Remifentanil: Patients receive remifentanil for analgesia and sedation during mechanical ventilation. The administration follows standard ICU clinical practice, typically initiated at a continuous infusion rate (e.g., approximately 0.18 mg/h or weight-based equivalent) and titrated based on patient response.
Study summary
The goal of this prospective clinical study is to learn about the population pharmacokinetics (PopPK), safety, and efficacy of remifentanil in low-body-weight patients in the Intensive Care Unit (ICU) who require mechanical ventilation. The main questions it aims to answer are:
1. What are the pharmacokinetic characteristics of remifentanil in low-weight ICU patients?
2. How does remifentanil (and concurrent propofol use) affect hemodynamic stability (such as blood pressure) and sedation efficacy in this population?
Participants receiving mechanical ventilation will receive remifentanil for analgesia and sedation according to a standardized protocol. They will undergo arterial blood sampling at specific time points to measure drug concentrations. Researchers will also record hemodynamic parameters. Additionally, a subset of patients receiving propofol as a rescue sedative will have plasma propofol concentrations measured to evaluate its influence on blood pressure changes.
Eligibility
Sex
ALL
Min age
—
Max age
—
Healthy volunteers
No
Inclusion Criteria:
* Age: ≥18 years old, regardless of sex;
* Normal weight: 18.5 kg/m² ≤ Body Mass Index (BMI) \< 24 kg/m² or Low weight: BMI \< 18.5 kg/m²;
* Admitted to the intensive care unit (ICU);
* Required invasive mechanical ventilation for more than 10 hours;
* The subject or their legal guardian has fully understood the potential risks and benefits of participating in this study and has signed the informed consent form.
Exclusion Criteria:
* Pregnant women;
* Presence of severe respiratory impairment or respiratory depression during the screening period;
* Known hypersensitivity to remifentanil or any of the excipients;
* Meeting other contraindications for opioid use
Primary outcome measure(s)
Plasma Concentration of Remifentanil — From the start of remifentanil administration, through the maintenance infusion phase, up to 2 hours after the end of infusion. Peripheral arterial blood samples (1mL each) drawn from an existing indwelling arterial blood pressure (ABP) catheter will be collected to determine the plasma concentration of remifentanil (unit: ng/mL). A sparse and opportunistic sampling strategy is employed to capture the full pharmacokinetic profile. Sampling points typically include:
1. Absorption/Distribution Phase: Approximately 2 samples within the first 2 hours of administration;
2. Maintenance Phase: Samples collected during steady-state infusion, and following dose adjustments to capture the new steady state (typically after re-equilibration);
3. Elimination Phase: Approximately 3 samples within 2 hours after the end of infusion.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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