This study looks at how well CPR (cardiopulmonary resuscitation) is done on kids who have cardiac arrests, which means their heart stops beating. The study is being done in several hospitals and will watch how chest compressions are performed and how well children recover after their heart stops. The study aims to find out if the way CPR is done affects how well kids do afterward. This includes looking at how deep and fast the chest compressions are, how much time is spent on compressions, and how care is given after the heart starts again.

Eligibility: Kids who received at least one minute of chest compressions, are between full-term birth and 17 years old, and have a device measuring CPR quality can participate. However, any child on ECMO therapy at the start of CPR cannot join.

• Participants will not receive any treatment; the study is observational.
• No additional hospital visits are needed; only information during the cardiac arrest will be used.
• No compensation is offered for participation in this study.