing cardiac surgery

BackgroundAfter pediatric cardiosurgical interventions, postoperative delirium can occur, which can be associated with undesirable consequences during and after the hospital stay. It is therefore important to avoid any factors causing delirium as far as possible. Electroencephalogram (EEG) monitoring can be used during anesthesia to individually adjust dosages of hypnotically acting drugs. It is necessary to gain knowledge about the relationship between intraoperative EEG and postoperative delirium in children.MethodsIn a dataset comprising 89 children (53 male, 36 female; median age: 0.99 (interquartile range: 0.51, 4.89) years) undergoing cardiac surgery involving use of a heart–lung machine, relationships between depth of anesthesia as measured by EEG (EEG index: Narcotrend Index (NI)), sevoflurane dosage, and body temperature were analyzed. A Cornell Assessment of Pediatric Delirium (CAP-D) score ≥ 9 indicated delirium.ResultsThe EEG could be used in patients of all age groups for patient monitoring during anesthesia. In the context of induced hypothermia, EEG monitoring supported individually adjusted sevoflurane dosing. The NI was significantly correlated with the body temperature; decreasing temperature was accompanied by a decreasing NI.A CAP-D score ≥ 9 was documented in 61 patients (68.5%); 28 patients (31.5%) had a CAP-D < 9. Delirious patients with an intubation time ≤ 24 h showed a moderate negative correlation between minimum NI (NImin) and CAP-D (rho = -0.41, 95% CI: -0.70 – -0.01, p = 0.046), i.e., CAP-D decreased with increasing NImin. In the analysis of all patients’ data, NImin and CAP-D showed a weak negative correlation (rho = -0.21, 95% CI: -0.40 – 0.01, p = 0.064). On average, the youngest patients had the highest CAP-D scores (p = 0.002). Patients with burst suppression / suppression EEG had a longer median intubation time in the intensive care unit than patients without such EEG (p = 0.023).There was no relationship between minimum temperature and CAP-D score.ConclusionsThe EEG can be used to individually adjust sevoflurane dosing during hypothermia. Of the patients extubated within 24 h and classified as delirious, patients with deeper levels of anesthesia had more severe delirium symptoms than patients with lighter levels of anesthesia.

Efficacy and safety of remimazolam for procedural sedation during ultrasound-guided transversus abdominis plane block and rectus sheath block in patients undergoing abdominal tumor surgery: a single-center randomized controlled trial

BackgroundTo explore the efficacy and safety of remimazolam for procedural sedation during ultrasound-guided nerve block administration in patients undergoing abdominal tumor surgery, in order to improve and optimize remimazolam use in procedural sedation and clinical anesthesia.MethodsThe enrolled patients were randomly divided into three groups: 50 patients in the remimazolam group (R group), 50 patients in the dexmedetomidine group (D group), and 50 patients in the midazolam group (M group). Before administering an ultrasound-guided nerve block, all patients received sufentanil AND remimazolam or midazolam or dexmedetomidine. Remimazolam 5 mg was administered intravenously in group R, dexmedetomidine 0.6 µg/kg was administered intravenously in group D, and midazolam 0.025 mg/kg was administered intravenously in group M. Sedation was evaluated by the Modified Observer’s Assessment of Alertness and Sedation scale.When the Modified Observer’s Alertness/Sedation (MOAA/S) score was ≤ 2, block operation was started. If the target sedation level was not reached, rescue sedatives of remimazolam 2.5 mg may be intravenously given in group R, dexmedetomidine 0.4 µg/kg be intravenously given in group D, 0.01 mg/kg midazolam may be intravenously given in Group M. Hemodynamic indicators (systolic and diastolic blood pressure, heart rate), pulse oxygen saturation, depth of anesthesia (Narcotrend), MOAA/S,and the incidences of hypoxemia, injection pain, bradycardia and requirement for rescue sedatives were monitored and recorded.ResultsCompared with the control groups (midazolam and dexmedetomidine groups), the Narcotrend index and MOAA/S decreased more in the remimazolam group (P < 0.01). Compared with the control groups, the incidence of hypoxemia and injection pain was slightly higher in the remimazolam group, but the difference was not statistically significant (P > 0.05). Compared with the dexmedetomidine group, the incidence of bradycardia was significantly lower in the remimazolam group.ConclusionRemimazolam can be used safely for procedural sedation during ultrasound-guided nerve block administration in patients undergoing abdominal tumor surgery. The sedation effect is better than that with either midazolam or dexmedetomidine, and sedation can be achieved quickly without obvious hemodynamic fluctuations. Remimazolam is associated with better heart rate stability, and slightly higher incidences of hypoxemia and injection pain than are midazolam and dexmedetomidine (no statistically significant difference). The higher incidence of hypoxemia with remimazolam may be related to enhanced sufentanil opioid analgesia, and the mechanism of injection pain with remimazolam must be studied further and clarified.Trial registrationThis study was approved by the Ethics Committee of Anhui Provincial Cancer Hospital (Ethical Review 2021, No. 23) and registered at https://www.chictr.org.cn (ChiCTR2000035388). The pre-registration time of this experiment is 09/08/2020, due to ethical committee of the hospital met irregularly,the ethical approval time is 21/06/2021. The recruitment of patients began after the ethical approval (21/06/2021) and registration update (06/07/2021).The study protocol followed the CONSORT guidelines. The study protocol was performed in the relevant guidelines.

Remimazolam besylate for the sedation of postoperative patients undergoing invasive mechanical ventilation in the ICU: a prospective dose‒response study

This single-center study aimed to determine the effective dose and safety of remimazolam besylate for the sedation of postoperative patients undergoing invasive mechanical ventilation in the intensive care unit (ICU). Mechanically ventilated patients admitted to the ICU after surgery were included. The Narcotrend index (NTI) was used to assess the depth of sedation, and the Richmond Agitation-Sedation Scale (RASS) score was also recorded. Remimazolam besylate was administered initially at a loading dose of 0.02 mg/kg, followed by a gradual increase of 0.005 mg/kg each time until the targeted depth of sedation was achieved (NTI 65–94). A maintenance dose of remimazolam besylate was administered starting at 0.2 mg/kg/h, followed by increments or subtractions of 0.05 mg/kg/h each time until a satisfactory depth of sedation was achieved and maintained for at least 30 min. The demographic data, anesthesia, surgery types, hemodynamics and respiratory parameters were recorded. Adverse events and adverse drug reactions were monitored for safety. Twenty-three patients were eventually included in this study covering a period of 1 year. A satisfactory depth of sedation was achieved by a single intravenous infusion of remimazolam besylate at a loading dose of 0.02–0.05 mg/kg followed by a maintenance dose of 0.20–0.35 mg/kg/h. There were no significant changes in hemodynamic and respiratory parameters within 10 min after the administration of remimazolam besylate. In addition, a significant correlation was observed between the NTI and the RASS score for assessing sedation (r = 0.721, P < 0.001). The NTI showed a predictive probability for a RASS score of 0.817. Remimazolam besylate was effective for mild/moderate sedation of invasively mechanically ventilated postoperative patients in the ICU while maintaining excellent respiratory and hemodynamic stability. The NTI can be used as a good tool for the objective evaluation of the depth of sedation and agitation.

Nongenetic and genetic predictors of haemodynamic instability induced by propofol and opioids: A retrospective clinical study.

Propofol and opioids are commonly used in anaesthesia, but are highly susceptible to haemodynamic instability, thereby threatening the patient's surgical safety and prognosis. The purpose of this study was to investigate the predictors of haemodynamic instability and establish its predictive model. A total of 150 Chinese patients undergoing thyroid or breast surgery participated in the study, with target-controlled infusion concentrations of propofol, opioids dosage, heart rate (HR), mean arterial pressure (MAP) and Narcotrend Index recorded at key points throughout the procedure. The Agena MassARRAY system was used to genotype candidate single nucleotide polymorphisms related to pharmacodynamics and pharmacokinetics of propofol and opioids. Among nongenetic factors, baseline HR (R= -.579, P <.001) and baseline MAP (R= -.725, P< .001) had a significant effect on the haemodynamic instability. Among genetic factors, the CT/CC genotype of GABRB1 rs4694846 (95% confidence interval [CI]: -11.309 to -3.155), AA/AG of OPRM1 rs1799971 (95%CI: 0.773 to 10.290), AA of CES2 rs8192925 (95%CI: 1.842 to 9.090) were associated with higher HR instability; the AA/GG genotype of NR1I2 rs6438550 (95%CI: 0.351 to 7.761), AA of BDNF rs2049046 (95%CI: -9.039 to -0.640) and GG of GABBR2 rs1167768 (95%CI: -10.146 to -1.740) were associated with higher MAP instability. The predictive models of HR and MAP fluctuations were developed, accounting for 45.0 and 59.2% of variations, respectively. We found that cardiovascular fundamentals and genetic variants of GABRB1, GABBR2, OPRM1, BDNF, CES2 and NR1I2 are associated with cardiovascular susceptibility, which can provide a reference for haemodynamic management in clinical anaesthesia.

Intranasal Dexmedetomidine for the Treatment of Pre-operative Anxiety and Insomnia: A Prospective, Randomized, Controlled, and Clinical Trial.

Background and ObjectiveSeveral patients with pre-operative anxiety and insomnia refuse to take sleeping pills because of the side effects of sleeping pills. This study aimed to evaluate the applicability of intranasal dexmedetomidine (DEX) in the treatment of pre-operative anxiety and insomnia.MethodsA total of 72 patients with insomnia and anxiety were randomly divided into two groups of intranasal DEX (n = 36) and intranasal normal saline (NS, n = 36). The primary outcomes included patients' time to fall asleep, total sleep time, insomnia severity index (ISI) after treatment, and satisfaction with the treatment effect. The secondary outcomes were mean arterial pressure (MAP), oxygen saturation (SPO2), heart rate (HR), Narcotrend index (NI) in the first 2 h of treatment, and the incidence of adverse events within 12 h after treatment.ResultsThe time to fall asleep (22.08 ± 3.95 min) and total sleep time (400.06 ± 28.84 min) in the DEX group were significantly different from those in the NS group [time to fall asleep, 89.31 ± 54.56 min; total sleep time (295.19 ± 73.51 min; P < 0.001)]. ISI after treatment in the DEX group was lower than that in the NS group (P < 0.001). Satisfaction with the treatment effect was better in the DEX group than that in the NS group (P < 0.001). The general vital signs in the two groups were stable during the treatment. The drowsiness rate in the NS group was higher than that in the DEX group (P < 0.001).ConclusionIntranasal DEX can significantly improve pre-operative anxiety and insomnia.Clinical Trial RegistrationThis study was registered on Chinese Clinical Trial Registry (http://www.chictr.org.cn/searchproj.aspx, ChiCTR2100044747).

Comparison of the median effective concentration (EC50) and effect of sevoflurane with or without remifentanil in cesarean section with supreme laryngeal mask under narcotrend monitoring: a randomized trial.

Remifentanil combined with sevoflurane is a standard protocol for obstetric general anesthesia (GA). In this study, we performed a randomized clinical trial to evaluate whether remifentanil has an effect on the median effective concentration (EC50) of sevoflurane and compare anesthetic outcomes of them in cesarean section with Supreme™ laryngeal mask airway (SLMA) under narcotrend monitoring. Ninety parturients with singleton births undergoing elective cesarean delivery (CD) with initial inhaled 1.0 minimum alveolar concentration (MAC) sevoflurane for anesthesia maintenance were assigned to three groups randomly and evenly: Group A (0.05 µg·kg-1·min-1 remifentanil combined with sevoflurane), Group B (0.1 µg·kg-1·min-1 remifentanil combined with sevoflurane), and Group C (normal saline combined with sevoflurane). Narcotrend was used to monitor the depth of anesthesia during the operation, with the level of anesthesia depth controlled within the D-E stage. The EC50 of sevoflurane was determined by Dixon's sequential method. The Narcotrend index, amount of bleeding, neonatal Apgar score, and corresponding treatment measures in the three groups were recorded. The results showed that the estimated EC50 of sevoflurane for obstetric GA was 0.80 MAC (95% CI: 0.63-0.95 MAC) in group A, 0.82 MAC (95% CI: 0.63-0.96 MAC) in group B, and 0.80 MAC (95% CI: 0.63-0.95 MAC) in group C. There was no statistically significant difference in the estimated EC50 of sevoflurane, time to wakefulness, Apgar score, amount of intraoperative bleeding, and postoperative bleeding within 24 hours between the three groups (all P>0.05). The addition of remifentanil at 0.05-0.1 µg·kg-1·min-1 did not change the EC50 of sevoflurane and anesthetic quality. The concentration of inhaled anesthetics can be minimized with Narcotrend monitoring. Chinese Clinical Trial Registry ChiCTR2000034512.

Relationship Between Anesthesia Depth and Quality of Seizures in Patients Undergoing Electroconvulsive Therapy: A Prospective Observational Study.

Electroconvulsive therapy under general anesthesia is an established treatment for mood disorders, such as therapy-resistant depression. As most anesthetic drugs used for induction of anesthesia increase the seizure threshold, adequate depth of anesthesia without diminishing the therapeutic efficacy of interventions is crucial. The aim of this study was to investigate whether anesthesia depth as assessed by Narcotrend (NCT) monitoring correlates with maximum seizure quality. An observational study was performed in psychiatric patients undergoing multiple interventions of electroconvulsive therapy. Seizure quality of each attendance was assessed evaluating electroencephalogram end point, electromyogram end point, postictal suppression index, the midictal amplitude, and a 3-step overall graduation. Narcotrend was used to assess anesthesia depth according to index-based electroencephalogram findings. Measurements were obtained before induction of anesthesia, before stimulation, and after arousal. Data were analyzed by means of linear mixed models and generalized estimating equations models. A total of 105 interventions in 12 patients were analyzed. Anesthesia depth before stimulation was significantly associated with seizure quality (standardized β = 0.244, P = 0.010), maximum sustained coherence (β = 0.207, P = 0.022), and electroencephalogram duration (β = 0.215, P = 0.012). A cutoff value of 41 or greater versus 40 or less for the NCT index was found appropriate to differentiate between good and less satisfactory overall seizure quality. Anesthesia depth index assessed by NCT monitoring was positively associated with seizure quality. Narcotrend monitoring may be useful in assessment of optimal anesthesia depth before stimulation.

Effects of circadian rhythm on Narcotrend index and target-controlled infusion concentration of propofol anesthesia

BackgroundThe effects of circadian rhythms on drug metabolism and efficacy are being increasingly recognized. However, the extent to which they affect general anesthesia remains unclear. This study aims to investigate the effects of circadian rhythms on anesthetic depth and the concentrations of propofol target-controlled infusion (TCI).MethodsSixty patients undergoing laparoscopic surgeries were sequentially assigned to four groups. Group ND (n = 15): Propofol TCI with Narcotrend monitor during the day (8:00–18:00), Group NN (n = 15): Propofol TCI with Narcotrend monitor during the night (22:00–5:00), Group CLTD (n = 15): Propofol closed-loop TCI guided by bispectral index (BIS) during the day (8:00–18:00), Group CLTN (n = 15): Propofol closed-loop TCI guided by BIS during the night (22:00–5:00). The Narcotrend index, mean arterial pressure (MAP) and heart rate (HR) were compared between group ND and NN at 7 time points, from 5 min before induction to the end of operation. The propofol TCI concentrations, MAP and HR were compared between group CLTD and CLTN at 7 time points, from 5 min after induction to the end of operation.ResultsThe Narcotrend index, MAP, and HR in group NN were lower than those in group ND from the beginning of mechanical ventilation to the end of operation (p < 0.05). The propofol TCI concentrations in group CLTN were lower than those in group CLTD from the beginning of operation to the end of operation (p < 0.05).ConclusionCircadian rhythms have a significant effect on the depth of anesthesia and drug infusion concentrations during propofol TCI. When using general anesthesia during night surgery, the propofol infusion concentration should be appropriately reduced compared to surgery during the day.Trial registrationThe present study was registered on the ClinicalTrials.gov website (NCT02440269) and approved by the Medical Ethics Committee of Southwest Hospital of Third Military Medical University (ethics lot number: 2016 Research No. 93). All patients provided informed written consent to participate in the study.

Age, minimum alveolar concentration and choice of depth of sedation monitor: examining the paradox of age when using the Narcotrend monitor: A secondary analysis of an observational study.

With an ageing global population, it is important to individualise titration of anaesthetics according to age and by measuring their effect on the brain. A recent study reported that during general surgery, the given concentration of volatile anaesthetics, expressed as a fraction of the minimum alveolar concentration (MAC fraction), decreases by around only 3% per age-decade, which is less than the 6% expected from age-adjusted MAC. Paradoxically, despite the excessive dosing, Bispectral index (BIS) values also increased. We planned to investigate the paradox of age when using the Narcotrend depth of anaesthesia monitor. Secondary analyses of a prospective observational study. Tertiary hospital in Switzerland, recordings took place during 2016 and 2017. One thousand and seventy-two patients undergoing cardiac surgery entered the study, and 909 with noise-free recordings and isoflurane anaesthesia were included in this analysis. We calculated mean end-tidal MAC fraction and mean index value of the Narcotrend depth of sedation monitor used in the study during the prebypass period. Statistical associations were modelled using linear regression, local weighted regression (LOESS) and a generalised additive model (GAM). Primary endpoints in this study were the change in end-tidal MAC fraction and mean Narcotrend index values, both measured per age-decade. We observed a linear decrease in end-tidal MAC fraction of 3.2% per age-decade [95% confidence interval (CI) -3.97% to -2.38%, P < 0.001], consistent with previous findings. In contrast to the BIS, mean Narcotrend index values decreased with age at 3.0 index points per age-decade (95% CI, -3.55 points to -2.36 points, P < 0.001), a direction of change commensurate with the increasing age-adjusted MAC fraction with patient age. These relationships were consistent regardless of whether age-adjusted MAC was displayed on the anaesthetic machine. We caution that the 'paradox of age' may in part depend on the choice of depth of sedation monitor. ClinicalTrials.gov Identifier: NCT02976584.

Correlation of exhaled propofol with Narcotrend index and calculated propofol plasma levels in children undergoing surgery under total intravenous anesthesia -\xa0an observational study

BackgroundExhaled propofol concentrations correlate with propofol concentrations in adult human blood and the brain tissue of rats, as well as with electroencephalography (EEG) based indices of anesthetic depth. The pharmacokinetics of propofol are however different in children compared to adults. The value of exhaled propofol measurements in pediatric anesthesia has not yet been investigated. Breathing system filters and breathing circuits can also interfere with the measurements. In this study, we investigated correlations between exhaled propofol (exP) concentrations and the Narkotrend Index (NI) as well as calculated propofol plasma concentrations.MethodsA multi-capillary-column (MCC) combined with ion mobility spectrometry (IMS) was used to determine exP. Optimal positioning of breathing system filters (near-patient or patient-distant) and sample line (proximal or distal to filter) were investigated. Measurements were taken during induction (I), maintenance (M) and emergence (E) of children under total intravenous anesthesia (TIVA). Correlations between ExP concentrations and NI and predicted plasma propofol concentrations (using pediatric pharmacokinetic models Kataria and Paedfusor) were assessed using Pearson correlation and regression analysis.ResultsNear-patient positioning of breathing system filters led to continuously rising exP values when exP was measured proximal to the filters, and lower concentrations when exP was measured distal to the filters. The breathing system filters were therefore subsequently attached between the breathing system tubes and the inspiratory and expiratory limbs of the anesthetic machine. ExP concentrations significantly correlated with NI and propofol concentrations predicted by pharmacokinetic models during induction and maintenance of anesthesia. During emergence, exP significantly correlated with predicted propofol concentrations, but not with NI.ConclusionIn this study, we demonstrated that exP correlates with calculated propofol concentrations and NI during induction and maintenance in pediatric patients. However, the correlations are highly variable and there are substantial obstacles: Without patient proximal placement of filters, the breathing circuit tubing must be changed after each patient, and furthermore, during ventilation, a considerable additional loss of heat and moisture can occur. Adhesion of propofol to plastic parts (endotracheal tube, breathing circle) may especially be problematic during emergence.Trial RegistrationThe study was registered in the German registry of clinical studies (DRKS-ID: DRKS00015795).

Analysis of influence factors of pharmacodynamics of propofol with target-controlled infusion during anesthetic recovery period.

To explore the pharmacodynamic (PD) characteristics of propofol during anesthetic recovery period with target-controlled infusion (TCI), and to identify the clinical variables related to the PD parameters. 20 patients scheduled for otolaryngology surgery were enrolled. After the surgery was finished, target effect site concentration was gradually decreased, blood samples were measured at 7 time points and the differences between the target and measured plasma concentration were compared. Observer's assessment of alertness/sedation (OAA/S) and Narcotrend index (NI) were used as two PD indicators by fitting sigmoid Emax model. Correlations between PD parameter and clinical variables were evaluated. Performance of the TCI system showed a positive bias at the end of the anesthesia sedation period and a negative bias in the anesthetic recovery period. PD parameters (EC50, r) calculated with OAA/S and NI were significantly different, EC50 of OAA/S was lower than EC50 of NI (1.53 ± 0.70 vs. 2.16 ± 0.99 µg/mL), r of OAA/S was higher than r of NI (57.07 ± 56.39 vs. 4.35 ± 4.42). Propofol dosage and hemodynamic parameters were significantly correlated with EC50 (OAA/S), lean body weight and gender were significantly correlated with EC50 (NI). NI provided a more stable and adequate assessment of the depth of anesthesia than OAA/S, and the influence factors should be taken into account for precise dosing.

Dexmedetomidine-induced polysomnography as a diagnostic method in obstructive sleep apnea: a reliable alternative method?

BackgroundUnder-diagnosis of obstructive sleep apnea (OSA) is common because of the demanding and time-consuming nature of polysomnography (PSG). Herein, we assessed the utility of a short daytime dexmedetomidine-induced PSG for diagnosis of OSA in adults. MethodsThis was a single-center, prospective, diagnostic trial. We evaluated 86 patients using a full overnight PSG and a short diurnal drug-induced PSG (DIPSG). DIPSG was induced by continuous intravenous dexmedetomidine infusion. Sedation depth was monitored and maintained using the Narcotrend index (50–70). Diagnostic performance for DIPSG with different apnea-hypopnea index (AHI) cut-off values were calculated. Bland–Altman plots used for analysis. Sleep architecture and position were compared. ResultsWe studied 47 OSA patients and 39 healthy volunteers. Sensitivity and specificity for detection of OSA by DIPSG were 92% and 79%, respectively, for an AHI cut-off value of 5, 90% and 77%, respectively, for an AHI cut-off value of 15, and 95% and 85%, respectively, for an AHI cut-off value of 30. The DIPSG bias was −5 (−25; 15) for AHI and −3 (−13; 7) for minimal oxygen saturation. N2 sleep was increased (32.9% vs. 50.75%, respectively; p < 0.01) and REM sleep was decreased (21.35% vs. 1.24%, respectively; p < 0.01) during DIPSG. Twenty-eight (33%) participants had postural shifts during DIPSG. No significant adverse events were observed during DIPSG. ConclusionsDexmedetomidine-induced PSG had a good sensitivity and specificity, and can be used as a screening tool for diagnosis of OSA in adults. Chinese Clinical Trial RegistrationChiCTR1900024044.

Effects of isoflurane, remifentanil and dexmedetomidine on selected EEG parameters derived from a Narcotrend Monitor before and after nociceptive stimulation at different MAC multiples in cats

BackgroundThe aim of this prospective and complete cross-over study was to evaluate the effects of isoflurane, remifentanil and dexmedetomidine on EEG parameters derived from the Narcotrend® Monitor before and after nociceptive stimulation at different isoflurane MAC (minimal alveolar concentration) multiples. Seven adult European Domestic Short Hair cats were used. Each cat went through 3 experimental treatments. Group I received isoflurane, group IR received isoflurane and a constant rate infusion (CRI) of remifentanil (18 μg/kg/h IV), and group ID received isoflurane and a CRI of dexmedetomidine (3 μg/kg/h IV). The isoflurane MAC in each group was determined via supramaximal electrical stimulation. The EEG parameters were derived by a Narcotrend Monitor at specific time points before and after nociceptive stimulation at 0.75, 1.0 and 1.5 MAC.The depth of anaesthesia was also assessed by a clinical score.ResultsThe mean MAC sparing effects in group IR and group ID were 9.8 and 55.2%, respectively. The best correlation of EEG and MAC multiples was found for the Narcotrend Index (NI) in group I (r = − 0.67). The NI was also able to differentiate between 0.75 MAC and 1.5 MAC in group IR. Spectral edge frequency had a lower correlation with MAC multiples in group I (r = − 0.62) but was able to differentiate between 0.75 MAC and 1.5 MAC in groups I and IR, and between 1.0 MAC and 1.5 MAC in group IR. Narcotrend Index, SEF 95 and MF increased significantly after nociceptive stimulation at 1.0 MAC in group I, and SEF 95 increased significantly at 0.75 MAC in group ID. The clinical score correlated closer than any of the EEG parameters with MAC in all groups, with highest correlation values in group I (r = − 0.89). Noxious stimulation led to a significant increase of the clinical score at 0.75 MAC and 1.0 MAC in group I.ConclusionsThe EEG parameters derived from the Narcotrend Monitor show correlation to isoflurane MAC multiples in cats, but the anaesthetic protocol and especially the addition of dexmedetomidine have great influence on the reliability. The Narcotrend Monitor can be used as an additional tool to assess anesthetic depth in cats.