A Comparative Study Protocol Investigating the Association Between Intraoperative Hypotension and the Use of Ring- Versus Propofol-Based Anesthesia in Elderly Patients Undergoing Non-Cardiac Surgery

Intraoperative hypotension (IOH) is a frequent and clinically significant complication during non-cardiac surgery, particularly in the geriatric population .On a population basis, the hypotensive harm threshold for AKI is a mean arterial pressure (MAP) of around 65 mm Hg. Maintaining MAP above this level during surgery is therefore recommended. Mounting evidence suggests that even brief periods of low arterial blood pressure are independently associated with an increased risk of postoperative myocardial injury acute kidney injury (AKI), and 30-day mortality . Elderly patients are uniquely vulnerable to these adverse outcomes due to age-related physiological decline, reduced cardiovascular reserve, and multiple comorbidities . Consequently, maintaining hemodynamic stability during the induction and maintenance of anaesthesia is a cornerstone of perioperative care in this fragile cohort .

Propofol remains the most widely utilized intravenous anesthetic agent worldwide ; however, its administration is frequently complicated by dose-dependent vasodilation and myocardial depression, leading to a high incidence of IOH . To mitigate these risks, ciprofol, a novel 2,6-disubstituted phenol derivative and GABA(A) receptor agonist, has been developed . While several studies and meta-analyses have demonstrated that ciprofol possesses higher potency and a more favorable safety profile compared with propofol , most evidence to date is derived from randomized controlled trials (RCTs) or specific procedural sedation settings. These studies often employ restrictive inclusion criteria and standardized protocols that may not fully reflect the complexities of real-world clinical practice.

The "real-world" impact of ciprofol on the incidence of IOH-especially when administered across diverse surgical settings and multi-institutional practices-remains poorly defined. Specifically, it is unclear whether ciprofol's theoretical pharmacological advantages translate into a lower incidence of IOH in elderly patients undergoing varied non-cardiac procedures in routine clinical care.

Inclusion criteria

• Surgical procedures recorded at the three participating hospitals: NanYi, AnYi, and ZhongDa
• Surgical procedures with a non-missing PATIENT_ID
• Patients who received either ciprofol alone or propofol alone during anesthesia
• Surgical procedures performed under general anesthesia
• Surgical procedures with a corresponding record in the anesthesia event dataset
• Surgical procedures with valid anesthesia start and end times, including times supplemented from operation-room or event records when necessary
• Surgical procedures with an anesthesia duration greater than 0 minutes and less than 24 hours
• Surgical procedures with at least one valid intraoperative MAP measurement recorded within the anesthesia time window
• Patients with available age information
• Patients with a recorded sex of male or female

Exclusion criteria

• Surgical procedures with a missing PATIENT_ID
• Procedures involving both ciprofol and propofol, neither drug, missing drug indicators, or other invalid drug coding
• Non-general anesthesia procedures or procedures for which the anesthesia method could not be confirmed as general anesthesia
• Surgical procedures with both the operation department and operation name missing
• Surgical procedures without a corresponding anesthesia event record
• Surgical procedures with invalid anesthesia timing, including an anesthesia end time earlier than or equal to the anesthesia start time
• Surgical procedures with an anesthesia duration of 24 hours or longer
• Surgical procedures without any valid intraoperative MAP measurement within the anesthesia time window
• Patients with missing age
• Records with sex values other than male or female