The analgesic effect of ultrasound-guided cervical erector spinae block in arthroscopic shoulder surgery: a randomized controlled clinical trial.

BACKGROUND: Erector spinae plane block (ESPB) is a novel fascial plane block technique that can provide effective perioperative analgesia for thoracic, abdominal and lumbar surgeries. However, the effect of cervical ESPB on postoperative analgesia after arthroscopic shoulder surgery is unknown. The aim of this study is to investigate the analgesic effect and safety of ultrasound-guided cervical ESPB in arthroscopic shoulder surgery. METHODS: Seventy patients undergoing arthroscopy shoulder surgery were randomly assigned to one of two groups: ESPB group (n = 35) or control group (n = 35). Patients in the ESPB group received an ultrasound-guided ESPB at the C7 level with 30 mL of 0.25% ropivacaine 30 min before induction of general anesthesia, whereas patients in the control group received no block. The primary outcome measures were the static visual analogue scale (VAS) pain scores at 4, 12, and 24 h after surgery. Secondary outcomes included heart rate (HR) and mean arterial pressure (MAP) before anesthesia (t1), 5 min after anesthesia (t2), 10 min after skin incision (t3), and 10 min after extubation (t4); intraoperative remifentanil consumption; the Bruggrmann comfort scale (BCS) score, quality of recovery-15 (QoR-15) scale score and the number of patients who required rescue analgesia 24 h after surgery; and adverse events. RESULTS: The static VAS scores at 4, 12 and 24 h after surgery were significantly lower in the ESPB group than those in the control group (2.17 ± 0.71 vs. 3.14 ± 1.19, 1.77 ± 0.77 vs. 2.63 ± 0.84, 0.74 ± 0.66 vs. 1.14 ± 0.88, all P < 0.05). There were no significant differences in HR or MAP at any time point during the perioperative period between the two groups (all P > 0.05). The intraoperative consumption of remifentanil was significantly less in the ESPB group compared to the control group (P < 0.05). The scores of BCS and QoR-15 scale were higher in the ESPB group 24 h after surgery than those in the control group (P < 0.05). Compared to the control group, fewer patients in the ESPB group required rescue analgesia 24 h after surgery (P < 0.05). No serious complications occurred in either group. CONCLUSIONS: Ultrasound-guided cervical ESPB can provide effective postoperative analgesia following arthroscopic shoulder surgery, resulting in a better postoperative recovery with fewer complications. TRIAL REGISTRATION: Chictr.org.cn identifier ChiCTR2300070731 (Date of registry: 21/04/2023, prospectively registered).

Opioid-free anaesthesia with dexmedetomidine and lidocaine versus remifentanil-based anaesthesia in cardiac surgery: study protocol of a French randomised, multicentre and single-blinded OFACS trial.

INTRODUCTION: Intraoperative opioids have been used for decades to reduce negative responses to nociception. However, opioids may have several, and sometimes serious, adverse effects. Cardiac surgery exposes patients to a high risk of postoperative complications, some of which are common to those caused by opioids: acute respiratory failure, postoperative cognitive dysfunction, postoperative ileus (POI) or death. An opioid-free anaesthesia (OFA) strategy, based on the use of dexmedetomidine and lidocaine, may limit these adverse effects, but no randomised trials on this issue have been published in cardiac surgery.We hypothesised that OFA versus opioid-based anaesthesia (OBA) may reduce the incidence of major opioid-related complications after cardiac surgery. METHODS AND ANALYSIS: Multicentre, randomised, parallel and single-blinded clinical trial in four cardiac surgical centres in France, including 268 patients scheduled for coronary artery bypass grafting under cardiac bypass, with or without aortic valve replacement. Patients will be randomised to either a control OBA protocol using remifentanil or an OFA protocol using dexmedetomidine/lidocaine. The primary composite endpoint is the occurrence of at least one of the following: (1) postoperative cognitive disorder evaluated by the Confusion Assessment Method for the Intensive Care Unit test, (2) POI, (3) acute respiratory distress or (4) death within the first 48 postoperative hours. Secondary endpoints are postoperative pain, morphine consumption, nausea-vomiting, shock, acute kidney injury, atrioventricular block, pneumonia and length of hospital stay. ETHICS AND DISSEMINATION: This trial has been approved by an independent ethics committee (Comité de Protection des Personnes Ouest III-Angers on 23 February 2021). Results will be submitted in international journals for peer reviewing. TRIAL REGISTRATION NUMBER: NCT04940689, EudraCT 2020-002126-90.

Serotonin Syndrome After Prolonged Remifentanil and Propofol Infusion for Craniotomy: A Case Report.

Serotonin syndrome (SS) is a life-threatening condition caused by serotonergic medications. We describe a unique case of SS likely caused by prolonged exposure to propofol and remifentanil alone. A young male presented for vestibular schwannoma resection. Several hours into the case, the patient demonstrated hyperthermia and hemodynamic instability, followed by clonus, rigidity, shivering, and tachycardia after emergence. SS was diagnosed using Hunter's criteria and improved with supportive measures. While the patient endorsed a history of methamphetamine use, his urine drug screen was negative. The possibility of SS should be considered when administering propofol and remifentanil, particularly with prolonged infusions.

Effect of Dexmedetomidine Combined with Remifentanil on Emergence Agitation During Awakening from Sevoflurane Anesthesia for Pediatric Liver Surgery.

BACKGROUND We aimed to assess the effect of dexmedetomidine (Dex) combined with remifentanil on emergence agitation (EA) during awakening from sevoflurane anesthesia for pediatric liver surgery. MATERIAL AND METHODS Sixty children who underwent liver surgery in our hospital were prospectively selected and randomly allocated into group A (placebo+remifentanil+sevoflurane) or group B (Dex+remifentanil+sevoflurane). Mean arterial pressure (MAP) and heart rate (HR) at different time points, agitation score during awakening, behavioral status, pain level, and the incidence of postoperative adverse effects were compared in both groups. RESULTS Children in group B had lower HR and MAP levels immediately after tracheal extubation and 5 min after tracheal extubation than those in group A. The Aono's scores, PAED agitation scores, and CHIPP scores at 15 min and 30 min of admission to the PACU were lower in group B than in group A. The incidence of agitation during postoperative anesthesia awakening was lower in group B in contrast to group A. There was no significant difference in postoperative adverse reactions between group A and group B. CONCLUSIONS In pediatric liver surgery, the use of Dex+remifentanil+sevoflurane anesthesia can reduce the incidence of EA during the awakening period, stabilize hemodynamic levels, and relieve postoperative pain, and has fewer postoperative adverse effects, which warrants clinical application.

Anesthetic management for cesarean section in two parturient with ascending aortic aneurysm: a case-based discussion.

BACKGROUND: The anesthetic management of parturients with ascending aortic aneurysm for cesarean section can be particularly challenging, primarily because of increased risk for aortic dissection or aneurysm rupture. CASE PRESENTATION: We present some aspects of the anesthetic management of two parturients with ascending aortic aneurysm for cesarean sections; amongst, the use of remifentanil with its effects on patient and newborn. We emphasize the importance of a cardio-obstetric team in the context of preoperative planning of such patients. Also, we reviewed some literature on the anesthetic management with its effect on peri-operative hemodynamic stability. CONCLUSION: Maintaining hemodynamic stability is paramount in the prevention of the rupture or dissection of ascending aortic aneurysm during labor of parturient.

Comparison between conventional-dose and high-dose rocuronium use in general anesthesia for Cesarean section.

Background: There have been few studies comparing the effects of high- and low-dose rocuronium during cesarean section by directly measuring the concentration. Therefore, we conducted a study to examine the blood concentrations and clinical effects of both doses of rocuronium on mothers and fetuses. Methods: Eighteen patients were randomly assigned to two groups: C Group (0.6 mg/kg), and H Group, (1.0 mg/kg). The primary outcome was the comparison of umbilical vein rocuronium concentration between two groups. We assessed ease of intubation, time from rocuronium administration to some TOF points, post-anesthesia care unit (PACU) stay time, infused remifentanil dose, maternal rocuronium concentration, and Apgar scores. Results: No differences were observed in demographic data, ease of intubation, PACU stay time, 1 min Apgar scores, umbilical venous blood gas analysis between both groups. However, the time from rocuronium administration to T3 disappearance was shorter (p=0.009) and time to T1 and T2 reappearance were longer (p=0.003, p=0.009) in H group than that in C group. The administered remifentanil dose (p=0.042) was lower in the H group than in the C group. Rocuronium concentrations in the umbilical vein (p=0.004) and maternal vein before cord clamping (p=0.002) and at discharge (p<0.001) were also found to be higher in the H group than in the C group. Conclusions: We observed no prolongation of PACU stay, and no differences in Apgar scores in H group compared to C group. It suggests that 1.0 mg/kg of rocuronium has no negative effects on the fetus and mother in cesarean section.

[Analysis of the application effect and safety of transnasal humidified rapid insufflation ventilatory exchange technique in hysteroscopic diagnostic and therapeutic surgery].

Objective: To investigate the effect and safety of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) technique in hysteroscopic diagnostic and therapeutic surgery. Methods: This study was a randomized controlled trial. A total of 100 female patients undergoing hysteroscopy surgery at Beijing Tongren Hospital from September to December 2023 were selected and randomly divided into two groups by the random number table method: the THRIVE group and the mask oxygen group, with 50 patients in each group. Patients in both groups were given total intravenous anesthesia with propofol combined with remifentanil and preserved spontaneous respiration. The THRIVE group was given oxygen by the THRIVE device with an oxygen flow rate of 50 L/min, while the mask oxygen group was given oxygen by the mask with an oxygen flow rate of 5 L/min; the oxygen concentration of both groups was set at 100%. The general condition of the patients, vital signs during the operation, the amount of anesthesia drugs used and the operation time were recorded. The primary observation index was the incidence of hypoxic events in the two groups; the secondary observation indexes were the incidence and time of intraoperative apnea as well as the corresponding oxygenation interventions and the incidence of non-hypoxic adverse events. Results: The age of the THRIVE group was (42±14) years, and the age of the mask oxygen group was (43±15) years. The duration of surgery in the THRIVE group was (15.9±3.4) min, which was statistically lower than that of the mask oxygen group (16.3±4.5) min (P=0.041), and there were no differences observed in the duration of awakening time and anesthesia time (both P>0.05). There was no significant difference in the dosage of propofol, remifentanil, and intraoperative vasoactive drugs between the two groups (all P>0.05). The SpO2 of the patients in the THRIVE group at the end of the operation was (99.7±1.1) %, which was higher than that of the mask-oxygen group (99.1±1.1) % (P<0.05). There was no difference in SpO2 of the two groups at the other time points (all P>0.05). There were no differences in HR and MAP of two group patients at each time point (all P>0.05). The incidence of hypoxic events in the THRIVE group was 12.0% (6/50), which was lower than that of 28.0% (14/50) in the mask oxygen group (P=0.045). The difference in the incidence and duration of apnea between the two groups was not statistically significant (all P>0.05). There were no cases of temporary need for laryngeal mask or tracheal intubation during surgery in both groups. There was no statistically significant difference in the incidence of intraoperative body movement, dizziness, nausea and vomiting between the two groups (all P>0.05), and no cardiac, cerebral, renal or other important organ insufficiency occurred in the two weeks after surgery. Conclusion: THRIVE technology can provide effective oxygenation for patients undergoing hysteroscopic diagnosis and treatment, maintain patients' circulatory stability, and improve the safety and efficiency of surgery.

Dexmedetomidine versus remifentanil in nasal surgery: a systematic review and meta-analysis.

BACKGROUND: Nasal surgeries, addressing anatomical variations for form and function, require careful anesthesia administration, including dexmedetomidine and remifentanil. This meta-analysis evaluates their safety and efficacy variations in nasal surgeries, emphasizing patient comfort and optimal outcomes. METHODS: Four electronic databases (PubMed, Scopus, Web of Science, and CINAHL Complete) were searched for records in English. Studies that measure the effect of dexmedetomidine versus remifentanil on patients underwent nasal surgery were included. The Cochrane Collaboration's tool was used to assess the quality of the included studies. A random-effect model was preferred and statistical analysis was performed by Stata software version 17. RESULTS: Out of an initial pool of 63 articles, five studies were selected for this analysis. All of these chosen studies were Randomized Controlled Trials (RCTs). The meta-analysis involved a total of 302 participants, with 152 in the remifentanil group and 150 in the dexmedetomidine group. The analysis aimed to compare the effects of Dexmedetomidine and Remifentanil on heart rate (HR) and mean arterial pressure (MAP) during surgery. Both groups exhibited similar MAP and HR, with the exception of a slightly lower HR in the remifentanil group at the 15th minute of surgery (Standardized Mean Difference: -0.24 [-0.83, 0.34]). Furthermore, when evaluating the impact of these medications on post-surgery outcomes, including pain levels, the use of pain relief medications, patient-surgeon satisfaction, agitation scores, and recovery time, no significant differences were observed between the two medications in any of these aspects. CONCLUSION: In summary, the study compared Dexmedetomidine and Remifentanil in nasal surgeries anesthesia. No significant differences were found in heart rate, blood pressure, satisfaction, pain, agitation, or recovery time. The study had limitations, and future research should establish standardized protocols and consider various surgical factors.

The comparison of the effect of non-pharmacological pain relief and pharmacological analgesia with remifentanil on fear of childbirth and postpartum depression: a randomized controlled clinical trial.

INTRODUCTION: Childbirth may be associated with psychological, social, and emotional effects and provide the background for women's health or illness throughout their life. This research aimed at comparing the impact of non-pharmacological pain relief and pharmacological analgesia with remifentanil on childbirth fear and postpartum depression. MATERIALS AND METHOD: This randomized clinical trial with two parallel arms was conducted on 66 women with term pregnancy referred to Taleghani Hospital in Tabriz for vaginal delivery during September 2022 to September 2023. First, all of the eligible participants were selected through Convenience Sampling. Then, they were randomly assigned into two groups of pharmacological analgesia with remifentanil and non-pharmacological analgesia with a ratio of 1:1 using stratified block randomization based on the number of births. Before the intervention, fear of childbirth (FOC) was measured using Delivery Fear Scale (DFS) between 4 and 6 cm cervical dilatation. Pain and fear during labor in dilatation of 8 cm were measured in both groups using VAS and DFS. After delivery, FOC was assessed using Delivery Fear Scale (W DEQ Version B) and postpartum depression using the Edinburgh's postpartum depression scale (EPDS). Significance level was considered 0.05. Mean difference (MD) was compared with Independent T-test and ANCOVA pre and post intervention. RESULTS: The mean score of FOC in the non-pharmacological analgesia group was significantly lower than that in the pharmacological analgesia group after the intervention by controlling the effect of the baseline score (MD: -6.33, 95%, Confidence Interval (CI): -12.79 to -0.12, p = 0.04). In the postpartum period, the mean score of FOC in the non-pharmacological analgesia group was significantly lower than that in the pharmacological analgesia group after controlling the effect of the baseline score (MD: -21.89; 95% CI: -35.12 to -8.66; p = 0.002). The mean score of postpartum depression in the non-pharmacological analgesia group was significantly lower than that in the pharmacological analgesia group (MD: -1.93, 95% CI: -3.48 to -0.37, p = 0.01). TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT): IRCT20170506033834N10. Date of registration: 05/07/2022 Date of first registration: 05/07/2022. URL: https://www.irct.ir/trial/61030; Date of recruitment start date05/07/2022. CONCLUSION: The study results indicated a reduction in FOC and postpartum depression among parturient women receiving non-pharmacological strategies with active participation in childbirth compared to women receiving pharmacological analgesia. Owing to the possible side effects of pharmacological methods for mother and fetus, non-pharmacological strategies with active participation of the mother in childbirth are recommended to reduce the FOC and postpartum depression.

Comparison of Deep and Moderate Neuromuscular Blockade for Major Laparoscopic Surgery in Children: A Randomized Controlled Trial.

BACKGROUND AND OBJECTIVE: Neuromuscular blocking agents are routinely used in laparoscopic surgery to optimize operative conditions. We compared the effect of a deep and moderate neuromuscular blockade (NMB) on surgical conditions and postoperative outcomes in children undergoing major laparoscopic surgery. METHODS: Sixty children aged 2-14 years scheduled to undergo major laparoscopic surgery were randomly allocated to deep (post-tetanic count 1-2 twitches) or moderate (train-of-four 1-2 twitches) NMB groups. The anesthesia was maintained with propofol and remifentanil, and the NMB was maintained with a rocuronium continuous infusion. At the end of the operation, the NMB were antagonized with sugammadex. The intra-abdominal pressure, airway pressure, Leiden Surgical Rating Scale, intraoperative hemodynamics, drug usages, duration of surgery, postoperative recovery time, pain, and complications were compared between the groups. RESULTS: The maximum and mean intra-abdominal pressure, the peak inspiratory pressure, and mean airway pressure were significantly lower in the deep NMB group than in the moderate NMB group (p < 0.001). The Leiden Surgical Rating Scale and the dosage of rocuronium were significantly higher in the deep NMB group than the moderate NMB group (p < 0.001). The intraoperative hemodynamics, duration of surgery, post-operative recovery time, pain, and the incidence rate of complications were not significantly different between the groups (p > 0.05). CONCLUSIONS: A deep NMB provided better operative conditions and similar recovery profiles compared with a moderate NMB as reversed with sugammadex in children undergoing major laparoscopic surgery. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry, No. ChiCTR2100053821.

The Influence of Audiovisual Distraction on Pain Reduction During Transcatheter Aortic Valve Implantation Under Monitored Anesthesia Care: A Prospective Randomized Trial.

OBJECTIVES: To investigate the effect of an audiovisual distraction system on the dose of remifentanil for perioperative sedation during transcatheter aortic valve implantation under monitored anesthesia care. DESIGN: Single-center prospective randomized nonblinded study. SETTING: Tertiary referral academic hospital. PARTICIPANTS: Ninety patients who underwent transfemoral transcatheter aortic valve implantation between July 2019 and July 2021. INTERVENTIONS: Patients were randomized to use either a novel audiovisual distraction system during the intervention (n = 45) or standard care without an audiovisual distraction system (n = 45). MEASUREMENTS AND MAIN RESULTS: Standardized questionnaires were given to each patient at admission and before and after the intervention to assess their levels of anxiety. Primary endpoints were the average and peak infusion rates of remifentanil. All patients were considered for the final analysis according to an intention-to-treat design. No relevant differences in pre- and postinterventional anxiety status were observed between the groups. Similarly, there were no significant differences in reported pain scores (p = 0.364). The average infusion rate (p = 0.028) and peak infusion rate (p = 0.025) of remifentanil were lower in the group with an audiovisual distraction system. CONCLUSIONS: Audiovisual distraction is a useful adjunct to reduce the dose of remifentanil under monitored anesthesia care during transcatheter aortic valve implantation. Larger studies are needed to evaluate potential positive effects on patient satisfaction, incidence of delirium, and possible economic benefits.

Comparison of remimazolam-based and propofol-based total intravenous anesthesia on hemodynamics during anesthesia induction in patients undergoing transcatheter aortic valve replacement: a randomized controlled trial.

PURPOSE: This study aimed to compare the hemodynamic effects of remimazolam- and propofol-based total intravenous anesthesia in patients who underwent transcatheter aortic valve replacement. METHODS: This was a single-center, single-blind, randomized controlled trial set at Nara Medical University, Kashihara, Japan. We included 36 patients aged ≥ 20 years scheduled to undergo elective transfemoral transcatheter aortic valve replacement (TAVR) under general anesthesia. The participants were randomly assigned to the remimazolam and propofol groups (n = 18 each). Remimazolam- or propofol-based total intravenous anesthesia was initiated at 12 mg/kg/min or 2.5 mcg/mL via target-controlled infusion, respectively, along with remifentanil. After confirming the loss of consciousness, the administration rate was adjusted using electroencephalographic monitoring. The primary outcome was the rate of arterial hypotension, defined as a mean arterial pressure < 60 mmHg, from anesthesia induction until the beginning of the surgical incision. The total doses of ephedrine and phenylephrine were also assessed. RESULTS: During anesthesia induction, the arterial hypotension rates were 11.9% and 21.6% in the remimazolam and propofol groups, respectively (P = 0.01). The total dose of ephedrine was higher in the propofol group (14.4 mg) than in the remimazolam group (1.6 mg) (P < 0.001); however, the total dose of phenylephrine was not significantly different between the two groups (propofol 0.31 mg vs. remimazolam: 0.17 mg, P = 0.10). CONCLUSION: Remimazolam-based total intravenous anesthesia resulted in a lower hypotension rate than propofol-based total intravenous anesthesia during induction in patients undergoing TAVR. Remimazolam-based total intravenous anesthesia can be used safely during anesthetic induction in patients with severe aortic stenosis.

Effect of remifentanil on three effect-site concentrations of propofol and their relationship during electroencephalography at loss of response, at maximum alpha power, and at onset of burst suppression: a prospective randomized trial.

PURPOSE: The effect-site concentration (Ce) at loss of response (Ce-LOR) to propofol closely correlates both with Ce as electroencephalographic alpha power becomes highest (Ce-alpha) and with Ce at onset of burst suppression (BS) (Ce-OBS), when no opioids are administered. Co-administration of opioids dose-dependently decreases Ce-LOR. We investigated the influence of remifentanil on the relationship between these three Ces. METHODS: After receiving approval from our local ethical committee, with written informed consent, we enrolled 90 participants (ASA-PS I or II) who were scheduled for elective surgery. Participants were randomly assigned to three groups: constant remifentanil Ce 0 ng/ml (Remi_0); 1 ng/mL (Remi_1); and 2 ng/mL (Remi_2). We recorded both raw EEG and EEG-derived parameters on a computer. After reaching remifentanil equilibrium, we administered propofol using a target-controlled infusion pump such that propofol Ce increased to about 0.3 µg/mL/min. After determining Ce-LOR, we administered 0.6 mg/kg of rocuronium and started mask ventilation. The study protocol ended after observation of BS. RESULTS: Three participants were excluded. Ce-LOR in each group (Remi_0, Remi_1, Remi_2) was 2.00 ± 0.58 µg/mL, 1.43 ± 0.49 µg/mL, and 1.37 ± 0.42 µg/mL. Ce-alpha was 2.91 ± 0.63 µg/mL, 2.30 ± 0.41 µg/mL, and 2.12 ± 0.39 µg/mL. Ce-OBS was 3.80 ± 0.69 µg/mL, 3.25 ± 0.68 µg/mL, and 2.90 ± 0.57 µg/mL. In three other instances, Ce was decreased by remifentanil. Generalized linear model analysis revealed that remifentanil had no influence on the relationship between the three Ces. CONCLUSION: During propofol anesthesia, even low concentrations of remifentanil shifted concentration-related electroencephalographic changes.

A dose-ranging study of the physiological and self-reported effects of repeated, rapid infusion of remifentanil in people with opioid use disorder and physical dependence on fentanyl.

RATIONALE: Understanding mechanisms of drug use decisions will inform the development of treatments for opioid use disorder (OUD). Decision-making experiments using neurobehavioral approaches require many trials or events of interest for statistical analysis, but the pharmacokinetics of most opioids limit dosing in humans. OBJECTIVES: This experiment characterized the effects of repeated infusions of the ultra-short acting opioid remifentanil in people with OUD and physical opioid dependence. METHODS: An inpatient study using a within-subjects, single-blind, escalating, within-session, pre-post design was conducted. Seven (3 female) subjects were maintained on oral oxycodone (40-60 mg, 4x/day = 160-240 total mg/day) for seven days prior to the dose-ranging session. Subjects received infusions of three ascending remifentanil doses (0.03, 0.1, 0.3 mcg/kg/infusion in 2 subjects; 0.1, 0.3, 1.0 mcg/kg/infusion in 5 subjects) every minute for 40 min per dose, with infusions administered over 5 s to model naturalistic delivery rates. End tidal carbon dioxide, respiration rate, oxygen saturation (SpO2) and heart rate were measured continuously. Blood pressure (BP), pupil diameter and self-reported drug effects were measured every 5 min. RESULTS: Pupil diameter, SpO2 and systolic BP decreased, and ratings on prototypic subjective effects questionnaire items increased, as a function of remifentanil dose. The number of infusions held because of sedation or physiological parameters exceeding predetermined cutoffs also increased with dose. CONCLUSIONS: This experiment established doses and procedures for the safe delivery of rapid, repeated remifentanil infusions to individuals with OUD and physical fentanyl dependence, which can be applied to the mechanistic study of opioid use decisions.

Postoperative pain after different doses of remifentanil infusion during anaesthesia: a meta-analysis.

BACKGROUND: This meta-analysis aimed to explore the correlation between the different doses of remifentanil-based anaesthesia and postoperative pain in randomised trials. METHODS: The electronic databases including PubMed, Cochrane, clinical trial registries, and Google Scholar were searched up to November 2022 for randomised controlled trials (RCTs) that assessed the dose dependent efficacy of remifentanil for postoperative pain intensity and hyperalgesia. RESULTS: 31 studies involving 2019 patients were included for analysis. Compared with the high remifentanil dose administration, patients in low doses showed less postoperative pain intensity at 1-2 h (weighted mean differences (WMD): 0.60, 95% CI, 0.05 to 1.15), 3-8 h (WMD: 0.38, 95% CI, 0.00 to 0.75), 24 h (WMD: 0.26, 95% CI, 0.04 to 0.48) and 48 h (WMD: 0.32, 95% CI, 0.09 to 0.55). Remifentanil-free regimen failed to decrease the pain score at 24 h (WMD: 0.10, 95% CI, -0.10 to 0.30) and 48 h (WMD: 0.15, 95% CI, -0.22 to 0.52) in comparison with remifentanil-based anaesthesia. After excluding trials with high heterogeneity, the dose of the remifentanil regimen was closely correlated with the postoperative pain score (P=0.03). In addition, the dose of the remifentanil regimen was not associated with the incidence of postoperative nausea and vomiting (PONV) (P=0.37). CONCLUSIONS: Our meta-analysis reveals that the low dose of remifentanil infusion is recommendable for general anaesthesia maintenance. No evidence suggests that remifentanil-free regimen has superiority in reducing postoperative pain. Moreover, remifentanil doesn't have a dose dependent effect in initiating PONV. TRIAL REGISTRATION: The protocol of present study was registered with PROSPERO (CRD42022378360).

Association between intraoperative remifentanil use and postoperative hyperalgesia in adolescent idiopathic scoliosis surgery: a retrospective study.

BACKGROUND: The liberal use of remifentanil in spine surgery has been associated with an increased incidence of postoperative hyperalgesia. Nevertheless, controversies remain as the existing evidence is inconclusive to determine the relationship between remifentanil use and the development of opioid-induced hyperalgesia. We hypothesized that intraoperative infusion of higher dose remifentanil during scoliosis surgery is associated with postoperative hyperalgesia, manifesting clinically as greater postoperative morphine consumption and pain scores. METHODS: Ninety-seven patients with adolescent idiopathic scoliosis (AIS) who underwent posterior spinal fusion surgery at a single tertiary institution from March 2019 until June 2020 were enrolled in this retrospective study. Anesthesia was maintained using a target-controlled infusion of remifentanil combined with volatile anesthetic desflurane in 92 patients, while five patients received it as part of total intravenous anesthesia. Intravenous ketamine, paracetamol, and fentanyl were administered as multimodal analgesia. All patients received patient-controlled analgesia (PCA) morphine postoperatively. Pain scores at rest and on movement, assessed using the numerical rating scale, and the cumulative PCA morphine consumption were collected at a six-hourly interval for up to 48 h. According to the median intraoperative remifentanil dose usage of 0.215 µg/kg/min, patients were divided into two groups: low dose and high dose group. RESULTS: There were no significant differences in the pain score and cumulative PCA morphine consumption between the low and high dose remifentanil group. The mean duration of remifentanil infusion was 134.9 ± 22.0 and 123.4 ± 23.7 min, respectively. CONCLUSION: Intraoperative use of remifentanil as an adjuvant in AIS patients undergoing posterior spinal fusion surgery was not associated with postoperative hyperalgesia.