Effect of remimazolam on the incidence of delirium after transcatheter aortic valve implantation under general anesthesia: a retrospective exploratory study

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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

BACKGROUND

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

METHODS

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

DISCUSSION

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

TRIAL REGISTRATION

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

Effectiveness of remimazolam in preventing postoperative delirium in elderly patients with proximal femoral fractures

PURPOSE

Elderly patients with proximal femoral fractures are known to be a high-risk group for postoperative delirium (POD). The aim of this study was to determine the association of the benzodiazepine drug remimazolam with POD in elderly patients with proximal femoral fractures.

METHODS

In this single-center retrospective observational study, we included patients aged 65 years or older who underwent general anesthesia for proximal femoral fractures. We collected data for the incidence of POD within 3 days after surgery. We also obtained data for complications, preoperative blood examinations, maintenance anesthetic and intraoperative vital data. The occurrence of POD in patients who received remimazolam for general anesthesia (remimazolam group) was compared to that in patients who received general anesthesia with other anesthetic agents (other group). We finally conducted a multivariate analysis to assess the independent association of remimazolam with the risk of POD.

RESULTS

A total of 230 patients, including 54 patients who received remimazolam for maintenance anesthesia, were included in this study. The incidence of POD in the patients was 26.1%. The incidence of delirium within 3 days after surgery was significantly lower in the remimazolam group than in the other group (14.8% vs. 29.5%, p  =  0.03). The multivariate analysis showed that the use of remimazolam independently reduced the occurrence of POD (adjusted odds ratio  =  0.42, p  =  0.04).

CONCLUSION

This retrospective observational study showed that the use of remimazolam is independently associated with a reduced incidence of POD. Remimazolam may be considered as an option to reduce POD in elderly patients with proximal femoral fractures.

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.

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

Background

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

Methods

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

Discussion

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

Trial registration

Chinese Clinical Trial Registry (ChiCTR2200056353).

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 .

The influence of delirium on mortality and length of ICU stay and analysis of risk factors for delirium after liver transplantation

Objective

To analyze the incidence, timing, risk factors and prognosis of delirium after liver transplantation (LT).

Methods

The clinical data of 321 patients undergoing LT in the Third Xiangya Hospital of Central South University from January 2018 to December 2022 were collected to investigate the incidence, onset, and risk factors for post-LT delirium and the impact of delirium on LT recipients' prognosis by statistical analysis.

Results

The incidence of post-LT delirium was 19.3% (62/321), and the median interval between LT and onset of delirium was 20.1 h. Univariate analysis showed that pre-LT variables (Model for End Stage Liver Disease (MELD) score, hospital stay, hepatic encephalopathy, infection, white blood cell (WBC) count, lymphocyte count, abnormal potassium, lactulose use), intraoperative variables (red blood cell transfusion, remimazolam use, dexmedetomidine use) and post-LT variables (hypernatraemia, acute rejection, reoperation, basiliximab use, tacrolimus concentration) were associated with post-LT delirium. Multivariate logistic regression analysis revealed that MELD score at LT ≥22 [OR = 3.400, 95% CI:1.468-7.876, p = 0.004], pre-LT hepatic encephalopathy [OR = 3.224, 95% CI:1.664-6.244, p = 0.001], infection within 2 months prior to LT [OR = 2.238, 95% CI:1.151-4.351, p = 0.018], acute rejection [OR = 2.974, 95% CI:1.322-6.690, p = 0.008], and reoperation [OR = 11.919, 95% CI:2.938-48.350, p = 0.001] were independent risk factors for post-LT delirium. Post-LT delirium was reduced in LT recipients exposing to intraoperative remimazolam [OR = 0.287, 95% CI: 0.113-0.733, p = 0.009] or ≥ 25 μg of intraoperative dexmedetomidine [OR = 0.441, 95% CI 0.225-0.867, p = 0.018]. As for clinical outcomes, patients with delirium had a higher percentage of staying at the (ICU) ≥7 d after LT than those without delirium [OR = 2.559, 95% CI 1.418-4.617, p = 0.002].

Conclusion

The incidence of delirium was high and the onset of delirium was early after LT. Risk factors for post-LT delirium included high MELD score at LT, pre-LT hepatic encephalopathy and infections, acute rejection and reoperation. Intraoperative use of remimazolam or dexmedetomidine reduced post-LT delirium. Delirium had a negative impact on the length of ICU stay.

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.

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.

Effect of Remimazolam on Postoperative Delirium in Older Adult Patients Undergoing Orthopedic Surgery: A Prospective Randomized Controlled Clinical Trial

Background

Postoperative delirium is common in older adult patients and associated with a poor prognosis. The use of benzodiazepine was identified as an independent risk factor for delirium, but there is no randomized controlled trial regarding the relationship between remimazolam, a new ultra-short acting benzodiazepine, and postoperative delirium. We designed a randomized controlled trial to evaluate if remimazolam increases the incidence of postoperative delirium compared with propofol in older adult patients undergoing orthopedic surgery with general anesthesia.

Patients and Methods

We enrolled 320 patients aged more than 60 with American Society of Anesthesiologists physical status I-III who underwent orthopedic surgery. Patients were randomized to two groups to receive intraoperative remimazolam or propofol, respectively. Our primary outcome was the incidence of delirium within 3 days after surgery. Secondary outcome was emergence quality including the incidence of emergence agitation, extubation time, and length of post-anesthesia care unit (PACU) stay. Adverse events were also recorded.

Results

The incidence of postoperative delirium was 15.6% in the remimazolam group and 12.4% in the propofol group (Risk ratio, 1.26; 95% CI, 0.72 to 2.21; Risk difference, 3.2%; 95% CI, -4.7% to 11.2%; P = 0.42). No significant differences were observed for time of delirium onset, duration of delirium, and delirium subtype between the two groups. Patients in remimazolam group had a lower incidence of hypotension after induction and consumed less vasoactive drugs intraoperatively, but had a longer postoperative extubation time and PACU stay.

Conclusion

General anesthesia with remimazolam was not associated with an increased incidence of postoperative delirium compared with propofol in older adult patients undergoing orthopedic surgery.