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.
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).
Study Type
OBSERVATIONAL
Enrollment
1,000
The Second Affiliated Hospital of Zhejiang University School of Medicin
Hangzhou, China
RECRUITINGIntraoperative Hypotension Burden Measured by the Time-Weighted Average of Mean Arterial Pressure (TWA-MAP) Below an Absolute Threshold (<65 mmHg) or a Relative Threshold (>20% Decrease From Baseline)
Intraoperative hypotension burden was quantified from mean arterial pressure (MAP) recordings obtained from anesthetic induction through the end of surgery (induction and maintenance periods).
Time frame: From anesthetic induction through the end of surgery (intraoperative period)
Vasoactive drug requirement
Time frame: Induction period and entire perioperative period Cumulative dose and frequency of vasoactive agents
Time to Extubation
Time from discontinuation of anesthetics to removal of the endotracheal tube.
Time frame: During anesthesia emergence
Quality of Recovery at 24 Hours Postoperatively as Assessed by the Quality of Recovery-15 (QoR-15) Questionnaire
Quality of postoperative recovery will be assessed using the Quality of Recovery-15 (QoR-15) questionnaire, a 15-item patient-reported instrument covering physical comfort, physical independence, emotional state, psychological support, and pain. Each item is scored on an 11-point scale from 0 to 10. The total score ranges from 0 to 150, with higher scores indicating better quality of recovery.
Time frame: 24 hours after surgery
Perioperative Anxiety Assessed by the Hospital Anxiety and Depression Scale - Anxiety Subscale (HADS-A)
Perioperative anxiety was assessed using the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS-A). The HADS-A consists of 7 items, each rated from 0 to 3, yielding a total score ranging from 0 to 21. Higher scores indicate greater anxiety (a worse outcome).
Time frame: Day of surgery and postoperative day 2
Composite of Major Organ Complications (Postoperative Delirium, Acute Kidney Injury, Stroke, Acute Myocardial Infarction, Pulmonary Infection, In-Hospital All-Cause Mortality, Postoperative Length of Stay, and Unplanned Reoperation)
postoperative delirium, acute kidney injury, stroke, acute myocardial infarction, or pulmonary infection. Postoperative delirium will be assessed using the Confusion Assessment Method or clinical documentation. Acute kidney injury will be defined according to Kidney Disease: Improving Global Outcomes criteria. Stroke and acute myocardial infarction will be diagnosed based on clinical, laboratory, electrocardiographic, imaging, and medical record evidence. Pulmonary infection will be diagnosed based on clinical symptoms, radiographic findings, laboratory results, and the need for antimicrobial treatment. In-hospital all-cause mortality will also be recorded.
Time frame: From the end of surgery until hospital discharge, an average of 7 days
Incidence of Anesthesia-Related Adverse Events (Composite)
The number/proportion of participants experiencing one or more anesthesia-related adverse events during the perioperative period was recorded. Anesthesia-related adverse events included intraoperative awareness and postoperative nausea and vomiting (PONV).
Time frame: perioperative
Length of Stay in the Post-Anesthesia Care Unit (PACU)
Length of stay in the post-anesthesia care unit (PACU), defined as the time from PACU admission until the patient meets PACU discharge readiness criteria, measured in minutes.
Time frame: From PACU admission until PACU discharge readiness, assessed up to 24 hours after surgery
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