Continuous Chest Compressions (Enrollment Completed)

This randomized clinical trial will test if one method for performing CPR is better than the other for patients with cardiac arrest. 

Cardiac arrest is a condition where the heart stops beating, and which leads to death unless treated immediately. Up to 95% of the people with cardiac arrest die with current treatments.  Therefore, improving care for cardiac arrest is a public health priority.  CPR is the process of pushing on the chest and providing oxygen to the lungs in an effort to preserve life and restore a heartbeat. 

In some regions, paramedics and first-responders do CPR as 30 chest compressions, followed by 2 breaths, followed by 30 chest compressions, then 2 more breaths, and so on.  This technique makes delivery of oxygen easier, but interrupts the flow of blood generated by chest compressions.  

In other regions, paramedics and first-responders do CPR as continuous chest compressions with no interruptions for breaths, and oxygen is administered through the mouth while chest compressions are going on.  This technique allows for more chest compressions to pump blood, but makes delivery of oxygen harder.

These two techniques for CPR have never been compared to each other.  Experts are uncertain which technique to recommend or which technique is best to teach. 

IN THIS STUDY, paramedics or first-responders will perform one of two study treatment plans.  Ambulances will be assigned to one or the other plan in advance of receiving any emergency call.  In all plans,  the patient will receive CPR and emergency interventions (for example, electrical shocks to the heart and medications) as indicated to restore a heartbeat.  The only difference between the plans is the manner of performing CPR for the first six minutes. After six minutes, rescuers will perform all other interventions according to their usual standard care.  

Study Plan #1:(Continuous Chest Compressions) CPR consists of doing chest compression continuously without any interruptions.  Oxygen is administered by placing a mask over the mouth and nose with or without pressure, but without pausing chest compressions. 

Study Plan #2:(Interrupted Chest Compressions) CPR consists of repeating cycles of 30 chest compressions, and 2 breaths.  Oxygen is administered under pressure from a mask over the mouth and nose during the pauses for 2 breaths.

After CPR, investigators monitor the patient's progress by reviewing paramedic and hospital records until the patient is discharged from the hospital.