Effects of an Early Intensive Blood Pressure-lowering Strategy Using Remifentanil and Dexmedetomidine in Patients with Spontaneous Intracerebral Hemorrhage: A Multicenter, Prospective, Superiority, Randomized Controlled Trial.

BACKGROUND: Although it has been established that elevated blood pressure and its variability worsen outcomes in spontaneous intracerebral hemorrhage, antihypertensives use during the acute phase still lacks robust evidence. A blood pressure-lowering regimen using remifentanil and dexmedetomidine might be a reasonable therapeutic option given their analgesic and antisympathetic effects. The objective of this superiority trial was to validate the efficacy and safety of this blood pressure-lowering strategy that uses remifentanil and dexmedetomidine in patients with acute intracerebral hemorrhage. METHODS: In this multicenter, prospective, single-blinded, superiority randomized controlled trial, patients with intracerebral hemorrhage and systolic blood pressure (SBP) 150 mmHg or greater were randomly allocated to the intervention group (a preset protocol with a standard guideline management using remifentanil and dexmedetomidine) or the control group (standard guideline-based management) to receive blood pressure-lowering treatment. The primary outcome was the SBP control rate (less than 140 mmHg) at 1 h posttreatment initiation. Secondary outcomes included blood pressure variability, neurologic function, and clinical outcomes. RESULTS: A total of 338 patients were allocated to the intervention (n = 167) or control group (n = 171). The SBP control rate at 1 h posttreatment initiation in the intervention group was higher than that in controls (101 of 161, 62.7% vs. 66 of 166, 39.8%; difference, 23.2%; 95% CI, 12.4 to 34.1%; P < 0.001). Analysis of secondary outcomes indicated that patients in the intervention group could effectively reduce agitation while achieving lighter sedation, but no improvement in clinical outcomes was observed. Regarding safety, the incidence of bradycardia and respiratory depression was higher in the intervention group. CONCLUSIONS: Among intracerebral hemorrhage patients with a SBP 150 mmHg or greater, a preset protocol using a remifentanil and dexmedetomidine-based standard guideline management significantly increased the SBP control rate at 1 h posttreatment compared with the standard guideline-based management.

Hypotension after general anaesthesia induction using remimazolam or propofol in geriatric patients undergoing sevoflurane anaesthesia with remifentanil: a single-centre, double-blind, randomised controlled trial.

BACKGROUND: The occurrence of hypotension after induction of general anaesthesia is common in geriatric patients, and should be prevented to minimise perioperative complications. Compared with propofol, remimazolam potentially has a lower incidence of hypotension. This study aimed to compare the incidence of hypotension after general anaesthesia induction with remimazolam or propofol in geriatric patients. METHODS: This single-centre, double-blind, randomised trial enrolled 90 patients aged ≥80 yr who received general anaesthesia for scheduled surgery. Patients were randomised to receive remimazolam (12 mg kg-1 h-1) or propofol (0.025 mg kg-1 s-1) for anaesthesia induction, with remifentanil and sevoflurane. The presence or absence of hypertension on the ward served as the stratification factor. The incidence of hypotension after the induction of general anaesthesia, defined as a noninvasive mean arterial pressure of <65 mm Hg measured every minute from initiation of drug administration to 3 min after tracheal intubation, was the primary outcome. Subgroup analysis was performed for the primary outcome using preoperative ward hypertension, clinical frailty scale, Charlson Comorbidity Index, and age. RESULTS: Three subjects were excluded before drug administration, and 87 subjects were included in the analysis. The incidence of hypotension was 72.1% (31/43) and 72.7% (32/44) with remimazolam or propofol, respectively. No statistically significant differences (adjusted odds ratio, 0.96; 95% confidence interval, 0.37-2.46; P=0.93) were observed between groups. Subgroup analysis revealed no significant differences between groups. CONCLUSIONS: Compared with propofol, remimazolam did not reduce the incidence of hypotension after general anaesthesia induction in patients aged ≥80 yr. CLINICAL TRIAL REGISTRATION: UMIN000042587.

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.

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.

Remifentanil for tracheal intubation without neuromuscular blocking drugs in adult patients: a systematic review and meta-analysis.

There is increasing interest in the use of short-acting opioids such as remifentanil to facilitate tracheal intubation. The aim of this systematic review was to determine the efficacy and safety of remifentanil for tracheal intubation compared with neuromuscular blocking drugs in adult patients. We conducted a systematic search for randomised controlled trials evaluating remifentanil for tracheal intubation. Primary outcomes included tracheal intubation conditions and adverse events. Twenty-one studies evaluating 1945 participants were included in the analysis. Use of remifentanil (1.5-4.0 µg.kg-1) showed no evidence of a difference in tracheal intubation success rate compared with neuromuscular blocking drugs (risk ratio (95%CI) 0.97 (0.94-1.01); six studies; 1232 participants; I2 28%; p = 0.16; moderate-certainty evidence). Compared with neuromuscular blocking drugs, the use of remifentanil (2.0-4.0 µg.kg-1) makes little to no difference in terms of producing excellent tracheal intubation conditions (risk ratio (95%CI) 1.16 (0.72-1.87); two studies; 121 participants; I2 31%, p = 0.54; moderate-certainty of evidence). There was no evidence of an effect between remifentanil (2.0-4.0 µg.kg-1) and neuromuscular blocking drugs for bradycardia (risk ratio (95%CI) 0.44 (0.01-13.90); two studies; 997 participants; I2 81%; p = 0.64) and hypotension (risk ratio (95%CI) 1.05 (0.44-2.49); three studies; 1071 participants; I2 92%; p = 0.92). However, the evidence for these two outcomes was judged to be of very low-certainty. We conclude that remifentanil may be used as an alternative drug for tracheal intubation in cases where neuromuscular blocking drugs are best avoided, but more studies are required to evaluate the haemodynamic adverse events of remifentanil at different doses.

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.

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.

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).

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).

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.

Substance-dependent EEG during recovery from anesthesia and optimization of monitoring.

The electroencephalographic (EEG) activity during anesthesia emergence contains information about the risk for a patient to experience postoperative delirium, but the EEG dynamics during emergence challenge monitoring approaches. Substance-specific emergence characteristics may additionally limit the reliability of commonly used processed EEG indices during emergence. This study aims to analyze the dynamics of different EEG indices during anesthesia emergence that was maintained with different anesthetic regimens. We used the EEG of 45 patients under general anesthesia from the emergence period. Fifteen patients per group received sevoflurane, isoflurane (+ sufentanil) or propofol (+ remifentanil) anesthesia. One channel EEG and the bispectral index (BIS A-1000) were recorded during the study. We replayed the EEG back to the Conox, Entropy Module, and the BIS Vista to evaluate and compare the index behavior. The volatile anesthetics induced significantly higher EEG frequencies, causing higher indices (AUC > 0.7) over most parts of emergence compared to propofol. The median duration of "awake" indices (i.e., > 80) before the return of responsiveness (RoR) was significantly longer for the volatile anesthetics (p < 0.001). The different indices correlated well under volatile anesthesia (rs > 0.6), with SE having the weakest correlation. For propofol, the correlation was lower (rs < 0.6). SE was significantly higher than BIS and, under propofol anesthesia, qCON. Systematic differences of EEG-based indices depend on the drugs and devices used. Thus, to avoid early awareness or anesthesia overdose using an EEG-based index during emergence, the anesthetic regimen, the monitor used, and the raw EEG trace should be considered for interpretation before making clinical decisions.

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.

Remifentanil-induced hyperalgesia: the current state of affairs.

Remifentanil-induced hyperalgesia (RIH) is a part of a general opioid-induced hyperalgesia (OIH) syndrome, seemingly resulting from abrupt cessation of continuous remifentanil infusion at rates equal or exceeding 0.3 mcg/kg/min. The intricate mechanisms of its development are still not completely understood. However, hyperactivation of the N -methyl d -aspartate receptor system, descending spinal facilitation and increased concentration of dynorphin (a κ-opioid ligand) are commonly proposed as possible mechanisms. Several ways of prevention and management have been suggested, such as slow withdrawal of remifentanil infusion, the addition of propofol, pretreatment with or concomitant administration of ketamine, buprenorphine, cyclooxygenase-2 inhibitors (NSAIDs), methadone, dexmedetomidine. In clinical and animal studies, these strategies exhibited varying success, and many are still being investigated.

[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.

Is target-controlled infusion better than manual controlled infusion during TIVA for elective neurosurgery? Results of a single-centre pilot study.

INTRODUCTION: Maintaining optimal systemic circulatory parameters is essential to ensure adequate cerebral perfusion (CPP) during neurosurgery, especially when autoregulation is impaired. AIM OF STUDY: To compare two types of total intravenous anaesthesia i.e. target controlled infusion (TCI) and manually controlled infusion (MCI) with propofol and remifentanil in terms of their control of cardiovascular parameters during neurosurgical resection of intracranial pathology. MATERIAL AND METHODS: Patients with supratentorial intracranial pathology were selected for the study. Patients in ASA grades III and IV and those with diseases of the circulatory system were excluded. Patients were randomly divided into two equal groups according to the method of general anaesthesia used i.e. TCI or MCI. During the neurosurgery, the values of mean arterial pressure (MAP), heart rate (HR), bispectral index (BIS) and central venous pressure were monitored and recorded at the designated 14 relevant (i.e. critical from the anaesthetist's and neurosurgeon's points of view) measurement points. RESULTS: Fifty patients (25 TCI and 25 MCI) were enrolled in the study. The groups did not differ with respect to sex, age and BMI, operation time or volume of removed lesions. TCI-anaesthetised patients had better MAP stability at the respective time points. CONCLUSIONS: Due to the greater stability of MAP, which has a direct effect on CPP, TCI appears to be the method of choice in anaesthesia for intracranial surgery.

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.

Effect of Remifentanil vs Neuromuscular Blockers During Rapid Sequence Intubation on Successful Intubation Without Major Complications Among Patients at Risk of Aspiration: A Randomized Clinical Trial.

Importance: It is uncertain whether a rapid-onset opioid is noninferior to a rapid-onset neuromuscular blocker during rapid sequence intubation when used in conjunction with a hypnotic agent. Objective: To determine whether remifentanil is noninferior to rapid-onset neuromuscular blockers for rapid sequence intubation. Design, Setting, and Participants: Multicenter, randomized, open-label, noninferiority trial among 1150 adults at risk of aspiration (fasting for <6 hours, bowel occlusion, recent trauma, or severe gastroesophageal reflux) who underwent tracheal intubation in the operating room at 15 hospitals in France from October 2019 to April 2021. Follow-up was completed on May 15, 2021. Interventions: Patients were randomized to receive neuromuscular blockers (1 mg/kg of succinylcholine or rocuronium; n = 575) or remifentanil (3 to 4 µg/kg; n = 575) immediately after injection of a hypnotic. Main Outcomes and Measures: The primary outcome was assessed in all randomized patients (as-randomized population) and in all eligible patients who received assigned treatment (per-protocol population). The primary outcome was successful tracheal intubation on the first attempt without major complications, defined as lung aspiration of digestive content, oxygen desaturation, major hemodynamic instability, sustained arrhythmia, cardiac arrest, and severe anaphylactic reaction. The prespecified noninferiority margin was 7.0%. Results: Among 1150 randomized patients (mean age, 50.7 [SD, 17.4] years; 573 [50%] women), 1130 (98.3%) completed the trial. In the as-randomized population, tracheal intubation on the first attempt without major complications occurred in 374 of 575 patients (66.1%) in the remifentanil group and 408 of 575 (71.6%) in the neuromuscular blocker group (between-group difference adjusted for randomization strata and center, -6.1%; 95% CI, -11.6% to -0.5%; P = .37 for noninferiority), demonstrating inferiority. In the per-protocol population, 374 of 565 patients (66.2%) in the remifentanil group and 403 of 565 (71.3%) in the neuromuscular blocker group had successful intubation without major complications (adjusted difference, -5.7%; 2-sided 95% CI, -11.3% to -0.1%; P = .32 for noninferiority). An adverse event of hemodynamic instability was recorded in 19 of 575 patients (3.3%) with remifentanil and 3 of 575 (0.5%) with neuromuscular blockers (adjusted difference, 2.8%; 95% CI, 1.2%-4.4%). Conclusions and Relevance: Among adults at risk of aspiration during rapid sequence intubation in the operating room, remifentanil, compared with neuromuscular blockers, did not meet the criterion for noninferiority with regard to successful intubation on first attempt without major complications. Although remifentanil was statistically inferior to neuromuscular blockers, the wide confidence interval around the effect estimate remains compatible with noninferiority and limits conclusions about the clinical relevance of the difference. Trial Registration: ClinicalTrials.gov Identifier: NCT03960801.

Effects of remifentanil on pharyngeal swallowing and esophageal motility: no impact of different bolus volumes and partial antagonism by methylnaltrexone.

Remifentanil impairs swallowing, and disturbed accommodation to bolus volume may be one of the underlying causes. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. So, this study aimed to investigate if remifentanil-induced swallowing dysfunction is dependent on the bolus volume and whether the effect of remifentanil could be counteracted by methylnaltrexone, a peripherally acting opioid antagonist. Nineteen healthy volunteers were included in this double-blinded, randomized, placebo-controlled, crossover study. Study participants received target-controlled remifentanil infusions and placebo infusions in a randomized order. Methylnaltrexone was administered by intravenous injection of doses of 0.3 mg/kg. Recordings of pressure and impedance data were acquired using a combined manometry and impedance solid-state catheter. Data were analyzed from three series of bolus swallows, baseline, during study medication exposure, and 15 min after methylnaltrexone. Remifentanil induced significant effects on multiple pharyngeal and esophageal function parameters. No significant differences in remifentanil-induced swallowing dysfunction related to different bolus volumes were found. Pharyngeal effects of remifentanil were not significantly counteracted by methylnaltrexone, whereas on the distal esophageal level, effects on distension pressures were counteracted. Changes in pharyngeal and esophageal pressure flow variables were consistent with previous results on remifentanil-induced swallowing dysfunction and uniform across all bolus volumes. The effects of remifentanil on the pharyngeal level and on the proximal esophagus appear to be predominantly centrally mediated, whereas the effects of remifentanil on the distal esophagus may be mediated by both central and peripheral mechanisms.NEW & NOTEWORTHY In this randomized controlled trial, we used the "Swallow Gateway" online platform to analyze the effects of remifentanil on pharyngeal and esophageal swallowing. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. By using methylnaltrexone, we demonstrated that effects of remifentanil on pharyngeal swallowing were predominantly centrally mediated, whereas its effects on the distal esophagus may be mediated by both central and peripheral mechanisms.

Dose-dependent Respiratory Depression by Remifentanil in the Rabbit Parabrachial Nucleus/Kölliker-Fuse Complex and Pre-Bötzinger Complex.

BACKGROUND: Recent studies showed partial reversal of opioid-induced respiratory depression in the pre-Bötzinger complex and the parabrachial nucleus/Kölliker-Fuse complex. The hypothesis for this study was that opioid antagonism in the parabrachial nucleus/Kölliker-Fuse complex plus pre-Bötzinger complex completely reverses respiratory depression from clinically relevant opioid concentrations. METHODS: Experiments were performed in 48 adult, artificially ventilated, decerebrate rabbits. The authors decreased baseline respiratory rate ~50% with intravenous, "analgesic" remifentanil infusion or produced apnea with remifentanil boluses and investigated the reversal with naloxone microinjections (1 mM, 700 nl) into the Kölliker-Fuse nucleus, parabrachial nucleus, and pre-Bötzinger complex. In another group of animals, naloxone was injected only into the pre-Bötzinger complex to determine whether prior parabrachial nucleus/Kölliker-Fuse complex injection impacted the naloxone effect. Last, the µ-opioid receptor agonist [d-Ala,2N-MePhe,4Gly-ol]-enkephalin (100 µM, 700 nl) was injected into the parabrachial nucleus/Kölliker-Fuse complex. The data are presented as medians (25 to 75%). RESULTS: Remifentanil infusion reduced the respiratory rate from 36 (31 to 40) to 16 (15 to 21) breaths/min. Naloxone microinjections into the bilateral Kölliker-Fuse nucleus, parabrachial nucleus, and pre-Bötzinger complex increased the rate to 17 (16 to 22, n = 19, P = 0.005), 23 (19 to 29, n = 19, P < 0.001), and 25 (22 to 28) breaths/min (n = 11, P < 0.001), respectively. Naloxone injection into the parabrachial nucleus/Kölliker-Fuse complex prevented apnea in 12 of 17 animals, increasing the respiratory rate to 10 (0 to 12) breaths/min (P < 0.001); subsequent pre-Bötzinger complex injection prevented apnea in all animals (13 [10 to 19] breaths/min, n = 12, P = 0.002). Naloxone injection into the pre-Bötzinger complex alone increased the respiratory rate to 21 (15 to 26) breaths/min during analgesic concentrations (n = 10, P = 0.008) but not during apnea (0 [0 to 0] breaths/min, n = 9, P = 0.500). [d-Ala,2N-MePhe,4Gly-ol]-enkephalin injection into the parabrachial nucleus/Kölliker-Fuse complex decreased respiratory rate to 3 (2 to 6) breaths/min. CONCLUSIONS: Opioid reversal in the parabrachial nucleus/Kölliker-Fuse complex plus pre-Bötzinger complex only partially reversed respiratory depression from analgesic and even less from "apneic" opioid doses. The lack of recovery pointed to opioid-induced depression of respiratory drive that determines the activity of these areas.