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Study on the Safety of Argon and Oxygen Ventilation for Patients Resuscitated from Cardiac Arrest

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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 studying the effects of a special gas mixture for patients who have experienced a cardiac arrest, which is when the heart suddenly stops beating. The treatment being tested is a mixture of argon and oxygen, delivered through a ventilator. This ventilator has been specially modified to allow patients to breathe in this gas mixture. The purpose of the study is to evaluate the safety of using this argon and oxygen mixture in patients who have been resuscitated after their heart stopped.

During the trial, patients who have been successfully resuscitated from a cardiac arrest will receive the argon and oxygen mixture through a ventilator. The study will monitor how well patients tolerate this treatment and whether it helps in their recovery. The trial will also look at how the treatment affects the heart and brain, as well as overall organ function and survival over a period of up to six months.

In addition to the argon and oxygen mixture, the study will also involve a comparison with another gas mixture containing nitrous oxide and oxygen. This will help researchers understand the differences in outcomes between the two treatments. The trial aims to gather important information that could lead to better treatment options for patients who have suffered a cardiac arrest.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the trial

    Participation begins after experiencing a cardiac arrest outside of a hospital setting, with a specific heart rhythm that can be treated with a shock.

    Eligibility requires being 18 years or older, unconscious after the heart starts beating again, and having received cardiopulmonary resuscitation (CPR) for 40 minutes or less.

    The study intervention must start within 4 hours after the heart starts beating again, with stable oxygen levels as determined by a physician.

  2. Step 2

    Treatment with argon/oxygen mixture

    The treatment involves breathing a gas mixture of 70% argon and 30% oxygen through a specially modified ventilator.

    This inhalation gas is administered to evaluate its safety and effects on heart and brain preservation after cardiac arrest.

  3. Step 3

    Monitoring and evaluation

    The primary focus is on monitoring the need to stop the argon treatment to maintain recommended oxygen levels and observing any adverse events related to blood pressure.

    Secondary evaluations include measuring specific proteins in the blood to assess heart and brain preservation, checking overall organ function, and tracking survival and neurological outcomes for up to 6 months.

Who can join the trial?

7 criteria

  • The person must have experienced a **witnessed non-traumatic OHCA**. OHCA stands for **Out-of-Hospital Cardiac Arrest**, which means the heart stopped beating outside of a hospital setting, and it was seen by someone.
  • The cause of the cardiac arrest should be presumably related to the heart, and the initial heart rhythm should be **shockable**. A shockable rhythm is a type of heart rhythm that can be treated with an electric shock to try to restart the heart.
  • The person must be **18 years or older**.
  • The person must be **unconscious** after the heart starts beating again on its own. This is known as **Return of Spontaneous Circulation (ROSC)**.
  • The **duration of CPR** (Cardiopulmonary Resuscitation) must be **40 minutes or less**. CPR is the emergency procedure used to try to restart the heart.
  • The study treatment must start **within 4 hours** after the heart starts beating again on its own (ROSC).
  • The person's **oxygen saturation (SaO2)** must be **94% or higher**. This is a measure of how much oxygen is in the blood, and it should be stable according to the doctor's criteria, with a **FiO2** of **30%**. FiO2 stands for **Fraction of Inspired Oxygen**, which is the percentage of oxygen a person is breathing in.

Who cannot join the trial?

4 criteria

  • Patients who have experienced a cardiac arrest outside of a hospital setting.
  • Patients who are not within the specified age range for the study.
  • Patients who belong to certain clinical trial groups that are not eligible for this study.
  • Patients who are considered part of a vulnerable population, which means they might need special protection or care.
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Investigated drugs

  • Argon (Ar) 70%/Oxygen (O2) 30% Ventilation

    is a special breathing mixture used in this trial. It is designed to help patients who have been resuscitated after a cardiac arrest outside of a hospital. The mixture contains 70% argon and 30% oxygen. Argon is a gas that is not usually used in medical treatments, but in this trial, it is being tested to see if it can safely help patients recover after their heart has been restarted. The goal is to see if this mixture can improve outcomes for these patients.

  • Experimental Ventilator

    is a specially modified machine used in this trial to deliver the argon and oxygen mixture to patients. This ventilator is different from regular ventilators because it is designed to safely provide the specific mixture of argon and oxygen. The trial is testing whether using this ventilator with the argon and oxygen mixture is safe for patients who have been resuscitated after a cardiac arrest.

What is already known about the treatment

Argon – Argon is administered through ventilation using a specially modified ventilator that delivers a mixture of 70% argon and 30% oxygen. It is currently being studied in clinical trials, such as the CPAr trial, to assess its safety in patients who have been resuscitated from out-of-hospital cardiac arrest. The main therapeutic indication for argon in this context is to support recovery after cardiac arrest. At the molecular level, argon is believed to exert neuroprotective effects, potentially reducing brain damage by modulating cellular responses to injury. It is classified as a noble gas with potential therapeutic applications in critical care settings.

Investigated diseases

Cardiac arrest – Cardiac arrest occurs when the heart suddenly stops beating, leading to a cessation of blood flow to the brain and other vital organs. This condition is often caused by an electrical disturbance in the heart that disrupts its pumping action. Without immediate medical intervention, cardiac arrest can lead to loss of consciousness and cessation of breathing. It is a critical emergency that requires prompt cardiopulmonary resuscitation (CPR) and defibrillation to restore heart function. The progression of cardiac arrest is rapid, and the chances of survival decrease significantly with each passing minute without treatment.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-516864-27-00Protocol codeIRFMN 7557/8154Estimated enrolment120 patientsSponsorIstituto Di Ricerche Farmacologiche Mario Negri

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