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Study Comparing Isoflurane and Propofol for Sedation in Critically Ill Patients on Mechanical Ventilation

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on patients who are critically ill and require mechanical ventilation, which is a machine that helps them breathe. The study is comparing two types of sedation, which is a way to help patients stay calm and comfortable while on the ventilator. One group of patients will receive sedation through inhalation using a medication called Isoflurane, while the other group will receive sedation through an intravenous method using a medication called Propofol. Both medications are commonly used to help patients relax and are administered in different ways.

The purpose of the study is to see which sedation method allows patients to be free from mechanical ventilation for more days within a 28-day period. Patients in this study are expected to need mechanical ventilation for more than 48 hours. The study will also look at other factors, such as the number of days patients spend in the intensive care unit (ICU), the time it takes for patients to be taken off the ventilator after stopping sedation, and the overall well-being of patients after they leave the hospital.

Throughout the study, researchers will monitor various aspects of the patients' health, including their mental state using a scale called the RASS (Richmond Agitation-Sedation Scale), and check for any signs of delirium, which is a state of confusion. They will also assess if patients experience anxiety, depression, or post-traumatic stress disorder after their hospital stay. The study aims to provide valuable information on the best sedation practices for critically ill patients who need mechanical ventilation.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization

    Upon joining the study, randomization occurs to determine the sedation method. This involves assigning either isoflurane for inhalation or propofol for intravenous use.

    The goal is to compare the effectiveness of these two sedation methods in critically ill patients.

  2. Step 2

    Sedation administration

    If assigned to the isoflurane group, sedation is administered through inhalation using a liquid form that turns into vapor.

    If assigned to the propofol group, sedation is administered intravenously as an emulsion for injection or infusion.

    Sedation is maintained to achieve a RASS (Richmond Agitation-Sedation Scale) score between -3 and -5, indicating a deep level of sedation.

  3. Step 3

    Mechanical ventilation

    Participants are expected to be on mechanical ventilation for at least 48 hours from the time of randomization.

    The primary objective is to assess the number of days free from mechanical ventilation by day 28.

  4. Step 4

    Monitoring and assessment

    Throughout the trial, various parameters are monitored, including the average RASS score during sedation, the need for additional hypnotics, and the presence of delirium.

    Assessments also include the time until extubation after sedation withdrawal and the number of days free from ICU stay by day 28.

  5. Step 5

    Follow-up evaluations

    Participants are evaluated for symptoms of anxiety, depression, or post-traumatic stress disorder 90 days after hospital discharge.

    Cognitive assessments are conducted 90 days post-discharge to identify any abnormal scores.

    The occurrence of any adverse reactions is recorded for both treatment groups.

  6. Step 6

    Trial completion

    The trial is expected to conclude by December 31, 2027.

    The final analysis will include the proportion of participants who died from any cause by day 60 and other secondary endpoints.

Who can join the trial?

3 criteria

  • Must be **18 years old or older**.
  • Must be on a **breathing machine** (mechanical ventilation) and expected to need it for at least **48 hours**.
  • Must need to maintain a **RASS** (Richmond Agitation-Sedation Scale) score between **-3 and -5**. This scale measures how awake or sleepy a person is, with these numbers indicating a deep level of sedation.

Who cannot join the trial?

5 criteria

  • Patients who are not in a critical condition cannot participate. A critical condition means the patient is very seriously ill and needs intensive medical care.
  • Patients who are not expected to need more than 48 hours of invasive mechanical ventilation cannot participate. Invasive mechanical ventilation is when a machine helps a patient breathe through a tube placed in their windpipe.
  • Patients who are not within the specified age range cannot participate. The age range includes adults and older adults.
  • Both male and female patients can participate, but those who do not meet other criteria cannot join.
  • Patients who are part of a vulnerable population cannot participate. A vulnerable population includes groups who may have difficulty giving informed consent or are at higher risk of harm.
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Investigated drugs

  • Isoflurane

    is a medication used for sedation in critically ill patients. It is administered through inhalation and helps to keep patients calm and comfortable while they are on mechanical ventilation. This medication is often used in hospital settings, especially in intensive care units, to manage sedation for patients who need assistance with breathing for extended periods.

  • Propofol

    is another medication used for sedation, but it is given intravenously. It is commonly used to sedate patients who are on mechanical ventilation. Propofol helps to ensure that patients remain relaxed and pain-free during their treatment in the intensive care unit. It is known for its quick onset and ability to be easily adjusted to the needs of the patient.

What is already known about the treatment

  • Isoflurane

    Isoflurane is administered through inhalation and is used as a sedative for patients in critical condition, particularly those requiring prolonged mechanical ventilation. It is well-established in medical literature as an inhaled anesthetic agent. The main therapeutic indication is to provide sedation for critically ill patients who need mechanical ventilation for more than 48 hours. Isoflurane works by enhancing the activity of certain neurotransmitters in the brain, leading to a calming effect. It is classified as a volatile anesthetic.

  • Propofol

    Propofol is administered intravenously and is used for sedation in critically ill patients, especially those on mechanical ventilation for extended periods. It is widely recognized in medical literature as a short-acting sedative-hypnotic agent. The primary therapeutic use is to maintain sedation in patients who require mechanical ventilation for more than 48 hours. Propofol acts by enhancing the inhibitory effects of the neurotransmitter GABA in the brain, resulting in sedation. It is classified as a general anesthetic.

Investigated diseases

Critical condition – A critical condition refers to a state where a patient is experiencing severe health issues that require immediate and intensive medical care. This condition often involves life-support measures, such as mechanical ventilation, to maintain vital functions. Patients in a critical condition may be unable to breathe on their own and require sedation to manage pain and anxiety. The progression of a critical condition can vary widely, depending on the underlying cause and the patient's response to treatment. It is characterized by instability in vital signs and requires constant monitoring and intervention.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-518521-14-00Protocol codeSI-CRITICEstimated enrolment620 patientsSponsorHospital Universitario La Paz

sourced from the EU Clinical Trials Register and site verification

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