Overview
This prospective observational cohort study evaluates the effectiveness and safety of two benzodiazepine sedatives-remimazolam and midazolam-used for general anesthesia induction in elderly patients (≥65 years) undergoing elective non-cardiac surgery. Elderly patients have reduced organ reserve and altered pharmacokinetics/pharmacodynamics, increasing their susceptibility to anesthesia-related complications such as intraoperative hypotension, delayed emergence, and postoperative delirium. Remimazolam, an ultra-short-acting benzodiazepine metabolized by organ-independent tissue esterases, is hypothesized to offer greater hemodynamic stability, faster recovery, and a more favorable safety profile than midazolam in this vulnerable population. Investigators prospectively observe and collect data without altering routine clinical care; the choice of sedative is made by the attending anesthesiologist according to standard practice. Propensity score methods will be used to reduce confounding by indication.
Description
This is a prospective, observational, cohort study. The exposure is the benzodiazepine sedative actually used at induction; patients are grouped as the remimazolam (RM) or midazolam (MZ) cohort based on the clinical record. Induction and maintenance are individualized by the attending anesthesiologist ; investigators only observe and collect data without altering routine care. All patients receive standard monitoring (ECG, SpO₂, non-invasive/invasive blood pressure, end-tidal CO₂, anesthetic depth). Collected data include demographics, medical history and risk factors, medication history, examination and laboratory results, and intraoperative variables (ASA class, surgery type and duration, hypotension, anesthetic and opioid doses, fluid balance, blood loss, transfusion).
Eligibility
Inclusion Criteria:
- Age 65 years or older.
- Scheduled for elective non-cardiac surgery under general anesthesia.
- American Society of Anesthesiologists physical status I to IV.
- Planned airway management with tracheal intubation or a laryngeal mask airway.
- Written informed consent provided by the participant or the participant's legally authorized representative.
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Exclusion Criteria:
- Long-term preoperative benzodiazepine use.
- Known allergy or contraindication to benzodiazepines, flumazenil, opioids, naloxone, or related drugs.
- History of drug abuse or alcoholism within the past 2 years.
- No preoperative cognitive assessment available.
- Preoperative cognitive impairment, defined as a Mini-Mental State 6.Examination score less than 18.
7.Refusal to provide informed consent.
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