Remifentanil Anesthesia Research Articles

High-Dose Remifentanil Anesthesia With Minimal Sedation in Neonates: A Single-Center Retrospective Study.

Introduction Remifentanil is an opioid with rapid onset and elimination. Theoretically, reducing sedation using high-dose remifentanil may contribute to early emergence and prevention of postanesthetic complications related to residual anesthesia. However, there have been few reports of high-dose remifentanil anesthesia in neonatal surgery. This study aims to describe the techniques of high-dose remifentanil anesthesia in neonates and their safety outcomes. Methods This is a single-center, retrospective observational study from January 2016 to February 2022. Medical records from neonatal surgical procedures performed using high-dose remifentanil anesthesia were reviewed. "High dose" was defined as 0.5 mcg/kg/min or more. Patient profiles, anesthetic drugs used, and intra- and post-operative adverse events, including cardiopulmonary complications, were abstracted. Results There were 15 neonatal abdominal operations performed under high-dose (>0.5 mcg/kg/min) remifentanil anesthesia during the study period. The average remifentanil infusion rate was 1.9 (0.68-3.1) mcg/kg/min. Hypotension occurred in two patients (13%). Bradycardia was not observed in any patients. The mean time for tracheal extubation was 16 minutes. Five patients (33%) received naloxone administration before extubation, and two patients (13%) experienced hypoxemia immediately after extubation. No patient had cardiorespiratory complications after leaving the operating room. Conclusions High-dose remifentanil can be used without impairing hemodynamic stability in neonatal surgery, although there is concern about respiratory depression. Further research is needed on its potential impact on long-term outcomes.

Role of scalp nerve block in improving the quality of rehabilitation in patients after meningioma resection: A randomized controlled clinical trial.

In this study, we analyzed whether scalp nerve block with ropivacaine can improve the quality of rehabilitation in patients after meningioma resection. We included 150 patients who were undergoing craniotomy in our hospital and categorized them into 2 groups - observation group (patients received an additional regional scalp nerve block anesthesia) and control group (patients underwent intravenous general anesthesia for surgery), using the random number table method approach (75 patients in each group). The main indicator of the study was the Karnofsky Performance Scale scores of patients at 3 days postoperatively, and the secondary indicator was the anesthesia satisfaction scores of patients after awakening from anesthesia. The application value of different anesthesia modes was studied and compared in the 2 groups. Patients in the observation group showed better anesthesia effects than those in the control group, with significantly higher Karnofsky Performance Scale scores at 3 days postoperatively (75.02 vs 66.43, P < .05) and anesthesia satisfaction scores. Compared with patients in the control group, patients in the observation group had lower pain degrees at different times after the surgery, markedly lower dose of propofol and remifentanil for anesthesia, and lower incidence of adverse reactions and postoperative complications. In addition, the satisfaction score of the patients and their families for the treatment was higher and the results of all the indicators were better in the observation group than in the control group, with statistically significant differences (P < .05). Scalp nerve block with ropivacaine significantly improves the quality of short-term postoperative rehabilitation in patients undergoing elective craniotomy for meningioma resection. This is presumably related to the improvements in intraoperative hemodynamics, relief from postoperative pain, and reduction in postoperative nausea and vomiting.

Effect of desflurane anesthesia on flash visual evoked potential monitoring in patients undergoing spine surgery: study protocol for a randomized controlled trial

BackgroundFlash visual evoked potentials (FVEPs) are a reliable method for protecting visual function during spine surgery in prone position. However, the popularization and application of FVEPs remain limited due to the unclear influence of various anesthetics on FVEPs. Exploring the effects of anesthetic drugs on FVEP and establishing appropriate anesthesia maintenance methods are particularly important for promoting and applying FVEP. According to the conventional concept, inhaled narcotic drugs significantly affect the success of FVEP monitoring, FVEP extraction, and interpretation. Nonetheless, our previous study demonstrated that sevoflurane-propofol balanced anesthesia was a practicable regimen for FVEPs. Desflurane is widely used in general anesthesia for its rapid recovery properties. As the effect of desflurane on FVEP remains unclear, this trial will investigate the effect of different inhaled concentrations of desflurane anesthesia on amplitude of FVEPs during spine surgery, aiming to identify more feasible anesthesia schemes for the clinical application of FVEP.Methods/ designA total of 70 patients undergoing elective spinal surgery will be enrolled in this prospective, randomized controlled, open-label, patient-assessor-blinded, superiority trial and randomly assigned to the low inhaled concentration of desflurane group (LD group) maintained with desflurane-propofolremifentanil-balanced anesthesia or high inhaled concentration of desflurane group (HD group) maintained with desflurane-remifentanil anesthesia maintenance group at a ratio of 1:1. All patients will be monitored for intraoperative FVEPs, and the baseline will be measured half an hour after induction under total intravenous anesthesia (TIVA). After that, patients will receive 0.5 minimum alveolar concentration (MAC) of desflurane combined with propofol and remifentanil for anesthesia maintenance in the LD group, while 0.7–1.0 MAC of desflurane and remifentanil will be maintained in the HD group. The primary outcome is the N75-P100 amplitude 1 h after the induction of anesthesia. We intend to use the dual measure evaluation, dual data entry, and statistical analysis by double trained assessors to ensure the reliability and accuracy of the results.DiscussionThis randomized controlled trial aims to explore the superiority effect of low inhaled concentration of desflurane combined with propofolremifentanil-balanced anesthesia versus high inhaled concentration of desflurane combined with remifentanil anesthesia on amplitude of FVEPs. The study is meant to be published in a peer-reviewed journal and might guide the anesthetic regimen for FVEPs. The conclusion is expected to provide high-quality evidence for the effect of desflurane on FVEPs and aim to explore more feasible anesthesia schemes for the clinical application of FVEPs and visual function protection.Trial registrationThis study was registered on clinicaltrials.gov on July 15, 2022. ClinicalTrials.gov Identifier: NCT05465330.

Effect of remifentanil in clinical anesthesia and postoperative analgesia

Purpose: To investigate the effect of remifentanil in clinical anesthesia and postoperative intravenous analgesia. Methods: A retrospective analysis was conducted on the medical records of 100 patients who received remifentanil for anesthesia and postoperative intravenous analgesia at Zibo Center Hospital, Zibo, China from February 2020 to February 2023. The patients were divided into study and control groups comprising 50 patients in each group. The study group received remifentanil intravenously (8 g/kg) while the control group received fentanyl (3 - 4 μg/kg). Heart rate (HR), mean arterial pressure (MAP), and Bispectral Index (BIS) were monitored 5 min before anesthesia (T1), 10 min after (T2), 40 min after (T3), and 5 min before the end of surgery (T4). The levels of blood glucose (Glu), angiotensin II (Ang II), and cortisol (Cor) were measured at T1, T2, T3, and T4. Analgesic and sedative effects were evaluated 3, 12 and 24 h after surgery using the visual analog scale (VAS) and Ramsay sedation score. Results: At T1, T2, T3, and T4, there were no significant differences in HR, MAP, and BIS between the two groups (p &gt; 0.05), while the levels of Glu, Ang II, and Cor in study group were significantly lower (p &lt; 0.05). At 3, 12 and 24 h after surgery, VAS score in the study group was significantly lower, while Ramsay's analgesia score was significantly higher (p &lt; 0.05). Total effectiveness was significantly higher in the study group (p &lt; 0.05). Recovery time for orientation, spontaneous breathing, awakening, stay in the recovery room, and incidence of adverse reactions were significantly lower in study group (p &lt; 0.05). Conclusion: The use of remifentanil for postoperative intravenous analgesia significantly lowers stress response, sedation and improves recovery time. It is, therefore, effective, and produces lower adverse effects than fentanyl. Large-scale investigation to determine the impact of confounding factors on the outcome of fentanyl/remifentanil combination is required.

Influence of Clinical and Genetic Factors on Propofol Dose Requirements: A Genome-wide Association Study.

Propofol is a widely used intravenous hypnotic. Dosing is based mostly on weight, with great interindividual variation in consumption. Suggested factors affecting propofol requirements include age, sex, ethnicity, anxiety, alcohol consumption, smoking, and concomitant valproate use. Genetic factors have not been widely explored. This study considered 1,000 women undergoing breast cancer surgery under propofol and remifentanil anesthesia. Depth of anesthesia was monitored with State Entropy (GE Healthcare, Finland). Propofol requirements during surgery were recorded. DNA from blood was genotyped with a genome-wide array. A multivariable linear regression model was used to assess the relevance of clinical variables and select those to be used as covariates in a genome-wide association study. Imputed genotype data were used to explore selected loci further. In silico functional annotation was used to explore possible consequences of the discovered genetic variants. Additionally, previously reported genetic associations from candidate gene studies were tested. Body mass index, smoking status, alcohol use, remifentanil dose (ln[mg · kg-1 · min-1]), and average State Entropy during surgery remained statistically significant in the multivariable model. Two loci reached genome-wide significance (P < 5 × 10-8). The most significant associations were for single-nucleotide polymorphisms rs997989 (30 kb from ROBO3), likely affecting expression of another nearby gene, FEZ1, and rs9518419, close to NALCN (sodium leak channel); rs10512538 near KCNJ2 encoding the Kir2.1 potassium channel showed suggestive association (P = 4.7 × 10-7). None of these single-nucleotide polymorphisms are coding variants but possibly affect the regulation of nearby genes. None of the single-nucleotide polymorphisms previously reported as affecting propofol pharmacokinetics or pharmacodynamics showed association in the data. In this first genome-wide association study exploring propofol requirements, This study discovered novel genetic associations suggesting new biologically relevant pathways for propofol and general anesthesia. The roles of the gene products of ROBO3/FEZ1, NALCN, and KCNJ2 in propofol anesthesia warrant further studies.

Sustained mitigation of ST-segment elevation in a patient with Brugada syndrome type 1 during sevoflurane and remifentanil anesthesia: a case report

BackgroundDuring general anesthesia, patients with Brugada syndrome are at risk of malignant arrhythmias following worsened ST-segment elevation, potentially leading to sudden cardiac death. The protocol for safe anesthetic management of patients with Brugada syndrome has not yet been established.Case presentationA 63-year-old man, diagnosed with a spontaneous Brugada type 1 pattern, was scheduled for a pleural biopsy using video-assisted thoracoscopic surgery under general anesthesia. We planned general anesthesia using volatile induction and maintenance anesthesia with sevoflurane and remifentanil. We monitored ST-segment morphology and observed sustained mitigation of ST-segment elevation throughout general anesthesia.ConclusionThe present case may indicate that safe anesthetic management of patients with Brugada syndrome depends on whether the anesthetics used can reduce ST-segment elevation.

Combination of Remimazolam, Remifentanil Anesthesia, and Enteral Nutrition Support Restores Vital Signs and Nutritional Status of Patients Undergoing Intravascular Interventional Therapy for Intracranial Aneurysms

Ninety-eight patients from our hospital were included in the study from March 2022 to March 2023. The patients were divided into two groups: 49 patients received propofol + remifentanil in the control group and 49 patients received remimazolam + remifentanil in the observation group. Postoperatively, the control group accepted parenteral nutrition support, while the observation group accepted enteral nutrition support. The observation group experienced a longer duration of consciousness loss but shorter times for consciousness recovery and trachea extubation than the control group. Although both groups experienced elevated mean blood pressure, heart rate, norepinephrine, angiotensin II, and plasma cortisol levels during tracheal intubation and extraction, the observation group showed differences compared to the control group. No statistical significance was discovered in the incidence of postoperative adverse reactions between the two groups (P = 0.29). Furthermore, tumor necrosis factor-α and interleukin-6 levels were lower in the observation group than in the control group, while total protein, albumin, and hemoglobin levels were higher. Overall, remimazolam combined with remifentanil demonstrated superiority over propofol combined with remifentanil in the perioperative period for patients undergoing intravascular interventional therapy for intracranial aneurysms.

Comparison of Recovery Effect for Sufentanil vs. Remifentanil Anesthesia in Elderly Patients Undergoing Curative Resection for Hepatocellular Carcinoma.

The aim of this work is to evaluate the clinical efficacy and safety of sufentanil vs. remifentanil anesthesia in elderly patients undergoing curative resection for hepatocellular carcinoma (HCC). Medical records of elderly patients aged ≥ 65years who received curative resection for HCC between January 2017 and December 2020 were retrospectively reviewed. The patients were divided into either the sufentanil group or the remifentanil group according to the method of analgesia used. Vital signs including mean arterial pressure (MAP), heart rate (HR), and arterial oxygen saturation (SpO2), distribution of T-cell subsets (CD3, CD4, and CD8 lymphocytes), distribution of the stress response index [cortisol (COR), interleukin (IL)-6, C-reactive protein (CRP), and glucose (GLU)] were recorded prior to anesthesia (T0), after induction of anesthesia (T1), at the end of surgery (T2), 24h after surgery (T3), and 72h after surgery (T4). Postoperative adverse events were collected. Repeated measure analysis of variance (ANOVA) showed that after controlling for baseline patient demographic and treatment characteristics as covariates, both between- and within-group effects were significant (all P < 0.01), and the interaction between time and treatments was also significant (all P < 0.01) in the vital signs (MAP, HR, and SpO2), distribution of T-cell subsets (CD3, CD4, and CD8 lymphocytes), and distribution of the stress response index (COR, IL-6, CRP, and GLU), indicating that sufentanil led to stable hemodynamic and respiratory functions, lower reduction of T-lymphocyte subsets, and stable stress response indices compared to remifentanil. There is no significant difference in adverse reactions between the two groups (P = 0.72). Sufentanil was associated with improved hemodynamic and respiratory function, less stress response, less inhibition of cellular immunity, and similar adverse reactions compared with remifentanil.

Retracted: Changes of Entropy Index and Cerebral Oxygen Metabolism in the Maintenance of Remifentanil Anesthesia and Their Predictive Value for Postoperative Hyperalgesia.

[This retracts the article DOI: 10.1155/2022/1080858.].

Effect of combined application of sevoflurane and remifentanil on laparoscopic surgery, postoperative recovery time and stress response

Purpose: To investigate the effect of application of sevoflurane and remifentanil on laparoscopic surgery, and its effect on patients’ postoperative recovery time and stress response. &#x0D; Methods: Ninety patients undergoing laparoscopic surgery in Zhongshan City People's Hospital, Guangdong Province, China were selected and randomly divided into propofol group (PG) and sevoflurane group (SG), with 45 patients in each group. Patients in PG were anesthetized with combination of propofol and remifentanil, while those in SG received combination of sevoflurane and remifentanil. Patients’ heart rate (HR), stroke volume (SV) and mean arterial pressure (MAP) were tested before anesthesia induction (T1), after intubation (T2), 15 min after pneumoperitoneum (T3), and after extubation (T4), in order to evaluate the stability of vital signs in the patients. &#x0D; Results: At T2, T3, and T4, HR, SV, and MAP were more stable in SG than in PG (p &lt; 0.05). At T3 and T4, the levels of ET-1, noradrenaline (NE) and cortisol (Cor) were significantly lower in SG than in PG (p &lt; 0.05). Furthermore, postoperative recovery time, spontaneous breathing time, time taken to open the eyes under command, and orientation recovery time were shorter in SG than in PG (p &lt; 0.05). After awakening, SG had significantly higher Ramsay score than PG (p &lt; 0.05). &#x0D; Conclusion: The combined use of sevoflurane and remifentanil for anesthesia in patients undergoing laparoscopic surgery results in stable vital signs, facilitates recovery after surgery, improve quality of recovery, and reduce stress response. Therefore, the combination anesthesia merits further mechanistic and large-scale investigation before clinical application.

The Effect of Propofol plus Remifentanil for PostoperativePain and Heart Rate Management in Patients Undergoing Abdominal Hysterectomy.

Purpose To explore the effect of propofol plus remifentanil for postoperative pain and heart rate management in patients undergoing abdominal hysterectomy. Methods In this prospective randomized controlled study, 96 patients who underwent abdominal hysterectomy in an affiliated hospital of Fujian Medical University from April 2016 to April 2017 were recruited and randomized into the study group (n = 48) and control group (n = 48) via the random number table method. The control group received remifentanil for anesthesia, and the study group was given propofol plus remifentanil. The postoperative pain and heart rates of patients were compared between the two groups. Results No significant difference was observed in the heart rate and adrenaline values between the two groups before anesthesia, and the study group had significantly lower adrenaline values and heart rates intraoperatively and 15 min after operation than the control group. Patients in the study group showed shorter time-lapse before independent breathing recovery, extubation, and resuscitation compared to those in the control group. The study group received less patient-controlled intravenous analgesia (PCIA) as compared to the study group within 48 h after operation. In the study group, the numeric rating scale (NRS) scores within 1 h, 2 h, 6 h, 8 h, and 12 h after operation were significantly lower than those in the control group (P < 0.001). Propofol plus remifentanil offer a viable alternative for postoperative pain management and stress alleviation after abdominal hysterectomy with a high safety profile. Further clinical trials are, however, required prior to clinical promotion.

Comparing the Experiences of Parturient Women With Remifentanil Analgesia and Elective Cesarean Section and Providing Improver Strategies: A Sequential Explanatory Mixed Method Study Protocol

Objectives: Women’s experience during childbirth can affect various aspects (psychological and physical), which has not yet been done accurately. The current study aimed to compare experiences of parturient women with remifentanil analgesia and elective cesarean section (C-section) and provide improver strategies for women living in Tabriz, Iran. Methods: This is a mixed-method study with an explanatory sequential approach. The first stage is quantitative and longitudinal. Participants will be divided into two groups of elective C-sections and parturient women who receive remifentanil. They will be matched concerning social class, type of provider, and birth rank. In the first stage, data will be collected using a socio-demographic questionnaire, Edinburgh’s Depression during pregnancy questionnaire, Labor Agentry Scale, and midwifery-neonatal outcomes checklist within 24 hours after delivery. Participants will be followed up to 30 days after delivery to complete the Edinburgh Postpartum Depression questionnaire. The second stage is a qualitative study to explain the perceptions of parturient women who had either elective C-section or painless delivery (using remifentanil), including factors related to labor experiences. In the third stage, a mixed study will be performed to provide strategies for improving labor experiences. Discussion: Women’s experiences during cesarean section can have different effects on maternal and neonatal outcomes; Following the use of two methods of continuous analgesia with remifentanil and spinal anesthesia and analgesia caused by these methods in cesarean section, women’s experiences may be different; The protocol presented in this study is a clinical guide to present this important issue (experiences of women during cesarean section looking for an appropriate method of analgesia). Ethical Code: IR.TBZMED.REC.1399.521, Pazhoohan Code: 65454.

Changes of Entropy Index and Cerebral Oxygen Metabolism in the Maintenance of Remifentanil Anesthesia and Their Predictive Value for Postoperative Hyperalgesia.

Objective To explore the changes of entropy index and cerebral oxygen metabolism in the maintenance of remifentanil anesthesia and the predictive value of postoperative hyperalgesia. Methods A total of 266 patients undergoing general anesthesia in our hospital from January 2020 to October 2021 were selected, and remifentanil was used to maintain anesthesia. The state entropy, reaction entropy, and cerebral oxygen metabolism indexes (cerebral oxygen uptake rate (CERO2), arterial-venous blood oxygen difference (Da-jvO2)) of patients before induction of anesthesia, 15 minutes during the operation, and at the end of the operation were compared. The influencing factors of postoperative hyperalgesia were analyzed. The logistic regression model of postoperative hyperalgesia was established, and the value of entropy index and cerebral oxygen metabolism in predicting postoperative hyperalgesia was evaluated by drawing the receiver operating characteristic curve (ROC). Results The state entropy, response entropy, and CERO2 at 30 min during the operation and at the end of the operation were lower than those before the induction of anesthesia, and Da-jvO2 was higher than that before the induction of anesthesia (P < 0.001). At the end of the operation, the state entropy, reaction entropy, and CERO2 were higher than 30 minutes during the operation, and Da-jvO2 was lower than 30 minutes during the operation (P < 0.001). The dosage of remifentanil, reaction entropy, and CERO2 at the end of the operation entered the logistic model. The AUC value of the reaction entropy and CERO2 combined to predict postoperative hyperalgesia at the end of the operation was 0.851 greater than the reaction entropy at the end of the operation (χ2 = 3.847, P = 0.036), CERO2 (χ2 = 2.589, P = 0.010) single index predictive value. Conclusion The entropy index and cerebral oxygen metabolism in general anesthesia patients change with the progress and discontinuation of remifentanil maintenance anesthesia, and the combination of the two has a high predictive power in postoperative hyperalgesia risk assessment. When the reaction entropy > 54.23, CERO2 > 34.14%, or the total dosage of remifentanil ≥ 30 μg/kg at the end of the operation, we should be highly vigilant of the occurrence of postoperative hyperalgesia and postoperative analgesia management should be strengthened.

Remifentanil Anesthesia on the Expression of Apoptosis-Related Proteins Bcl-2 and Bax in Rat Myocardial Cells with Ischemia-Reperfusion Injury

Ischemia-reperfusion damage to the myocardium is inevitable. This study mainly explored the effect of remifentanil anesthesia on the expression of apoptosis-related proteins Bcl-2 and Bax in rat myocardial ischemia-reperfusion injury. Select 48 mice (n=6). First, prepare solutions of different concentrations of remifentanil. A model of ischemia-reperfusion cardiomyocytes was established, and 6 slices of tissue were taken from each specimen, and the positive cells were observed with an optical microscope and magnified 100 times. Bcl-2 and Bax were positive in the cytoplasm and yellowish-brown particles in the inner membrane. According to the distribution of positive cells, randomly select 3 clear fields of view from each part, count the number of positive cells in each field, and then take the average of the proportion of positive cells to get Bcl-2 or Bax protein-positive Index (PEI). Comparison of mRNA levels in each group: Compared with the R3 group, the ratio of the M, R1, and R2 groups increased, and the mRNA expression level of the M group increased almost 3 times, P&lt;0.05. The results of the study show that remifentanil reduces the mortality of myocardial cells by regulating the appearance of Bcl-2 and Bax proteins, and has a certain protective effect on the rat heart during myocardial ischemia and reperfusion. There is no statistically significant difference in the protective effect of remifentanil on myocardial ischemia-reperfusion.

Anesthetic Effect of Sufentanil Combined with Remifentanil in Patients Undergoing Radical Gastrectomy

Objective: To explore and analyze the anesthetic effect of sufentanil combined with remifentanil in patients undergoing radical gastrectomy for gastric cancer. Methods: In this study, 100 patients receiving radical gastrectomy for gastric cancer in our hospital were selected as the research subjects, and the period from June 2019 to February 2021 was divided into different anesthesia regimens. Fifty patients receiving remifentanil anesthesia were used as the control group, and 50 patients receiving remifentanil combined with sufentanil anesthesia were used as the research group. The anesthetic effect of the two groups of patients was analyzed and compared. Results: The HR and MAP of the study group at different time after intubation were lower than those of the control group (P&lt;0.05). The changes of HR and MAP before and after intubation in two groups were significant compared with those before intubation (P&lt;0.05). The postoperative VAS score of the study group was significantly better than that of the control group (P&lt;0.05). Conclusions: In radical gastrectomy for gastric cancer, the choice of sufentanil and remifentanil as the anesthesia scheme can effectively stabilize the hemodynamics of patients, relieve the degree of postoperative pain, with obvious clinical value.

Spurious electroencephalographic activity due to pulsation artifact in the depth of anesthesia monitor

BackgroundThe depth of anesthesia (DOA) is estimated based on the anesthesia-induced electroencephalogram (EEG) changes. However, the surgical environment, as well as the patient him/herself, generates electrical interferences that cause EEG waveform distortion.Case presentationA 52-year-old patient required general anesthesia due to the right femur necrotizing fasciitis. He had no history of epilepsy or head injury. His cardiovascular status was stable without arrhythmia under propofol and remifentanil anesthesia. The DOA was evaluated with Root® with SedLine® Brain Function Monitoring (Masimo Inc, Irvine, CA). The EEG showed a rhythmic, heart rate time-locked pulsation artifact, which diminished after electrode repositioning. Offline analysis revealed that the pulse wave-like interference in EEG was observed at the heart rate frequency.ConclusionsWe experienced an anesthesia case that involves a pulsation artifact generated by the superficial temporal artery contaminating the EEG signal. Numerous clinical conditions, including pulsation artifact, disturb anesthesia EEG.

A Role for Transmembrane Protein 16C/Slack Impairment in Excitatory Nociceptive Synaptic Plasticity in the Pathogenesis of Remifentanil-induced Hyperalgesia in Rats

Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembrane protein 16C (TMEM16C)/Slack is required for α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptor (AMPAR) activation in remifentanil-induced postoperative hyperalgesia. Remifentanil anesthesia reduced the paw withdrawal threshold from 2 h to 48 h postoperatively, with a decrease in the expression of TMEM16C and Slack in the dorsal root ganglia (DRG) and spinal cord. Knockdown of TMEM16C in the DRG reduced the expression of Slack and elevated the basal peripheral sensitivity and AMPAR expression and function. Overexpression of TMEM16C in the DRG impaired remifentanil-induced ERK1/2 phosphorylation and behavioral hyperalgesia. AMPAR-mediated current and neuronal excitability were downregulated by TMEM16C overexpression in the spinal cord. Taken together, these findings suggest that TMEM16C/Slack regulation of excitatory synaptic plasticity via GluA1-containing AMPARs is critical in the pathogenesis of remifentanil-induced postoperative hyperalgesia in rats.

Effects of prophylactic atropine on the time to tracheal intubation with the pre-administration of remifentanil.

Pre-administration of remifentanil in target-controlled propofol and remifentanil anaesthesia could prolong the time of onset of muscle relaxation owing to haemodynamic effects, thereby prolonging the time to tracheal intubation. Although the sympatholytic effects of remifentanil result in bradycardia and hypotension, these responses can be attenuated by the administration of atropine. Therefore, we investigated whether prophylactic administration of atropine could prevent the prolongation of the time to tracheal intubation. Sixty-four patients were included in this study. They were randomised into Group A (atropine 0.5mg, n=32) and Group S (saline 0.9%, n=32), immediately before the pre-administration of remifentanil. The primary outcome was the time to tracheal intubation and the secondary outcomes were rocuronium onset time, time to loss of consciousness (LOC), time to reach a value of 60 on the bispectral index (BIS) and haemodynamic variables. The median [Interquartile range] of the time to tracheal intubation was 240 [214, 288]s in Group S and 190 [176, 212]s in Group A(median difference: 50s, 95% confidence interval: 27-80s, P=.001). Rocuronium onset time was significantly decreased in Group A compared to that in Group S (129 [110, 156] vs 172 [154, 200], P=.001). The times to LOC and reach 60 on the BIS were not significantly different between the two groups. Cardiac output(CO) and heart rate were less decreased in Group A than in Group S (P=.02, P<.001, respectively). Prophylactic administration of atropine could compensate for the reduction in CO in cases pre-administered with remifentanil in target-controlled propofol and remifentanil anaesthesia. This in turn prevented the prolongation of rocuronium onset time and reduced the time to tracheal intubation.

Sevoflurane versus PRopofol combined with Remifentanil anesthesia Impact on postoperative Neurologic function in supratentorial Gliomas (SPRING): protocol for a randomized controlled trial

BackgroundPatients with intracranial tumors are more sensitive to anesthetics than the general population and are therefore more susceptible to postoperative neurologic and neurocognitive dysfunction. Sevoflurane or propofol combined with remifentanil are widely used general anesthetic regimens for craniotomy, with neither regimen shown to be superior to the other in terms of neuroprotective efficacy and anesthesia quality. There is no evidence regarding the variable effects on postoperative neurologic and neurocognitive functional outcome under these two general anesthetic regimens. This trial will compare inhalational sevoflurane or intravenous propofol combined with remifentanil anesthesia in patients with supratentorial gliomas and test the hypothesis that postoperative neurologic function is equally affected between the two regimens.MethodsThis is a prospective, single-center, randomized parallel arm equivalent clinical trial, which is approved by China Ethics Committee of Registering Clinical Trials (ChiECRCT-20,160,051). Patients with supratentorial gliomas diagnosed by magnetic resonance imaging will be eligible for the trial. Written informed consent will be obtained before randomly assigning each subject to either the sevoflurane-remifentanil or propofol-remifentanil group for anesthesia maintenance to achieve an equal-desired depth of anesthesia. Intraoperative intervention and monitoring will follow a standard anesthetic management protocol. All of the physiological parameters and other medications administered during the intervention will be recorded. The primary outcome will be neurologic function change assessed by National Institute of Health Stroke Scale (NIHSS) within 4 h after general anesthesia when observer’s assessment of alertness/sedation (OAA/S) reaches 4. Secondary outcomes will include NIHSS and modified NIHSS change 1 and 2 days after general anesthesia, hemodynamic stability, intraoperative brain relaxation, quality of anesthesia emergence, quality of anesthesia recovery, postoperative cognitive function, postoperative pain, postoperative neurologic complications, as well as perioperative medical expense.DiscussionThis randomized equivalency trial will primarily compare the impacts of sevoflurane-remifentanil and propofol-remifentanil anesthesia on short-term postoperative neurologic function in patients with supratentorial gliomas undergoing craniotomy. The exclusion criteria are strict to ensure that the groups are comparable in all aspects. Repeated and routine neurologic evaluations after operation are always important to evaluate neurosurgical patients’ recovery and any newly presenting complications. The results of this trial would help specifically to interpret anesthetic residual effects on postoperative outcomes, and perhaps would help the anesthesiologist to select the optimal anesthetic regimen to minimize its impact on neurologic function in this specific patient population.Trial registrationThe study was registered and approved by the Chinese Clinical Trial Registry (Chinese Clinical Trial Registry, ChiCTR-IOR-16009177). Principle investigator: Nan Lin (email address: linnan127@gmail.com) and Ruquan Han (email address: hanrq666@aliyun.com) Date of Registration: September 8th, 2016. Country of recruitment: China.

Adaptive drug interaction model to predict depth of anesthesia in the operating room

The availability of accurate models for predicting the drug effect in patients undergoing general anesthesia is an important factor in producing a personalized drug infusion. These models should consider different clinical factors to provide realistic predictions. This paper proposes a new methodology for modeling the depth of hypnosis (DOH) during anesthesia. The model, which is based on a pharmacokinetic–pharmacodynamic structure, explicitly takes into account the interaction between the hypnotic and opioid drugs delivered during surgery. Patients undergoing general surgery with intravenous propofol–remifentanil anesthesia were considered. The bispectral index (BIS) was used for monitoring the DOH. In contrast with previous research, the uniqueness of this study lies in the proposal of an adaptive model to deal simultaneously with the variabilities in the clinical response of the patients, the drug interactions, and the variable time delay introduced by the BIS monitor. The proposed method was validated using data from 17 patients undergoing general anesthesia. Successful results were obtained for predicting the evolution of BIS during the induction and maintenance phases of propofol–remifentanil anesthesia. Specifically, the convenience of an adaptive model that included all the factors likely to affect the anesthetic process was demonstrated. The proposed methodology can be used for the development of new models to be employed in model predictive control strategies for closed-loop anesthesia.