Optimal Ventilation for Cardiac Arrest Study This study is about helping kids who have had a cardiac arrest, which means their heart stopped beating properly. Cardiac arrest can be very serious, and many children don't survive or have brain problems afterward. Researchers want to see if a special group of treatments, called the OPTI-VENT bundle, can help kids survive and leave the hospital without brain issues. The study focuses on children who have had at least one minute of CPR, which is a lifesaving technique that helps pump blood when the heart isn't working. Eligibility: Kids are part of the study if they have a breathing tube (invasive airway) within the first 5 minutes of CPR and receive at least one minute of CPR. Kids can't join if their heart stopped outside the hospital and they were brought in for that reason, or if they were already getting certain life-support treatments (like ECMO).

• The study aims to improve survival rates and brain health after cardiac arrest.
• No extra visits are needed, the study takes place during usual hospital care.
• There are no extra risks, as it uses current hospital treatments.