Anesthesia Induction With Intravenous Bolus or Continuous Infusion of Remimazolam

Comparison of Anesthetic Induction Time and Change of Bispectral Index Between Intravenous Bolus Administration and Continuous Infusion of Remimazolam for Anesthetic Induction: a Prospective Randomized Single-blind Study

Bolus injection and continuous infusion are two widely used methods for intravenous administration of drugs. Bolus injection possibly leads to a rather high drug plasma concentration temporarily, however, it can induce a rapid onset of drug effects and attain a desired clinical state fast. On the contrary, continuous infusion is able to avoid excessive drug levels in plasma, but it takes longer to achieve the proper effect.

In this study, the investigators hypothesize that the bolus injection of remimazolam can reduce anesthesia induction time when compared to the continuous infusion of remimazolam, and also maintain hemodynamic stability. (The researchers will investigate the effect of the bolus injection of remimazolam during anesthesia induction in terms of its safety and efficacy when compared with the continuous infusion.)

Inclusion Criteria:

• Adults 19 years of age or older undergoing surgery under general anesthesia
• ASA I-III

Exclusion Criteria:

• Intraoperative regional blocks (e.g. spinal anesthesia, epidural anesthesia, peripheral nerve block)
• Liver resection or liver transplantation
• Cardiopulmonary bypass
• Uncontrolled HTN (SBP ≧180 mmHg, or ≧160 in patients taking antihypertensive drugs)
• Uncontrolled DM (HbA1c antihypertensive drugs ≧9.0%)
• Total bilirubin ≧3.0 mg/ml or AST or ALS ≧2.5 times the upper limit of normal
• Serum creatinine ≧2.0 mg/ml or ESRD on dialysis
• COPD in need of treatment
• Patients who are expected to have difficulty in tracheal extubation immediately after surgery for postoperative lung management
• Resistance to benzodiazepines
• Hypersensitivity to benzodiazepines, remifentanil, fentanyl citrate, rocuronium, sugammadex, flumazenil, or other anesthetic drugs
• Myasthenia gravis or myasthenic syndrome
• Myocardial infarction, transient ischemic attack, stroke, newly diagnosed coronary artery disease, percutaneous coronary intervention, or coronary artery bypass graft within 6 months
• Implantation of rate-responsive cardiac pacemaker with bioelectrical impedance sensor
• Organic brain disorder, or other neurologic diseases that cannot adequately measure EEG (BIS)
• Severe allergic diseases
• Cognitive impairment that makes it impossible to understand the instructions and informed consent of this study