Effect of Circadian Rhythm on the Sedative Efficacy and Recovery Quality of Ciprofol General Anesthesia: A Multi-Center Observational Study

The goal of this multi-center observational study is to learn about the effect of circadian rhythm (morning vs. afternoon surgery) on the sedative efficacy, hemodynamic stability (especially induction-associated hypotension), and recovery quality of ciprofol general anesthesia in adult patients undergoing elective non-cardiac and non-cranial surgery, comparing target-controlled infusion (TCI) and non-TCI administration modes.

The main question it aims to answer is:

Does circadian rhythm (time of surgery: morning vs. afternoon) affect the sedative efficacy, incidence of induction-associated hypotension, and recovery quality of ciprofol general anesthesia? Eligible patients aged 18-65 years with ASA physical status I-II and BMI 18-30 kg/m² undergoing elective general anesthesia for non-cardiac and non-cranial surgery (duration 1-2 hours) will be grouped by anesthesia start time (morning: 08:00-11:00; afternoon: 14:00-17:00) and receive ciprofol induction and maintenance via TCI or non-TCI infusion. Perioperative data including hemodynamic changes, ciprofol dosage, recovery time, and adverse events will be recorded and analyzed.

Study Overview

• Status: Not yet recruiting
• Conditions: Circadian Rhythm; Hemodynamic Instability; Anesthetics Adverse Reaction; Ciprofol
• Intervention / Treatment: Other: Surgery commences in the morning.; Other: Surgery commences in the afternoon.

• Study Type: Observational
• Enrollment (Estimated): 480

Contacts and Locations

• Study Contact: Name: Jie Chen; Phone Number: 00-86-023-13527517763; Email: 305045@hospital.cqmu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Patients scheduled for surgical procedures under general anesthesia.

Description

Inclusion Criteria:

1. Aged 18-65 years, with ASA physical status I-II.
2. Body Mass Index (BMI) between 18-30 kg/m².
3. Scheduled for elective non-cardiac and non-intracranial surgery under general anesthesia, with an expected operative duration of 1-2 hours.
4. Morning group: surgery start time between 08:00 and 11:00, with completion no later than 13:00; Afternoon group: surgery start time between 14:00 and 17:00, with completion no later than 19:00.
5. Willing to participate and having provided signed informed consent.

Exclusion Criteria:

1. Severe hepatic or renal insufficiency (Child-Pugh Class C or eGFR < 30 ml/min/1.73m²).
2. Severe cardiovascular, respiratory, or neurological diseases.
3. Long-term use of sedative-hypnotics, anxiolytics, antidepressants, or glucocorticoids.
4. Known allergy to ciprofol, propofol, or their excipients.
5. Recent (within 3 months) history of shift work, transmeridian travel, or other conditions that may cause circadian rhythm disruption.
6. Pregnant or lactating women.
7. Any other condition deemed by the investigator as unsuitable for participation in this study.

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Morning TCI group (MT); The surgery start time was between 08:00 and 11:00, and the end time did not exceed 13:00. Patients in the TCI group underwent anesthetic induction and maintenance with ciprofol via target-controlled infusion (TCI) operated in Keo mode based on the effect-site target concentration (Ce).	Other: Surgery commences in the morning.; The morning group was defined as patients whose surgery commenced between 08:00 and 11:00 and concluded by 13:00.
Afternoon TCI group (AT); The surgery start time was between 14：00 and 17:00, and the end time did not exceed 19:00. Patients in the TCI group underwent anesthetic induction and maintenance with ciprofol via target-controlled infusion (TCI) operated in Keo mode based on the effect-site target concentration (Ce).	Other: Surgery commences in the afternoon.; The afternoon group was defined as patients whose surgery commenced between 14:00 and 17:00 and concluded by 19:00.
Morning non-TCI/Manual group (MC); The surgery start time was between 08:00 and 11:00, and the end time did not exceed 13:00.Patients in the non-TCI group undergo anesthetic induction with ciprofol via manual bolus injection.	Other: Surgery commences in the morning.; The morning group was defined as patients whose surgery commenced between 08:00 and 11:00 and concluded by 13:00.
Afternoon non-TCI/Manual group (AC); The surgery start time was between 14：00 and 17:00, and the end time did not exceed 19:00.Patients in the non-TCI group undergo anesthetic induction with ciprofol via manual bolus injection.	Other: Surgery commences in the afternoon.; The afternoon group was defined as patients whose surgery commenced between 14:00 and 17:00 and concluded by 19:00.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of hypotension during the induction period	The incidence of hypotension was assessed during anesthetic induction with ciprofol. Hypotension is defined as a mean arterial pressure (MAP) < 65 mmHg at any time from the initiation of anesthetic induction to 5 minutes after tracheal intubation, and/or a MAP reduction of over 20% relative to baseline, with a duration of ≥ 1 minute.	From the time of initial anesthetic drug administration until 5 minutes after completion of tracheal intubation (maximum duration limited to 20 minutes)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of mean arterial pressure decreasing by >30% from baseline during the induction period and lasting for ≥1 minute.	Incidence of mean arterial pressure decreasing by >30% from baseline during the induction period and lasting for ≥1 minute.	From the time of initial anesthetic drug administration until 5 minutes after completion of tracheal intubation (maximum duration limited to 20 minutes)
Incidence of MAP staying below 65 mmHg for at least 1 minute during the anesthetic maintenance	Incidence of MAP staying below 65 mmHg for at least 1 minute throughout anesthetic maintenance	From 5 minutes after completion of tracheal intubation until the time of discontinuation of all anesthetic agents at the end of surgery, assessed up to 24 hours.
Incidence of MAP reduction > 20% from baseline during the anesthetic maintenance period	Incidence of MAP reduction > 20% from baseline during the anesthetic maintenance period	From 5 minutes after completion of tracheal intubation until the time of discontinuation of all anesthetic agents at the end of surgery, assessed up to 24 hours.
Incidence of MAP reduction > 30% from baseline during the anesthetic maintenance period	Incidence of MAP reduction > 30% from baseline during the anesthetic maintenance period	From 5 minutes after completion of tracheal intubation until the time of discontinuation of all anesthetic agents at the end of surgery, assessed up to 24 hours.
Total administered dose of vasoactive agents	Total administered dose of various vasoactive agents during the entire anesthetic period	From the time of initial anesthetic drug administration until the time of discontinuation of anesthetic infusion at the end of surgery,assessed up to 24 hours.
Incidence of hypertension throughout anesthesia	Incidence of hypertension throughout anesthesia.Hypertension is defined when blood pressure rises by > 30% from baseline MAP, or SBP ≥ 160 mmHg and/or DBP ≥ 100 mmHg, and persists for ≥ 1 minute.	From the time of initial anesthetic drug administration until the time of discontinuation of anesthetic infusion at the end of surgery,assessed up to 24 hours.
Time to successful anesthetic induction	Time to loss of eyelash reflex following ciprofol administration	From the time of initial anesthetic drug administration until the time of disappearance of the patient's eyelash reflex, assessed up to 20 minutes.
Time to emergence	Time from discontinuation of anesthesia to the patient's first eye opening	From the time of discontinuation of anesthetic infusion until the time of the patient's first eye opening, assessed up to 2 hours.
Time to extubation	Time from discontinuation of anesthesia to tracheal extubation	From the time of discontinuation of anesthetic infusion until the time of tracheal tube removal, assessed up to 2 hours.
Bispectral Index	recorded BIS values at pre-induction, at loss of consciousness, at tracheal intubation, every 15 minutes intraoperatively, at the end of surgery, and at recovery of consciousness.	From the patient's awake state before anesthetic induction until the time when the patient emerges from anesthesia and leaves the operating room for the ward after surgery, assessed up to 24 hours.

Collaborators and Investigators

• Sponsor: Jie Chen
• Collaborators: Chongqing Medical University; People's Hospital of Chongqing Liangjiang New Area.

Study record dates

Study Major Dates

• Study Start (Estimated): June 8, 2026
• Primary Completion (Estimated): May 30, 2027
• Study Completion (Estimated): May 30, 2027

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: June 29, 2026
• First Posted (Actual): July 7, 2026

Study Record Updates

• Last Update Posted (Actual): July 7, 2026
• Last Update Submitted That Met QC Criteria: June 29, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 2026EC083

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No