Neurological sedative indicators during general anesthesia with remimazolam

Effect-Site Concentration of Remimazolam by Age Groups During Target-Controlled Infusion for Total Intravenous Anesthesia: A Retrospective Comparative Study

Purpose

Pharmacokinetic and pharmacodynamic (PKPD) models exist for remimazolam, but data for target-controlled infusion (TCI) are limited. The Schüttler PKPD model, a three-compartment model including body weight as a covariate, does not account for age as a variable. This study aimed to investigate remimazolam's effect-site concentration (Ce) in different age groups during sedation and general anesthesia with TCI using Schüttler PKPD model.

Patients and methods

Records of patients who underwent remimazolam TCI with the Schüttler model were reviewed. During anesthesia induction, the target Ce of remimazolam was gradually increased until loss of responsiveness, and it was titrated to maintain bispectral index of 40-70 during operation. Patients were categorized into young (20-40 years, n=24), middle-aged (41-60 years, n=27), and elderly (61-80 years, n=35) groups. Bispectral index and hemodynamic variables were also assessed.

Results

The elderly group had significantly lower remimazolam Ce compared to the young and middle-aged groups at all sedation levels, intubation, and surgery. Mean highest intraoperative Ce was 0.78±0.10, 0.71±0.07, and 0.61±0.10 µg/mL in young, middle-aged, and elderly groups, respectively (P<0.001). The recovery of responsiveness during emergence occurred at significantly lower Ce in the elderly group (0.28±0.06 µg/mL) than in the young (0.41±0.07 µg/mL) and middle-aged groups (0.35±0.07 µg/mL, P<0.001). Ce during sedation and general anesthesia was comparable between the young and middle-aged groups. The bispectral index was similar across groups but fluctuated more in the elderly group during general anesthesia. Elderly patients also showed the greatest systolic blood pressure suppression (18.4 ± 13.29% before intubation and 34.31 ± 14.91% during surgery).

Conclusion

Older patients may require lower target Ce during remimazolam TCI for sedation and anesthesia, with emergence occurring at lower Ce. Blood pressure suppression may be greater in elderly patients under deep sedation or general anesthesia.

Effect of remimazolam versus propofol on hypotension after anesthetic induction in patients undergoing coronary artery bypass grafting: A randomized controlled trial

STUDY OBJECTIVE

There is scarce evidence on the hemodynamic stability of remimazolam during anesthetic induction in patients with significant coronary artery disease. This study aims to compare the effects of remimazolam and propofol on post-induction hypotension in patients undergoing coronary artery bypass grafting (CABG).

DESIGN

Randomized controlled trial.

SETTING

Tertiary teaching hospital.

PATIENTS

Adult patients undergoing isolated CABG.

INTERVENTIONS

Patients were randomly allocated to received either remimazolam (n = 50) or propofol (n = 50) for anesthetic induction. The remimazolam group received an initial infusion at 6 mg/kg/h, which was later adjusted to 1-2 mg/kg/h to maintain a bispectral index of 40-60 after loss of consciousness. In the propofol group, a 1.5 mg/kg bolus of propofol was administered, followed by 1-1.5% sevoflurane inhalation as needed to achieve the target bispectral index.

MEASUREMENTS

The primary outcome was the area under the curve (AUC) below the baseline mean arterial pressure (MAP) during the first 10 min after anesthetic induction. Secondary outcomes included the AUC for MAP <65 mmHg and the requirement for vasopressors.

MAIN RESULTS

The remimazolam group demonstrated a significantly lower AUC under the baseline MAP compared to the propofol group (mean [SD], 169.8 [101.0] mmHg·min vs. 220.6 [102.4] mmHg·min; mean difference [95% confidence interval], 50.8 [10.4-91.2] mmHg·min; P = 0.014). Additionally, the remimazolam group had a reduced AUC for MAP <65 mmHg (7.3 [10.3] mmHg·min vs. 13.9 [14.9] mmHg·min; P = 0.007) and a lower frequency of vasopressor use compared to the propofol group (60% vs. 88%, P = 0.001).

CONCLUSIONS

Remimazolam may offer improved hemodynamic stability during anesthetic induction in patients undergoing CABG, suggesting its potential advantage over propofol for patients with significant coronary artery disease in terms of hemodynamic stability.

Early processed electroencephalography for the monitoring of deeply sedated mechanically ventilated critically ill patients

BACKGROUND

Deep sedation may be indicated in the intensive care unit (ICU) for the management of acute organ failure, but leads to sedative-induced delirium. Whether processed electroencephalography (p-EEG) is useful in this setting is unclear.

AIM

To describe the PSI index in deeply sedated critically ill patients with acute organ failure, and to examine a potential association between low PSI values and ICU delirium. [Correction added on 16 October 2024, after first online publication: Aim subsection in Abstract has been added on this version.] METHODS: We conducted a single-centre observational study of non-neurological ICU patients sedated according to a standardized guideline of deep sedation (Richmond Agitation Sedation Scale [RASS] between -5 and -4) during the acute phase of respiratory and/or cardio-circulatory failure. The SedLine (Masimo Incorporated, Irvine, California) was used to monitor the Patient State Index (PSI) (ranging from 0 to 100, <25 = very deep sedation and >50 = light sedation to full awareness) during the first 72 h of care. Delirium was assessed with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU).

RESULTS

The median duration of PSI monitoring was 43 h. Patients spent 49% in median of the total PSI monitoring duration with a PSI <25. Patients with delirium (n = 41/97, 42%) spent a higher percentage of total monitored time with PSI <25 (median 67% [19-91] vs. 47% [12.2-78.9]) in non-delirious patients (p .047). After adjusting for the cumulative dose of analgesia and sedation, increased time spent with PSI <25 was associated with higher delirium (odds ratio 1.014; 95% CI 1.001-1.027, p = .036).

CONCLUSIONS

A clinical protocol of deep sedation targeted to RASS at the acute ICU phase may be associated with prolonged EEG suppression and increased delirium. Whether PSI-targeted sedation may help reducing sedative dose and delirium deserves further clinical investigation.

RELEVANCE TO CLINICAL PRACTICE

Patients requiring deep sedation are at high risk of being over-sedated and developing delirium despite the application of an evidence-based sedation guideline. Development of early objective measures are essential to improve sedation management in these critically ill patients.

Efficacy of Single-Bolus Administration of Remimazolam During Induction of Anesthesia in Patients Undergoing Cardiac Surgery: A Prospective, Single-Center, Randomized Controlled Study

BACKGROUND

Remimazolam is a recently marketed ultrashort-acting benzodiazepine. This drug is considered safe and effective during general anesthesia; however, limited information is available about its effects on patients undergoing cardiac surgery. Therefore, the present study was conducted to evaluate the efficacy and hemodynamic stability of a bolus administration of remimazolam during anesthesia induction in patients undergoing cardiac surgery.

METHODS

Patients undergoing elective cardiac surgery were randomly assigned to any 1 of the following 3 groups: anesthesia induction with a continuous infusion of remimazolam 6 mg/kg/h (continuous group), a single-bolus injection of remimazolam 0.1 mg/kg (bolus 0.1 group), or a single-bolus injection of remimazolam 0.2 mg/kg (bolus 0.2 group). Time to loss of responsiveness, defined as modified Observer's Assessment of Alertness/Sedation Scale <3, and changes in hemodynamic status during anesthetic induction were measured.

RESULTS

Times to loss of responsiveness were 137 ± 20, 71 ± 35, and 48 ± 9 seconds in the continuous, bolus 0.1, and bolus 0.2 groups, respectively. The greatest mean difference was observed between the continuous and bolus 0.2 groups (89.0, 95% confidence interval [CI], 79.1-98.9), followed by the continuous and bolus 0.1 groups (65.8, 95% CI, 46.9-84.7), and lastly between the bolus 0.2 and bolus 0.1 groups (23.2, 95% CI, 6.6-39.8). No significant differences were found in terms of arterial blood pressures and heart rates of the patients.

CONCLUSIONS

A single-bolus injection of remimazolam provided efficient anesthetic induction in patients undergoing cardiac surgery. A 0.2 mg/kg bolus injection of remimazolam resulted in the shortest time to loss of responsiveness among the 3 groups, without significantly altering the hemodynamic parameters. Therefore, this dosing can be considered a favorable anesthetic induction method for patients undergoing cardiac surgery.

Extubation and removal of supraglottic airway devices in pediatric anesthesia

In pediatric anesthesia, respiratory adverse events often occur during emergence from anesthesia and at the time of endotracheal tube or supraglottic device removal. The removal of airway devices and extubation are conducted either while patients are deeply anesthetized or when patients awaken from anesthesia and have regained consciousness. The airways of children are easily irritated by external stimuli and are structurally prone to collapse, and the timing of both methods of airway device removal is similarly associated with various airway complications, including upper airway obstruction, coughing, or serious adverse events such as laryngospasm and desaturation. In current pediatric anesthesia practice, the choice of the timing and method of extubation is made by anesthesiologists. To achieve a smooth and safe recovery from anesthesia, understanding the unique characteristics of pediatric airways and the factors likely to contribute to an increased risk of perioperative complications remains essential. These factors include patient age, comorbidities, and physical conditions. The level of anesthesia and readiness for removal of airway devices should be evaluated carefully for each patient, and quick identification of airway problems and intervention is required if patients fail to maintain the airway and sufficient ventilation after removal of airway devices.

Remimazolam in General Anesthesia: A Comprehensive Review of Its Applications and Clinical Efficacy

Remimazolam is a novel ultra-short-acting benzodiazepine with a unique pharmacokinetic profile that makes it an attractive option for use in general anesthesia. This review paper provides an in-depth analysis of remimazolam's applications in the field of general anesthesia, focusing on its pharmacological properties, clinical efficacy, safety profile, and potential advantages compared to other anesthetic agents. Remimazolam acts on GABAa receptors, offering rapid onset and recovery times due to its unique metabolic pathway involving tissue esterases. Clinical trials have demonstrated its efficacy in procedural sedation and general anesthesia, showing a favorable safety profile with minimal cardiovascular and respiratory depression. Compared to traditional anesthetics such as propofol, remimazolam presents distinct advantages, including predictable pharmacokinetics, reduced risk of prolonged sedation, and a reliable safety margin. These attributes position remimazolam as a promising agent in various clinical settings. The purpose of this review is to synthesize current evidence on remimazolam and discuss its potential to improve clinical outcomes in anesthesia practice.

Effect of remimazolam and propofol anesthesia on autonomic nerve activities during Le Fort I osteotomy under general anesthesia: blinded randomized clinical trial

Background

This study evaluated the effect of remimazolam and propofol on changes in autonomic nerve activity caused by surgical stimulation during orthognathic surgery, using power spectrum analysis of blood pressure variability (BPV) and heart rate variability (HRV), and their respective associations with cardiovascular fluctuations.

Methods

A total of 34 patients undergoing Le Fort I osteotomy were randomized to the remimazolam (Group R, 17 cases) or propofol (Group P, 17 cases) groups. Observables included the low-frequency component of BPV (BPV LF; index of vasomotor sympathetic nerve activity), high-frequency component of HRV (HRV HF; index of parasympathetic nerve activity), balance index of the low- and high-frequency components of HRV (HRV LF/HF; index of sympathetic nerve activity), heart rate (HR), and systolic blood pressure (SBP). Four observations were made: (1) baseline, (2) immediately before down-fracture, (3) down-fracture, and (4) 5 min after down-fracture. Data from each observation period were compared using a two-way analysis of variance with a mixed model. A Bonferroni multiple comparison test was performed in the absence of any interaction. One-way analysis of variance followed by Tukey's multiple comparisons test was performed when a significant interaction was observed between time and group, with P < 0.05 indicating statistical significance.

Results

Evaluation of autonomic nerve activity in comparison with baseline during down-fracture showed a significant increase in BPV LF (P < 0.001), an increasing trend in HRV LF/HF in Group P, and an increasing trend in HRV HF in Group R. There were no significant differences in HR or SBP between the two groups.

Conclusion

During down-fracture of Le Fort I osteotomy, sympathetic nerve activity was predominant with propofol anesthesia, and parasympathetic nerve activity was predominant with remimazolam anesthesia.

Remimazolam for simultaneous percutaneous mitral valve clip and percutaneous left atrial appendage closure in an elderly patient with impaired cardiac function: A case report

Remimazolam is a short-acting benzodiazepine sedative with a short half-life and little circulatory depression. The safe use of remimazolam in the anesthetic management of an elderly patient with impaired cardiac function is reported. The patient's hemodynamics remained stable, and the patient was managed without serious complications. Remimazolam may be an option for sedation in elderly patients with reduced cardiac function.

An ultra-short-acting benzodiazepine in thalamic nucleus reuniens undermines fear extinction via intermediation of hippocamposeptal circuits

Benzodiazepines, commonly used for anxiolytics, hinder conditioned fear extinction, and the underlying circuit mechanisms are unclear. Utilizing remimazolam, an ultra-short-acting benzodiazepine, here we reveal its impact on the thalamic nucleus reuniens (RE) and interconnected hippocamposeptal circuits during fear extinction. Systemic or RE-specific administration of remimazolam impedes fear extinction by reducing RE activation through A type GABA receptors. Remimazolam enhances long-range GABAergic inhibition from lateral septum (LS) to RE, underlying the compromised fear extinction. RE projects to ventral hippocampus (vHPC), which in turn sends projections characterized by feed-forward inhibition to the GABAergic neurons of the LS. This is coupled with long-range GABAergic projections from the LS to RE, collectively constituting an overall positive feedback circuit construct that promotes fear extinction. RE-specific remimazolam negates the facilitation of fear extinction by disrupting this circuit. Thus, remimazolam in RE disrupts fear extinction caused by hippocamposeptal intermediation, offering mechanistic insights for the dilemma of combining anxiolytics with extinction-based exposure therapy.

Remimazolam-Induced Anaphylaxis and Cardiovascular Collapse: A Narrative Systematic Review of Eleven Cases

Background and Objectives: Remimazolam, a novel benzodiazepine, is used for procedural sedation and general anesthesia due to its rapid onset and short duration of action. However, remimazolam-induced anaphylaxis (RIA) is a rare but severe complication. This study aimed to analyze RIA characteristics, focusing on cardiovascular collapse, and provide guidelines for safe remimazolam use. Methods: This study conducted a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Research articles retrieved from PubMed on 26 May 2023, using the keywords 'remimazolam AND anaphylaxis' were evaluated based on the inclusion criteria of being written in English and aligning with the World Allergy Organization criteria for anaphylaxis, while studies not meeting these criteria were excluded. All published articles up to the search date were included without any date restrictions. The review analyzed factors such as age, sex, type of anesthesia, remimazolam dose (bolus/continuous), allergic symptoms and sign, epinephrine use, serum tryptase levels, and skin prick tests. Results: Among eleven cases, the mean age was 55.6 ± 19.6 years, with 81.8% male. Hypotension (81.8%) was the most common symptom, followed by bradycardia (54.5%) and desaturation (36.4%). Two patients experienced cardiac arrest. Serum tryptase levels confirmed anaphylaxis in ten cases. Epinephrine was the primary treatment, with intravenous doses ranging from 0.1 mg to 0.3 mg. Conclusions: Vigilance is crucial when administering remimazolam, adhering to recommended dosages, and promptly treating RIA with epinephrine. Further research is needed to understand the risk factors and refine the management strategies. Guidelines for safe remimazolam use are proposed.

Prospective Randomized Controlled Trial Comparing Anesthetic Management With Remimazolam Besylate and Flumazenil Versus Propofol During Awake Craniotomy Following an Asleep-awake-asleep Method

BACKGROUND

Awake craniotomy is performed to resect brain tumors in eloquent brain areas to maximize tumor reduction and minimize neurological damage. Evidence suggests that intraoperative anesthetic management of awake craniotomy with remimazolam is safe. We compared the time to arousal and efficacy of anesthetic management with remimazolam and propofol during awake craniotomy.

METHODS

In a single-institution randomized, prospective study, patients who underwent elective awake craniotomy were randomized to receive remimazolam and reversal with flumazenil (group R) or propofol (group P). The primary end point was time to awaken. Secondary end points were time to loss of consciousness during induction of anesthesia, the frequency of intraoperative complications (pain, hypertension, seizures, nausea, vomiting, and delayed arousal), and postoperative nausea and vomiting. Intraoperative task performance was assessed using a numerical rating scale (NRS) score.

RESULTS

Fifty-eight patients were recruited, of which 52 (26 in each group) were available for the efficacy analysis. Patients in group R had faster mean (±SD) arousal times than those in the P group (890.8±239.8 vs. 1075.4±317.5 s; P=0.013)and higher and more reliable intraoperative task performance (NRS score 8.81±1.50 vs. 7.69±2.36; P=0.043). There were no significant intraoperative complications.

CONCLUSIONS

Compared with propofol, remimazolam was associated with more rapid loss of consciousness and, after administration of flumazenil, with faster arousal times and improved intraoperative task performance.

Remimazolam-flumazenil provides fast recovery from general anesthesia compared to propofol during radiofrequency catheter ablation of atrial fibrillation

The optimal anesthetic agent for radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) and its impact on the recovery profiles remain uncertain. We compared the recovery and hemodynamic parameters between the remimazolam-flumazenil and propofol groups during RFCA. Patients were randomized into the remimazolam-flumazenil and propofol groups. The primary outcome measure was the time to eye opening following the discontinuation of anesthetic agents. Secondary outcomes included time to extubation, time to discharge from the operating room, intraprocedural hemodynamic variables and postoperative quality outcomes. Fifty-three patients were included in the final analysis (n = 26 in the remimazolam-flumazenil and n = 27 in the propofol group). The time to eye opening was significantly shorter in the remimazolam-flumazenil group compared to the propofol group (median [interquartile range]: 174 [157-216] vs. 353 [230-483] s, P < 0.001). The mean blood pressure and bispectral index were significantly higher in the remimazolam-flumazenil group compared to the propofol group (mean difference [95% CI], 7.2 [1.7-12.7] mmHg and 6 [3-8]; P = 0.011 and < 0.001, respectively), which were within target ranges in both groups. Other secondary outcomes were comparable between the groups. Consequently, remimazolam emerges as a promising anesthetic agent, characterized by rapid recovery and stable hemodynamics, during RFCA of AF.Trial registration: NCT05397886.

Comparative Analysis of the Performance of Electroencephalogram Parameters for Monitoring the Depth of Sedation During Remimazolam Target-Controlled Infusion

BACKGROUND

The changes in hypnotic indicators in remimazolam sedation remain unclear. We investigated the correlation of the electroencephalogram (EEG) parameters with the effect-site remimazolam concentration and the depth of sedation in patients receiving a target-controlled infusion of remimazolam.

METHODS

This prospective observational study enrolled 35 patients (32 analyzed) who underwent lower extremity varicose vein surgery or lower extremity orthopedic surgery under spinal anesthesia. We administered remimazolam by target-controlled infusion using the pharmacokinetic model introduced by Schüttler et al. The EEG data were continuously recorded, including the bispectral index (BIS), patient state index (PSI), spectral edge frequency (SEF), and raw EEG signals. The relative beta ratio (RBR), defined as log (spectral power [30-47 Hz]/spectral power [11-20 Hz]), was obtained by analyzing raw EEG. The level of sedation corresponding to each effect-site remimazolam concentration was assessed using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S). The prediction probability (Pk) and Spearman's correlation coefficients (R) were calculated between effect-site remimazolam concentration, MOAA/S, and EEG parameters.

RESULTS

BIS and PSI showed significantly higher Pk for effect-site remimazolam concentration (Pk = 0.76 [0.72-0.79], P < .001 for BIS; Pk = 0.76 [0.73-0.79], P < .001 for PSI) compared to RBR (Pk = 0.71 [0.68-0.74], P < .001) and SEF (Pk = 0.58 [0.53-0.63], P = .002). BIS, PSI, and RBR showed significantly higher correlation coefficients for effect-site remimazolam concentration (R = -0.70 [-0.78 to -0.63], P < .001 for BIS; R = -0.72 [-0.79 to -0.66], P < .001 for PSI; R = -0.61 [-0.69 to -0.54], P < .001 for RBR) compared to SEF (R = -0.22 [-0.36 to -0.08], P = .002). BIS and PSI also had significantly higher Pk and correlation coefficients for MOAA/S (Pk = 0.81 [0.79-0.83], P < .001; R = 0.84 [0.81-0.88], P < .001 for BIS) (Pk = 0.80 [0.78-0.83], P < .001; R = 0.82 [0.78-0.87], P < .001 for PSI) compared to RBR (Pk = 0.74 [0.72-0.77], P < .001; R = 0.72 [0.65-0.78], P < .001) and SEF (Pk = 0.55 [0.50-0.59], P = .041; R = 0.13 [-0.01 to 0.27], P = .067).

CONCLUSIONS

BIS, PSI, and RBR showed an acceptable correlation with the effect-site remimazolam concentration and depth of sedation in this study, suggesting that these EEG-derived parameters are potentially reliable hypnotic indicators during remimazolam sedation. BIS and PSI showed superior performance as hypnotic indicators to RBR and SEF in patients receiving target-controlled infusion of remimazolam.

Comparison of the bispectral indices of patients receiving remimazolam and propofol for general anesthesia: a randomized crossover trial

BACKGROUND

Remimazolam is a safe and effective new benzodiazepine sedative that has unique advantages in anesthesia induction and maintenance. The differences in the electroencephalogram bispectral index (BIS) during general anesthesia between propofol and remimazolam deserve further exploration.

METHODS

Single-center randomized crossover study. Patients who required multiple hysteroscopic surgery were randomly assigned to use remimazolam (0.27 mg/kg for induction and 1 mg/kg/h for maintenance) first and then propofol (2.0 mg/kg for induction and 6 mg/kg/h for maintenance) during hysteroscopic surgery again 3 months later, or in the opposite order. Both drugs were used at the latest ED95 for unconsciousness. The BIS values (primary endpoint), intraoperative conditions, and incidence of adverse reactions (secondary endpoints) were compared at each time point. BIS values were analyzed with a mixed model of repeated measurements (MMRM).

RESULTS

Seventeen patients completed the study. The lowest BIS value in the remimazolam regimen was significantly higher than that in the propofol regimen (p = 0.001). The MMRM analysis of the BIS values revealed significant differences between the regimens at each time point (p < 0.001). The intraoperative diastolic blood pressure and heart rate changes were smaller, the recovery was faster, and there were fewer adverse reactions and less injection pain, but a greater incidence of intraoperative body movement and hiccups, in the remimazolam regimen.

CONCLUSION

The trial indicated that remimazolam maintained a higher BIS level than propofol. The correlation between the BIS and the depth of anesthesia induced by remimazolam needs to be further studied.

TRIAL REGISTRATION

This trial is registered at ClinicalTrials.gov: ChiCTR2200064551.

Remimazolam for general anesthesia in a patient with aortic stenosis and severe obesity undergoing transcatheter aortic valve implantation

INTRODUCTION

There is currently limited research on the clinical use of remimazolam in severely obese patients. In this report, we describe the anesthesia management of transcatheter aortic valve implantation (TAVI) in a severely obese patient using remimazolam.

CASE DESCRIPTION

A 76-year-old woman (height 1.54 m; total body weight 104 kg; body mass index 43.9 kg/m2) was scheduled for TAVI via the femoral artery approach for aortic valve stenosis. Preoperative echocardiography showed an aortic valve peak flow of 4.0 m/s and an effective orifice area of 0.75 cm2. Anesthesia induction was performed with a bolus dose of 100 μg fentanyl, 15 mg remimazolam, 60 mg rocuronium, and a continuous infusion of remifentanil at 0.4 mg/h. Intraoperatively, remimazolam was administered at a rate of 35 mg/h. General anesthesia management was completed without any complications, although the patient required temporary catecholamine and inhalation anesthesia assistance due to hemodynamic changes.

CONCLUSION

Owing to its pharmacological advantages, remimazolam may be an option for anesthesia induction and maintenance in severely obese patients with unstable circulation.

Intraoperative Neurophysiological Monitoring in Neurosurgery

Intraoperative neurophysiological monitoring (IONM) is a crucial advancement in neurosurgery, enhancing procedural safety and precision. This technique involves continuous real-time assessment of neurophysiological signals, aiding surgeons in timely interventions to protect neural structures. In addition to inherent limitations, IONM necessitates a detailed anesthetic plan for accurate signal recording. Given the growing importance of IONM in neurosurgery, we conducted a narrative review including the most relevant studies about the modalities and their application in different fields of neurosurgery. In particular, this review provides insights for all physicians and healthcare professionals unfamiliar with IONM, elucidating commonly used techniques in neurosurgery. In particular, it discusses the roles of IONM in various neurosurgical settings such as tumoral brain resection, neurovascular surgery, epilepsy surgery, spinal surgery, and peripheral nerve surgery. Furthermore, it offers an overview of the anesthesiologic strategies and limitations of techniques essential for the effective implementation of IONM.

Effect of converting from propofol to remimazolam with flumazenil reversal on recovery from anesthesia in outpatients with mental disabilities: a randomized controlled trial

BACKGROUND

General anesthesia is often necessary for dental treatment of outpatients with mental disabilities. Rapid recovery and effective management of postoperative nausea and vomiting (PONV) are critical for outpatients. This study aimed to investigate the effect of transitioning from propofol to remimazolam with flumazenil reversal administered toward the end of surgery during propofol-based total intravenous anesthesia (TIVA) on recovery.

METHODS

Adults with mental disabilities scheduled to undergo dental treatment were randomly assigned to receive either propofol-based TIVA (Group P) or propofol-remimazolam-based TIVA with flumazenil reversal (Group PR). Propofol was replaced with remimazolam 1 h before the end of surgery in Group PR; moreover, 0.5 mg of flumazenil was administered after the neuromuscular blockade reversal agent. The primary outcome was the duration of stay in the post-anesthesia care unit (PACU). The secondary outcomes included time to eye-opening, time to extubation, occurrence of PONV, and quality of recovery.

RESULTS

Fifty-four patients were included in this study. The duration of stay in the PACU in Group PR was significantly shorter than that in Group P (mean difference, 8.7 min; confidence interval [95% CI], 3.3-14.2; P = 0.002). Group PR exhibited a shorter time to eye opening (mean difference, 5.4 min; 95% CI, 3.3-8.1; P < 0.001) and time to extubation (mean difference, 5.5 min; 95% CI, 3.6-7.9; P < 0.001) than Group P. Neither group required the administration of rescue analgesics, and the incidence of PONV was not reported.

CONCLUSIONS

Transitioning from propofol to remimazolam 1 h before the end of surgery followed by flumazenil reversal reduced the duration of stay in the PACU and the time to eye opening and extubation without affecting the incidence of PONV and quality of recovery.

TRIAL REGISTRATION NUMBER

Clinical Research Information Service (KCT0007794), Clinical trial first registration date: 12/10/2022.

Clinical Application and Research Progress of Remimazolam for Pediatric Patients

Remimazolam is a novel ultrashort-acting benzodiazepine that allosterically modulates γ-aminobutyric acid type A (GABAA) receptors to exert sedative effects. Remimazolam has the properties of controllable sedation, rapid onset, and a short duration of action, along with minor depression of circulation and respiration. Remimazolam has been approved for clinical use since 2020 in Japan, and it has been applied for procedural sedation, general anesthesia induction and maintenance, and sedation in ICU patients, and has been proven to be safe and effective. Currently, no consensus has been reached on the clinical application of remimazolam in pediatric patients. This review introduces the clinical research progress and limitations of remimazolam in recent years, aiming to supply scientific guidance and a theoretical reference for the application of remimazolam in pediatric anaesthesia.

Anaesthetic efficacy and postinduction hypotension with remimazolam compared with propofol: a multicentre randomised controlled trial

Remimazolam, a short-acting benzodiazepine, may be used for induction and maintenance of total intravenous anaesthesia, but its role in the management of patients with multiple comorbidities remains unclear. In this phase 3 randomised controlled trial, we compared the anaesthetic efficacy and the incidence of postinduction hypotension during total intravenous anaesthesia with remimazolam vs. propofol. A total of 365 patients (ASA physical status 3 or 4) scheduled for elective surgery were assigned randomly to receive total intravenous anaesthesia with remimazolam (n = 270) or propofol (n = 95). Primary outcome was anaesthetic effect, quantified as the percentage of time with Narcotrend® Index values ≤ 60, during surgery (skin incision to last skin suture), with a non-inferiority margin of -10%. Secondary outcome was the incidence of postinduction hypotensive events. Mean (SD) percentage of time with Narcotrend Index values ≤ 60 during surgery across all patients receiving remimazolam (93% (20.7)) was non-inferior to propofol (99% (4.2)), mean difference (97.5%CI) -6.28% (-8.89-infinite); p = 0.003. Mean (SD) number of postinduction hypotension events was 62 (38.1) and 71 (41.1) for patients allocated to the remimazolam and propofol groups, respectively; p = 0.015. Noradrenaline administration events (requirement for a bolus and/or infusion) were also lower in patients allocated to remimazolam compared with propofol (14 (13.5) vs. 20 (14.6), respectively; p < 0.001). In conclusion, in patients who were ASA physical status 3 or 4, the anaesthetic effect of remimazolam was non-inferior to propofol.

Comparison between remimazolam and propofol anaesthesia for interventional neuroradiology: a randomised controlled trial

BACKGROUND

General anaesthesia can immobile patients during interventional neuroradiology to improve image quality. Remimazolam, an ultrashort-acting benzodiazepine, is advantageous for haemodynamic stability. This study compared remimazolam and propofol anaesthesia during neuroradiology procedures regarding intraoperative hypotensive events and rapid recovery.

METHODS

This single-masked randomised-controlled study included 76 participants who underwent elective endovascular embolisation in a single centre. Patients were randomised between a continuous remimazolam infusion (n = 38) or a target-controlled propofol infusion group (n = 38). In the remimazolam group, flumazenil (0.2 mg) was administered at the end of the procedure. Phenylephrine was titrated to maintain the mean arterial pressure within ± 20% of the baseline value. The primary outcome was the total phenylephrine dose during the procedure.

RESULTS

The total phenylephrine dose was 0.0 [0.0-30.0] μg in the remimazolam group and 30.0 [0.0-205.0] μg in the propofol group (p = 0.001). Hypotensive events were observed in 11 (28.9%) patients in the remimazolam group and 23 (60.5%) patients in the propofol group (p = 0.001). Recovery times to spontaneous breathing, eye-opening, extubation, and orientation were shorter in the remimazolam group than in the propofol group (all p < 0.001).

CONCLUSIONS

Remimazolam anaesthesia showed superior haemodynamic stability compared with propofol anaesthesia during neuroradiology procedures. Systematic use of flumazenil enabled rapid recovery from remimazolam anaesthesia.

REGISTRATION

University Hospital Medical Information Network Clinical Trials Registry; Registration number: UMIN000047384; URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000054046.

Minimal alveolar concentration of sevoflurane in combination with remimazolam in adults during laryngeal mask insertion: an up-down sequential allocation study

BACKGROUND

Remimazolam is a novel ultrashort-acting intravenous benzodiazepine sedative-hypnotic. The combination of remimazolam and sevoflurane does not increase respiratory sensitivity, produce bronchospasm, or cause other adverse conditions. We aimed to observe the effects of different remimazolam doses on the minimum alveolar concentration (MAC) of sevoflurane at end-expiration during laryngeal mask insertion and evaluate the effect of sex on the efficacy of the combination of remimazolam on the suppression of laryngeal mask insertion in adult patients.

METHODS

We included 240 patients undergoing laparoscopic surgery under general anesthesia with elective placement of a laryngeal mask (120 males and 120 females). The patients were randomly divided into four groups according to sex: a control group (randomization for female patients, RF0; randomization for male patients, RM0) and three remimazolam groups (RF1, RM1 / RM2, RF2 / RM3, RF3), with 30 patients in each group. Induction was established by vital capacity rapid inhalation induction (VCRII), using 8% sevoflurane and 100% oxygen (6 L/min) in all patients. The (RF1, RM1), (RM2, RF2), and (RM3, RF3) groups were continuously injected with remimazolam at doses of 1, 1.5, and 2.0 mg/kg/h, respectively, while the (RM0, RF0) group was injected with an equal volume of normal saline. The end-expiratory concentration of sevoflurane was adjusted to a preset value after the patient's eyelash reflex disappeared. After the end-expiratory concentration of sevoflurane was kept stable for at least 15 min, the laryngeal mask was placed, and the patient's physical response to the mask placement was observed immediately and within 30 s of placement. The MAC of sevoflurane was measured using the up-and-down sequential method of Dixon.

RESULTS

The calculated MAC of end-expiratory sevoflurane during laryngeal mask insertion in adult females was (2.94 ± 0.18)%, (2.69 ± 0.16)%, (2.32 ± 0.16)% and (1.83 ± 0.15)% in groups RF0, RF1, RF2 and RF3; (2.98 ± 0.18)%, (2.80 ± 0.19)%, (2.54 ± 0.15)% and (2.15 ± 0.15)% in male groups RM0, RM1, RM2 and RM3, respectively. The MAC values were significantly lower in the (RF1-RF3, RM1-RM3) group when compared to the (RF0, RM0) group. There was no significant difference between (RF0, RF1) and (RM0, RM1), but the MAC value of the RF2-RF3 group was significantly lower than that of the RM2-RM3 group.

CONCLUSIONS

Remimazolam can effectively reduce end-expiratory sevoflurane MAC values during laryngeal mask placement in adults. When remimazolam was measured above 1.5 mg/kg/h, the effect of inhibiting laryngeal mask implantation in female patients was stronger than that in male patients. Remimazolam at a dose of 1-2 mg/kg/h combined with sevoflurane induction can be safely and effectively used in these patients.

Comparison of recovery profiles between total intravenous anaesthesia with propofol or remimazolam reversed with flumazenil in patients undergoing breast surgery: A randomised controlled trial

BACKGROUND

Remimazolam, a short acting benzodiazepine, is being used for general anaesthesia. The results of studies comparing recovery after propofol with that of remimazolam are inconsistent. Given that flumazenil reverses the sedative effects of remimazolam, we hypothesised that it would speed up recovery from remimazolam general anaesthesia.

OBJECTIVES

The aim of this trial was to compare the speed of recovery from general anaesthesia between propofol and remimazolam reversed with flumazenil in patients undergoing minimally invasive breast surgery.

DESIGN

Randomised, single-centre, double-blind controlled trial.

SETTING

A tertiary teaching hospital in South Korea from August 2022 to December 2022.

PATIENTS

Adult patients (≥19 years of age) about to undergo general anaesthesia for scheduled breast cancer surgery.

INTERVENTIONS

Patients were randomly allocated to either the propofol or the remimazolam/flumazenil group. The emergence process was monitored by only one anaesthesiologist.

MAIN OUTCOME MEASURES

The primary outcome was the time to eye opening to command during recovery from the general anaesthesia. Time to removal of the supraglottic airway (SGA) time to discharge, and the Riker sedation agitation scale (SAS) score (1 to 4) during emergence were compared as secondary outcomes.

RESULTS

The remimazolam group had a significantly shorter mean time to eye opening than the propofol group [127 ± 51 vs. 314 ± 140 s; mean difference 187 s (95% confidence interval (CI), 133 to 241 s; P  < 0.001]. The remimazolam group also had shorter times to SGA removal [169 ± 51 vs. 366 ± 149 s; mean difference 198 s (95% CI, 140 to 255 s); P  < 0.001] and time to discharge from the operating room [243 ± 55 vs. 449 ± 159 s; mean difference 206 s (95% CI, 145 to 267 s); P  < 0.001]. The SAS scores during emergence also differed significantly, with 1 patient in the propofol group and 25 in the remimazolam group attaining scores of 4 ( P  < 0.001).

CONCLUSION

Administration of remimazolam with flumazenil may be a promising option for patients undergoing breast cancer surgery, providing faster recovery and better SAS scores than propofol during emergence from general anaesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05435911).

Anesthesia Management Using Remimazolam for Lower Limb Amputation in a Patient With Septic Shock Due to Necrotizing Fasciitis

We report a case of a patient with necrotizing fasciitis and septic shock caused by streptococcal toxic shock syndrome, who was anesthetized and managed with remimazolam. The patient, a woman in her 40s, was admitted to the ICU with a diagnosis of necrotizing fasciitis of the right lower extremity and septic shock and was scheduled for above-the-knee amputation under general anesthesia. She was anesthetized with remimazolam for sedation and fentanyl and remifentanil for analgesia. Intraoperatively, we were able to maintain hemodynamic stability with similar or only slightly higher doses of circulatory agonists during admission. In the present case, remimazolam, an ultrashort-acting benzodiazepine, was safely used to provide anesthesia to a patient in septic shock due to necrotizing fasciitis, who was receiving high doses of vasopressor agents for cardiovascular support, as it was necessary to select an anesthetic drug that would cause minimal circulatory depression.

Remimazolam and Remifentanil Anesthetics for an Adolescent Patient with Stiff-Person Syndrome: A Case Report

Stiff-person syndrome (SPS) is a rare autoimmune disease characterized by fluctuating rigidity and stiffness of the axial muscles. There are no reports on the use of remimazolam in a patient with SPS. A 16-year-old Japanese woman with SPS was scheduled to undergo intrathecal baclofen pump exchange. General anesthesia was induced and maintained using remimazolam, remifentanil, and intermittent rocuronium bromide. No intraoperative mobility or significant autonomic symptoms were observed. Additionally, electroencephalographic signature showed sufficient anesthetic depth. The patient's emergence from general anesthesia was uneventful. In conclusion, remimazolam could be considered an effective anesthetic drug for patients with SPS.

The safety of remimazolam versus propofol in gastroscopic sedation: a meta-analysis

BACKGROUND

This meta-analysis was designed to compare the safety and efficiency of remimazolam with those of propofol in patients undergoing gastroscope sedation.

METHODS

We searched PubMed, Cochrane Library, Embase, Ovid, Wanfang Database, China National Knowledge Infrastructure, SINOMED, and ClinicalTrials.gov for studies that reported on remimazolam versus propofol for gastroscope sedation from establishment to February 25, 2023. The sedative efficiency and the incidence of adverse events were assessed as outcomes. Version 2 of the Cochrane risk-of-bias assessment tool was used to assess the risk of bias. Review Manager 5.4 and STATA 17 were used to perform all statistical analyses.

RESULTS

A total of 26 randomized controlled trials involving 3,641 patients were included in this meta-analysis. The results showed that remimazolam had a significantly lower incidence of respiratory depression (risk ratio [RR] = 0.40, 95% confidence interval [CI]: 0.28-0.57; p < 0.01, GRADE high), hypoxemia (RR = 0.34, 95% CI: 0.23-0.49; p < 0.01, GRADE high), bradycardia (RR = 0.34, 95% CI: 0.23-0.51; p < 0.01, GRADE high), dizziness (RR = 0.45, 95% CI: 0.31-0.65; p < 0.01, GRADE high), injection site pain (RR = 0.06, 95% CI: 0.03-0.13; p < 0.01, GRADE high), nausea or vomiting (RR = 0.79, 95% CI: 0.62-1.00; p = 0.05, GRADE moderate), and hypotension (RR = 0.36, 95% CI: 0.26-0.48; p < 0.01, GRADE low).

CONCLUSIONS

Remimazolam can be used safely in gastroscopic sedation and reduces the incidence of respiratory depression, hypoxemia, bradycardia, injection site pain, and dizziness compared with propofol, and doesn't increase the incidence of nausea and vomiting.

The Role of Remimazolam in Neurosurgery and in Patients With Neurological Diseases: A Narrative Review

Remimazolam is a novel ultrashort-acting benzodiazepine that produces sedation by acting as a positive allosteric modulator of the gamma-amino butyric acid-A receptor. Its high water solubility and metabolism via tissue esterases allow for a rapid onset of sedation/anesthesia and prompt arousal despite prolonged use. In addition, the effects of remimazolam can be reversed with flumazenil. This narrative review discusses the role of remimazolam in patients undergoing neurosurgical and neuroradiological procedures, specifically its role during awake craniotomies and compatibility with neuromonitoring. Considerations for remimazolam use in patients with neurological diseases are also highlighted. In addition, the impact of remimazolam on postoperative excitation, risk for postoperative delirium, and delayed neurocognitive recovery are discussed. Although there seems to be a clinical promise for remimazolam based on limited case studies and our own institutional experience of its use, further clinical investigation is warranted to understand the potential impact of remimazolam on surgical and neurological outcomes.

Clinical Trial Comparing Remimazolam with Propofol During Intravenous Anesthesia: A Prospective Randomised Clinical Trial

BACKGROUND AND OBJECTIVE

Remimazolam is a water-soluble sedative-anesthetic with short-acting properties and less hemodynamic effects. Currently, it is primarily used for gastroenteroscopy sedation.

AIM

The aim of this study is to investigate the effectiveness and safety of Remimazolam as an alternative intravenous anesthetic agent in surgical patients, in order to expand clinical options beyond Propofol.

METHODS

Eighty patients aged 20-69 and classified as an American Society of Anesthesiologists physical status I-II were randomly assigned to either the Remimazolam group (RM group) or the Propofol group (PR group) for anesthesia induction and maintenance. Hemodynamics and Bispectral Index (BIS) were recorded before and after anesthesia, along with other relevant indices such as the time, to loss of consciousness (LoC), operation time, anesthesia time, awakening time, the number of cases of injection site pain. Additionally, the Ramsay sedation score, intraoperative awareness, dreaming, and postoperative adverse events were also assessed.

RESULTS

After anesthesia, both groups experienced a significant decrease in blood pressure compared to baseline values, however, the reduction in blood pressure was less significant in the RM group than in the PR group (P<0.05). The heart rate of patients in the RM group remained relatively stable at all time points. There were significantly more cases of injection site pain and use of pressor or atropine during operation observed in the PR group compared to the RM group (P<0.05). There were no significant differences between the two groups in terms of time to loss of consciousness, anesthesia time, operation time, awakening time, and intraoperative awareness (P>0.05). However, at 5 and 30 minutes after awakening, the Ramsay sedation score was significantly better in the RM group compared to the PR group (P<0.05).

CONCLUSION

When remimazolam is used for intravenous anesthesia induction and maintenance, it can achieve a favorable anesthetic effect while maintaining a relatively stable blood pressure and heart rate. Patients experience shorter awakening times (8.3±3.7 min), better awakening quality (5 min Ramsay sedation score is 2 points), and no intraoperative awareness.

Effect of remimazolam vs. propofol on hemodynamics during general anesthesia induction in elderly patients: Single-center, randomized controlled trial

The current study aimed to compare the effects between remimazolam and propofol on hemodynamic stability during the induction of general anesthesia in elderly patients. We used propofol at a rate of 60 mg/(kg·h) in the propofol group (group P) or remimazolam at a rate of 6 mg/(kg·h) in the remimazolam group (group R) for the induction. A processed electroencephalogram was used to determine whether the induction was successful and when to stop the infusion of the study drug. We measured when patients entered the operating room (T 0), when the induction was successful (T 1), and when before (T 2) and 5 min after successful endotracheal intubation (T 3). We found that mean arterial pressure (MAP) was lower at T 1-3, compared with T 0 in both groups, but higher at T 2 in the group R, while ΔMAP T0-T2 and ΔMAP max were smaller in the group R (ΔMAP T0-T2: the difference between MAP at time point T 0 and T 2, ΔMAP max: the difference between MAP at time point T 0 and the lowest value from T 0 to T 3). Cardiac index and stroke volume index did not differ between groups, whereas systemic vascular resistance index was higher at T 1-3 in the group R. These findings show that remimazolam, compared with propofol, better maintains hemodynamic stability during the induction, which may be attributed to its ability to better maintain systemic vascular resistance levels.

Intraoperative cardiac arrest caused by unexpected vasospastic angina requiring prolonged resuscitation using extracorporeal membrane oxygenation: a case report

BACKGROUND

Vasospastic angina (VSA) occurring during surgery is rare but can lead to sudden intraoperative cardiac arrest.

CASE PRESENTATION

A 77-year-old man with hypertension, and no history of coronary artery disease, displayed an abrupt ST-segment elevation on the electrocardiogram (ECG) during laparoscopic inguinal hernia surgery under general anesthesia. Subsequently, ventricular fibrillation (VF) occurred, with a finding suggesting ischemic myocardial contracture by transesophageal echocardiography. VF was refractory to cardiopulmonary resuscitation (CPR), and veno-arterial extracorporeal membrane oxygenation (VA ECMO) was introduced. Spontaneous circulation resumed 77 min post-cardiac arrest. VSA was confirmed through the patient's clinical course and coronary angiography. Subsequently, VA ECMO was terminated, and the patient was discharged uneventfully.

CONCLUSIONS

Extracorporeal CPR may be a valuable alternative to extended resuscitation for refractory ventricular arrhythmias by VSA.

Assessment of explicit and implicit memories during remimazolam anaesthesia using the process dissociation procedure: A prospective cohort study

BACKGROUND

Memory formation during remimazolam anaesthesia, where a bispectral index (BIS) is sometimes not maintained at less than 60 despite the maximal dose, is worthy of evaluation.

OBJECTIVE

Investigate the formation of explicit and implicit memories using the process dissociation procedure during remimazolam anaesthesia at a BIS of 60 to 80.

DESIGN

A prospective cohort study.

SETTING

A tertiary medical centre in Seoul, South Korea, between March 2022 and July 2022.

PATIENTS

One hundred patients undergoing general anaesthesia using remimazolam.

INTERVENTIONS

The BIS was maintained at 60 to 80 during anaesthesia induction with remimazolam. Words were spoken to patients via headphones for 15 min.

MAIN OUTCOME MEASURE

The primary outcome was the probability of explicit or implicit memory formation as calculated using the original and extended models, within 24 h after word presentation. Conscious recall memory was assessed using a short-structured interview within 1 and 24 h after surgery. Memory formation was inferred to be absent if 0 was included in the 95% confidence interval (CI) of the probability.

RESULTS

The main results showed no evidence of explicit or implicit memory. The 95% CI of the probability of explicit memory formation included 0 for both models, -0.01 (-0.04 to 0.02) and -0.04 (-0.10 to 0.01), respectively. The 95% CI of the probability of implicit memory formation did not include 0 when evaluated using the original model, 0.08 (0.06 to 0.10), but included 0 when evaluated using the extended model, 0.00 (-0.03 to 0.03). The modified Brice interview revealed no evidence of awareness.

CONCLUSIONS

There was no evidence of explicit or implicit memory formation during remimazolam anaesthesia (BIS 60 to 80). Further research is warranted to establish whether explicit and implicit memories are still absent even in the presence of surgical stimulation.

CLINICAL TRIAL REGISTRATION

KCT0006752 ( http://cris.nih.go.kr ).

Remimazolam and serious adverse events: A scoping review

Remimazolam is anticipated to be an interesting anaesthetic and sedative. It combines the pharmacodynamic properties of midazolam with pharmacokinetic properties similar to remifentanil. However, worrisome case reports of anaphylaxis, delayed emergence and re-sedation have emerged recently and necessitate further investigation.PubMed (including MEDLINE) and EMBASE were searched for all studies reporting serious adverse events where remimazolam was administered for sedation or anaesthesia.Thirty-six case reports and 73 trials were identified, involving a total of 6740 patients who received remimazolam. Hypotension was reported in 911 cases, delayed emergence in 68 cases, anaphylaxis in 10 cases and re-sedation in 8 cases. The incidence of hypotension seems to be lower compared with other anaesthetics, even in high-risk patients.Delayed emergence might be related to the metabolism of remimazolam through carboxylesterase 1 (CES1), a tissue esterase predominant in the liver. There is significant interindividual variation, and it is inhibited by flavonoids, fatty acids and alcohol. Individual benzodiazepine sensitivity has also been reported. A higher BMI, older age and low plasma albumin concentration are risk factors for delayed emergence. Anaphylaxis might be related to a non-IgE-mediated effect of the excipient dextran-40 or a partially IgE-mediated reaction to remimazolam itself. Resedation has been reported after flumazenil reversal and is explained by the specific pharmacokinetic properties of flumazenil and remimazolam. Reversal by flumazenil should be reserved for and used carefully in patients with delayed emergence.

VISUAL ABSTRACT

http://links.lww.com/EJA/A864 .

Efficacy and safety of remimazolam besilate for sedation in outpatients undergoing impacted third molar extraction: a prospective exploratory study

BACKGROUND

Dental treatments often cause anxiety, fear, and stress in patients. Intravenous sedation is widely used to alleviate these concerns, and various agents are employed for sedation. However, it is important to find safer and more effective sedation agents, considering the adverse effects associated with current agents. This study aimed to investigate the efficacy and safety of remimazolam besilate (hereinafter called "remimazolam") and to determine the optimal dosages for sedation in outpatients undergoing dental procedures.

METHODS

Thirty-one outpatients aged 18-65 years scheduled for impacted third molar extraction were included in the study. Remimazolam was administered as a single dose of 0.05 mg/kg followed by a continuous infusion at a rate of 0.35 mg/kg/h, with the infusion rate adjusted to maintain a sedation level at a Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score of 2-4. The primary endpoint was the sedation success rate with remimazolam monotherapy, and the secondary endpoints included induction time, recovery time, time until discharge, remimazolam dose, respiratory and circulatory dynamics, and frequency of adverse events.

RESULTS

The sedation success rate with remimazolam monotherapy was 100%. The remimazolam induction dose was 0.08 (0.07-0.09) mg/kg, and the anesthesia induction time was 3.2 (2.6-3.9) min. The mean infusion rate of remimazolam during the procedure was 0.40 (0.38-0.42) mg/kg/h. The time from the end of remimazolam administration to awakening was 8.0 (6.7-9.3) min, and the time from the end of remimazolam administration to discharge was 14.0 (12.5-15.5) min. There were no significant respiratory or circulatory effects requiring intervention during sedation.

CONCLUSIONS

Continuous intravenous administration of remimazolam can achieve optimal sedation levels without significantly affecting respiratory or circulatory dynamics. The study also provided guidance on the appropriate dosage of remimazolam for achieving moderate sedation during dental procedures. Additionally, the study findings suggest that electroencephalogram monitoring can be a reliable indicator of the level of sedation during dental procedural sedation with remimazolam.

TRIAL REGISTRATION

The study was registered in the Japan Registry of Clinical Trials (No. jRCTs061220052) on 30/08/2022.

Remimazolam: a randomized controlled study of its suitability for insertion of a supraglottic airway

PURPOSE

Loss of motor response to thrusting the jaw forward is a useful indicator for uncomplicated insertion of a supraglottic airway. The aim of this study was to assess the suitability of remimazolam for insertion of a supraglottic airway assessed by loss of response to jaw thrusting.

METHODS

Seventy patients, who were scheduled for elective surgeries under general anesthesia, were allocated randomly to one of two groups. In one group (remimazolam group), remimazolam was infused 12 mg kg-1 h-1 (50 mg maximum), and in the other (propofol group), propofol was infused at 120 mg kg-1 h-1 (500 mg maximum). Once the eyelash reflex disappeared, response to jaw thrusting was assessed. Primary outcome measure was the proportion of patients with loss of response to jaw thrusting before reaching the maximum dose of the test drug. We planned an interim analysis (of one time) after 40 patients, using the Pocock adjustment method.

RESULTS

From the interim analysis results, the study was stopped after recruitment of 40 patients. Loss of response to jaw thrusting was observed in all of 21 patients (100%) in the propofol group, and in 9 of 19 patients (47%) in the remimazolam group. There was a significant difference in the proportion between the groups (P = 0.0001, 95% CI for difference 30-75%).

CONCLUSION

Remimazolam frequently does not inhibit response to jaw thrusting, and thus remimazolam is not a suitable induction agent for uncomplicated insertion of a supraglottic airway unless either a neuromuscular blocking agent or an opioid is co-administered.

Anesthesia using remimazolam during coronary artery bypass surgery in a patient with decreased left ventricular function

Key Clinical Message

Remimazolam is a new benzodiazepine sedative and has the characteristic of causing minimal effects on circulation. This case indicates that it can be considered as an option for anesthesia management of patients with decreased cardiac function.

Abstract

Some patients who undergo cardiac surgery have reduced cardiac function, which can often make anesthesia management difficult owing to severe hypotension at the time of anesthesia induction. Therefore, it is important to select drugs that cause minimal circulatory depression. On the other hand, in 2020, the use of remimazolam, a short-acting benzodiazepine sedative, was approved in Japan, and reports of its use in various patients have been increasing. This drug has the characteristic of causing minimal effects on circulation. We here report the safe use of remimazolam in the anesthesia management of a patient with decreased cardiac function who was diagnosed as having angina pectoris. The patient was a 73-year-old man scheduled for coronary artery bypass graft (CABG) surgery. Remimazolam was used for sedation purposes during anesthesia induction. During surgery, there were no significant hemodynamic changes and the patient remained in stable cardiovascular condition. Our present case indicates that remimazolam can be considered as an option for anesthesia management in CABG for patients with decreased cardiac function.

Comparative analysis of the effect of electromyogram to bispectral index and 95% spectral edge frequency under remimazolam and propofol anesthesia: a prospective, randomized, controlled clinical trial

Background

Bispectral index (BIS), an index used to monitor the depth of anesthesia, can be interfered with by the electromyogram (EMG) signal. The 95% spectral edge frequency (SEF95) also can reflect the sedation depth. Remimazolam in monitored anesthesia care results in higher BIS values than propofol, though in the same sedation level assessed by Modified Observers Assessment of Alertness and Sedation (MOAA/S). Our study aims to illustrate whether EMG is involved in remimazolam causing higher BIS value than propofol preliminarily and to explore the correlations among BIS, EMG, and SEF95 under propofol and remimazolam anesthesia.

Patients and methods

Twenty-eight patients were randomly divided into propofol (P) and remimazolam (RM) groups. Patients in the two groups received alfentanil 10 μg/kg, followed by propofol 2 mg/kg and remimazolam 0.15 mg/kg. Blood pressure (BP), heart rate (HR), and oxygen saturation (SpO2) were routinely monitored. The BIS, EMG, and SEF95 were obtained through BIS VISTATM. The primary outcomes were BIS, EMG, and the correlation between BIS and EMG in both groups. Other outcomes were SEF95, the correlation between BIS and SEF95, and the correlation between EMG and SEF95. And all the statistical and comparative analysis between these signals was conducted with SPSS 26.0 and GraphPad Prism 8.

Results

BIS values, EMG, and SEF95 were significantly higher in the RM group than in the P group (all p < 0.001). There was a strong positive correlation between BIS and EMG in the RM group (r = 0.416). Nevertheless, the BIS in the P group showed a weak negative correlation with EMG (r = -0.219). Both P (r = 0.787) and RM group (r = 0.559) had a reasonably significant correlation coefficient between BIS and SEF95. SEF95 almost did not correlate with EMG in the RM group (r = 0.101).

Conclusion

Bispectral index can be interfered with high EMG intensity under remimazolam anesthesia. However, EMG can hardly affect the accuracy of BIS under propofol anesthesia due to low EMG intensity and a weak negative correlation between EMG and BIS. Moreover, SEF95 may have a great application prospect in predicting the sedation condition of remimazolam.

Recovery of memory retention after anesthesia with remimazolam: an exploratory, randomized, open, propofol-controlled, single-center clinical trial

PURPOSE

Remimazolam, a newly developed ultra-short-acting benzodiazepine, provides early recovery of consciousness but its effects on memory recovery are unclear. This study examined memory recovery after emergence from general anesthesia using remimazolam.

METHODS

Seventy-four patients undergoing breast surgery between October 2021 and March 2022 were enrolled and randomly assigned to receive propofol (control group) or remimazolam as general anesthetic during surgery. The primary endpoint was the number of posters patients remembered 24 h after surgery (among four posters shown after recovering from anesthesia) as an assessment of memory retention. The secondary endpoints were the recall of a numeric character patients had been shown just before anesthetic induction, as an assessment of retrograde amnesia 24 h after surgery.

RESULTS

Sixty-six patients (propofol, 32; remimazolam, 34) were assessed. Patients in the remimazolam group remembered significantly fewer posters shown to them after surgery than those in the propofol group (0 [0 - 2] vs. 2 [1 - 3], p < 0.001). In the remimazolam group, the patients who received flumazenil remembered a higher number of posters than those who did not receive flumazenil (3 [1 - 4] vs. 0 [0 - 0], p < 0.001). All patients remembered all events that occurred during the preoperative period as well as the numeric character.

CONCLUSION

Patients recovering from remimazolam anesthesia without receiving flumazenil do not remember events after regaining consciousness. IRB: Kyushu University School of Medicine Hospital Institutional Review Board (IRB) (approval number: 20212006).

TRIAL REGISTRATION

This clinical trial was registered with the University Hospital Medical Information Network (UMIN) Center on September 28, 2021 (UMIN-CTR: UMIN000045593).

IMPLICATION STATEMENT

Memory recovery is slower following emergence from remimazolam than from propofol anesthesia.

Comparison of remimazolam-remifentanil and propofol-remifentanil during laparoscopic cholecystectomy

BACKGROUND

Remimazolam is a novel benzodiazepine with fast onset and short half-life. We compared the effects of remimazolam and propofol on recovery profiles for general anesthesia in patients undergoing laparoscopic cholecystectomy.

METHODS

We randomly assigned 108 patients to either a remimazolam (n=54) or propofol (n=54) group. Remimazolam and propofol were used for induction and maintanance of anesthesia. Following anesthesia, we recorded the time until an Aldrete score of 9 was achieved as the primary surrogate marker of complete recovery. The time to reach a Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score of 2 and the time from the end of anesthesia to eye opening time, recovery time of orientation, time to spontaneous breathing, extubation time, and the time required for analgesics were measured. Heart rate, blood pressure, and bispectral index were assessed before, during, and after pneumoperitoneum.

RESULTS

We included 101 patients in the analysis. In the remimazolam group, it took longer to reach an Aldrete score of 9 after the drug infusion ended (P = 0.031). There was no difference in the time to reach MOAA/S 2 between the two groups. The time to eye opening, recovery time of orientation, and time required for analgesics were longer and heart rate was higher in the remimazolam group. Neither blood pressure, nor extubation time differed between groups.

CONCLUSIONS

Remimazolam and propofol provided safe induction and maintenance of anesthesia in patients undergoing laparoscopic cholecystectomy. The recovery time from anesthesia was longer than that with propofol. Fewer hemodynamic changes were observed with remimazolam, but further studies are needed.

Comparison of Postoperative Nausea and Vomiting Incidence between Remimazolam and Sevoflurane in Tympanoplasty with Mastoidectomy: A Single-Center, Double-Blind, Randomized Controlled Trial

Background and Objectives: Postoperative nausea and vomiting (PONV) is a common adverse effect of general anesthesia, especially in middle ear surgery. Remimazolam is a newer benzodiazepine recently approved for use in general anesthesia. This study aimed to compare the incidence rate of PONV after tympanoplasty with mastoidectomy between using remimazolam and sevoflurane. Materials and Methods: This study included 80 patients undergoing elective tympanoplasty with mastoidectomy. The patients were randomly assigned to either the remimazolam or sevoflurane group. The primary outcome was the incidence rate of PONV 12 h after surgery. The secondary outcomes were the incidence rate of PONV 12-24 and 24-48 h after surgery, severity of PONV, incidence rate of vomiting, administration of rescue antiemetics, hemodynamic stability, and recovery profiles. Results: The incidence rate of PONV 0-12 h after tympanoplasty with mastoidectomy was significantly lower in the remimazolam group compared with that in the sevoflurane group (28.9 vs. 57.9%; p = 0.011). However, the incidence rate of delayed PONV did not differ between the two groups. PONV severity in the early periods after the surgery was significantly lower in the remimazolam group than in the sevoflurane group. The incidence rate of adverse hemodynamic events was lower in the remimazolam group than in the sevoflurane group, but there was no difference in the overall trends of hemodynamic data between the two groups. There was no difference in recovery profiles between the two groups. Conclusions: Remimazolam can significantly reduce the incidence rate of early PONV after tympanoplasty with mastoidectomy under general anesthesia.

Evaluation of total intravenous anesthesia with remimazolam in general anesthesia for pulmonary endarterectomy of chronic thromboembolic pulmonary hypertension: a case report

BACKGROUND

Pulmonary endarterectomy (PEA) is a treatment modality for chronic thromboembolic pulmonary hypertension (CTEPH). PEA requires anesthesia management to prevent an increase in pulmonary vascular resistance (PVR) and circulatory failure. Therefore, it is necessary to select an anesthetic agent that can achieve these goals as much as possible. On the other hand, remimazolam, a short-acting sedative, was launched in Japan in 2020, and its use in various cases has been increasingly reported. This report demonstrates that remimazolam can be used safely in the anesthetic management of PEA.

CASE PRESENTATION

A 57-year-old man was scheduled to undergo PEA for CTEPH. Remimazolam was used for sedation from induction of anesthesia. Hemodynamics were stable during surgery without circulatory failure. Anesthesia was managed intraoperatively without any particular increase in PVR.

DISCUSSION

Anesthesia was successfully managed without any complications. This case suggests that remimazolam is one of the options for anesthetic management in PEA.

Determination of the 95% effective dose of remimazolam tosylate in anesthesia induction inhibits endotracheal intubation response in senile patients

Background and Purpose: The prevalence of elderly patients prompts anesthesiologists to determine the optimal dose of medication due to the altered pharmacokinetics and pharmacodynamics of this population. The present study aimed to determine the 95% effective dose (ED₉₅) of remimazolam tosylate in anesthesia induction to inhibit endotracheal intubation-related cardiovascular reaction in frail and non-frail senile patients. Methods: A prospective sequential allocation dose-finding study of remimazolam tosylate was conducted on 80 elderly patients who received general anesthesia between May and June 2022 at the First Affiliated Hospital of Nanchang University. The initial dose was 0.3 mg/kg. The blood pressure and heart rate fluctuations during intubation were either <20% (negative cardiovascular response) or ≥20% (positive cardiovascular response). If positive, the dose of the next patient was increased by 0.02 mg/kg, while if negative, it was reduced by 0.02 mg/kg according to the 95:5 biased coin design (BCD). The ED₉₅ and 95% confidence intervals (CIs) were determined using R-Foundation isotonic regression and bootstrapping methods. Results: The ED₉₅ of remimazolam tosylate to inhibit the response during tracheal intubation was 0.297 mg/kg (95% CI: 0.231-0.451 mg/kg) and 0.331 mg/kg (95% CI: 0.272-0.472 mg/kg) in frail and non-frail senile patients, respectively. Conculation and Implications: The CI of the two groups overlap, and no difference was detected in the ED₉₅ of remimazolam tosylate in inhibiting endotracheal intubation-related cardiovascular response in frail and non-frail senile patients. These results suggested that remimazolam tosylate is an optimal anesthesia inducer for all elderly patients. Clinical Trial Registration: https://www.chictr.org.cn, identifier ChiCTR2200055709.

Efficacy and safety of remimazolam tosilate versus propofol in patients undergoing day surgery: a prospective randomized controlled trial

BACKGROUND

Remimazolam tosilate (RT) is a novel short-acting GABA (A) receptor agonist that has a rapid recovery from procedural sedation and can be fully reversed by flumazenil. To date, there have been relatively few articles comparing RT and propofol for general anesthesia. This study aimed to assess the efficacy and safety of RT with or without flumazenil compared with propofol in general anesthesia for day surgery.

METHODS

115 patients scheduled for day surgery were randomized into three groups: RT (n = 39), RT + flumazenil (n = 38) and propofol (n = 38). The primary endpoints were anesthesia induction time and time until fully alert. Anesthesia success rate, bispectral index (BIS) values, injection pain, opioid and vasopressor dosages, postoperative recovery profiles and perioperative inflammatory and cognitive changes were assessed. Any adverse events were recorded.

RESULTS

Induction times were similar among the three groups (P = 0.437), but the median time until fully alert in patients treated with RT was longer than that of the propofol or RT + flumazenil groups (17.6 min vs. 12.3 min vs. 12.3 min, P < 0.001). The three groups had comparable postoperative recovery quality and inflammatory and cognitive state changes (P > 0.05). Smaller percentages of patients who received RT (26.3%) and RT + flumazenil (31.6%) developed hypotension during anesthesia maintenance compared with propofol (68.4%), and consequently less ephedrine (P < 0.001) and phenylephrine (P = 0.015) were needed in the RT group. Furthermore, serum triglyceride levels were lower (P < 0.001) and injection pain was much less frequent in the RT with or without flumazenil groups compared with the propofol group (5.3% vs. 0% vs. 18.4%).

CONCLUSION

RT permits rapid induction and comparable recovery profile compared with propofol in general anesthesia for day surgery, but has a prolonged recovery time without flumazenil. The safety profile of RT was superior to propofol in terms of hypotension and injection pain.

TRIAL REGISTRATION

The study was registered at Chinese Clinical Trial Registry http://www.chictr.org.cn/ (Registration date: 19/7/2021; Trial ID: ChiCTR2100048904).

Comparison of the recovery profile of remimazolam with flumazenil and propofol anesthesia for open thyroidectomy

BACKGROUND

Previous studies have consistently reported a slower recovery of consciousness following remimazolam-based total intravenous anesthesia without flumazenil than with propofol. This study aimed to compare the reversal effect of flumazenil on the recovery of consciousness after remimazolam-based total intravenous anesthesia with the propofol recovery profile.

METHODS

This prospective, single-blinded, randomized trial included 57 patients undergoing elective open thyroidectomy at a tertiary university hospital. Patients were randomly allocated to receive either remimazolam- or propofol-based total intravenous anesthesia (remimazolam group: 28 patients, propofol group: 29 patients). The primary outcome was the time from the end of general anesthesia to first eye opening (min). The secondary outcomes were the time from the end of the general anesthesia to extubation (min), initial modified Aldrete score measured at the post-anesthesia care unit, length of stay at the post-anesthesia care unit (min), occurrence of postoperative nausea and vomiting during the first 24 h postoperatively, and Korean version of Quality of Recovery-15 score at 24 h postoperatively.

RESULTS

The remimazolam group showed significantly faster first eye opening time (2.3 [interquartile range, IQR: 1.8-3.3] min vs. 5.0 [IQR: 3.5-7.8] min, median difference:-2.7 [95% confidence interval, CI: -3.7 to -1.5] min, P < 0.001) and extubation time (3.2 [IQR: 2.4-4.2] min vs. 5.7 [IQR: 4.7-8.3] min, median difference: -2.7 [97.5% CI: -5.0 to -1.6] min, P < 0.001). There were no significant differences in other postoperative outcomes.

CONCLUSIONS

The planned incorporation of flumazenil with remimazolam-based total intravenous anesthesia provided rapid and reliable recovery of consciousness.

The safety and efficacy of remimazolam tosylate for induction and maintenance of general anesthesia in pediatric patients undergoing elective surgery: Study protocol for a multicenter, randomized, single-blind, positive-controlled clinical trial

Introduction: Remimazolam is an ultra-short-acting benzodiazepine sedative agent commonly used in general anesthesia, procedural sedation, and intensive care unit (ICU) sedation. This study aimed to explore the efficacy and safety of remimazolam versus propofol for the induction and maintenance of general anesthesia in preschool-age children undergoing elective surgery. Methods and analysis: In this multicenter, randomized, single-blind, positive-controlled non-inferior clinical trial, one hundred ninety-two children aged 3-6 years will be randomly allocated as a 3:1 ratio into two groups: Group R with an intravenous dose of remimazolam 0.3 mg/kg for the induction of anesthesia followed by a constant infusion rate of remimazolam 1-3 mg/kg/h to maintain anesthesia, and Group P with an intravenous dose of propofol 2.5 mg/kg for the induction of anesthesia followed by a constant infusion rate of propofol 4-12 mg/kg/h to maintain anesthesia. The primary outcome will be the rate of the successful induction and maintenance of anesthesia. The secondary outcomes will include the time to LoC, the Bispectral Index (BIS) value, awakening time, extubation time, post-anesthesia care unit (PACU) discharge time, usage of additional sedative drugs during the induction period, usage of remedial drugs in PACU, emergence delirium, pain in PACU, behavior scores at day 3 after surgery, parental and anesthesiologists' satisfaction, and adverse events. Ethics and dissemination: This study has been approved by the ethics review boards at all participating hospitals. The Ethics Committee of the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University (Reference No. LCKY 2020-380, November 13, 2020) is the central ethics committee.

Motor-evoked potentials monitoring with remimazolam during thoracic descending aortic aneurysm surgery: a case report

Paraplegia remains the most devastating complication following thoracoabdominal aortic surgery. Motor-evoked potential (MEP) monitoring has been widely used to assess intraoperative motor function. MEP amplitude is affected by various factors, including anesthetic agents and measurement time; however, there are no reports regarding MEP monitoring using remimazolam in thoracoabdominal aortic surgery. A 57-year-old woman underwent open repair of a thoracic descending aorta for a chronic dissecting aortic aneurysm under remimazolam and remifentanil anesthesia. The administration rate of remimazolam was adjusted using spectral edge frequency of SedLine^®, which ranged from 0.2 to 1.0 mg/kg/h after anesthetic induction with 12 mg/kg/h. Muscle MEPs were obtained using subdermal needle electrodes at the abductor pollicis brevis muscle and abductor hallucis. There were no significant changes, which were defined as a 50% reduction of MEP amplitude from each baseline value, including during split circulation. On postoperative day one, she had no motor deficits nor signs of intraoperative awareness. Remimazolam might be well tolerated for MEP monitoring in patients undergoing thoracic descending aortic aneurysm surgery.

Can Remimazolam Be a New Sedative Option for Outpatients Undergoing Ambulatory Oral and Maxillofacial Surgery?

PURPOSE

Midazolam is a classic sedative drug. The sedative effect of remimazolam has not been demonstrated in ambulatory oral and maxillofacial surgery (OMS). This study aimed to measure whether remimazolam can achieve the same sedation effects compared with midazolam, but with a faster recovery and fewer adverse reactions in outpatients undergoing ambulatory OMS.

MATERIALS AND METHODS

This was a prospective, randomized, controlled, single-center study of 40 patients who underwent ambulatory OMS at Peking University Hospital of Stomatology, Beijing, China, between April 2021 and June 2021. The patients were randomly divided into a midazolam group (Group M) and a remimazolam group (Group R). The success rate of sedation, which was defined as completion of the operation with no rescue sedative medication, was the primary outcome. In this study, bispectral index and modified observer's assessment of alertness/sedation value, intraoperative adverse events, time to discharge, and the number of additional doses of sedative were compared. Descriptive, comparative analyses were conducted.

RESULTS

Forty patients were eligible for this study, and the final sample size was 40 (including 25 males, average age was 29). The success rate of sedation in Group R was statistically significantly higher than that in Group M (Group R vs Group M: 95% [19/20] vs 70% [14/20], P = .037, 95% confidence interval [CI]: 0.681 to 0.913). The median number of additional doses of the medications per 5 minutes in Group R was lower than that in Group M (0.51 [0.19, 0.71] vs 0.82 [0.51, 1.25], P = .006, 95% CI: 0.013 to 0.583). Group R showed a higher bispectral index number (93.9 ± 4.6 vs 86.6 ± 7.2, P = .001, 95% CI: 3.451 to 11.149) at the end of the surgery and a higher modified observer's assessment of alertness/sedation score (4.70 ± 0.47 vs 4.05 ± 0.68, P = .001, 95% CI: 0.273 to 1.027) after 5 minutes at the recovery room compared with Group M.

CONCLUSIONS

The success rate of remimazolam is higher than that of midazolam. The use of remimazolam is effective for sedation of patients undergoing ambulatory OMS.

A Remimazolam and Remifentanil Anesthetic for a Pediatric Patient With a Medium-Chain Acyl-CoA Dehydrogenase Deficiency: A Case Report

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is one of the most common fatty acid oxidation disorders. The choice of anesthetics and blood glucose management are crucial to prevent metabolic decompensation. A 5-year-old Japanese boy with MCAD deficiency was scheduled to undergo surgery for an inguinal hernia. Glucose was continuously infused perioperatively, and his glucose concentrations were within the normal range. Anesthesia was induced and maintained with remimazolam, remifentanil, and intermittent rocuronium. No metabolic decompensation was observed. This case indicates the importance of a continuous intravenous glucose infusion, and that remimazolam can be the first-line anesthetic for a patient with MCAD deficiency.

Assessing the Safety of Total Intravenous Anesthesia with Remimazolam in General Anesthesia for Transcatheter Aortic Valve Implantation of Severe Aortic Valve Stenosis: A Case Series

Background and Objectives: In patients with severe aortic stenosis (sAS), it is crucial to maintain hemodynamic stability during the induction and maintenance of general anesthesia for transcatheter aortic valve implantation (TAVI). In this study, we assessed the efficacy and safety of remimazolam in maintaining hemodynamic stability during anesthetic induction and maintenance. Cases: TAVI was performed on seven patients with sAS, and remimazolam was administered for total intravenous anesthesia (TIVA) of general anesthesia with induction (3.0 mg/kg/h) and maintenance (1.0 mg/kg/h). All patients underwent TAVI without major hemodynamic concerns and later recovered. Conclusions: Remimazolam can be safely used for induction and maintenance of general anesthesia in patients with sAS when performing TAVI.

Long-term delayed emergence after remimazolam-based general anesthesia: a case report

Background

Remimazolam is an ultra-short-acting benzodiazepine anesthetic that is antagonized by flumazenil, and it is typically expected to be applied in anesthesia with the purpose of ensuring early postoperative recovery. We report a case of long-term delayed emergence with re-sedation even after three times of flumazenil administration.

Case presentation

A 71-year-old man was scheduled for a robotic-assisted laparoscopic radical prostatectomy for prostate cancer. We used remimazolam for anesthetic induction and maintenance. The intraoperative bispectral index (BIS) was 30–50. Flumazenil was administered as patient emergence was delayed after surgery; however, re-sedation was observed. This finding persisted till 12 h after surgery, and the patient awakened on postoperative day 2.

Conclusions

Remimazolam is a short-acting anesthetic, but long-term delayed emergence with re-sedation may occur even after flumazenil administration. Anesthesia using remimazolam requires anesthesia management that takes into account the individual differences in sensitivity and metabolism, with BIS as the indicator.

Comparison of remimazolam-based and propofol-based total intravenous anesthesia on postoperative quality of recovery: A randomized non-inferiority trial

STUDY OBJECTIVE

The quality of recovery (QoR) of remimazolam-based and propofol-based total intravenous anesthesia was compared as measured by QoR-15 scores.

DESIGN

A prospective, double-blind, randomized controlled, non-inferiority trial.

SETTING

An operating room, a post-anesthesia care unit (PACU), and a hospital ward.

PATIENTS

Female patients (n = 140; 20-65 years) scheduled for open thyroidectomy were enrolled and randomly assigned to the remimazolam or propofol group.

INTERVENTIONS

The remimazolam group received continuous remimazolam infusions and effect-site target-controlled remifentanil infusions. The propofol group received effect-site target-controlled infusions of propofol and remifentanil.

MEASUREMENTS

The primary outcome was QoR-15 on postoperative day 1 (POD1). The mean difference between the groups was compared against a non-inferiority margin of -8. Secondary outcomes were QoR-15 on POD2, hemodynamic data, time to lose and recover consciousness, sedation score upon PACU admission, pain, and postoperative nausea and vomiting profiles at the PACU and ward. Group-time interaction effects in hemodynamic data and QoR-15 were analyzed using a linear mixed model.

MAIN RESULTS

The total QoR-15 score on POD1 in the remimazolam group was non-inferior to that in the propofol group (mean [SD] 111.2 [18.8] vs. 109.1 [18.9]; mean difference [95% CI] 2.1 [-4.2, 8.5]; p = 0.002 for non-inferiority). The QoR-15 score on POD2 was comparable between the groups, and no group-time interaction was observed. At the end of anesthesia, after extubation, and upon arrival at the PACU, mean arterial pressure was significantly higher in the remimazolam group. Remimazolam group was more sedated at the time of admission to PACU. Pain intensity and the requirement for analgesics were lower in the remimazolam group than in the propofol group.

CONCLUSIONS

Remimazolam-based total intravenous anesthesia provided a similar QoR to propofol. Remimazolam and propofol can be used interchangeably for general anesthesia in female patients undergoing thyroid surgery.