Comparison of Hemodynamics and Respiratory Function Between Ciprofol and Propofol in Elderly Patients Undergoing Non-intubated General Anesthesia

Inclusion Criteria (1)Elderly patients scheduled to undergo gastrointestinal endoscopy; (2)Aged 65-80 years; (3)American Society of Anesthesiologists (ASA) status of Ⅰ-Ⅲ; Exclusion Criteria

1. Declined to participate in the study;
2. Had known allergies or contraindications to benzodiazepines, ciprofol, propofol, or related compounds;
3. Had a history of alcohol abuse or dependence on sedative-hypnotics drugs;
4. Severe cardiovascular diseases, including uncontrolled hypertension(SBP ≥160 mmHg or DBP ≥100 mmHg despite medical treatment) or hypotension (SBP ≤90 mmHg or DBP ≤60 mmHg), resting bradycardia (heart rate < 45 bpm), severe arrhythmia, heart failure, Adams-Stokes syndrome, unstable angina, myocardial infarction within the past 6 months, third-degree atrioventricular block, and QT interval ≥ 450 ms;
5. Severe respiratory diseases, including respiratory insufficiency and chronic obstructive pulmonary disease(COPD), bronchospasm requiring treatment within the previous 3 months, acute respiratory infection accompanied by fever, wheezing, pulmonary rales or cough within the past week, predicted difficult airway(Mallampati grade Ⅳ), and baseline hypoxemia (SpO₂ < 90%);
6. Liver, kidney, blood system, nervous system, metabolic system or mental diseases with significant clinical significance;
7. Severe gastrointestinal diseases such as gastric retention and persistent gastrointestinal bleeding;
8. Demonstrated uncooperative behavior or impaired communication ability. Randomization and Group Allocation A total of 108 eligible elderly patients undergoing elective non-intubated general anesthesia at the Cardiovascular and Cerebrovascular Disease Hospital, General Hospital of Ningxia Medical University will be recruited. A computer-generated random number sequence will allocate subjects at a 1:1 ratio into the ciprofol group (Group C) and the propofol group (Group P).

Baseline Demographic Data Gender, age, height, weight, BMI, ASA classification, smoking history, alcohol consumption, underlying diseases, Modified Mallampati score, thyromental distance, snoring history, etc.

Outcome Measures

1. Primary Outcome Measures Hemodynamic parameters:systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR) were recorded at the following time points: baseline before drug administration (T0), immediately after loss of consciousness (T1), at endoscope insertion (T2), and 1 min (T3), 2 min (T4), 3 min (T5), 4 min (T6), and 5 min (T7) after loss of consciousness.
2. Incidence of respiratory-related adverse events: A respiratory-related adverse event was defined as the occurrence of any of the following events during sedation and anesthesia: (1)Altered ventilation: respiratory rate (RR)<8 bpm, or PETCO₂ decreased by more than 50% from baseline and lasting>30 s; (2)Apnea: cessation of thoracic movement during the procedure, or abruptly flattened PETCO₂ waveform lasting>15 s; (3)Hypoxemia: SpO₂<93% lasting>15 s; (4)Severe hypoxemia: SpO₂ ≤ 85%. Anesthetic Protocol All patients maintained an 8-hour fast and a 4-hour liquid restriction preoperatively, with no preoperative medications administered. Standardized bowel preparation was completed within 24 hours.

After entering the room, the patients were placed in the left lateral position, received oxygen via nasal cannula at 6 L/min, and an upper extremity venous access was established. The non-invasive continuous arterial pressure and cardiac output monitoring system (Model:NICAP-T20A,Hunan Manite Medical Equipment Co., Ltd.) was used for continuous hemodynamic monitoring. A standard NIBP cuff was placed on the left upper arm for regular calibration. An ear clip sensor was attached to the right ear (the long handle end was placed inside the ear cavity close to the ear hole, and the curved end closely fitted the back of the ear), and a toe clip sensor was fixed at the root of the second or third toe of the right foot for continuous measurement. The system was manually calibrated every 1 min using brachial arterial blood pressure as the reference standard. The NICAP system continuously monitored hemodynamic parameters including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR).Ventilation was monitored using a sidestream capnography (Model:KMI605C,Kingst). A pulse oximetry probe was connected, and a transnasal carbon dioxide sampling catheter was placed at the nasal vestibule to continuously sample exhaled gas. Respiratory rate (RR), pulse oxygen saturation (SpO₂), end-tidal carbon dioxide (PETCO₂) were recorded continuously.

Midazolam(Jiangsu Nhwa Pharmaceutical Co., Ltd.) 0.01 mg/kg was injected intravenously first. After the patient's circulation and respiration stabilized, the measured values were recorded as baseline data(T0). Ciprofol(Haisco Pharmaceutical Group Co., Ltd.) or propofol(Xi'an Libang Pharmaceutical Co., Ltd. ) was then infused intravenously at a rate of 10 mL/min. The modified observer's assessment of alertness/sedation (MOAA/S) scale was used to assess sedation depth every 5 seconds. Loss of consciousness was defined as MOAA/S score ≤ 1, at which drug administration was stopped, and the total induction dose of ciprofol or propofol was recorded. SBP, DBP, MAP, HR, SV,CO,SV and SVR were recorded at time points: before drug administration(T0), immediately after loss of consciousness(T1), immediately at endoscope insertion(T2), 1 min(T3), 2 min(T4), 3 min(T5), 4 min(T6) and 5 min(T7) after loss of consciousness. The incidence of respiratory-related adverse event was documented simultaneously. During anesthesia, anesthesiologists administered additional boluses of one-third of the initial induction dose of ciprofol or propofol according to the patient's responses such as eye opening, verbal response and body movement, with an interval of at least 1 min between injections.

During anesthesia, hypotension (SBP < 90 mmHg, or MAP decreased by more than 20% from baseline and lasting >2 min) was treated with intravenous ephedrine 6 mg. Bradycardia (HR < 45 bpm lasting >30 s) was managed with intravenous atropine 0.5 mg. In the event of altered ventilation (RR< 8 bpm or PETCO₂ decreased by more than 50% from baseline and lasting > 30 s), apnea (cessation of thoracic movement or abruptly flattened PETCO₂ waveform lasting>15 s), hypoxemia (SpO₂ < 93% lasting > 15 s), or severe hypoxemia ( SpO₂ ≤ 85%) . Anesthesiologists performed jaw thrust, increased oxygen flow, or provided mask-assisted ventilation; tracheal intubation was performed if necessary.