We have read the recent study by Min et al. [1], entitled “Hypotension after induction of anesthesia with remimazolam or etomidate: a non-inferiority randomized controlled trial in patients undergoing coronary artery bypass grafting” with interest. The authors provided significant new information on the function of remimazolam in a high-risk cardiac group, supporting its use as an anesthesia-induction drug. Nevertheless, we would like to highlight several pharmacodynamic issues and address the interpretive constraints of their study that warrant further investigations.

Mechanistically, remimazolam, a soft, ester-based benzodiazepine, modulates GABA-A receptors to produce sedative effects similar to those of midazolam. In terms of pharmacokinetics, it undergoes rapid metabolism through tissue esterases, irrespective of the patient’s hepatic or renal functional status [2]. Such organ-independent clearance makes remimazolam more appealing, particularly for cardiac anesthesia, where end-organ perfusion may fluctuate. The drug also has rapid onset and offset properties. Whether its GABAergic activity resembles that of etomidate, which alters GABA-A receptor channels while maintaining exceptional hemodynamic stability, remains unclear. For patients with advanced ventricular compromise, etomidate is considered the gold standard because its use preserves sympathetic tone and avoids myocardial depression.

Temporal pharmacodynamics must also be considered. The short, context-sensitive half-life of remimazolam can be beneficial in environments where a fast neurological assessment is vital. In cardiac surgery, particularly in cases requiring extended pre-bypass periods, its short duration of action may necessitate the use of supplementary medications to maintain sufficient sedation and hemodynamic control, which were not addressed in the study by Min et al. [1]

Despite the double-blind design of their study, the distinct onset profiles and administration characteristics of remimazolam and etomidate may have allowed experienced anesthesiologists to identify the assigned agent. This perceptibility imposes a risk of expectancy bias, which could have influenced subjective assessments and therapeutic treatments. The manuscript does not report any assessment of the effectiveness of the blinding procedures. Could the authors clarify whether such assessments were conducted to verify the success of blinding, particularly among the anesthesia providers? This information is needed to determine the robustness of internal validity, given the possibility of expectation bias, particularly in hemodynamic evaluations.

Furthermore, other than in the anesthesia-induction phase, hemodynamic behavior under remimazolam anesthesia remains unreported. Anesthetic selection has a major impact on events such as reperfusion, cardiopulmonary bypass start and termination, and sternotomy. Data covering all these phases are requisite to establish a complete profile of the effects of remimazolam.

Although Min et al. offered insights in their paper, the pharmacological subtleties and clinical complexity surrounding the use of remimazolam in cardiac anesthesia warrant further research, particularly in fragile cardiac subgroups and surgeries involving protracted intraoperative environments.