Efficacy and safety of remimazolam versus propofol for general anesthesia: a multicenter, single-blind, randomized, parallel-group, phase IIb/III trial

Remimazolam: its clinical pharmacology and evolving role in anesthesia and sedation practice

PURPOSE OF REVIEW

Remimazolam is a novel benzodiazepine anesthetic/sedative, designed as a rapidly metabolized carboxylic acid. Since its recent launch, the role of remimazolam in modern anesthesia and sedation practice is still evolving. This review aims to outline the clinical pharmacology and clinical utility of remimazolam to elucidate its potential advantages and limitations.

RECENT FINDINGS

Remimazolam is "short-acting" but not ultra-short-acting compared with propofol based on context-sensitive decrement times. But compared to propofol, the availability of the benzodiazepine antagonist, flumazenil, is considered an advantage, particularly in certain emergency situations such as in patients with difficult airways. However, because flumazenil is shorter acting than remimazolam when remimazolam accumulates or is present in a high concentration, the reappearance of remimazolam sedation may occur after the initial reversal of anesthesia/sedation from flumazenil administration. Although it is beneficial that remimazolam causes less respiratory depression and hypotension than propofol, serious respiratory depression and hypotension can still occur. Remimazolam administration causes minimal or no pain on injection. Remimazolam is associated with less postoperative nausea and vomiting than inhaled anesthetics, but propofol is clearly superior in this regard. The anesthetic/sedative effects may be prolonged by severe hepatic impairment; remimazolam tolerance can occur in long-term benzodiazepine users.

SUMMARY

Remimazolam may be beneficial to use in procedural sedation and general anesthesia for patients with difficult airways or hemodynamic instability. Further clinical studies with remimazolam are warranted to identify the potential benefits in other settings and patient populations.

Effect of remimazolam versus propofol anesthesia on postoperative delirium in neurovascular surgery: study protocol for a randomized controlled, non-inferiority trial

BACKGROUND

Remimazolam is a short-acting benzodiazepine newly approved for the induction and maintenance of general anesthesia. Remimazolam emerges as an ideal drug for the neurosurgical population due to its rapid emergence, enabling early neurological assessment, and its ability to maintain perfusion pressure, which is crucial for preventing cerebral ischemia. However, the use of benzodiazepine has been associated with an increased risk of postoperative delirium (POD). There is currently limited evidence about the relationship between remimazolam-based total intravenous anesthesia (TIVA) and POD.

METHODS

In this double-blind, randomized, non-inferiority trial, we plan to include 696 adult patients with American Society of Anesthesiologists physical status class I to III, undergoing elective neurovascular surgery under general anesthesia. After informed consent, the patients will be randomized to receive either remimazolam or propofol-based TIVA with a 1:1 ratio. The primary outcome is the incidence of POD within 5 days after surgery. Secondary outcomes include subtypes, number of positive assessments and severity of POD, emergence agitation, intraoperative awareness and undesirable patient movement, intraoperative hypotension, and postoperative cognitive function. The data will be analyzed in modified intention to treat.

DISCUSSION

This trial will evaluate the effect of remimazolam on the development of POD compared to propofol anesthesia. The results of this trial will provide evidence regarding the choice of optimal anesthetics to minimize the risk of POD in neurosurgical patients.

TRIAL REGISTRATION

The study protocol was prospectively registered at the Clinical trials ( https://clinicaltrials.gov , NCT06115031, principal investigator: Jiseon Jeong; date of first registration: November 2, 2023, before the recruitment of the first participant.

Remimazolam anaphylaxis in a patient not allergic to brotizolam: a case report and literature review

BACKGROUND

Remimazolam is a recently developed, ultrashort-acting benzodiazepine that is used as a general anesthetic. Some cases of remimazolam anaphylaxis have been reported, but its characteristics are not fully understood. We present an interesting case report and review of the literature to better understand remimazolam anaphylaxis.

CASE PRESENTATION

A 75-year-old man scheduled for robot-assisted gastrectomy was administered remimazolam for the induction of general anesthesia. After intubation, low end-expiratory CO2, high airway pressure and concurrent circulatory collapse were observed. Bronchoscopy revealed marked tracheal and bronchial edema, which we diagnosed as anaphylaxis. The patient suffered cardiac arrest after bronchoscopy but recovered immediately with intravenous adrenaline administration and chest compressions. We performed skin prick tests for the drugs used during induction except for remimazolam, considering the high risk of systemic adverse reactions to remimazolam. We diagnosed remimazolam anaphylaxis because the skin prick test results for the other drugs used during anesthesia were negative, and these drugs could have been used without allergic reactions during the subsequent surgery. Furthermore, this patient had experienced severe anaphylactic-like reactions when he underwent cardiac surgery a year earlier, in which midazolam had been used, but it was not thought to be the allergen at that time. Based on these findings, cross-reactivity to remimazolam and midazolam was suspected. However, the patient had previously received another benzodiazepine, brotizolam, to which he was not allergic, suggesting that cross-reactivity of remimazolam may vary among benzodiazepines. In this article, we reviewed the 11 cases of remimazolam anaphylaxis that have been described in the literature.

CONCLUSIONS

Remimazolam is an ultrashort-acting sedative; however, it can cause life-threatening anaphylaxis. In addition, its cross-reactivity with other benzodiazepines is not fully understood. To increase the safety of this drug, further research and more experience in its use are needed.

Changes in oxygen supply-demand balance during induction of general anesthesia: an exploratory study using remimazolam

PURPOSE

This study was performed to evaluate the changes in oxygen supply-demand balance during induction of general anesthesia using an indirect calorimeter capable of measuring oxygen consumption (VO2) and carbon dioxide production (VCO2).

METHODS

This study included patients scheduled for surgery in whom remimazolam was administered as a general anesthetic. VO2 and VCO2 were measured at different intervals: upon awakening (T1), 15 min after tracheal intubation (T2), and 1 h after T2 (T3). Oxygen delivery (DO2) was calculated simultaneously with these measurements. VO2 was ascertained using an indirect calorimeter and further calculated using vital signs, among other factors. DO2 was derived from cardiac output and arterial blood gas analysis performed with an arterial pressure-based cardiac output measurement system.

RESULTS

VO2, VCO2, and DO2 decreased significantly from T1 to T2 and T3 [VO2/body surface area (BSA) (ml/min/m2): T1, 130 (122-146); T2, 107 (83-139); T3, 97 (93-121); p = 0.011], [VCO2/BSA (ml/min/m2): T1, 115 (105-129); T2, 90 (71-107); T3, 81 (69-101); p = 0.011], [DO2/BSA (ml/min/m2): T1, 467 (395-582); T2, 347 (286-392); T3, 382 (238-414); p = 0.0020]. Among the study subjects, a subset exhibited minimal reduction in VCO2. Although the respiratory frequency was titrated on the basis of end-tidal CO2 levels, there was no significant difference between the groups.

CONCLUSION

General anesthetic induction with remimazolam decreased VO2, VCO2, and DO2.

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.

Comparison of hypotension incidence between remimazolam and propofol in patients with hypertension undergoing neurosurgery: prospective, randomized, single-blind trial

BACKGROUND

Remimazolam, a newer benzodiazepine that targets the GABAA receptor, is thought to allow more stable blood pressure management during anesthesia induction. In contrast, propofol is associated with vasodilatory effects and an increased risk of hypotension, particularly in patients with comorbidities. This study aimed to identify medications that can maintain stable vital signs throughout the induction phase.

METHODS

We conducted a single-center, two-group, randomized controlled trial to investigate and compare the incidence of hypotension between remimazolam- and propofol-based total intravenous anesthesia (TIVA). We selected patients aged between 19 and 75 years scheduled for neurosurgery under general anesthesia, who were classified as American Society of Anesthesiologists Physical Status I-III and had a history of hypertension.

RESULTS

We included 94 patients in the final analysis. The incidence of hypotension was higher in the propofol group (91.3%) than in the remimazolam group (85.4%; P = 0.057). There was no significant difference in the incidence of hypotension among the various antihypertensive medications despite the majority of patients being on multiple medications. In comparison with the propofol group, the remimazolam group demonstrated a higher heart rate immediately after intubation.

CONCLUSIONS

Our study indicated that the hypotension incidence of remimazolam-based TIVA was comparable to that of propofol-based TIVA throughout the induction phase of EEG-guided anesthesia. Both remimazolam and propofol may be equally suitable for general anesthesia in patients undergoing neurosurgery.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT05164146).

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 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.

Predictive model for post-induction hypotension in patients undergoing transcatheter aortic valve implantation: a retrospective observational study

PURPOSE

Post-induction hypotension (PIH) is an independent risk factor for prolonged postoperative stay and hospital death. Patients undergoing transcatheter aortic valve implantation (TAVI) are prone to develop PIH. This study aimed to develop a predictive model for PIH in patients undergoing TAVI.

METHODS

This single-center retrospective observational study included 163 patients who underwent TAVI. PIH was defined as at least one measurement of systolic arterial pressure <90 mmHg or at least one incident of norepinephrine infusion at a rate >6 µg/min from anesthetic induction until 20 min post-induction. Multivariate logistic regression analysis was performed to develop a predictive model for PIH in patients undergoing TAVI.

RESULTS

In total, 161 patients were analyzed. The prevalence of PIH was 57.8%. Multivariable logistic regression analysis showed that baseline mean arterial pressure ≥90 mmHg [adjusted odds ratio (aOR): 0.413, 95% confidence interval (95% CI): 0.193-0.887; p=0.023] and higher doses of fentanyl (per 1-µg/kg increase, aOR: 0.619, 95% CI: 0.418-0.915; p=0.016) and ketamine (per 1-mg/kg increase, aOR: 0.163, 95% CI: 0.062-0.430; p=0.002) for induction were significantly associated with lower risk of PIH. A higher dose of propofol (per 1-mg/kg increase, aOR: 3.240, 95% CI: 1.320-7.920; p=0.010) for induction was significantly associated with higher risk of PIH. The area under the curve (AUC) for this model was 0.802.

CONCLUSION

The present study developed predictive models for PIH in patients who underwent TAVI. This model may be helpful for anesthesiologists in preventing PIH in patients undergoing TAVI.

Comparison of Remimazolam Tosilate and Propofol Sedation on the Early Postoperative Quality of Recovery in Patients Undergoing Day Surgery: A Prospective Randomized Controlled Trial

Purpose

Remimazolam tosilate is a novel ultrafast-acting benzodiazepine that has a rapid emergence even after continuous infusion when using flumazenil. So far, relatively few articles are still focusing on the quality of recovery after general anesthesia with remimazolam, especially in day surgery. This study aimed to compare the early postoperative quality of recovery of remimazolam tosilate with flumazenil and propofol in patients undergoing day surgery.

Patients and Methods

137 patients scheduled for day surgery were randomly divided into the remimazolam tosilate or propofol group. The primary endpoint was the incidence of overall recovery assessed with the early postoperative quality of recovery scale (PostopQRS) on postoperative day 1 (POD 1). The Richmond Agitation-Sedation Scale (RASS) scores in the post-anesthesia care unit (PACU), extubation time, postoperative recovery profiles, and perioperative data were documented. Any adverse events were recorded.

Results

The incidence of overall recovery on POD1 was 47.7% in the remimazolam tosilate group and 65.1% in the propofol group (odds ratio, 0.52; 95% confidence interval (CI) 0.26 to 1.06; P = 0.072). In general, the overall recovery of the PostopQRS increased over time, and its interaction between time and group was significant (P = 0.003). Among the five dimensions of PostopQRS, there exist statistical differences between groups including emotional state and cognitive recovery. Upon arrival at the PACU, the remimazolam group was more sedated and took longer to recover to a RASS score similar to propofol. The frequency of application of vasoactive drugs during anesthesia was similar in both groups (P = 0.119). Despite rapid emergence with remimazolam after flumazenil reversal, re-sedation (10.8%) or somnolence (60%) in the PACU was observed, and the length of PACU stay in patients treated with remimazolam tosilate was longer than that of the propofol (35 min vs 30 min, P<0.001).

Conclusion

General anesthesia with remimazolam tosilate in conjunction with flumazenil reversal permits rapid recovery of consciousness in day surgery, but there was a notable occurrence of re-sedation or somnolence observed in PACU.

The 90% effective dose (ED90) of remimazolam for inhibiting responses to the insertion of a duodenoscope during ERCP

BACKGROUND

Compared to midazolam, remimazolam has a faster onset and offset of hypnotic effect, as well as cardiorespiratory stability, this study aims to determine the 90% effective dose (ED90) of remimazolam to inhibit responses to insertion of a duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

A dose-response study was carried out undergoing ERCP who received remimazolam-alfentanil anesthesia using 10 µg/kg of alfentanil between September 2021 and November 2021. The initial dose of remimazolam was 0.2 mg/kg. The dose was then decided based on the responses of earlier patients by exploiting the sequential ascend and descend according to a 9: 1 biased coin design. Upon failure, the dose of remimazolam was increased by 0.025 mg/kg in the next patient. When the insertion was successful, the succeeding patient was randomized to an identical dose or a dose that was lower by 0.025 mg/kg.The ED90 of remimazolam for inhibiting responses to the insertion of a duodenoscope during ERCP was calculated. Adverse events and complications of remimazolam were recorded.

RESULTS

A total of 55 elderly patients (age > 65) were included in the study. 45 successfully anesthetized patients, and 10 unsuccessfully. The ED90 of remimazolam was 0.300 mg/kg (95% CI = 0.287-0.320). ED95 was 0.315 (95% CI = 0.312-0.323) and ED99 was 0.323 (95% CI = 0.323-0.325). Among the patients, 9 patients developed hypotension, 2 patients developed bradycardia and 1 patient developed tachycardia, and hypoxia occurred in 2 patients.

CONCLUSIONS

A loading dose of 0.300 mg / kg of remimazolam for elderly patients undergoing ERCP can safely, effectively, and quickly induce patients to fall asleep and inhibit responses to the insertion of a duodenoscope.

TRIAL REGISTRATION

The study protocol was registered at the website ClinicalTrials.gov on 22/09/2021(NCT05053763).

Adverse Drug Events Observed with the Newly Approved Remimazolam in Comparison to Propofol for General Anesthesia in Patients Undergoing Surgery: A Meta-analysis

INTRODUCTION

Developments in anesthetic pharmacology have been aiming at minimizing physiological disturbance in addition to maintaining and improving titrateability, recovery profile, and patient experience. Remimazolam, a GABAAlpha receptor agonist, is a new intravenous anesthetic agent which has recently been approved for use. This analysis aimed to systematically compare the adverse drug events reported with the newly approved remimazolam in comparison to propofol for general anesthesia (GA) in patients undergoing surgery.

METHODS

Electronic databases were searched from 15 May to 20 December 2023 for relevant publications which compared the outcomes reported with the newly approved remimazolam versus propofol in patients undergoing surgery. Relevant reported adverse drug events were the endpoints of this study. The statistical analysis was carried out using the latest version of the RevMan software. Data analysis was represented by risk ratio (RR) with 95% confidence intervals (CI).

RESULTS

Sixteen studies with a total number of 1897 participants were included in this analysis; 1104 participants received remimazolam and 793 participants received propofol. The risks for hypotension (RR 0.50, 95% CI 0.43-0.58; P = 0.00001), hypoxemia (RR 0.43, 95% CI 0.19-0.99; P = 0.05), bradycardia (RR 0.53, 95% CI 0.36-0.78; P = 0.001), pain at injection site (RR 0.07, 95% CI 0.01-0.56; P = 0.01), and total adverse events (RR 0.33, 95% CI 0.24-0.47; P = 0.00001) were significantly lower with remimazolam. However, no significant differences were observed in terms of postoperative nausea and vomiting (RR 0.98, 95% CI 0.66-1.46; P = 0.93), dizziness (RR 0.42, 95% CI 0.11-1.57; P = 0.20), psychiatric symptoms (RR 1.09, 95% CI 0.45-2.67; P = 0.85), and respiratory depression (RR 0.81, 95% CI 0.24-2.76; P = 0.74).

CONCLUSION

Our current analysis showed that the newly approved remimazolam was apparently associated with significantly fewer adverse drug events in comparison to propofol for GA in patients undergoing surgery. Therefore, this new drug should be further studied and more research with larger population sizes should be carried out to confirm this hypothesis.

Effect of remimazolam vs propofol on emergence from general anesthesia in patients undergoing cerebral endovascular procedures: A randomized controlled, non-inferiority trial

STUDY OBJECTIVE

This study aimed to compare the time to emergence from general anesthesia with remimazolam versus propofol in patients undergoing cerebral endovascular procedures.

DESIGN

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

SETTING

An academic hospital.

PATIENTS

Adult patients scheduled for cerebral endovascular procedures.

INTERVENTIONS

Patients were randomized at a 1:1 ratio to undergo surgery under general anesthesia with remimazolam (0.1 mg kg-1 for induction and 0.3-0.7 mg kg-1 h-1 for maintenance) or propofol (1-1.5 mg kg-1 for induction and 4-10 mg kg-1 h-1 for maintenance).

MEASUREMENTS

The primary outcome was the time to emergence from anesthesia. The non-inferiority margin was -2.55 min in group difference. Major secondary outcomes included hypotension during induction, incidence of postoperative delirium and Modified Rankin Scale (mRs) at 30 days and 90 days after surgery.

MAIN RESULTS

Of the 142 randomized patients, 129 completed the trial. In the modified intention-to-treat analysis, the mean time to emergence from anesthesia was 16.1 [10.4] min in the remimazolam group vs. 19.0 [11.2] min in the propofol group. The group difference was -2.9 min [95% CI -6.5, 0.7] (P = 0.003 for non-inferiority). The remimazolam group had lower rate of hypotension during induction (11.3% vs 25.4%, P = 0.03) and use of vasopressors during surgery (29.6% vs 62.0%, P < 0.001). The two groups did not differ in postoperative delirium and mRs at 30 and 90 days after surgery.

CONCLUSIONS

In patients undergoing cerebral endovascular procedures, remimazolam did not increase the time from anesthesia vs propofol.

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.

Exploring the Utility of remimazolam in cesarean sections under general anesthesia: A preliminary retrospective analysis and Implications for future study

Background

Remimazolam has recently been introduced as a maintenance agent for general anesthesia. However, the effect of remimazolam on peripartum prognosis has not been reported. Therefore, this study aimed to compare the effects of remimazolam and propofol for uterotonic drugs following cesarean section.

Methods

The electronic medical records of 51 adult women who underwent elective cesarean sections by single obstetrician under general anesthesia were collected. Participants were categorized into two groups: the propofol group and the remimazolam group. General anesthesia was maintained by continuous infusion of propofol or remimazolam after delivery. The number of uterotonic drugs administered during the cesarean section, the estimated blood loss (EBL), and length of hospital stay (LOS) after delivery were assessed.

Results

Of the 51 patients included in the study, 35 were in the propofol group and 16 in the remimazolam group. In the remimazolam group, five patients (31.3%, 5/16) received more uterotonics than the standard regimen. Conversely, in the propofol group, 19 patients (54.3%, 19/35) were injected with more uterotonics than the standard regimen. Logistic regression analysis showed that abnormal positioning of the placenta (P = 0.079) and not using remimazolam (P = 0.100) were the most relevant factors associated with the increased use of uterotonics. There was no significant difference in EBL between the two groups. The use of remimazolam was clinically relevant with a shorter LOS (P = 0.059).

Conclusions

The use of remimazolam as a maintenance agent did not result in significantly higher use of intrapartum uterotonics compared to the use of propofol. These results cannot exclude all adverse effects of remimazolam during cesarean delivery. Further randomized controlled trials must be conducted to obtain high-quality evidence.

Effectiveness and safety of remimazolam combined with alfentanil in hysteroscopic examination: A prospective, randomized, single-blind trial

BACKGROUND

Remimazolam is a novel, ultrashort-acting benzodiazepine. This study aimed to compare the efficacy and safety of remimazolam and propofol for hysteroscopic examination, to determine the optimal dose of remimazolam combined with alfentanil for painless hysteroscopy, and to calculate its median effective dose (ED50).

METHODS

Step 1: A total of 208 patients undergoing hysteroscopic examination were prospectively included in this study. Patients were randomized into 4 groups: 0.2 mg/kg remimazolam (group A), 0.25 mg/kg remimazolam besylate (group B), 0.3 mg/kg remimazolam (group C), and 2 mg/kg propofol (group D), with 52 patients in each group. One minute after losing consciousness, patients received an intravenous injection of alfentanil at 5 µg/kg, followed by a continuous infusion of alfentanil at 0.5 µg/kg/min. If patients showed frowning, movement, or MOAA/S > 1, sedatives were added: 0.05 mg/kg/dose of remimazolam for groups A, B, and C, and 0.5 mg/kg/dose of propofol for group D. Step 2: Dixon's up-and-down method was used to calculate the ED50 of remimazolam combined with alfentanil during hysteroscopic examination.

MAIN RESULTS

The sedation success rates of the remimazolam groups were 88.46%, 94.23%, and 98.08%, respectively, compared to 96.15% in the propofol group, with no significant difference (P = .175). MAP in groups A and B was higher than in group D (P < .05), and significantly higher in group C than in group D (P = .0016). SpO2 values in groups A, B, and C were higher than in group D at T2 to T3 (P < .001). HR in groups A, B, and C was significantly higher than in group D (P < .001). The ED50 of remimazolam combined with alfentanil in hysteroscopy was 0.244 mg/kg, 95%CI (0.195-0.22) and ED95 was 0.282 mg/kg, 95%CI (0.261-1.619).

CONCLUSION

In hysteroscopy, the sedative effect of remimazolam is like that of propofol, with 0.25 mg/kg remimazolam showing better safety and efficacy, and less impact on the respiratory and circulatory systems. Additionally, under the influence of alfentanil, the ED50 of remimazolam in hysteroscopy is 0.244 mg/kg, with no severe adverse reactions observed.

Remimazolam to prevent hemodynamic instability during catheter ablation under general anesthesia: a randomized controlled trial

PURPOSE

Maintaining hemodynamic stability during cardiac ablation under general anesthesia is challenging. Remimazolam, a novel ultrashort-acting benzodiazepine, is characterized by maintaining comparatively stable blood pressure and does not influence the cardiac conduction system, which renders it a reasonable choice for general anesthesia for cardiac ablation. We aimed to evaluate whether remimazolam is associated with a decreased incidence of intraoperative hypotension compared with desflurane.

METHODS

In this single-centre, parallel-group, prospective, single-blind, randomized clinical trial, we randomized patients (1:1) into a remimazolam group (remimazolam-based total intravenous anesthesia) or desflurane group (propofol-induced and desflurane-maintained inhalational anesthesia) during cardiac ablation procedures for arrhythmia. The primary outcome was the incidence of intraoperative hypotensive events, defined as mean arterial pressure of < 60 mm Hg at any period.

RESULTS

Overall, we enrolled 96 patients between 2 August 2022 and 19 May 2023 (47 and 49 patients in the remimazolam and desflurane groups, respectively). The remimazolam group showed a significantly lower incidence of hypotensive events (14/47, 30%) than the desflurane group (29/49, 59%; relative risk [RR], 0.5; 95% confidence interval [CI], 0.31 to 0.83; P = 0.004). Remimazolam was associated with a lower requirement for bolus or continuous vasopressor infusion than desflurane was (23/47, 49% vs 43/49, 88%; RR, 0.56; 95% CI, 0.41 to 0.76; P < 0.001). No between-group differences existed in the incidence of perioperative complications such as nausea, vomiting, oxygen desaturation, delayed emergence, or pain.

CONCLUSIONS

Remimazolam was a viable option for general anesthesia for cardiac ablation. Remimazolam-based total intravenous anesthesia was associated with significantly fewer hypotensive events and vasopressor requirements than desflurane-based inhalational anesthesia was, without significantly more complications.

STUDY REGISTRATION

ClinicalTrials.gov (NCT05486377); first submitted 1 August 2022.

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.

Comparative Analysis of the Hemodynamic Effects of Remimazolam and Propofol During General Anesthesia: A Retrospective Study

PURPOSE

Hypotension is common during anesthesia induction. However, minimal hemodynamic effects of remimazolam anesthesia have been reported. We hypothesized that remimazolam would have weaker hemodynamic effects than would propofol. To test this, we simultaneously evaluated the hemodynamics using the estimated continuous cardiac output (esCCO) system and heart rate variability (HRV) during anesthesia induction.

METHODS

This was a single-center, observational, retrospective study of patients undergoing dental surgery under general anesthesia between 2020 and 2022. Seventy patients were divided into two groups: remimazolam (R group; n=34) and propofol (P group; n=36). The information obtained from the anesthesia records, patient information, esCCO system parameters, and HRV were integrated and analyzed. The percentages of various parameters were set to 100% for the pre-induction phase as the baseline.

RESULTS

The %MAP (noninvasive mean arterial blood pressure) decreased over a narrower range in the R compared to the P group (-17.8% (-26.3%, -11.9%) vs. -22.6% (-32.9%, -17.0%); P=0.039). The %HR (heart rate) increased significantly in the R group and decreased in the P group (+10.7% (+6.5%, +18.6%) vs. -6.5% (-14.5%, +8.4%); P<0.01). The %SVesCCO (stroke volume calculated using the esCCO system) decreased significantly in both groups, but the R group showed a smaller difference compared to the P group (- 5.1% (-7.7%, -2.1%) vs. -10.0% (-13.8%, -5.6%); P<0.01). The rates of change in %LF nu (normalized unit of low frequency) and %HF nu (normalized unit of high frequency) were lower for the R than for the P group, although the difference was not significant (+6.8% (-14.5%, 32.4%) vs. +9.2% (-7.2%, +59.7%), P=0.30; +7.9% (-51.0%, +66.9%) vs. +22.8% (-26.1%, +61.6%), P=0.57).

CONCLUSION

Remimazolam demonstrated a lower MAP reduction rate than propofol. A compensatory increase in HR occurred with a decrease in stroke volume. However, the HR increase was not attributable to the autonomic nervous system.

Comparison of efficacy and safety of equivalent doses of remimazolam versus propofol for gastroscopy anesthesia in elderly patients

Remimazolam, a novel intravenous anesthetic, has been proven to be safe and efficacious in the gastroscopy setting among the elderly. However, reports comparing the effectiveness and safety of using equivalent doses of remimazolam with propofol have not been seen. The aim of this study was to compare the sedation efficacy and safety of the 95% effective doses (ED95) of remimazolam versus propofol combined with sufentanil in the gastroscopy setting among the elderly. In the first step of this two-step study, a modified up-and-down method was used to calculate the ED95 of remimazolam and propofol when combined with 0.1 µg/kg sufentanil in inhibiting body movement of elderly patients undergoing gastroscopy. In the second step, ED95 of both agents calculated in the first step were administered, endpoints of efficacy, safety, and incidence of adverse events were compared. A total of 46 individuals completed the first step. The ED95 of remimazolam was 0.163 mg/kg (95% CI 0.160-0.170 mg/kg), and that of propofol was 1.042 mg/kg (95% CI 1.007-1.112 mg/kg). In the second step, 240 patients completed the trial. The anesthetic effective rates of the remimazolam group and the propofol group were 78% and 83%, respectively, with no statistical difference (P = 0.312). Patients in the remimazolam group had more stable circulatory functions (P < 0.0001) and a lower incidence of pain on injection (3.3% vs. 19.5%, P < 0.0001). The incidence of hypotension was low in the remimazolam versus propofol group (15.6% vs. 39.0%, P < 0.0001). Overall adverse event was low in the remimazolam versus propofol group (21.3% vs. 62.7%, P < 0.0001).In this study, we found that when anesthesia was administered to elderly gastroscopy patients based on 95% effective doses of remimazolam and propofol, remimazolam was as effective as propofol, but was safer with a lower incidence of adverse events.Study registration: Chinese Clinical Trial Registry, ChiCTR2000034234. Registered 29/06/2020, https://www.chictr.org.cn .

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.

Predicted effect-site concentrations of remimazolam for i-gel insertion: a prospective randomized controlled study

This study is the first to report 50% and 95% effect-site concentrations (EC50 and EC95, respectively) of the new short-acting benzodiazepine, remimazolam, for the successful insertion of i-gels with co-administration of fentanyl. Thirty patients (38 ± 5 years old, male/female = 4/26) were randomly assigned into five groups to receive one of five different remimazolam doses (0.1, 0.15, 0.2, 0.25, and 0.3 mg/kg bolus followed by infusion of 1, 1.5, 2, 2.5, and 3 mg/kg/h, respectively, for 10 min), which were designed to maintain a constant effect-site concentration of remimazolam at the time of i-gel insertion. At 6 min after the start of remimazolam infusion, all patients received 2 µg/kg fentanyl. i-gel insertion was attempted at 10 min and the success or failure of insertion were assessed by the patient response. Probit analysis was used to estimate the EC50 and EC95 values of remimazolam with 95% confidence intervals (CIs). In the five remimazolam dose groups, two, two, four, five, and six of the six patients in each group had an i-gel successfully inserted. Two patients in the lowest remimazolam dose group were conscious at the time of i-gel insertion and were counted as failures. The EC50 and EC95 values of remimazolam were 0.88 (95% CI, 0.65-1.11) and 1.57 (95% CI, 1.09-2.05) µg/ml, respectively. An effect-site concentration of ≥ 1.57 µg/ml was needed to insert an i-gel using remimazolam anesthesia, even with 2 µg/kg fentanyl. Trial registration: The study was registered in Japan Registry of Clinical Trials on 19 April 2021, Code jRCTs041210009.

Efficacy of remimazolam tosilate versus propofol for total intravenous anaesthesia in urological surgery: A randomised clinical trial

BACKGROUND

Remimazolam is a novel ultra-short-acting benzodiazepine sedative that acts on the gamma-aminobutyric acid type A receptor (GABAAR).

OBJECTIVE

To compare the efficacies of remimazolam (RMZ), and propofol (PROP) combined with remifentanil and cisatracurium for total intravenous anaesthesia (TIVA) in patients undergoing urological surgery.

DESIGN

A prospective, single-blind, randomised, noninferiority clinical trial.

SETTING

Single centre from 1 January 2022 to 30 March 2022.

PATIENTS

A total of 146 adult patients undergoing elective urological surgery.

INTERVENTION

Patients were randomly allocated in a 1 : 1 ratio to the PROP or RMZ groups. In the PROP group, anaesthesia was induced with propofol at 100 mg min -1 to reach a bispectral index score (BIS) of 40 to 60. After loss of consciousness (LOC), intravenous fentanyl 3 μg kg -1 was administered, followed by cisatracurium 0.3 mg kg -1 . Patients were intubated 3 min after cisatracurium administration. Anaesthesia was maintained with the combination of propofol (plasma concentration: 2.5 to 4 μg ml -1 ) and remifentanil (plasma concentration: 2.5 to 4 ng ml -1 ). In the RMZ group, anaesthesia was induced with remimazolam tosilate starting at 10 mg kg -1  h -1 to reach a BIS of 40 to 60 and maintained between 0.2 and 2 mg kg -1  h -1 . After LOC, fentanyl and cisatracurium were administered and intubation was performed as in the PROP group. Anaesthesia was maintained with a combination of remimazolam (0.2 to 2 mg kg -1  h -1 ) and remifentanil (plasma concentration: 2.5 to 4 ng ml -1 ).

MAIN OUTCOME MEASURES

The primary outcome was the TIVA success rate. The predefined noninferiority margin considered an absolute difference of 6% in the primary outcome between the groups. The secondary outcomes were vital signs, anaesthesia and surgery characteristics, and adverse events.

RESULTS

All patients completed the trial. The success rates of TIVA with remimazolam and propofol were 100 and 98.6%, respectively. The incidence of hypotension during anaesthesia was lower in the RMZ group (26%) than in the PROP group (46.6%) ( P  = 0.016). The median [IQR] total consumption of ephedrine during anaesthesia was higher in the PROP group 10 [0 to 12.5] mg than in the RMZ group 0 [0 to 10] mg ( P  = 0.0002). The incidence of injection pain was significantly higher in the PROP group (76.7%) than in the RMZ group (0; P  < 0.001). No significant differences in the controllability of the anaesthesia depth, anaesthesia and surgery characteristics, or vital signs were observed between the groups.

CONCLUSION

Remimazolam demonstrated noninferior efficacy to propofol combined with remifentanil and cisatracurium for TIVA in patients undergoing urological surgery.

TRIAL REGISTRATION

Chictr.org.cn, identifier: ChiCTR2100050923.

CLINICAL REGISTRATION

The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100050923, Principal investigator: Xuehai Guan, Date of registration: 8 November 2021, https://www.chictr.org.cn/showproj.html?proj=133466 ).

The Rise of Remimazolam: A Review of Pharmacology, Clinical Efficacy, and Safety Profiles

Anesthesiologists often use benzodiazepines (BZDs) due to their remarkable amnestic and anxiolytic capabilities. Because of this, they are perfect for use during the perioperative phase, when patients' anxiety levels are already high. Remimazolam has replaced certain commonly used intravenous (IV) anesthetics due to its excellent safety profile, rapid onset of action, and short half-life. The four classes of BZDs, 2-keto-benzodiazepines, 3-hydroxy-benzodiazepines, triazolobenzodiazepines, and 7-nitro-benzodiazepines based on chemical structure, provide various levels of drowsiness, forgetfulness, and anxiolysis. Based on their elimination half-life, short-acting BZDs typically have a half-life ranging from one to 12 hours, e.g., oxazepam; intermediate-acting BZDs have an average elimination half-life of 12 to 40 hours, e.g., alprazolam; and long-acting BZDs have an average elimination half-life of more than 40 hours, e.g., diazepam. The chloride ion channel is conformationally shifted by the benzodiazepine molecule resulting in central nervous system (CNS) inhibition and hyperpolarization. Each type of benzodiazepine has a favored use. For example, diazepam is used to treat anxiety. Midazolam is used for its anxiolytic and anterograde amnestic effects during the perioperative phase. Anxiety and epilepsy are two conditions that lorazepam effectively treats. There are now phase II and III clinical studies investigating remimazolam. It is not sensitive to alterations in its surroundings and has a brief half-life so that it may be removed rapidly, even after extensive infusion. Being a soft drug means the body easily breaks it down via metabolism, which explains many features. Remimazolam is hydrolyzed into methanol and its carboxylic acid metabolite CNS 7054 by esterase metabolism. Therefore, remimazolam has a shorter onset time and faster recovery than other BZDs. Remimazolam is metabolized independently of any particular organ. Patients with hepatic and renal problems will not see any changes in metabolism or excretion since the drug's ester moiety makes it a substrate for general tissue esterase enzymes. Like its predecessor, midazolam, it has a high potential for addiction. Some side effects that could occur during infusion include headaches and drowsiness. In clinical trials, hypotension, respiratory depression, and bradycardia were noted in participants. BZDs are helpful when used in conjunction with anesthesia. Remimazolam stands out, thanks to its unique pharmacokinetics, pharmacodynamics, safety profile, and potential medical applications. Its desirable properties make it a potential surgical premedication and sedative in the critical care unit. Anesthesiologists and other doctors could have access to more consistent and safer medication. However, additional comprehensive clinical trials are necessary to understand remimazolam's advantages and disadvantages.

Comparison of the negative effect of remimazolam and propofol on cardiac contractility: Analysis of a randomised parallel-group trial and a preclinical ex vivo study

Remimazolam is a newly developed ultra-short-acting benzodiazepine that exerts sedative effects. This study aimed to clarify the effects of remimazolam on cardiac contractility. In a randomised-parallel group trial, haemodynamic parameters were compared between propofol (n = 11) and remimazolam (n = 12) groups during the induction of general anaesthesia in patients undergoing non-cardiac surgery. In a preclinical study, the direct effects of remimazolam on cardiac contractility were also evaluated using isolated rat hearts. RNA sequence data obtained from rat and human hearts were analysed to assess the expression patterns of the cardiac γ-aminobutyric acid type A (GABAA ) receptor subunits. In a clinical study, the proportional change of the maximum rate of arterial pressure rise was milder during the study period in the remimazolam group (propofol: -52.6 [10.2] (mean [standard deviation])% vs. remimazolam: -39.7% [10.5%], p = 0.007). In a preclinical study, remimazolam did not exert a negative effect on left ventricle developed pressure, whereas propofol did exert a negative effect after bolus administration of a high dose (propofol: -26.9% [3.5%] vs. remimazolam: -1.1 [6.9%], p < 0.001). Analysis of the RNA sequence revealed a lack of γ subunits, which are part of the major benzodiazepine binding site of the GABAA receptor, in rat and human hearts. These results indicate that remimazolam does not have a direct negative effect on cardiac contractility, which might contribute to its milder effect on cardiac contractility during the induction of general anaesthesia. The expression patterns of cardiac GABAA receptor subunits might be associated with the unique pharmacokinetics of benzodiazepines in the heart.

Anti-inflammatory potential of remimazolam: A laboratory and clinical investigation

BACKGROUND

Anesthetic agents, particularly intravenous anesthetics, may affect immune function and tumorigenic factors. We herein investigated whether the anti-inflammatory effects of anesthetic agents are attributed to their antioxidant properties. The antioxidant and anti-inflammatory effects of remimazolam, a new anesthetic, remain unclear. We hypothesized that remimazolam exerts anti-inflammatory effects due to its antioxidant properties, which may affect the postoperative inflammatory response. This retrospective clinical study examined this hypothesis using laboratory and clinical approaches.

METHODS

The antioxidant effects of remimazolam and dexmedetomidine were assessed by electron spin resonance (ESR) spectroscopy, and postoperative inflammatory responses were compared in 143 patients who underwent transcatheter aortic valve replacement at Kindai University Hospital between April 2021 and December 2022. The primary endpoint was the presence or absence of the antioxidant effects of the anesthetics themselves using ESR.

RESULTS

Remimazolam at clinical concentrations exerted antioxidant effects, whereas dexmedetomidine did not. Increases in C-reactive protein (CRP) levels on POD3 from preoperative values were significantly smaller in the remimazolam group than in the dexmedetomidine group (1.33 ± 1.29 vs. 2.17 ± 1.84, p = .014).

CONCLUSIONS

Remimazolam exerted stronger anti-inflammatory effects than dexmedetomidine, and these effects were enhanced by its antioxidant properties, which may have affected postoperative CRP production.

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).

Utility of Remimazolam for Fast-Track Recovery Following Surgical Aortic Valve Replacement in an Elderly Patient With Severe Aortic Stenosis: A Case Report

Remimazolam is an ultra-short-acting benzodiazepine that has minimal hemodynamic effects and is useful for early extubation after cardiac surgery. We present a case of an elderly patient with severe aortic stenosis (AS) who underwent surgical aortic valve replacement (AVR), was extubated in the operating room, and recovered quickly without postoperative delirium. An 87-year-old woman with severe AS underwent AVR under cardiopulmonary bypass. General anesthesia was induced with remimazolam 10 mg over one minute and fentanyl 100 µg, and maintained with remimazolam 0.4-0.7 mg/kg/hour, fentanyl, and remifentanil. Intraoperative hemodynamic condition was stable without vasopressors. Remimazolam was discontinued after sternum closure. She recovered consciousness five minutes after the completion of the surgery, and the tracheal tube was removed in the operating room. Remimazolam may be useful for fast-track recovery following surgical AVR in an elderly patient with severe AS.

Benefits of remimazolam as an anesthetic sedative for older patients: A review

Owing to the decreased levels of receptors in the peripheral and central nervous systems, the functions of various organ systems decline in older patients. When administering anesthesia to older patients, it is necessary to consider the effects of medication on the homeostatic balance. Remimazolam, a new benzodiazepine, was recently developed as an anesthetic drug that has shown promise in clinical anesthesia application owing to its molecular structure, targets, pharmacodynamics, and pharmacokinetic characteristics. Remimazolam exhibits a rapid onset and metabolism, with minor effects on liver and kidney functions. Moreover, the drug has a specific antagonist, flumazenil. It is safer to use in older patients than other anesthetic sedatives and has been widely used since its introduction. Comparisons of the pharmacokinetics, metabolic pathways, effects on target organs, and hemodynamics of different drugs with those of commonly used anesthetic sedative drugs are useful to inform clinical practice. This article elaborates on the benefits of remimazolam compared with those of other anesthetic sedatives for sedation in older patients to demonstrate how it offers a new option for anesthetics in older patients. In cases involving older patients with increased clinical complexities or very old patients requiring anesthesia, remimazolam can be selected as the preferred anesthetic sedative, as outlined in this review.

Randomized controlled trial of remimazolam compared with placebo in Japanese patients undergoing upper gastrointestinal endoscopy: Phase III investigator-initiated clinical trial

OBJECTIVES

To assess the effectiveness of remimazolam against normal saline (placebo) as a sedative agent for endoscopy in a multicenter, randomized, double-blind, investigator-initiated phase III controlled trial.

METHODS

We included 48 Japanese patients undergoing upper gastrointestinal endoscopy. For the procedure, an initial remimazolam dose of 3 mg and additional doses of 1 mg were administered, as determined in the phase II clinical study. The primary study end-point was the successful sedation rate during gastrointestinal endoscopy, determined as a Modified Observer's Assessment of Alertness/Sedation score ≤4 before the start of endoscopy, the completion of gastrointestinal endoscopy, and two or fewer additional doses per 6 min.

RESULTS

The successful endoscopy sedation rates were 91.9% and 9.1% in the remimazolam and placebo groups, respectively (P < 0.01). The time from the end of endoscopy to arousal was 0.0 (0.0-0.0) min for both groups. The number of additional doses required to achieve sedation was lower in the remimazolam group than that in the placebo group (P < 0.01).

CONCLUSIONS

Remimazolam demonstrated a significantly higher sedation effect during upper gastrointestinal endoscopy in Japanese patients with safe and fast recovery compared with placebo.

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.

Remimazolam: A Retrospective Study of Initial Safety and Recovery Data in Diverse Procedural Sedation

PURPOSE

The new ultra-short-acting benzodiazepine, remimazolam, offers a pharmacokinetic and pharmacodynamic advantage over commonly used procedural sedation medication. This retrospective study explored the real-world utilization of remimazolam during procedural sedation to support the development of a nurse sedation protocol. The primary outcome was to identify associations between recovery time, adverse reactions, and dose-response in expanded patient populations.

METHODS

This study reviewed charts of 292 adult patients from 3 hospitals within one institution who received remimazolam during procedural sedation between June 1, 2021 and December 31, 2021. Data were analyzed using logistic and linear regression.

FINDINGS

The median time to alert in patients receiving remimazolam alone was 12 minutes (interquartile range 10, 17) and increased when additional sedation medications were utilized. Receiving additional sedative medication significantly increased the odds of hypoxia (OR 2.77, 95% CI 1.30-5.91, P = 0.008) after adjusting for body mass index (BMI), American Society of Anesthesiologists physical status (ASA-PS), and total remimazolam dose. There was a 25% increase in odds of experiencing hypoxia for every 5 kg/m2 increase in BMI (95% CI 1.01-1.54, P = 0.037).

IMPLICATIONS

Remimazolam presents as a promising option for nurse procedural sedation, offering minimal impact on hemodynamics and respirations, quick recovery, and no residual sedative effects.

The Effect of Sex on the Remimazolam Dosage Required for Successful i-gel Supraglottic Airway Insertion with Remifentanil in Non-Paralyzed Patients: An Up-and-Down Sequential Allocation Trial

(1) Background: The physiological and pharmacological variations between men and women are known to influence drug efficacy. The objective of this study was to determine the 50% and 95% effective doses (ED50 and ED95) of remimazolam required for i-gel supraglottic airway (ISA) insertion under remifentanil infusion without neuromuscular blocking agents (NMBAs) in both males and females. (2) Methods: Patients aged 19-65 years, scheduled for general anesthesia using ISA, were enrolled in this study. Patients were divided into two groups based on their sex. The anesthesia process began with a remifentanil infusion targeting an effect-site concentration of 3.0 ng/mL, accompanied by a remimazolam injection. The initial remimazolam dose was 0.25 mg/kg, and it was adjusted with a step size of 0.05 mg/kg based on the outcome of ISA insertion in the preceding patient. (3) Results: The ED50 of remimazolam (mean ± standard error) was 0.28 ± 0.02 mg/kg in the male group and 0.18 ± 0.02 mg/kg in the female group (p < 0.001). Additionally, ED95, which was calculated using the isotonic regression method, was significantly comparable between the male and female groups (male: 0.35 mg/kg, 95% confidence interval [CI] = 0.34-0.35; female: 0.29 mg/kg, 95% CI = 0.25-0.30). (4) Conclusions: This study showed that both the ED50 and the ED95 of remimazolam for successful ISA insertion was higher for men than that for women. Therefore, while using remimazolam alongside remifentanil infusion without NMBAs for ISA insertion, one should consider the patient's sex for appropriate dosing.

Effect of remimazolam on electroencephalogram burst suppression in elderly patients undergoing cardiac surgery: Protocol for a randomized controlled noninferiority trial

Background

Postoperative delirium (POD) is a common complication following cardiac surgery and increases postoperative morbidity and mortality. Intraoperative electroencephalogram (EEG) burst suppression suggests excessively deep anesthesia and predicts POD. Use of remimazolam provides a stable hemodynamic status and an appropriate depth of anesthesia. We aim to assess remimazolam administered for anesthesia and sedation in elderly patients having cardiac surgery.

Methods

This is a randomized controlled clinical trial with noninferiority design. A total of 260 elderly patients aged equal to or greater than 60 years undergoing cardiac surgery will be randomly allocated to receive remimazolam or propofol (1:1) for general anesthesia and postoperative sedation until extubation. The primary outcome is the cumulative time with EEG burst suppression which is obtained from the SedLine system. The noninferiority margin is 2.0 min. The secondary outcomes include the POD occurrence within the first 5 days postoperatively and the duration of perioperative hypotension.

Discussion

This noninferiority trial is the first to evaluate the effect of perioperative remimazolam administration on EEG burst suppression, POD occurrence, and duration of hypotension in elderly patients who undergo cardiac surgery.

Trial registration

Chinese Clinical Trial Registry (ChiCTR2200056353).

Dreaming during gastrointestinal endoscopy under propofol, ciprofol, or remimazolam anesthesia: study protocol for a parallel-design double-blind, single-center trial

BACKGROUND

Dreaming sometimes occurs during sedation. It has been reported that factors such as different anesthetics, depth of anesthesia, age, sex, and preoperative psychological state may affect dreams. Ciprofol and remimazolam are novel choices for painless endoscopy. Herein, we aimed to investigate dreaming during gastrointestinal endoscopy under propofol, ciprofol, and remimazolam anesthesia respectively.

METHODS

This is a prospective, parallel-design double-blind, single-center clinical trial. Three hundred and sixty subjects undergoing elective painless gastroscopy, colonoscopy, or gastroenteroscopy will be enrolled. Eligible subjects will undergo propofol-, ciprofol-, or remimazolam-induced anesthesia to finish the examination. Interviews about the modified Brice questionnaire will be conducted in the recovery room. Incidence of dreaming is set as the primary outcome. Secondary outcomes include type of dreams, improvement of sleep quality, evaluation of patients, incidence of insufficient anesthesia, and intraoperative awareness. Safety outcomes are the incidences of hypotension and hypoxia during examination and adverse events during recovery.

DISCUSSION

This study may observe different incidences of dreaming and diverse types of dreams, which might lead to different evaluations to the anesthesia procedure. Based on the coming results, anesthesiologists can make a better medication plan for patients who are going to undergo painless diagnosis and treatment.

TRIAL REGISTRATION

This trial was registered at the Chinese Clinical Trial Registry on May 18, 2023 (registration number ChiCTR2300071565).

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.

Remimazolam sedation for awake tracheal intubation

We present a case of a 55-year-old woman presenting for an elective minor procedure. Following a previous anaesthetic, a 'can't intubate, can't oxygenate' incident had been documented. She had since undergone awake tracheal intubation for procedures requiring general anaesthesia. We were able to safely facilitate awake tracheal intubation using remimazolam for sedation. Remimazolam is a novel ultra-short acting benzodiazepine with similar pharmacodynamic effects to its parent compound midazolam, having minimal cardiovascular or respiratory effects and offering excellent anxiolysis and amnesia. It has a significantly shorter duration of action than midazolam, making it a valuable sedative agent for awake tracheal intubation. The patient remained stable throughout the procedure, with minimal effects on the respiratory and cardiovascular systems. The quality of sedation was reported as highly satisfactory by both the patient and the team.

Application of remimazolam transversus abdominis plane block in gastrointestinal tumor surgery

BACKGROUND

Transversus abdominis plane block (TAPB) is a block of the abdominal afferent nerve fibers between the internal oblique muscle and the transverse abdominal muscle achieved with local anesthetics. It can effectively block the conduction of the anterior nerve of the abdominal wall and exert a good analgesic effect. However, the effect of combining the block with remimazolam on anesthesia in patients undergoing gastrointestinal tumor surgery is still unclear.

AIM

To examine the effects of combining TAPB with remimazolam on the stress response and postoperative recovery of gastrointestinal tumor surgery patients.

METHODS

A retrospective analysis was conducted on the clinical data of 102 individuals diagnosed with gastrointestinal malignancies who underwent laparoscopic surgery under general anesthesia between April 2020 and June 2023. The patients were categorized into a control group (n = 51), receiving remimazolam for general anesthesia, and an observation group (n = 51), receiving TAPB combined with remimazolam for general anesthesia. A comparison was made between both groups in terms of hemodynamic parameters, stress markers, pain levels, recovery quality, analgesic effects, and adverse reactions during the perioperative period.

RESULTS

The observation group had significantly higher heart rates at time points 1 min after induction and upon leaving the operating room than the control group (P < 0.05). The mean arterial pressure at time point T1 in the observation group was significantly higher than that in the control group (P < 0.05). Five minutes after extubation, the levels of the hormones adrenaline and noradrenaline in the observation group were considerably lower than those in the control group (P < 0.05). At 12 h, 24 h, and 48 h following surgery, the visual analog scale scores of the observation group were considerably lower than those of the control group (P < 0.05). The observation group had shorter awakening and extubation times and lower Riker sedation-agitation scale scores than the control group (P < 0.05). The observation group exhibited considerably fewer effective pump presses, lower fentanyl dosages, and lower incidences of rescue analgesia within 24 h following surgery than the control group (P < 0.05).

CONCLUSION

The application effect of TAPB combined with remimazolam general anesthesia in anesthesia of patients undergoing gastrointestinal tumor surgery is good, which is helpful to promote faster recovery after operation.

Efficacy and safety of remimazolam compared with propofol in hypertensive patients undergoing breast cancer surgery: a single-center, randomized, controlled study

BACKGROUND

Remimazolam, as a novel anesthetic, has recently been shown to improve hemodynamic stability during anesthesia induction and maintenance; however, it has not been reported in the hypertensive population. This study aimed to compare the effects of remimazolam and propofol on hemodynamic stability in hypertensive patients undergoing breast cancer surgery.

METHODS

We enrolled 120 hypertensive patients undergoing breast cancer surgery in this prospective study and randomly allocated them to remimazolam (n = 60) or propofol (n = 60) groups. Anesthesia regimens were consistent between groups, except for the administration of remimazolam and propofol. Our primary outcome was the incidence of post-induction hypotension, which was either an absolute mean arterial pressure (MAP) < 60 mmHg or a > 30% relative drop in MAP compared to baseline within 20 min of induction or from induction to the start of surgery. Secondary outcomes included minimum MAP and MAP at different time points during anesthesia, the application of vasoactive drugs, adverse events, and the patient's self-reported Quality of Recovery-40 scale for the day after surgery.

RESULTS

The incidence of post-induction hypotension was lower and the minimum MAP during induction was higher in the remimazolam group than those in the propofol group. There were no significant differences between the two groups in the remaining outcomes.

CONCLUSION

Remimazolam is safe and effective in hypertensive patients undergoing breast cancer surgery. Induction with remimazolam in hypertensive patients may result in more stable hemodynamics than propofol.

TRIAL REGISTRATION

This study was registered at the Chinese Clinical Trials Registry ( http://www.chictr.org.cn ) on 03/12/2020, with registration number ChiCTR2000040579.

Remimazolam-Based Anesthesia in Patients with Heart Failure Due to Mitral Regurgitation and Low Left Ventricular Function: A Case Series

Background and Objectives: Remimazolam is a new ultrashort-acting benzodiazepine anesthetic. Remimazolam appears to be useful in patients with severe valvular disease because of its minimal cardiovascular impact. In this retrospective case series study, we assessed the efficacy and safety of remimazolam for maintaining hemodynamic stability during anesthetic induction and maintenance. Cases: MitraClip was performed on 18 cases with severe mitral regurgitation with low left ventricular function who presented with heart failure, and remimazolam was administered for general anesthesia with induction (12 mg/kg/h) and maintenance (1 mg/kg/h). The impact of remimazolam on the hemodynamics at anesthetic induction and during anesthetic maintenance was investigated retrospectively using electronic medical records. Blood pressure decreased significantly during anesthetic induction with remimazolam (78.5 [72, 81.25] and 66.1 [62.2, 74.2], median [IQR], p = 0.0001), but only mildly, by about 10 mmHg. There was no significant change in the cardiac index (2.0 [1.8, 2.4] vs. 1.9 [1.8, 2.3], p = 0.57642) or pulse rate (73.5 ± 8.85 vs. 74.7 ± 11.7, mean ± SD, p = 0.0876) during anesthetic induction with remimazolam. All patients underwent MitraClip without major hemodynamic concerns, with no or small increases in inotropes. Conclusions: Remimazolam may be used safely in patients with severe mitral regurgitation and low left ventricular function presenting with heart failure.

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.

Comparison of different weight-based scalars of remimazolam tosylate for anesthesia induction in obese patients: study protocol for a prospective, controlled trial

BACKGROUND

The physiologic and anthropometric characteristics changes associated with obesity may result in the alternation of pharmacologic management. Remimazolam tosylate is a new type of ultra-short-acting benzodiazepine with stable context-sensitive half-time (CSHT) and no lipid accumulation after long-time infusion. Although remimazolam tosylate has potential advantages for the induction and maintenance of anesthesia in obese patients, the appropriate induction dosing scalars among obese patients are unknown. Therefore, we aim to compare the different weight-based scalars for dosing remimazolam tosylate of anesthesia induction among obese patients.

METHODS/DESIGN

The study will be performed as a prospective, single-center, double-blind, controlled clinical trial. The study design is a comparison of remimazolam tosylate requirements based on total body weight (TBW) or lean body weight (LBW) to reach a Modified Observer's Assessment of Alertness and Sedation (MOAA/S) score of 0 among obese subjects (BMI ≥ 35 kg/m2). Another twenty normal-weight subjects (18.5 kg/m2 ≤ BMI < 25 kg/m2) will be enrolled as a control group, whose induction dose is scaled based on TBW. The infusion rate of remimazolam tosylate during induction is 12 mg/kg/h in all groups.

DISCUSSION

Results of the present study will provide evidence of dose scalar of remimazolam tosylate to guide the clinical practice of anesthesia induction in obese patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR220005664. Registered on 9 February 2022, https://www.chictr.org.cn/showproj.aspx?proj=151150 .

Safety and efficacy of remimazolam for general anesthesia in elderly patients undergoing laparoscopic cholecystectomy: a randomized controlled trial

Introduction

There is insufficient evidence regarding the efficacy and safety of remimazolam in elderly patients. Therefore, this study evaluated the differences in the anesthesia characteristics and perioperative hemodynamic profiles of elderly patients receiving total intravenous anesthesia with remimazolam or propofol.

Methods

Eighty-four patients aged >65 years with an American Society of Anesthesiologists physical status of I-III were randomly assigned to Group R (receiving remimazolam, n = 42) or Group P (receiving propofol, n = 42). In Group R, remimazolam was initiated at a rate of 6 mg/kg/h until loss of consciousness (LOC) was achieved and maintained at 1 mg/kg/h subsequently. In Group P, 1.0-1.5 mg/kg of propofol was injected for 1 min and maintained at 100 μg/kg/min subsequently. The maintenance infusion rate was adjusted to maintain an appropriate depth of anesthesia until the end of the surgery. The primary outcome was the time to LOC. The depth of anesthesia scores and hemodynamic profiles were recorded perioperatively.

Results

The time to LOC was significantly longer in Group R (120 s) than in Group P (60 s) (p < 0.001). The time to eye-opening (Group R, 10 min; Group P, 10 min; p = 0.056), the incidence of maintenance of hemodynamic changes within 20% of the peri-anesthetic values, and treatments for hemodynamic instability did not differ significantly between the groups. The depth of anesthesia scores did not differ significantly between the groups; however, the scores were higher in Group R than those in Group P before endotracheal intubation. The hemodynamic parameters did not differ significantly at any time point. The time to extubation was longer in Group R (12 min) than that in Group P (10 min) (p = 0.007). Similarly, the time to discharge from the operating room was significantly longer in Group R (15 min) compared to Group P (12 min) (p = 0.018).

Conclusion

Remimazolam does not exhibit a comparable effect to propofol in terms of anesthesia induction and recovery. However, it demonstrates a similar effect to propofol regarding intraoperative anesthesia depth and hemodynamic profile in elderly patients undergoing remifentanil-based total intravenous anesthesia.

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 ).

Comparison of propofol vs. remimazolam on emergence profiles after general anesthesia: A randomized clinical trial

STUDY OBJECTIVE

The emergence profiles in patients undergoing total intravenous anesthesia with either propofol or remimazolam with flumazenil reversal were compared.

DESIGN

A prospective, double-blind, randomized trial.

SETTING

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

PATIENTS

Adult patients (n = 100) having American Society of Anesthesiologists (ASA) physical status of I-III undergoing general anesthesia were enrolled and randomly assigned to the propofol or the remimazolam group.

INTERVENTIONS

The propofol group received target-controlled infusion of propofol, and the remimazolam group received continuous infusion of remimazolam. Continuous infusion of remifentanil was used in both groups. For emergence, flumazenil was used in increments of 0.2 mg in the remimazolam group.

MEASUREMENTS

The primary outcome was the time required for the patient to obey verbal commands. The secondary outcomes included the time to bispectral index (BIS) over 80, the time to laryngeal mask airway (LMA) removal, the Richmond Agitation-Sedation Scale (RASS) scores in the PACU, and adverse events throughout the study period.

MAIN RESULTS

The time taken to obey verbal commands was significantly longer in the propofol group than the remimazolam group (14 [9, 19]) vs. 5 [3, 7]) minutes, P < 0.001; median difference -9, 95% confidence interval -11 to -6). The times to BIS over 80 and to LMA removal were also significantly longer in the propofol group. In addition, the RASS score upon arrival to the PACU differed significantly between the two groups (P = 0.006). Re-sedation in the PACU was observed in 11 (22%) of the patients in the remimazolam group.

CONCLUSIONS

Remimazolam-based total intravenous anesthesia with flumazenil reversal may be effective in reducing emergence time, but a significant incidence of re-sedation was observed in the PACU. Further studies are needed to determine adequate dose and timing of routine flumazenil use and minimize the risk of re-sedation.

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 .