Post-induction hypotension (PIH) is a common and critical complication during general anesthesia, particularly in frail elderly patients whose physiological reserves are significantly diminished. PIH is strongly associated with adverse postoperative outcomes, including acute kidney injury (AKI) and myocardial injury. Propofol is the most widely used induction agent but frequently induces circulatory depression. Ciprofol, a novel anesthetic agent developed by optimizing the molecular structure of propofol, has demonstrated improved hemodynamic stability and fewer adverse effects in general populations. However, its specific impact on frail elderly patients remains unestablished.

The primary purpose of this single-center, randomized, double-blind, controlled trial is to compare the effects of propofol and ciprofol during anesthesia induction on the incidence of PIH in frail elderly patients undergoing major abdominal surgery. The investigator's hypothesis is that ciprofol will significantly lower the incidence of PIH compared to propofol. Additionally, the study will evaluate secondary clinical outcomes, such as postoperative AKI, postoperative cardiac complications, and the overall quality of recovery, to provide an evidence-based clinical guide for selecting optimal induction agents for this vulnerable patient population.

Background and Rationale:

Frail elderly patients exhibit an accumulation of multi-system physiological decline, making them highly vulnerable to surgical and anesthetic stressors. During the induction of general anesthesia, these patients are at an exceptionally high risk for severe and prolonged hypotension due to reduced cardiac stroke volume, impaired autonomic nervous system regulation, and altered pharmacokinetics. Post-induction hypotension (PIH)-occurring from the initiation of anesthesia to 10 minutes post-intubation-is directly influenced by the choice of induction agent and the patient's baseline condition, with fewer confounding factors than intraoperative hypotension.

While propofol is highly efficient, its prominent side effect is cardiovascular depression. Ciprofol is an innovative 2,6-disubstituted phenol derivative that maintains the rapid onset and recovery advantages of propofol while offering enhanced hemodynamic stability. To date, clinical evidence comparing these two agents specifically in the frail elderly population is lacking. This study seeks to evaluate whether ciprofol can mitigate the risk of PIH in frail elderly patients undergoing major abdominal surgery and to observe its downstream impacts on major organ protection and postoperative recovery quality.

Study Workflow and Anesthesia Management:

1. Patient Screening: Patients aged 60 or older with a frailty score >= 3 undergoing major abdominal surgery under general anesthesia with planned invasive blood pressure monitoring will be screened on the day before surgery.

2. Randomization and Blinding: Eligible participants will be randomized in a 1:1 ratio to either the Propofol Group or the Ciprofol Group. Both patients and outcome assessors will be blinded to the group allocation.

3. Intervention:

   • Propofol Group: Anesthesia induction will be performed using midazolam, sufentanil, propofol, and rocuronium.
   • Ciprofol Group: Anesthesia induction will be performed using midazolam, sufentanil, ciprofol, and rocuronium.

4. Monitoring and Follow-up: Standardized intraoperative and perioperative management will be applied uniformly across both groups. Hemodynamic parameters will be monitored continuously. Postoperatively, patients will be followed up to evaluate acute kidney injury (AKI) within 48 hours, cardiac complications (including MINS, congestive heart failure, and acute myocardial infarction) within 7 days or during hospitalization, and overall recovery quality metrics (including mechanical ventilation time, PACU and ICU stay duration, and total postoperative hospital stay).

Inclusion Criteria:

• Patients scheduled to undergo major abdominal surgery under general anesthesia.
• Frailty score >= 3[cite: 2].
• Age >= 60 years[cite: 2].
• American Society of Anesthesiologists (ASA) physical status class >= II[cite: 2].
• Planned invasive blood pressure monitoring[cite: 2].

Exclusion Criteria:

• Severe cardiac arrhythmia[cite: 2].
• Severe valvular heart disease[cite: 2].
• Poorly controlled hypertension with medication (systolic blood pressure >= 180 mmHg and/or diastolic blood pressure >= 110 mmHg)[cite: 2].
• Pre-existing preoperative hypotension (mean arterial pressure < 65 mmHg)[cite: 2].
• Preoperative renal dysfunction (serum creatinine greater than the upper limit of normal)[cite: 2].