Remimazolam for induction of anesthesia in elderly patients with severe aortic stenosis: a prospective, observational pilot study

Effect of different anesthesia depths on perioperative heart rate variability and hemodynamics in middle-aged and elderly patients undergoing general anesthesia

BACKGROUND

To analyze the effects of different anesthesia depths on perioperative heart rate variability and hemodynamics in middle-aged and elderly patients undergoing general anesthesia, and to provide a basis for clinical application.

METHODS

A total of 111 patients with gastric cancer who were treated with epidural anesthesia combined with general anesthesia were selected as the study subjects, and the patients were randomly divided into group A, group B and group C. The bispectral index (BIS) was maintained by adjusting the infusion speed of anesthetics, the BIS of group A was maintained at 50 ~ 59, the BIS of group B was maintained at 40 ~ 49, and the BIS of group C was maintained at 30 ~ 39. The high-frequency power (HFP), low-frequency power (LFP), total power (TP), mean arterial pressure (MAP), heart rate (HR), diastolic blood pressure (DBP), and systolic blood pressure (SBP) were measured before anesthesia induction (T1), immediately after intubation (T2), 3 min after intubation (T3), and 6 min after extubation (T4). The cognitive function of the patients was evaluated before and 48 h after surgery.

RESULTS

The HFP, LFP/HFP, TP, HR, DBP and SBP between the three groups at T1 ~ T3 are significantly difference from each other (P < 0.05). There were significant differences in spontaneous breathing recovery time, eye opening time and extubation time among group A, B and C groups, and group B had the lowest spontaneous breathing recovery time, eye opening time and extubation time (P < 0.05). There was no significant difference in the incidence of adverse reactions during anesthesia between the three groups. The cognitive function score of group B was significantly higher than that of group A and group C (P < 0.05).

CONCLUSIONS

BIS maintenance of 40 ~ 49 has little effect on perioperative heart rate variability and hemodynamics in middle-aged and elderly patients undergoing general anesthesia, which is helpful for postoperative recovery.

The Impact of Fentanyl on the Effective Dose of Remimazolam-Induced Sedation in Elderly Female Patients: An Up-and-Down Sequential Allocation Trial

Purpose

This study aimed to investigate the influence of fentanyl on the effective dose of remimazolam-induced sedation in elderly female patients undergoing general anesthesia.

Patients and Methods

Sixty female patients aged 65-80 years undergoing selective general anesthesia were randomized into two groups: Group R+F received an initial dose of remimazolam (7.5 mg) with fentanyl (1 μg/kg), while Group R received remimazolam alone. Dosing adjustments (±2.5 mg) were made based on the response of the preceding patient using the up-and-down allocation technique. The ED50 and ED95 were calculated using a sequential formula and probit regression. Probit regression was also used to assess the relative potency of remimazolam between groups. Sedation levels were evaluated using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale.

Results

The ED50 for remimazolam was significantly lower in Group R+F compared to Group R (p= 0.007). Probit regression estimated the ED50 and ED95 values for Group R+F at 4.878 mg (95% CI, 3.845-5.859) and 8.184 mg (95% CI, 6.636-13.546), respectively. In contrast, Group R demonstrated ED50 and ED95 values of 6.733 mg (95% CI, 5.533-8.068) and 11.298 mg (95% CI, 9.101-19.617), respectively.

Conclusion

This study provides compelling evidence that the administration of 1 μg/kg of fentanyl significantly reduces the required sedative dose of remimazolam by approximately 30% during induction in elderly patients. Importantly, the concomitant use of 1 μg/kg of fentanyl does not increase the risk of adverse effects such as hypotension, respiratory depression.

Remimazolam anesthesia in pediatric patients undergoing cardiac catheterization for congenital heart disease: a retrospective observational study

BACKGROUND

Benzodiazepines are used in pediatric patients with congenital heart disease (CHD) because of their mild hemodynamic depressant effects. A novel short-acting benzodiazepine, remimazolam, is expected to be suitable for these patients. We examined the characteristics of remimazolam anesthesia in pediatric patients with CHD undergoing cardiac catheterization.

METHODS

This single-center retrospective study included pediatric patients undergoing cardiac catheterization for CHD. The primary outcome was the remimazolam dose for loss of consciousness. Secondary outcomes included the mean maintenance remimazolam dose, recovery time from anesthesia, predicted remimazolam concentration at emergence, decrease in blood pressure and heart rate, vasopressor administration during anesthesia, electroencephalogram index (bispectral index: BIS or patient state index: PSI), and life-threatening adverse events.

RESULTS

Thirty-nine patients, aged 2 months to 16 years, were included. Thirty-three patients received a median [interquartile] midazolam dose of 0.10 [0.10-0.10] mg.kg-1 in the pre-anesthesia room. The remimazolam dose for loss of consciousness was 0.34 [0.26-0.45] mg.kg-1. The mean maintenance dose was 1.0 [0.8-1.4] mg.kg-1.h-1. The recovery time was 15 [12-17] min. The predicted remimazolam concentration at emergence was 0.4-1.2 µg.ml-1 in 3-6-year-old patients. Blood pressure and heart rate decreased by 30% in 15 and 6 patients, respectively. Vasopressors were administered as a bolus in 8 patients. The BIS or PSI did not fall ≤ 60 or ≤ 50, respectively, in 51% of patients before tracheal intubation. No life-threatening adverse events were reported.

CONCLUSIONS

Remimazolam is a good alternative anesthetic agent for pediatric patients undergoing cardiac catheterization for CHD.

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

STUDY OBJECTIVE

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

DESIGN

Randomized controlled trial.

SETTING

Tertiary teaching hospital.

PATIENTS

Adult patients undergoing isolated CABG.

INTERVENTIONS

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

MEASUREMENTS

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

MAIN RESULTS

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

CONCLUSIONS

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

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.

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.

Clinical experience with remimazolam in pediatric anesthesiology: An educational focused review

Remimazolam is a novel ultrashort-acting benzodiazepine, which like midazolam, results in sedation, anxiolysis, and amnesia through its agonistic effects on the gamma-amino butyric acid A receptor. As opposed to midazolam, its unique metabolism is via tissue esterases, which results in a rapid elimination with a limited context sensitive half-life and prompt dissipation of its effect when administration is discontinued. Remimazolam received FDA approval for use in adults in 2020. In preliminary and initial clinical trials, its efficacy and safety has been suggested in the adult population, both as a primary agent for procedural sedation or as an adjunct to general anesthesia. There are limited data regarding the use of remimazolam in infants and children and its use in this population remains off label as it does not hold FDA-approval in pediatric-aged patients. This narrative outlines the pharmacologic properties of this unique medication, reviews previous published reports of its role in pediatric-aged patients, and discusses dosing parameters and clinical use in this population.

Remimazolam for anesthesia and sedation in cardiac surgery and for cardiac patients undergoing non-cardiac surgery: a systematic-narrative hybrid review

INTRODUCTION

Remimazolam, an ultra-short-acting benzodiazepine recognized and approved as an anesthetic and sedative in multiple countries, offers a distinctive pharmacokinetic profile, boasting advantages such as rapid onset, short action duration, and rapid recovery. These attributes may contribute to enhanced hemodynamic stability and a diminished risk of respiratory depression compared to other sedatives.

EVIDENCE ACQUISITION

We conducted the first comprehensive systematically structured narrative review to evaluate the role and potential application of remimazolam in cardiac surgery. Twenty-one studies published from 2021 to 2023 delved into remimazolam's application in open cardiac surgery, cardiac catheterization or electrophysiology laboratories, and high-risk cardiovascular patients undergoing non-cardiac surgery.

EVIDENCE SYNTHESIS

Overall, remimazolam usage was apparently linked to potentially superior hemodynamic stability compared to other hypnotic drugs. However, findings regarding the reduction in postoperative delirium incidence with remimazolam and the doses of remimazolam for anesthesia induction and maintenance were inconsistent across the studies.

CONCLUSIONS

Though remimazolam has demonstrated potential safety, efficacy, and ease-of-use for both anesthesia induction and maintenance in cardiac surgery patients and high-risk cardiovascular patients undergoing non-cardiac surgery, further research is imperative to delve into specific patient subgroups (e.g., the elderly or emergent procedures) so as to ascertain optimal dose ranges to suit diverse clinical scenarios.

Noradrenaline infusion prevents anesthesia-induced hypotension in severe aortic stenosis patients undergoing transcatheter aortic valve replacement: a retrospective observational study

BACKGROUND

Patients with severe aortic valve stenosis (AS) are particularly prone to developing hypotension during general anesthesia induction, which increases postoperative morbidity and mortality. Although the preventive effect of a single vasopressor dose on anesthesia-induced hypotension has been reported, the effects of continuous vasopressor infusion are unknown. This study aimed to assess the effect of noradrenaline (NAd) infusion on hemodynamic stability during general anesthesia induction in severe AS patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS

This single-center, retrospective study included severe AS patients who underwent elective TAVR. Patients in the NAd group received a continuous prophylactic NAd infusion of 0.1 μg/kg/min from the time of anesthesia induction. The control group received inotropes and vasopressors as indicated by the occurrence of hypotension. The primary outcome was the lowest mean blood pressure (MBP) before the start of surgery.

RESULTS

The study included 68 patients in the NAd group and 113 in the control group. The lowest MBP before the start of surgery was significantly higher in the NAd group than in the control group (63 ± 15 vs 47 ± 13 mmHg, P < 0.01). MBP immediately before intubation was also significantly higher in the NAd group (75 ± 17 vs 57 ± 16 mmHg, P < 0.01). Differences in postoperative complications between the groups were negligible.

CONCLUSION

Continuous administration of NAd at 0.1 μg/kg/min in patients with severe AS might prevent hypotension during general anesthesia induction for TAVR.

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

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

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.

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

PURPOSE

This study aimed to compare the hemodynamic effects of remimazolam- and propofol-based total intravenous anesthesia in patients who underwent transcatheter aortic valve replacement.

METHODS

This was a single-center, single-blind, randomized controlled trial set at Nara Medical University, Kashihara, Japan. We included 36 patients aged ≥ 20 years scheduled to undergo elective transfemoral transcatheter aortic valve replacement (TAVR) under general anesthesia. The participants were randomly assigned to the remimazolam and propofol groups (n = 18 each). Remimazolam- or propofol-based total intravenous anesthesia was initiated at 12 mg/kg/min or 2.5 mcg/mL via target-controlled infusion, respectively, along with remifentanil. After confirming the loss of consciousness, the administration rate was adjusted using electroencephalographic monitoring. The primary outcome was the rate of arterial hypotension, defined as a mean arterial pressure < 60 mmHg, from anesthesia induction until the beginning of the surgical incision. The total doses of ephedrine and phenylephrine were also assessed.

RESULTS

During anesthesia induction, the arterial hypotension rates were 11.9% and 21.6% in the remimazolam and propofol groups, respectively (P = 0.01). The total dose of ephedrine was higher in the propofol group (14.4 mg) than in the remimazolam group (1.6 mg) (P < 0.001); however, the total dose of phenylephrine was not significantly different between the two groups (propofol 0.31 mg vs. remimazolam: 0.17 mg, P = 0.10).

CONCLUSION

Remimazolam-based total intravenous anesthesia resulted in a lower hypotension rate than propofol-based total intravenous anesthesia during induction in patients undergoing TAVR. Remimazolam-based total intravenous anesthesia can be used safely during anesthetic induction in patients with severe aortic stenosis.

Effect of 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.

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.

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.

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.

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.

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.

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 .

Anesthetic management with remimazolam in very elderly patients undergoing hybrid surgery of transcatheter aortic valve implantation plus off-pump coronary artery bypass grafting: report of two cases

BACKGROUND

Remimazolam is a short-acting benzodiazepine with small circulatory depression. We used remimazolam for general anesthesia management in two very elderly patients undergoing hybrid surgery of transcatheter aortic valve implantation (TAVI) plus off-pump coronary artery bypass grafting (OPCABG).

CASE PRESENTATION

A 96-year-old man (case 1) and a 92-year-old woman (case 2) had complex coronary artery disease (CAD) and severe aortic stenosis (AS) and were scheduled for TAVI plus OPCAB. Anesthesia in both patients was induced with 6 mg/kg/h remimazolam and fentanyl and maintained with 0.3 mg/kg/h and 0.5 mg/kg/h remimazolam and fentanyl, respectively. Although catecholamines were required, we successfully maintained circulation during the induction of anesthesia and the procedures of OPCAB and TAVI. Both patients were discharged without complications.

CONCLUSION

Remimazolam can be a useful option for safe general anesthesia in very elderly patients when performing hybrid surgery.

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.

General anesthesia with remimazolam for emergency cesarean section in a patient with acute infective endocarditis: a case report

BACKGROUND

The anesthetic management of pregnant women with acute heart failure remains challenging with regard to maintaining the hemodynamic status of the mother and baby. The likelihood of decreased blood pressure is lower with remimazolam than with propofol. However, there is no report of general anesthesia with remimazolam for cesarean section.

CASE PRESENTATION

The patient was a 34-year-old pregnant woman who was diagnosed with acute heart failure associated with infective endocarditis. We performed cesarean section under general anesthesia using remimazolam, with percutaneous cardiopulmonary support on standby. The mother's mean blood pressure was maintained above 65 mmHg during the surgery, without catecholamines or vasopressors. The infant's Apgar scores were 4 at 1 min and 7 at 5 min.

CONCLUSION

Cesarean section was successfully performed under general anesthesia with remimazolam in a pregnant patient with acute heart failure. Further studies are needed to clarify the association between remimazolam and neonatal hypotension.

Effects of Remimazolam Anesthesia with Two Induction Doses on Hemodynamics and Recovery Profile in Older Patients: Comparison with Propofol Anesthesia

Remimazolam has advantages such as hemodynamic stability and rapid onset. We investigated the effects of induction doses on hemodynamics and recovery profiles for remimazolam compared to propofol in older patients. Sixty-nine patients aged >65 years were randomly assigned to either the propofol anesthesia group (P group) or the remimazolam anesthesia group with an induction dose of 6 mg/kg/h (R6 group) or 12 mg/kg/h (R12 group), followed by 1 mg/kg/h. P group was anesthetized with 4 µg/mL of propofol effect-site concentration (Ce) with target-control infusion, followed by 2.5-3 µg/mL of Ce. The primary outcome was the difference between the baseline mean arterial pressure (MAP) and the lowest MAP during anesthesia (ΔMAP). ΔMAP was comparable between the P, R6, and R12 groups (43.8 ± 13.8 mmHg, 39.2 ± 14.3 mmHg, and 39.2 ± 13.5 mmHg, p = 0.443). However, the frequencies of vasoactive drug use were 54.5%, 17.4%, and 30.4% (p = 0.029), and the median doses of ephedrine 3 (0-6) mg, 0 (0-0) mg, and 0 (0-0) mg (p = 0.034), which were significantly different. This study showed remimazolam anesthesia with an induction dose of 6 mg/kg/h, rather than 12 mg/kg/h, could reduce the requirement for vasoactive drugs compared to propofol anesthesia.

Can remimazolam be safely used in cardiac tamponade?: A case report

RATIONALE

Remimazolam, a benzodiazepine drug, has recently been developed and is currently used for the induction and maintenance of anesthesia. Remimazolam provides hemodynamic stability during anesthesia induction. However, in patients with cardiac tamponade, it is unclear how hemodynamic stability is maintained during the induction and maintenance of general anesthesia with remimazolam.

PATIENT CONCERNS

An 88-year-old male patient had developed hemopericardium due to penetration of a pigtail catheter into the left ventricle during pericardiocentesis, which was performed to treat massive pericardial effusion.

DIAGNOSES

The patient was diagnosed with acute cardiac tamponade and a hemothorax. Hemopericardium and hemothorax were confirmed on chest radiography and computed tomography performed immediately after pericardiocentesis.

INTERVENTIONS

Decompressive pericardiostomy was performed through a left anterolateral thoracotomy with 1-lung ventilation under general anesthesia. Remimazolam was administered for total intravenous anesthesia.

OUTCOMES

Severe hypotension and bradycardia occurred during the induction of anesthesia with remimazolam (6 mg/kg/hours).

LESSONS

Remimazolam may induce severe hemodynamic instability during induction of general anesthesia in patient with cardiac tamponade.

Bibliometric Analysis of Global Trends in Remimazolam-Related Research Over the Past 15 Years: Compared with Propofol

Purpose

Although remimazolam is a popular novel anesthetic, there is a lack of data in the literature about current and future trends. Therefore, the aim of this study was to explore emerging trends and potential hotspots of remimazolam research over the past 15 years through bibliometric methods.

Methods

Relevant articles on remimazolam published from 2007 to 2022 and propofol from 1997 to 2001 were retrieved from the Web of Science Core Collection database. Data were collected using Microsoft Excel and graphs were generated with the Bibliometrix package in R software. Visual bibliometric maps were created using VOS viewer and CiteSpace software.

Results

In total, 184 articles were included for analysis. Remimazolam-related research tended to increase, especially from 2020 to 2022. China produced the most publications (327), whereas the USA dominated in quality (h-index = 16). Among institutions, PAION Deutschland GmbH produced the most articles (Np = 21). Similar to initial research and development of propofol, the hotspots of remimazolam research have extended beyond pharmacokinetics and pharmacodynamics to adverse reactions, clinical scenarios, specific populations, and compatible regimens, as confirmed by high numbers of common references and keywords.

Conclusion

Remimazolam research has developed rapidly over the past two years. Remimazolam can achieve faster onset and recovery, and more stable hemodynamics than midazolam or propofol, enabling gradual piloting of applications from endoscopy and general anesthesia to sedation of critical care patients; foreseeing specific population (patients with hepatic or renal impairment and reduced cardiovascular reserve, the elderly, and children) through compatible anesthetics regimens to more optimal and safe. Future studies of remimazolam are likely to include adverse reactions, effects on different organ systems, and identification of monitoring indicators.

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

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

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.

Remimazolam as the Primary Agent for Sedation During Cardiac Catheterization in Three Patients With Comorbid Cardiac Conduction Abnormalities

General anesthesia or procedural sedation may be required to ensure immobility, facilitate completion of the procedure, and ensure patient comfort during diagnostic or therapeutic procedures in the cardiac catheterization suite. Although propofol and dexmedetomidine are two of the more commonly chosen agents, concerns regarding their impact on inotropic, chronotropic or dromotropic function may limit their applicability based on underlying patient comorbid conditions. We present three patients with comorbid conditions involving pacemaker (natural or implanted) function or cardiac conduction which impacted the choice of agent for procedural sedation during procedures in the cardiac catheterization suite. Remimazolam, a novel ester-metabolized benzodiazepine, was used as the primary agent for sedation in an effort to limit detrimental effects on chronotropic and dromotropic function which may be seen with propofol or dexmedetomidine. Remimazolam's potential utility in procedural sedation is discussed, previous reports of its use are reviewed, and dosing algorithms are presented.

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

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

Remimazolam Requires Less Vasopressor Support during Induction and Maintenance of General Anesthesia in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement: A Retrospective Analysis from a Single Center

Introduction

We compared the hemodynamics during general anesthesia with remimazolam and conventional anesthetics in patients with severe aortic stenosis (AS).

Methods

This was a retrospective single-center analysis. We reviewed the records of 42 patients who underwent transcatheter aortic valve implantation with a transfemoral artery approach under general anesthesia from January to December 2020. Patients were divided into three groups based on the general anesthetic used for (induction/maintenance) remimazolam/remimazolam (Group R/R), propofol/sevoflurane (Group P/S), and midazolam/propofol (Group M/P). Vasopressor use (ephedrine, phenylephrine, and noradrenaline) was compared among the groups.

Results

The number of patients in each group was 15 (Group R/R), 13 (Group P/S), and 14 (Group M/P), with no significant difference in background characteristics and intraoperative vital signs. For anesthesia induction, doses of ephedrine and phenylephrine used were significantly lower in Group R/R (ephedrine [mg]: Group R/R 2 [0-4] vs. Group P/S 8 [8-12], P < 0.001, Group R/R vs. Group M/P 5 [0-15], P = 0.39; phenylephrine (mg): Group R/R 0 [0-0.08] vs. Group P/S 0.15 [0.10-0.20], P = 0.03, Group M/P 0.21 [0.04-0.40], P = 0.08). For anesthesia maintenance, the noradrenaline dose used was low in the Group R/R (noradrenaline [μg/kg/min]: Group R/R 0.019 [0.015-0.039], Group P/S 0.042 [0.035-0.045], P = 0.02, Group M/P 0.048 [0.040-0.059], P < 0.01).

Conclusion

In patients with severe AS, induction and maintenance of anesthesia with remimazolam resulted in less overall vasopressor use than conventional general anesthetics.

Profile of Remimazolam in Anesthesiology: A Narrative Review of Clinical Research Progress

Remimazolam is a novel short-acting γ-aminobutyric acid (GABA) receptor agonist with typical characteristics of benzodiazepine sedative drugs, nonorgan-dependent metabolism, long-term infusion without accumulation, and no injection pain. It is quite different from the other current sedative drugs and has broad prospects for application. It has been established that the metabolites of remimazolam are inactive, and the interactions with other drugs are weak with slight cardiopulmonary suppressive effects, showing good effectiveness and safety. During the 2-year period that it has been on the market, remimazolam has been used in multiple clinical scenarios, such as the induction and maintenance of general anesthesia and sedation in outpatient minor procedures or examinations. However, it's use has also prompted widespread concern around the world. Therefore, given its short- and rapid-acting, controllable characteristics remimazolam deserves in-depth study in order for it to be used in fast-track surgery, comfort diagnosis and treatment. Notably, such agents might be of great significance, especially in elderly individuals, patients with critical diseases or patients with liver and kidney insufficiency. The current study reviews recent clinical studies (2015-2022) on remimazolam and summarizes the characteristics of its applications. Specifically, the use of remimazolam in some specific populations are described. This study attempts to provide scientific support for the clinical application of this novel sedative drug in the field of anesthesia.

The hemodynamic stability of remimazolam compared with propofol in patients undergoing endoscopic submucosal dissection: A randomized trial

Objective

Hypotension is common in propofol anesthesia. Whether remimazolam could reduce intraoperative hypotension remains unknown. We therefore tested the primary hypothesis that remimazolam reduces the incidence of intraoperative hypotension compared with propofol in adult patients undergoing endoscopic submucosal dissection (ESD) surgery.

Materials and methods

We conducted a prospective trial to compare patients who received either remimazolam or propofol bolus induction and thereafter intravenous infusion. The hemodynamic parameters were measured using CNAP® Monitor 500 system. Our primary analysis was to compare the incidence of hypotension defined as systolic blood pressure below 90 mmHg between remimazolam and propofol during the whole anesthesia period.

Results

The incidence of hypotension decreased by 50%, from 67.9% in propofol group to 32.1% in remimazolam group (p &lt; 0.01). Patients received less amount of intraoperative phenylephrine in the remimazolam group than the propofol group (0 [0–40] μg vs. 80 [0–200] μg, p &lt; 0.01). Time-weighted average and cumulative time of hypotension was lower in remimazolam group compared with propofol group (p &lt; 0.05). Cardiac output continuously measured by CNAP was preserved much better in remimazolam group compared with propofol group (p = 0.01), while systemic vascular resistance did not differ between the groups. The median time from discontinuation until full alertness was 4 [3–11.8] min in the remimazolam group compared with 15 [12.0–19.8] min in the propofol group (p &lt; 0.01).

Conclusion

Remimazolam has better hemodynamic stability than propofol in adult patients undergoing ESD surgery. The benefits of remimazolam on hemodynamic stability and hypotension prevention may be partly contributed to its better preservation of cardiac output.

Clinical Trial Registration

[http://www.chictr.org.cn/com/25/showproj.aspx?proj=61104], identifier [ChiCTR2000037975].

Novel anesthetics in pediatric practice: is it time?

PURPOSE OF REVIEW

Steadily mounting evidence of anesthesia-induced developmental neurotoxicity has been a challenge in pediatric anesthesiology. Considering that presently used anesthetics have, in different animal models, been shown to cause lasting behavioral impairments when administered at the peak of brain development, the nagging question, 'Is it time for the development of a new anesthetic' must be pondered.

RECENT FINDINGS

The emerging 'soft analogs' of intravenous anesthetics aim to overcome the shortcomings of currently available clinical drugs. Remimazolam, a novel ester-analog of midazolam, is a well tolerated intravenous drug with beneficial pharmacological properties. Two novel etomidate analogs currently in development are causing less adrenocortical suppression while maintaining equally favorable hemodynamic stability and rapid metabolism. Quaternary lidocaine derivatives are explored as more potent and longer lasting alternatives to currently available local anesthetics. Xenon, a noble gas with anesthetic properties, is being considered as an anesthetic-sparing adjuvant in pediatric population. Finally, alphaxalone is being reevaluated in a new drug formulation because of its favorable pharmacological properties.

SUMMARY

Although a number of exciting anesthetic drugs are under development, there is currently no clear evidence to suggest their lack of neurotoxic properties in young brain. Well designed preclinical studies are needed to evaluate their neurotoxic potential.

Effect-site concentration of remimazolam at loss and recovery of responsiveness during general anesthesia: a simulation study

Background

The objective of this study was to investigate the effect-site concentration (Ce) of remimazolam at loss of response (LOR) and recovery of response (ROR) in patients underwent general anesthesia using simulation. In addition, the relationships between patient’s factors and simulated Ce at LOR and ROR were examined.

Methods

The medical records of 81 patients who underwent elective surgery under general anesthesia using remimazolam with simulation of Ce between August 4, 2021 and October 12, 2021, were retrospectively reviewed. Remimazolam was administered as an induction dose of 6 or 12 mg/kg/h until the patient became unresponsive, followed by 0.3–2 mg/kg/h to maintain BIS values below 60. Simultaneously, simulations of manual infusion mode were performed using Asan Pump software and the Ce of remimazolam was simulated using the Schüttler model. Whenever infusion rate of remimazolam was manually changed, the simulated Ce was confirmed almost simultaneously. LOR and ROR, defined as unresponsive and eye-opening to verbal commands, respectively, were recorded in the Asan Pump program.

Results

The median (1Q, 3Q) simulated Ce at LOR and ROR were 0.7 (0.5, 0.9) and 0.3 (0.2, 0.4) μg/ml, respectively. LOR was achieved in 1.9 min after remimazolam infusion with cumulative doses of 0.3 mg/kg. There was a significant relationship between age and simulated Ce at ROR (Ce at ROR = –0.0043 × age + 0.57, r = 0.30, P = 0.014).

Conclusions

For optimal dosage adjustment, simulating Ce while administering remimazolam with a weight-based dose during anesthesia is helpful. Elderly patients may recover from anesthesia at lower Ce of remimazolam.

Total intravenous anesthesia induced and maintained by a combination of remimazolam and remifentanil without a neuromuscular blocking agent: a prospective, observational pilot study

Background

A novel short-acting benzodiazepine, Remimazolam, has recently been approved for general anesthesia and sedation. Hence, we investigated the feasibility and safety of remimazolam during the induction and maintenance of general anesthesia without using a neuromuscular blocking agent (NMBA) in patients undergoing hysteroscopic surgery.

Methods

This prospective observational study included 38 patients undergoing hysteroscopic surgery. Remimazolam and remifentanil were the main anesthetic agents without an NMBA, and a supraglottic airway was inserted to protect the airway. The induction time, amount of each anesthetic agent used during anesthesia, intraoperative bispectral index (BIS) hemodynamic parameters, and recovery profiles were measured.

Results

General anesthesia was successfully administered to 37 patients using remimazolam and remifentanil without NMBA. The induction doses of remimazolam and remifentanil were 0.4 mg/kg (interquartile range [IQR] 0.34–0.47 mg/kg) and 1.07 μg/kg (IQR, 0.90–1.29 μg/kg), respectively. Additionally, the maintenance doses of remimazolam and remifentanil were 1.14 mg/kg/h (IQR, 0.88–1.55 mg/kg/h) and 0.06 μg/kg/min (IQR, 0.04–0.08 μg/kg/min), respectively. Intraoperative BIS values had risen temporarily > 60 in eight patients (21.6%) despite administration of 2 mg/kg/h of remimazolam; thus, they were treated with supplementary midazolam. The median recovery time was 7 min (IQR, 5–8 min) after 40 min (IQR, 40.0–57.5 min) of total mean anesthesia time. There was no correlation between the infusion dose of remimazolam and recovery profiles, such as recovery time, final BIS of anesthesia, modified observer assessment of alertness/sedation (OAA/S) scale or post-anesthesia recovery (PAR) score when arriving at the PACU, and length of stay in the PACU (all P > 0.05).

Conclusion

Remimazolam can be combined with remifentanil without an NMBA in female patients who undergo hysteroscopic surgery, during which a supraglottic airway is a feasible method to protect the airway.

Trial registration

The study protocol was registered at ClinicalTrials.gov (NCT05025410) on 27/08/2021.

Review of remimazolam and sedatives in the intensive care unit

Remimazolam is a novel intravenous ultra-short acting benzodiazepine that has the potential of being a safe and effective new sedative for use in intensive care unit (ICU) settings. Because remimazolam metabolizes rapidly by being hydrolyzed to an inactive metabolite (CNS 7054) through non-specific tissue esterase activity, specific dosing adjustment for older adults and for patients with renal or hepatic impairment patients (except for those with severe hepatic impairment) is not required. In addition, research has shown that remimazolam may be reversed by administration of flumazenil, as its half time was sufficiently short compared to flumazenil. It shows a lower incidence of cardiorespiratory depression, less injection pain, and no fatal complications such as propofol infusion syndrome and malignant hyperthermia of inhalational anesthetics. Future studies to study the suitability of remimazolam for managing the sedation of ICU patients who need sedation for a long time over several days is required.

Quality of Recovery After General Anesthesia with Remimazolam in Patients' Undergoing Urologic Surgery: A Randomized Controlled Trial Comparing Remimazolam with Propofol

Background

Remimazolam is a new medication with sedative and hypnotic effects. It has been demonstrated non-inferior to propofol in general anesthesia with regard to efficacy and safety. However, whether general anesthesia with remimazolam is better than propofol in terms of patients' recovery quality remains unknown.

Patients and Methods

Patients enrolled in this study were randomized to remimazolam or propofol group. In remimazolam group, general anesthesia was induced with remimazolam and sufentanil and maintained with remimazolam and remifentanil. In propofol group, general anesthesia was induced with propofol and sufentanil and maintained with propofol and remifentanil. Neuromuscular blocking agent cisatracurium was also injected during anesthesia. Sedation level was monitored by bispectral index (BIS). Our primary outcome was the quality of patients' postoperative recovery, using the Quality of Recovery-15 (QoR-15) scale. Secondary outcomes included SpO2, HR, MBP and frequency of application of vasoactive drugs during anesthesia, as well as incidences of adverse events in the post anesthesia care unit (PACU).

Results

The global scores of QoR-15 scale were lower in remimazolam group at postoperative day 1 and day 3 compared to propofol group, but differences between the two groups only had clinical significance at postoperative day 1. Among the five dimensions of QoR-15 scale, scores for physical comfort and emotional state were lower in remimazolam group than propofol group. MBP and HR were higher in remimazolam group than propofol group after anesthesia induction. SpO2 was similar in the two groups. The frequency of application of vasoactive drugs during anesthesia was higher in propofol group than remimazolam group. There was no statistical difference in the incidences of adverse events between the two groups.

Conclusion

General anesthesia with remimazolam can provide more stable hemodynamics but also cause temporary reduction in the quality of recovery in patients undergoing urologic surgery, compared to propofol.