Remimazolam: pharmacological characteristics and clinical applications in anesthesiology

Remimazolam-based anesthesia in a patient with hypertrophic obstructive cardiomyopathy undergoing radical colorectal cancer surgery: A case report

BACKGROUND

The goal of anesthesia in patients with hypertrophic obstructive cardiomyopathy (HOCM) is to reduce the risk of left ventricular outflow tract obstruction triggered by anesthetics. Remimazolam is a newly developed anesthetic that has been reported to have superior hemodynamic stability. There have been no reports on the completion of non-cardiac surgery with remimazolam in patients with HOCM.

METHODS

Here we report the case of a 49-year-old man diagnosed with hypertrophic obstructive cardiomyopathy who underwent resection of colon cancer with remimazolam and remifentanil anesthesia. A bolus 0.3 mg/kg remimazolam was administered for anesthesia induction, and then adjusted to 2 mg/kg/h to maintain anesthesia. Set the pain threshold index to 50 to auto-control the infusion speed of remifentanil.

RESULTS

No hypotension occurred during anesthesia, and norepinephrine was not administered. After conversion to open surgery, the patient's blood pressure elevated and reduced with urapidil and esmolol.

CONCLUSION

In this patient with HOCM, remimazolam and remifentanil provided adequate anesthesia for induction and maintenance to complete the right hemicolectomy.

Remimazolam for Procedural Sedation in Older Patients: A Systematic Review and Meta-Analysis with Trial Sequential Analysis

This systematic review and meta-analysis with trial sequential analysis (TSA) aimed to evaluate the efficacy and safety of remimazolam compared to other sedatives for procedural sedation in older patients. We registered the protocol of this systematic review and meta-analysis with TSA in the PROSPERO network (CRD42023441209). Two investigators performed a systematic, comprehensive, and independent search of the PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases to identify randomized controlled trials (RCTs) comparing remimazolam with other sedatives in older patients undergoing procedural sedation. Conventional meta-analysis and TSA were also performed. Seven RCTs (1502 patients) were included. Pooled results demonstrated that remimazolam was associated with a low incidence of hypoxemia, hypotension, bradycardia, respiratory depression, and injection pain. Remimazolam also required a long time to cause loss of consciousness. There were no differences in rates of sedation success, dizziness/headache, postoperative nausea and vomiting, or recovery time. Older patients receiving procedural sedation with remimazolam had a lower risk of hypoxemia, hypotension, bradycardia, respiratory depression, and injection pain than those receiving other sedatives, suggesting that remimazolam may be more suitable for procedural sedation in older patients.

Effect of Remimazolam Supplementation on Propofol Requirements During Hysteroscopy: A Double-Blind, Dose-Response Study

BACKGROUND

Propofol is commonly used for procedural sedation but may increase side effects in a dose-dependent manner. Remimazolam, an ultrashort-acting benzodiazepine, has been approved for procedural sedation but may delay awakening. This study tested the hypothesis that remimazolam as a supplement reduces effect-site propofol concentration (Ceprop) required to suppress response to cervical dilation in patients undergoing hysteroscopy.

METHODS

One hundred and fifty patients who were scheduled for hysteroscopy were randomized to receive 0, 0.05, 0.1, 0.15, or 0.2 mg·kg-1 intravenous remimazolam, followed by a bolus of sufentanil 0.15 μg⋅kg-1, and a target-controlled propofol infusion. The initial target Ceprop was 3.5 μg·mL-1 and was increased or decreased in subsequent patients by steps of 0.5 μg·mL-1 according to whether there was loss of response to cervical dilation in the previous patient. We used up-down sequential analysis to determine values of Ceprop that suppressed response to cervical dilation in 50% of patients (EC50).

RESULTS

The EC50 of propofol for suppressing response to cervical dilation was lower in patients given 0.1 mg·kg-1 (2.08 [95% confidence interval, CI, 1.88-2.28] μg·mL-1), 0.15 mg⋅kg-1 (1.83 [1.56-2.10] μg·mL-1), and 0.2 mg⋅kg-1 (1.43 [1.27-1.58] μg·mL-1) remimazolam than those given 0 mg⋅kg-1 (3.67 [3.49-3.86] μg·mL-1) or 0.05 mg⋅kg-1 (3.47 [3.28-3.67] μg·mL-1) remimazolam (all were P < .005). Remimazolam at doses of 0.1, 0.15, and 0.2 mg·kg-1 decreased EC50 of propofol by 43.3% (95% CI, 41.3%-45.5%), 50.3% (48.0%-52.8%), and 61.2% (58.7%-63.8%), respectively, from baseline (remimazolam 0 mg⋅kg-1). Propofol consumption was lower in patients given 0.1 mg⋅kg-1 (4.15 [3.51-5.44] mg·kg-1), 0.15 mg⋅kg-1 (3.54 [3.16-4.46] mg·kg-1), and 0.2 mg⋅kg-1 (2.74 [1.73-4.01] mg·kg-1) remimazolam than those given 0 mg⋅kg-1 (6.09 [4.99-7.35] mg·kg-1) remimazolam (all were P < .005). Time to anesthesia emergence did not differ significantly among the 5 groups.

CONCLUSIONS

For women undergoing hysteroscopic procedures, remimazolam at doses from 0.1 to 0.2 mg·kg-1 reduced the EC50 of propofol inhibiting response to cervical dilation and the total propofol requirement. Whether the combination could improve perioperative outcomes deserves further investigation.

Safety and effcacy of remimazolam tosilate for sedation during combined spinal-epidural anesthesia for orthopedic procedures: a randomized controlled trial

OBJECTIVE

The objective of this study was to assess the efficacy and safety of Remimazolam in the context of combined spinal-epidural anesthesia for sedation during orthopedic surgery.

METHODS

This randomized controlled trial enrolled patients scheduled for orthopedic surgery under combined spinal-epidural anesthesia (N = 80), who were randomly allocated to receive either dexmedetomidine (Group-D) or remimazolam (Group-R). The target sedation range aimed for a Ramsay score of 2-5 or a BIS value of 60-80 to evaluate the effectiveness and safety of remimazolam during sedation.

RESULTS

The time taken to achieve the desired level of sedation was significantly shorter in the remimazolam group compared to the dexmedetomidine group (3.69 ± 0.75 vs. 9.59 ± 1.03; P < 0.0001). Patients in the remimazolam group exhibited quicker recovery, fewer intraoperative adverse events, more consistent vital signs, and greater satisfaction at various time points throughout the surgery.

CONCLUSION

This preliminary study demonstrates that remimazolam tosilate serves as a safe and effective sedative for orthopedic surgery performed under combined spinal-epidural anesthesia, in comparison with dexmedetomidine.

Comparison of remimazolam and dexmedetomidine for intraoperative sedation in patients undergoing lower extremity surgery under spinal anesthesia: a randomized clinical trial

BACKGROUND

Dexmedetomidine sedation has advantages, such as low incidence of respiratory depression and prolonged block duration, but also significant disadvantages, such as slow onset, high rate of sedation failure, and a long context-sensitive half-life. Remimazolam provides rapid sedation and recovery, high sedation efficacy and has minimal hemodynamic effects. We hypothesized that patients who received remimazolam would require less rescue midazolam than dexmedetomidine.

METHODS

Patients (n=103) scheduled for surgery under spinal anesthesia were randomized to receive dexmedetomidine (DEX group) or remimazolam (RMZ group) targeting a Modified Observer's Assessment of Alertness/Sedation score of 3 or 4. Rescue midazolam was administered if the patient failed to be sedated after the initial loading dose or despite infusion rate adjustment.

RESULTS

Rescue midazolam administration was significantly higher in the DEX group (0% vs 39.2%; p<0.001). Patients in the RMZ group reached the target sedation level more rapidly. The incidences of bradycardia (0% vs 25.5%; p<0.001) and hypertension (0% vs 21.6%; p<0.001) were higher in the DEX group. Respiratory depression occurred at a higher rate in the RMZ group (21.2% vs 2.0%; p=0.002), but no patients required manual ventilation. Patients in the RMZ group recovered faster, had a shorter PACU stay and higher satisfaction scores. Hypotensive episodes in the PACU were more frequent in the DEX group (1.9% vs 29.4%; p<0.001).

CONCLUSIONS

Remimazolam showed excellent sedation efficacy, minimal hemodynamic effects, and fewer adverse events in the PACU than dexmedetomidine. However, it is important to note that respiratory depression was more frequent with the use of remimazolam.

TRIAL REGISTRATION NUMBER

NCT05447507.

Simultaneously Predicting the Pharmacokinetics of CES1-Metabolized Drugs and Their Metabolites Using Physiologically Based Pharmacokinetic Model in Cirrhosis Subjects

Hepatic carboxylesterase 1 (CES1) metabolizes numerous prodrugs into active ingredients or direct-acting drugs into inactive metabolites. We aimed to develop a semi-physiologically based pharmacokinetic (semi-PBPK) model to simultaneously predict the pharmacokinetics of CES1 substrates and their active metabolites in liver cirrhosis (LC) patients. Six prodrugs (enalapril, benazepril, cilazapril, temocapril, perindopril and oseltamivir) and three direct-acting drugs (flumazenil, pethidine and remimazolam) were selected. Parameters such as organ blood flows, plasma-binding protein concentrations, functional liver volume, hepatic enzymatic activity, glomerular filtration rate (GFR) and gastrointestinal transit rate were integrated into the simulation. The pharmacokinetic profiles of these drugs and their active metabolites were simulated for 1000 virtual individuals. The developed semi-PBPK model, after validation in healthy individuals, was extrapolated to LC patients. Most of the observations fell within the 5th and 95th percentiles of simulations from 1000 virtual patients. The estimated AUC and Cmax were within 0.5-2-fold of the observed values. The sensitivity analysis showed that the decreased plasma exposure of active metabolites due to the decreased CES1 was partly attenuated by the decreased GFR. Conclusion: The developed PBPK model successfully predicted the pharmacokinetics of CES1 substrates and their metabolites in healthy individuals and LC patients, facilitating tailored dosing of CES1 substrates in LC patients.

Modern sedative agents and techniques used in dentistry for patients with special needs: A review

According to the World Health Organisation, approximately 1.3 billion people worldwide experience substantial disability due to physical, mental or sensory impairment. People with special needs require special consideration and more time or altered delivery methods when receiving dental treatments. Various factors, such as patients' lack of cooperation, cognitive impairment and complex medical status, may lead dental practitioners to recommend conscious sedation. Several pharmacological agents and administrative routes are available, which achieve varying levels of sedation ranging from minimal to deep. Pre-operative assessment and careful case selection are necessary to determine the appropriate sedative agent, route of administration and level of sedation for each patient. Thus, a thorough understanding of the pharmacokinetics, risks and benefits, and implications of various sedatives available for PSN is essential to achieve the desired clinical outcomes. This review critically presents the considerations associated with the use of various sedative agents for PSN in dentistry. Considerations include patients' pre-anaesthesia medical comorbidities, cardiorespiratory adverse effects and cooperativeness, and the viable alternative treatment modalities.

Preliminary Experience With Remimazolam for Procedural Sedation and as an Adjunct to General Anesthesia During Diagnostic and Interventional Cardiac Procedures

Background

Remimazolam is a benzodiazepine which, like midazolam, has sedative, anxiolytic, and amnestic properties. Ester metabolism results in a half-life of 5 - 10 min, a limited context sensitive half-life, and rapid recovery when the infusion is discontinued.

Methods

Following the Institutional Review Board (IRB) approval, we performed a retrospective chart review of patients who received remimazolam in the cardiac catheterization, cardiac magnetic resonance imaging (MRI), and electrophysiology suites. The primary objective was to assess efficacy and safety. The secondary objective was to describe bolus and infusion dosing of remimazolam and the need for adjunctive agents to optimize procedural sedation conditions.

Results

The study cohort included 26 patients with a median age of 18 years and a total of 33 anesthetic encounters. The most common procedures were endomyocardial biopsy or isolated hemodynamic assessment (right or left heart catheterization). Remimazolam was the primary agent for sedation in 82% of the procedures. The majority of cases (25 encounters, 76%) included a bolus dose of remimazolam prior to the start of an infusion. For those patients who received a starting bolus dose, dosing typically ranged between 30 and 110 µg/kg. Continuous infusion rates of remimazolam varied from 5 to 20 µg/kg/min. No adverse hemodynamic or respiratory effects were noted. Midazolam, fentanyl, and dexmedetomidine were the most frequently used adjunctive agents. One patient required transition to general anesthesia due to the need for a surgical intervention based on the findings of the cardiac catheterization. All other patients were effectively sedated.

Conclusions

Our preliminary experience demonstrates that remimazolam effectively provided sedation for diagnostic and therapeutic cardiovascular procedures. Future studies are needed to further define dosing parameters for both bolus dosing and continuous infusion as well as to compare remimazolam to other commonly used for procedural sedation in patients with congenital and acquired heart disease.

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.

Comparison of Remimazolam versus Sevoflurane on the Postoperative Quality of Recovery in Cervical Spine Surgery: A Prospective Randomized Controlled Double-Blind Trial

Purpose

Remimazolam is a newly developed ultra-short-acting benzodiazepine. We compared overall functional recovery, including the postoperative Quality of Recovery-15 (QoR-15) questionnaire scores, between balanced inhalational anesthesia using sevoflurane and total intravenous anesthesia (TIVA) with remimazolam in patients undergoing anterior cervical discectomy and fusion (ACDF).

Patients and Methods

Seventy-two patients were randomized to the remimazolam (group R) or sevoflurane (group S) group. The primary outcome was the total QoR-15 score on postoperative day (POD) 1. We also assessed the total QoR-15 score on POD2, sub-scores of the QoR-15, perioperative parameters, and postoperative recovery profiles. Group-time interaction effects on the QoR-15 and its sub-scores were analyzed using a linear mixed model.

Results

The total QoR-15 score on POD1 (120.2 in group R vs 114.3 in group S, P=0.189) was not statistically different between the groups. There were no significant group-time interaction effects on total QoR-15 scores. Instead, patients in group R showed significantly better sub-scores in psychological and postoperative nausea and vomiting (PONV) items on POD1, as well as a lower degree of PONV, than those in group S. Among the five dimensions of the QoR-15, a significant group-time interaction effect was observed for psychological support. Group R showed significantly less changeability in blood pressure and heart rate with a lower dose of intraoperatively administered vasopressor than group S.

Conclusion

Considering QoR-15, including PONV reduction, and intraoperative hemodynamic stability, remimazolam can be used as the novel and safe anesthetic agent for maintaining general anesthesia instead of sevoflurane in patients undergoing ACDF.

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

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

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

BACKGROUND AND OBJECTIVE

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

[Comparison of clinical effects and safety of remidazolam and esketamine for preoperative sedation in children]

OBJECTIVE

To compare the clinical effects and safety of remiazolam and esketamine in preoperative sedation in children.

METHODS

This study was conducted among 61 children (1-4 years old) undergoing elective bilateral tonsillectomy with or without adenoidectomy under general anesthesia from January 2022 to March 2023. The children were randomized into two groups to receive preoperative sedation with intravenous administration of 0.2 mg/kg remidazolam (R group, 30 cases) or 0.5 mg/kg esketamine (S group, 31 cases). The two groups were compared for PSAS score, vital signs (MAP, SpO2, and HR), sedation score, mask acceptance score at induction, sedation onset time, postoperative recovery time, MAP and HR after induction, Ramsay sedation score after awakening, doses of propofol and remifentanil during anesthesia, emergence agitation (EA), postoperative adverse effects and negative postoperative behavioral changes (NPOBCs) on the 7th and 14th days after operation.

RESULTS

The PSAS score, sedation score, mask acceptance score at induction, MAP and HR after induction, Ramsay sedation score after awakening, propofol dose during anesthesia induction, and the incidence of EA and NPOBCs after operation were all similar between the two groups (P > 0.05). Compared with those in S group, the sedation onset time was slightly longer, the recovery time was shorter, and the doses of propofol and remifentanil for anesthesia maintenance was higher (P < 0.05) in R group. Sedation with remidazolam did not cause significant changes in MAP, SpO2 or HR (P > 0.05), while administration of esketamine significantly increased MAP and HR (P < 0.05) without obviously affecting SpO2 (P > 0.05).

CONCLUSION

In children aged 1-4 years, compared with 0.5 mg/kg esketamine, intravenous injection of 0.2 mg/kg remidazolam for preoperative sedation has a slightly longer onset time and is associated with a shorter recovery time and more stable hemodynamics, suggesting its good feasibility and safety.

Incidence of intraoperative hypotension in older patients undergoing total intravenous anesthesia by remimazolam versus propofol: A randomized controlled trial

BACKGROUND

An increase in the frequency of surgeries among older individuals is observed in some countries. Hypotension is common and exaggerated in older patients and can lead to increased morbidity and mortality. Total intravenous anesthesia is commonly administered with propofol, while remimazolam has been suggested as an alternative to propofol because of advantages such as a more stable hemodynamic profile and less respiratory suppression. We conducted a single-blind, parallel-group randomized controlled trial to compare the incidence of intraoperative hypotension between patients administered with remimazolam and propofol.

METHODS

A total of 132 patients, aged between 65 to 80 years and undergoing laparoscopic cholecystectomy or transurethral resection of bladder tumors were randomly assigned to the propofol or remimazolam group with a permuted block system while being blinded to the hypnotic agent. Remifentanil was administered via target-controlled infusion in both groups, with an initial effect-site concentration of 3.0 ng/mL and titration range of 1.5 to 4.0 ng/mL intraoperatively. The primary outcome of this study was the overall incidence of hypotension during general anesthesia.

RESULTS

Patients in the propofol group experienced higher intraoperative hypotension than those in the remimazolam group (59.7% vs 33.3%, P = .006). Multivariate logistic regression analysis showed that remimazolam administration was associated with reduced hypotension (adjusted odds ratio, 0.34; 95% CI, 0.16-0.73). Secondary outcomes such as recovery time, delirium, and postoperative nausea and vomiting were comparable in both groups.

CONCLUSION

Total intravenous anesthesia with remimazolam was associated with less intraoperative hypotension than propofol in older patients, with a comparable recovery profile.

Finding the ideal sedative: a non-inferiority study of remimazolam vs propofol in endoscopic retrograde cholangiopancreatography

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) requires an ideal sedative that provides a predictable action duration and meets safety requirements. We compared the efficacies and safeties of remimazolam and propofol in patients who had undergone ERCP.

METHODS

In this prospective, randomized, single-blind, single-center study, we compared the performances of remimazolam and propofol for inpatient ERCP. Study medications were administered under the supervision of an endoscopist. One hundred and ten patients scheduled to undergo ERCP were randomly assigned to receive remimazolam or propofol. The primary endpoint was a composite of successful completion of the procedure and no requirement for rescue medication. Secondary endpoints included sedation efficacy, recovery time, and adverse events.

RESULTS

Of the 110 patients randomized, 108 underwent sedation, and ERCP (53 received remimazolam and 55 propofol). The primary endpoint was met for remimazolam and propofol in 100% of patients in both arms. Incidences and frequencies of emergent adverse events, including desaturation, requiring treatment were comparable in both arms. However, ERCP was started sooner in the propofol arm (mean, 63.18 ± 16.56 s) than in the remimazolam arm (75.23 ± 32.27 s; P-value = 0.02). Time to full alertness after ERCP was also significantly shorter in the propofol arm (304.18 ± 146.25 vs 448.34 ± 224.09 s; P-value <0.001).

CONCLUSION

Remimazolam is not inferior to propofol in achieving successful ERCP completion without rescue medication. Incidences of adverse events were comparable. Remimazolam is a safe and effective alternative to propofol for ERCP sedation, expanding options for clinicians and improving patient outcomes.

Safety and efficacy of remimazolam compared with midazolam during bronchoscopy: a single-center, randomized controlled study

Although remimazolam is an ultra-short-acting benzodiazepine with a shorter elimination half-life and faster recovery time than midazolam, studies evaluating its safety and efficacy during bronchoscopy are limited. This study aimed to compare the safety and efficacy of remimazolam with those of midazolam for bronchoscopy. This prospective randomized parallel-group study was conducted at a single institution. The primary outcome was the time from the end of the procedure to full alertness. Other procedural time parameters, satisfaction profiles, and adverse effects were thoroughly evaluated. The time taken to reach peak sedation and the time from the end of the procedure to full alertness was significantly shorter in the remimazolam group than in the midazolam group (median [interquartile range], 2 min [1-4] vs. 3 min [2-5], P = 0.006; and median, 2 min [1-5] vs. 5 min [1-12], P = 0.035, respectively). In patients with non-biopsy procedures (n = 79), participant satisfaction was significantly higher in the remimazolam group than in the midazolam group (median rated scale, 10 vs. 7, P = 0.042). Physician satisfaction and willingness to repeat the procedure were similar between groups. Although the incidence of adverse effects was similar between the groups and there was no significant difference, the midazolam group had a higher antidote administration rate than the remimazolam group (15.7% vs. 4.1%, P = 0.092). Remimazolam is effective and safe for achieving adequate sedation, with a shorter onset time and faster neuropsychiatric recovery than midazolam. It may be a new option for sedation during bronchoscopy.Trial registration: The trial registration number is NCT05994547, and the date of first registration is 16/08/2023.

Comparison of oxygen reserve index according to the remimazolam or dexmedetomidine for intraoperative sedation under regional anesthesia-A single-blind randomized controlled trial

Introduction

We aimed to evaluate the difference in intraoperative oxygen reserve index (ORi) between the sedatives remimazolam (RMMZ) and dexmedetomidine (DEX).

Methods

Seventy-eight adult patients scheduled for sedation under regional anesthesia were randomly assigned to either the DEX (n = 39) or RMMZ (n = 39) group. The primary outcome was the difference in perioperative ORi between the groups. The secondary outcomes included respiratory depression, hypo- or hypertension, heart rate (HR), blood pressure, respiratory rate and postoperative outcomes. Additionally, the number of patients who experienced a decrease in intraoperative ORi to < 50% and the associated factors were analyzed.

Results

The ORi was significantly higher in the RMMZ group at 15 min after sedation maintenance. There were no significant differences in respiratory depression between the two groups. The intraoperative HR was significantly higher in the RMMZ group after the induction of sedation, 15 min after sedation maintenance, and at the end of surgery. No other results were significantly different between the two groups. The incidence of a decrease in intraoperative ORi to < 50% was significantly higher in the DEX group. Factors associated with a decrease in the intraoperative ORi to < 50% were diabetes mellitus, low baseline peripheral oxygen saturation (SpO2), and DEX use. In the receiver operating characteristic curve analysis for a decrease in the intraoperative ORi to < 50%, the cutoff baseline SpO2 was 97%.

Conclusion

RMMZ is recommended as a sedative for patients with a low baseline SpO2 and intraoperative bradycardia. Further studies should be conducted to establish the criteria for a significant ORi reduction.

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.

Pharmacokinetics of remimazolam after intravenous infusion in anaesthetised children

BACKGROUND

The pharmacokinetic properties of the new benzodiazepine remimazolam have been studied only in adults. We investigated the pharmacokinetics of remimazolam after i.v. infusion in anaesthetised paediatric patients.

METHODS

Twenty-four children (2-6 yr, ASA physical status 1-2, BMI 15-18 kg m-2) undergoing general anaesthesia with sevoflurane were enrolled. During surgery, remimazolam was administered as an i.v. infusion over 1 h at 5 mg kg-1 h-1 for 5 min, followed by 1.5 mg kg-1 h-1 for 55 min. Plasma concentrations of remimazolam and its metabolite CNS7054 were determined from arterial blood samples using ultra-high performance liquid chromatography-mass spectrometry. Pharmacokinetic modelling was performed by population analysis.

RESULTS

Pharmacokinetics were best described by a three-compartment model for remimazolam and a two-compartment model for CNS7054 linked by a transit compartment. Remimazolam showed a high clearance of 15.9 (12.9, 18.2) ml kg-1 min-1 (median, Q25, Q75), a small central volume of distribution of 0.11 (0.08, 0.14) L kg-1 and a short terminal half-life of 67 (49, 85) min. The context-sensitive half-time after an infusion of 4 h was 17 (12, 21) min. The metabolite CNS7054 showed a low clearance of 0.89 (0.33, 1.40) ml kg-1 min-1, a small central volume of distribution of 0.011 (0.005, 0.016) L kg-1, and a long terminal half-life of 321 (230, 770) min.

CONCLUSIONS

Remimazolam in children was characterised by a high clearance and short context-sensitive half-time. When normalised to weight, pharmacokinetic properties were similar to those reported for adults.

CLINICAL TRIAL REGISTRATION

ChiCTR2200057629.

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

Key Clinical Message

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

Abstract

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

Pharmacokinetic and Pharmacodynamic Changes in the Elderly: Impact on Anesthetics

Anesthesiologists are increasingly required to care for frail elderly patients. A detailed knowledge of the influence of age on the pharmacokinetics and dynamics of the anesthetic drugs is essential for optimal safety and care. For most of the anesthetic drugs, the elderly need lower doses to achieve the same plasma concentrations, and at any given plasma and effect-site concentration, they will have more profound clinical effects than younger patients. Caution is required, with close monitoring of clinical effects and active titration of dose administration to achieve the desired level of effect, ideally following the "start low, go slow" principle.

Effects of remimazolam on hemodynamic changes during cardiac ablation for atrial fibrillation under general anesthesia: a propensity-score-matched retrospective cohort study

PURPOSE

Abrupt hemodynamic changes or life-threatening arrhythmias are frequently observed in individuals receiving anesthesia for cardiac arrhythmia ablation. Remimazolam is a novel ultra-short-acting benzodiazepine that has been associated with better hemodynamic stability than conventional anesthetic agents do. This study aimed to investigate whether remimazolam reduces vasoactive agent use compared with desflurane in individuals undergoing ablation for atrial fibrillation under general anesthesia.

METHODS

In a retrospective cohort study, we reviewed electronic medical records of adult patients who underwent ablation for atrial fibrillation under general anesthesia between July 2021 and July 2022. We divided patients into remimazolam and desflurane groups according to the principal agent used for anesthesia. The primary endpoint was the overall incidence of vasoactive agent use. We compared the groups using propensity-score matching (PSM) analysis.

RESULTS

A total of 177 patients were included-78 in the remimazolam group and 99 in the desflurane group. After PSM, 78 final patients were included in each group. The overall incidence of vasoactive agent use was significantly lower in the remimazolam group than in the desflurane group (41% vs 74% before PSM; 41% vs 73% after PSM; both, P < 0.001). The incidence rate, duration, and maximum dose of continuous vasopressor infusion were also significantly lower in the remimazolam group (P < 0.001). Use of remimazolam was not associated with increased complications after the ablation procedures.

CONCLUSIONS

General anesthesia using remimazolam vs desflurane was associated with significantly reduced vasoactive agent requirement and better hemodynamic stability without increased postoperative complications in patients undergoing ablation for atrial fibrillation.

Remimazolam's Effects on Postoperative Nausea and Vomiting Are Similar to Those of Propofol after Laparoscopic Gynecological Surgery: A Randomized Controlled Trial

(1) Background: Remimazolam is a novel benzodiazepine that prevents postoperative nausea and vomiting (PONV), is more effective than volatile anesthetics, and was recently approved for use in Japan. (2) Methods: This prospective, double-blind, randomized controlled trial study aimed to compare the efficacy of remimazolam and propofol as general anesthetics in terms of the incidence of PONV after laparoscopic gynecological surgery (UMIN000046237). High-risk female patients who underwent general anesthesia with either remimazolam or propofol for the maintenance of anesthesia were enrolled. The primary outcome was the incidence of PONV in the two groups (i.e., REM versus PROP) 2 h and 24 h after surgery. The incidence of vomiting without nausea, rescue antiemetic use, and the severity of nausea were also evaluated. (3) Results: No significant differences in PONV were identified between the REM and PROP groups at 2 h or 24 h. Furthermore, no differences were observed in any of the measured parameters, and no adverse events were reported. (4) Conclusions: The results of the present study suggest that remimazolam may be as effective as propofol in preventing PONV; however, further investigation is necessary to identify possible differences between these two agents.

Remimazolam for Sedation During Fiberoptic Intubation in an Adolescent

In specific clinical scenarios, fiberoptic intubation (FOI) may be the preferred technique for airway management and endotracheal intubation. In addition to topical anesthesia of the airway, sedation is frequently necessary, especially in younger patients, to facilitate the procedure. The goal is to facilitate the procedure by providing sedation, anxiolysis, and analgesia with maintenance of spontaneous ventilation. Remimazolam is a novel benzodiazepine with a short half-life and limited context sensitive half-life that can be titrated by continuous infusion. These novel properties may make it a suitable agent for sedation during FOI of the trachea. We report the novel use of a combination of remimazolam and remifentanil infusions to provide sedation during FOI in an adolescent. The basic pharmacology of remimazolam is presented and previous reports of its use for sedation during FOI are reviewed.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Post-induction hypotension with remimazolam versus propofol in patients routinely administered angiotensin axis blockades: a randomized control trial

BACKGROUND

Certain routine medication could result in post-induction hypotension (PIH), such as angiotensin axis blockades, which are frequently administered as a first-line therapy against hypertension. Remimazolam is reportedly associated with lesser intraoperative hypotension than propofol. This study compared the overall incidence of PIH following remimazolam or propofol administration in patients managed by angiotensin axis blockades.

METHODS

This single-blind, parallel-group, randomized control trial was conducted in a tertiary university hospital in South Korea. Patients undergoing surgery with general anesthesia were considered for enrollment if the inclusion criteria were met: administration of an angiotensin converting enzyme inhibitor or angiotensin receptor blocker, 19 to 65 years old, American Society of Anesthesiologists physical status classification ≤ III, and no involvement in other clinical trials. The primary outcome was the overall incidence of PIH, defined as a mean blood pressure (MBP) < 65 mmHg or decrease by ≥ 30% of the baseline MBP. The time points of measurement were baseline, just before the initial intubation attempt, and 1, 5, 10, and 15 min following intubation. The heart rate, systolic and diastolic blood pressures, and bispectral index were also recorded. Groups P and R included patients administered propofol and remimazolam, respectively, as an induction agent.

RESULTS

A total of 81 patients were analyzed, of the 82 randomized patients. PIH was less frequent in group R than group P (62.5% versus 82.9%; t value 4.27, P = 0.04, adjusted odds ratio = 0.32 [95% confidence interval 0.10-0.99]). The decrease in the MBP from baseline was 9.6 mmHg lesser in group R than in group P before the initial intubation attempt (95% confidence interval 3.3-15.9). A similar trend was observed for systolic and diastolic blood pressures. No severe adverse events were observed in either group.

CONCLUSION

Remimazolam results in less frequent PIH than propofol in patients undergoing routine administration of angiotensin axis blockades.

TRIAL REGISTRATION

This trial was retrospectively registered on Clinical Research Information Service (CRIS), Republic of Korea (KCT0007488). Registration date: 30/06/2022.

Frequency and characteristics of patients with bispectral index values of 60 or higher during the induction and maintenance of general anesthesia with remimazolam

In Korea, the approved anesthetic regimen of remimazolam starts with 6 mg/kg/h or 12 mg/kg/h until loss of consciousness, followed by maintenance at 1-2 mg/kg/h. Some patients receiving remimazolam for general anesthesia experience occasional difficulty maintaining bispectral index (BIS) value ˂ 60. This retrospective study aimed to analyze the data from patients undergoing elective surgery under remimazolam based-general anesthesia to determine the frequency and physical characteristics of patients with BIS values ˂ 60. The criterion was established for patients with a poorly maintained BIS value < 60. The frequency and physical characteristics of patients who satisfied this criterion were investigated through their medical records. The modified Brice interview was conducted within 24 h after surgery. Among the 1500 patients included in the analysis, 61 (4.1%) met the criteria for BIS ˂ 60. Based on the modified Brice interview, none of the patients with poorly maintained BIS ˂ 60 complained of intraoperative awareness based on the modified Brice interview or exhibit specific physical characteristics. These patients accounted for less than 5% of the total population studied. Notably, physical characteristics alone are insufficient to predict such patients before surgery.

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

BACKGROUND

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

CASE PRESENTATION

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

DISCUSSION

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

A randomized, controlled clinical trial comparing remimazolam to propofol when combined with alfentanil for sedation during ERCP procedures

STUDY OBJECTIVE

In many countries, the combination of propofol and opioid is used as the preferred sedative regime during ERCP. However, the most serious risks of propofol sedation are oxygen deficiency and hypotension. Compared to midazolam, remimazolam has a faster onset and offset of hypnotic effect, as well as cardiorespiratory stability, and to achieve widespread acceptance for procedural sedation, remimazolam must replace propofol which is the most commonly used for procedural sedation. The objective of this study was to compare the safety and efficacy profiles of the remimazolam and propofol when combined with alfentanil for sedation during ERCP procedures.

DESIGN

A randomized, controlled, single-center trial.

SETTING

The Endoscopic Centre of Tianjin Nankai Hospital, China.

PATIENTS

518 patients undergoing elective ERCP under deep sedation.

INTERVENTIONS

Patients scheduled for ERCP were randomly assigned to be sedated with either a combination of remimazolam-alfentanil or propofol-alfentanil.

MEASUREMENTS

The primary outcome was the prevalence of hypoxia, which was defined as SpO₂ < 90% for >10 s. Other outcomes were the need for airway maneuver, procedure, and sedation-related outcomes and side effects (e.g., nausea, vomiting, and cardiovascular adverse events).

MAIN RESULTS

A total of 518 patients underwent randomization. Of these, 250 were assigned to the remimazolam group and 255 to the propofol group. During ERCP, 9.6% of patients in the remimazolam group showed hypoxia, while in the propofol group, 15.7% showed hypoxia (p = 0.04). The need for airway maneuvering due to hypoxia was significantly greater in the propofol group (p = 0.04). Furthermore, patients sedated with remimazolam had a lower percentage of hypotension than patients sedated with propofol (p < 0.001). Patients receiving remimazolam sedation expressed higher satisfaction scores and were recommended the same sedation for the next ERCP. The procedure time in the remimazolam group was much longer than in the propofol group due to the complexity of the patient's disease, which resulted in a longer sedation time.

CONCLUSION

During elective ERCP, patients administered with remimazolam showed fewer respiratory depression events under deep sedation with hemodynamic advantages over propofol when administered in combination with alfentanil.

Monitored Anesthesia Care Using Remimazolam and Ketamine Combination for Brief Gynecological Surgeries: A Report for Four Cases

Remimazolam is a benzodiazepine with rapid onset and recovery time. Ketamine provides analgesia and sedation without compromising hemodynamics. Combining both agents may provide good anesthesia and analgesia with fewer complications. We report four cases of monitored anesthesia care with a combination of remimazolam and ketamine for brief gynecological surgeries. We applied 0.5 mg/kg bolus ketamine and infused patients with remimazolam at 6 mg/kg/h for induction and 1 mg/kg/h for maintenance. Then, 25 µg of fentanyl was administered for analgesia 4 min before the procedure, and additional fentanyl was administered as needed. Remimazolam was discontinued shortly after surgery. We conducted satisfactory monitored anesthesia care with a combination of remimazolam and ketamine in all four cases.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparison of the Incidence of Postoperative Acute Kidney Injury Following the Administration of Remimazolam or Sevoflurane in Elderly Patients Undergoing Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

We evaluated the incidence of postoperative acute kidney injury (AKI) and complications when remimazolam (RMMZ) or sevoflurane (SEVO) were used in elderly patients undergoing total knee arthroplasty.

METHODS

Seventy-eight participants aged ≥65 were randomly allocated to either the RMMZ or SEVO group. The primary outcome was the incidence of AKI on postoperative day (POD) 2. The secondary outcomes included intraoperative heart rate (HR), blood pressure (BP), total drug administered, emergence time, postoperative complications on POD 2, and hospital length of stay (HLOS).

RESULTS

The incidence of AKI was comparable between the RMMZ and SEVO groups. The doses of intraoperative remifentanil, vasodilators, and additional sedatives were significantly higher in the RMMZ group than in the SEVO group. Overall intraoperative HR and BP tended to remain higher in the RMMZ group. The emergence time in the operating room was significantly faster in the RMMZ group; however, the time required for an Aldrete score ≥ 9 was comparable between the RMMZ and SEVO groups. Postoperative complications and HLOS were comparable between the RMMZ and SEVO groups.

CONCLUSION

RMMZ may be recommended for patients who are expected to decrease in intraoperative vital signs. However, stable hemodynamics with RMMZ were not sufficient to influence the prevention of AKI.

Anaesthetic Management of a Patient With Immune-Mediated Necrotizing Muscle Disease With the Use of a Novel Ultrashort-Acting Benzodiazepine, Remimazolam: A Case Report

We reported the anesthetic management of remimazolam, a novel ultra-short-acting benzodiazepine, for a 21-month-old female with immune-mediated necrotizing myopathy (IMNM). Remimazolam has a similar chemical structure to midazolam but possesses a unique side chain that reduces its propensity to accumulate in the body, thereby minimizing prolonged sedation or respiratory depression. Our experience supports that remimazolam could be a suitable agent for anesthetizing the patient with IMNM.

Effective dose of remimazolam co-administered with remifentanil to facilitate I-gel insertion without neuromuscular blocking agents: an up-and-down sequential allocation trial

BACKGROUND

Remimazolam is a new anesthetic drug developed and is an ultra-short-acting agent with rapid onset and offset. The pharmacology of this drug seems to be ideal for short surgeries eligible for I-gel insertion. Therefore, this study aimed to determine the optimal bolus dose of remimazolam for I-gel insertion when co-administered with remifentanil without neuromuscular blocking agents (NMBAs).

METHODS

Patients aged 19-65 years with American Society of Anesthesiologists physical status I or II scheduled for general anesthesia were enrolled. The first dose of remimazolam was 0.15 mg/kg and remifentanil was co-administered at an effect-site concentration (Ce) of 3.0 ng/mL. The dose of remimazolam for the following patient was decreased or increased by 0.05 mg/kg depending on the success or failure of I-gel insertion in the previous patient.

RESULTS

The remimazolam bolus dose required for successful I-gel insertion in 50% of adult patients using modified Dixon's up-and-down method with remifentanil Ce 3.0 ng/mL and no NMBAs was 0.280 ± 0.048 mg/kg. Isotonic regression analysis showed that the 50% and 95% effective doses were 0.244 (83% confidence interval [CI] 0.213-0.313) mg/kg and 0.444 (95% CI 0.436-0.448) mg/kg, respectively. The mean time to loss of consciousness (Modified Observer's Assessment of Alertness/Sedation score < 2) was 52.2 s. Three patients (12.0%) showed a reduction in systolic blood pressure of more than 30% from baseline.

CONCLUSIONS

Selecting the appropriate dose of remimazolam/remifentanil without NMBAs makes it feasible to insert the I-gel.

TRIAL REGISTRATION

This study protocol was registered at http://cris.nih.go.kr (KCT0007801, 12th, October, 2022).

Remimazolam Compared to Propofol During Hysteroscopy: A Safety and Efficacy Analysis

INTRODUCTION

Propofol is the main drug used to induce sedation for endoscopic procedures, and few drugs had shaken its dominant clinical use for a decade until the development of remimazolam. Remimazolam has been demonstrated to perform well in post-marketing studies on sedation for colonoscopy or other procedures requiring short periods of sedation. This study aimed to establish whether remimazolam was effective and safe for inducing sedation for hysteroscopy.

METHODS

One hundred patients who were scheduled to undergo hysteroscopy were randomly assigned to receive induction with remimazolam or propofol. A dose of 0.25 mg/kg remimazolam was administered. Propofol was started at 2-2.5 mg/kg. Before remimazolam or propofol induction, 1 μg/kg fentanyl was infused. Hemodynamic parameters, vital signs, and bispectral index (BIS) values were measured and adverse events recorded to evaluate safety. We comprehensively evaluated the efficacy and safety of the two drugs by the success rate of induction, fluctuation of vital signs, depth of anesthesia, adverse reactions, recovery time, and other indicators.

RESULTS

Information on 83 patients was successfully recorded and carefully documented. The success rate of sedation in the remimazolam group (group R) was 93%, which was lower than for the propofol group (group P) (100%), but there was no statistically significant difference between the two groups. The incidence of adverse reactions in group R (7.5%) was significantly lower than that in group P (67.4%), and the results were statistically significant (P < 0.01). The fluctuation of vital signs in group P was more severe after induction, especially in patients with cardiovascular diseases.

CONCLUSIONS

Remimazolam avoids the injection pain produced by propofol sedation, has a better pre-sedation experience, had the advantage of stable hemodynamics after injection compared to propofol, and a lower respiratory depression rate in the study patients.

Remimazolam dose for successful insertion of a supraglottic airway device with opioids: a dose-determination study using Dixon's up-and-down method

PURPOSE

Remimazolam, an ultra-short-acting benzodiazepine, was recently approved in numerous jurisdictions as an induction drug for general anesthesia. We aimed to determine the doses of remimazolam that would allow placement of a supraglottic airway device (SGD) in 50% and 95% of nonparalyzed patients (ED50 and ED95).

METHODS

In this prospective study, 30 American Society of Anesthesiology Physical Status I-II grade female patients scheduled for hysteroscopic surgery were enrolled. Anesthesia was induced with 1 μg·kg-1 of fentanyl and continuous infusion of remimazolam without neuromuscular blockade. An i-gel® SGD was inserted 2.5 min after the start of remimazolam infusion. We used Dixon's up-and-down method and isotonic regression to determine the ED50 and ED95 of remimazolam for insertion of an SGD.

RESULTS

Twenty-eight patients were included in the final analysis. The ED50 and ED95 of remimazolam required for successful i-gel insertion were 8.8 mg·kg-1·hr-1 (95% confidence interval [CI], 6.3 to 10.6) and 10.7 mg·kg-1·hr-1 (95% CI, 10.6 to 11.7), respectively. A nonfully relaxed jaw was found in 7/13 patients (54%) in the success group and 14/15 patients (93%) in the failure group (difference in proportions, 40%; 95% CI, 7 to 65; P = 0.02). Bucking or other movements during SGD insertion only occurred in the failure group (11/15, 73%).

CONCLUSION

In 95% of nonparalyzed female patients undergoing hysteroscopy, 10.7 mg·kg-1·hr-1 of remimazolam with 1 μg·kg-1 of fentanyl facilitates i-gel insertion. Remimazolam showed a high incidence of poor jaw relaxation and bucking or other movements during SGD insertion.

STUDY REGISTRATION

Clinical Trial Registry of the Republic of Korea (KCT0006527, https://cris.nih.go.kr ; registered 1 September 2021; principal investigator: Ji Seon Jeong).

An Adequate Infusion Rate of Remimazolam for Induction of General Anesthesia in Adult Patients: A Prospective Up-and-Down Dose-Finding Study

Remimazolam is a recently developed anesthetic agent for general anesthesia and sedation. Currently, the optimal infusion rate for the induction of general anesthesia within two minutes remains unclear. We estimated the 50% and 90% effective doses (ED₅₀ and ED₉₀) of remimazolam required for loss of responsiveness within two minutes in adult patients using the up-and-down method. The starting infusion rate of remimazolam was 0.1 mg/kg/min and was increased or decreased by 0.02 mg/kg/min intervals in the following patient according to the success or failure of the previous patient. Success was defined as a loss of responsiveness within two minutes. Patient enrollment continued until six crossover pairs were observed. The ED₅₀ and ED₉₀ were estimated by centered isotonic regression and the pooled adjacent violators algorithm with bootstrapping, respectively. Twenty patients were included in the analysis. The ED₅₀ and ED₉₀ of remimazolam for loss of responsiveness within two minutes were 0.07 mg/kg/min (90% CI: 0.05, 0.09 mg/kg/min) and 0.10 mg/kg/min (90% CI: 0.10, 0.15 mg/kg/min), respectively. Vital signs were stable with an infusion rate of 0.10 mg/kg/min, and no patients required inotrope/vasopressor. Intravenous infusion of remimazolam at a rate of 0.10 mg/kg/min can be an effective approach to inducing general anesthesia in adult patients.

The use of remimazolam versus propofol for induction and maintenance of general anesthesia: A systematic review and meta-analysis

Background: The primary objective of this study was to compare the risk of hypotension, as well as the induction and recovery characteristics between remimazolam and propofol in patients receiving surgery under general anesthesia. Methods: The Embase, Medline, Google scholar, and the Cochrane Library databases were searched from inception to March 2022 for randomized controlled trials The primary outcome was the risk of post-induction hypotension between the two agents, while the secondary outcomes included anesthetic depth, induction efficacy, time to loss of consciousness (LOC), hemodynamic profiles, time to eye opening, extubation time as well as the incidence of injection pain and postoperative nausea/vomiting (PONV). Results: Meta-analysis of eight studies published from 2020 to 2022 involving 738 patients revealed a significantly lower risk of post-induction hypotension with the use of remimazolam compared to that with propofol [risk ratio (RR) = 0.57, 95% confidence interval (CI): 0.43 to 0.75, p < 0.0001, I2 = 12%, five studies, 564 patients]. After anesthetic induction, the anesthetic depth measured by bispectral index (BIS) was lighter in the remimazolam group than that in the propofol group (MD = 9.26, 95% confidence interval: 3.06 to 15.47, p = 0.003, I2 = 94%, five studies, 490 patients). The time to loss of consciousness was also longer in the former compared to the latter (MD = 15.49 s, 95%CI: 6.53 to 24.46, p = 0.0007, I2 = 61%, three studies, 331 patients). However, the use of remimazolam correlated with a lower risk of injection pain (RR = 0.03, 95%CI: 0.01 to 0.16, p < 0.0001, I2 = 0%, three studies, 407 patients) despite comparable efficacy of anesthetic induction (RR = 0.98, 95%CI: 0.9 to 1.06, p = 0.57, I2 = 76%, two studies, 319 patients). Our results demonstrated no difference in time to eye opening, extubation time, and risk of PONV between the two groups. Conclusion: Remimazolam was associated with a lower risk of post-induction hypotension after anesthetic induction compared with propofol with similar recovery characteristics. Further studies are required to support our findings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/; Identifier: CRD42022320658.

Efficacy and Safety of the Remimazolam-Alfentanil Combination for Sedation During Gastroscopy: A Randomized, Double-blind, Single-center Controlled Trial

PURPOSE

Propofol infusion is a popular single drug of choice for sedation in the gastrointestinal endoscopy suite. Drug combinations are more beneficial than single-drug regimens in gastroscopy sedation. However, the cardiopulmonary complications of propofol sedation raise concern. Remimazolam is a novel, ultra-short-acting benzodiazepine sedative, and alfentanil is a weak opioid. During endoscopic procedures, remimazolam is an effective and safe sedative procedure. No synergistic effect has been reported when remimazolam was combined with alfentanil in gastroscopy sedation. Here, we evaluated the effective dose, sedative efficacy, and safety of the remimazolam-alfentanil combination in gastroscopy sedation and compared the results with those of the propofol-alfentanil combination.

METHODS

This study was conducted in two parts. In Part 1, Dixon's up-and-down method (sequential distribution) was adopted for determining the 95% effective dose (ED95) (95% CI) and 95% CI of remimazolam combined with 5 µg/kg alfentanil. In Part 2, after obtaining the predictive remimazolam ED95, 161 patients were randomized into the remimazolam group (remimazolam-alfentanil) and the propofol group (propofol-alfentanil). The effectiveness of the drug combinations was measured according to successful sedation parameters. Changes in vital signs and the appearance of adverse events were used to assess the safety of drug combinations. Evaluation of patient and physician satisfaction was included as quality indicators of treatment.

RESULTS

Baseline demographic and clinical characteristics were comparable between the 2 parts of the study. The ED95 of remimazolam in inhibiting a positive response to gastroscopy placement into the pharyngeal cavity was 0.33 mg/kg (95% CI, 0.289 to 1.023). The procedure success rate was 97.53% in the remimazolam group and 97.50% in the propofol group. The difference in the success rate of the procedure between the remimazolam and propofol groups was 0.03% (95% CI, -2.5 to 2.4). However, the incidence of injection pain, hypotension, respiratory depression, and dizziness was lower in the remimazolam group compared with the propofol group (P < 0.05). Furthermore, patients from the propofol group were more likely to be drowsy, and their work efficiency was reduced the day after leaving the hospital, whereas patients in the remimazolam group were less affected (P < 0.05).

IMPLICATIONS

The ED95 of remimazolam was 0.33 mg/kg when it was combined with alfentanil (5 µg/kg) for gastroscopy sedation. The sedation strategy of remimazolam-alfentanil has noninferior efficacy, fewer adverse effects, and a better postoperative recovery process than propofol-alfentanil for patients undergoing gastroscopy. Chinese Clinical Trials Registry identifier: ChiCTR2100051565.

Prevention of postoperative nausea and vomiting after gynaecological day surgery under remimazolam general anesthesia: a randomized double-blind controlled study

Purpose

To observe the effect of different antiemetic drugs for the prevention of postoperative nausea and vomiting (PONV) after gynaecological day surgery under remimazolam general anesthesia.

Methods

One hundred ninety-two patients were selected for gynaecological day surgery and randomly divided into three groups: droperidol group (DD group), tropisetron group (DT group) and control group (DC group). Flurbiprofen axetil 50 mg and dexamethasone 5 mg were given intravenously before induction of anesthesia, and 2 min later droperidol 1 mg was given intravenously to the DD group, tropisetron 5 mg to the DT group and saline (5 ml) to the DC group. Induction of anesthesia: remimazolam 6 mg/kg/h was continuously infused until sleep, mivacurium 0.2 mg/kg and alfentanil 20ug/kg were slowly pushed, 3 min later intubation was performed to control breathing. Maintenance of anesthesia: 40ug/kg/h of alfentanil, 1 mg/kg/h of remimazolam continuous infusion. After awakening and extubation, the patient was transferred to the PACU. PONV were recorded in the PACU and an electronic questionnaire was pushed 24 h after surgery.

Results

The incidence of PONV within the PACU was significantly lower in the DD (14.5%)and DT(26.7%) groups than in the DC(50%) group (p < 0.01), there was no significantly difference between the DT and DD groups. There were no significant difference in the incidence of PONV in 24 h after surgery between the three groups(DD:DT:DC = 44.5%:45.1%:63.8%,p > 0.05).

Conclusions

Droperidol or tropisetron combined with dexamethasone is superior to dexamethasone alone for the prevention of PONV in the PACU after remimazolam combined with alfentanil anesthesia, with no significant difference in the incidence of PONV in 24 h after surgery.

Efficacy and Safety of Remimazolam Besylate versus Dexmedetomidine for Sedation in Non-Intubated Older Patients with Agitated Delirium After Orthopedic Surgery: A Randomized Controlled Trial

Purpose

The purpose of the present study was to investigate the efficacy and safety of remimazolam besylate compared with dexmedetomidine for the relief of agitated delirium in non-intubated older patients after orthopedic surgery.

Patients and methods

Seventy-five patients were randomly divided into two groups. Patients assigned to the remimazolam group received a loading dose of 0.075 mg/kg remimazolam besylate over 1 minute, followed by a continuous infusion of 0.1 to 0.3 mg/kg/h. Subjects randomized to the dexmedetomidine group received a loading infusion of 0.5 μg/kg dexmedetomidine over 10 minutes, followed by a maintenance dose of 0.2 to 0.7 μg/kg/h. Meanwhile, RASS score-guided dose titration was followed. To assess the efficacy of the study drugs in terms of time to resolution of agitation, time to first achievement of target sedation, percentage of time within the target sedation range, and time to delirium resolution. Safety of the sedatives was evaluated by adverse events during hospitalization.

Results

Time to resolution of agitation did not differ between the two groups. The time to first achievement of target sedation was 19.0 (9.5 to 31.0) minutes for remimazolam besylate vs 43.5 (15.0 to 142.5) minutes for dexmedetomidine (P < 0.001). Percentage of time within the target sedation range was 77.8% for remimazolam besylate-treated patients and 67.4% for dexmedetomidine-treated patients (P = 0.001). Patients in the remimazolam group had longer time to delirium resolution (29.5 [21.3 to 32.5] hours) than those in the dexmedetomidine group (22.8 [18.9 to 28.5] hours) (P = 0.042). Patients sedated with remimazolam besylate had more oversedation (P = 0.036) but less hypotension (P = 0.007).

Conclusion

Compared with dexmedetomidine, remimazolam besylate was equally effective in relieving agitation, and resulted in earlier achievement of sedation goal and more controllable sedation. Remimazolam may be an ideal agent for obtaining rapid tranquillisation.