If someone experiences cardiac arrest-a condition in which the heart suddenly stops beating-what’s the best way to keep that person alive?
A new study led by UBC researchers, and recently published in JAMA, compared the survival rates of two different strategies used by paramedics when treating cardiac arrests: 1) performing resuscitation at the scene, or 2) transporting the patient to hospital with resuscitation en route.
Dr. Brian Grunau, the study’s lead author and an assistant professor in UBC’s department of emergency medicine, explains why the chances of survival among patients transported to hospital are so slim.
What did your study find?
Our study, which included nearly 44,000 patients from across North America including British Columbia and Ontario, found that cardiac arrest patients who are transported to hospital during resuscitation had a greater chance of dying than patients treated at the scene. Among patients who were immediately transported to hospital, only 3.8 per cent survived and were discharged compared to 12.6 per cent for patients treated at the scene.
Why are survival rates higher when cardiac arrest patients are treated on-scene?
Paramedics are experts in cardiac arrest resuscitations, and can apply nearly all cardiac arrest treatments at the scene of the cardiac arrest that are available in hospital. Secondly, transporting a patient with cardiac arrest to hospital can interfere with important ongoing treatments, such as CPR, defibrillation, and medications. Thus, there is often no advantage of transporting a patient with ongoing CPR to hospital, but rather paramedics should dedicate their efforts and expertise at the scene.
In addition to lower survival rates, what are some other risks associated with immediate ambulance transport?
When paramedics are transporting cardiac patients to hospital, they are standing and administering CPR, so they can fall and injure themselves. And when ambulances drive down busy city streets, there’s always the potential for accidents and further injury.
If the patient will clearly benefit from transport to hospital, that’s what paramedics will do, however the risks and benefits must be clearly identified. We found that overall, treating patients at the scene of the cardiac arrest led to improved outcomes.
B.C. already prioritizes on-scene resuscitation for cardiac arrest. But how can the province, and other jurisdictions across Canada and around the world, improve survival rates and save lives?
In B.C., only about five per cent of cardiac patients undergo CPR en route to hospital. The evidence suggests survival can be improved if paramedics are trained to perform the best quality of resuscitation possible at the scene of the cardiac arrest, rather than prioritizing transport to hospital.
What should people do if they witness what appears to be a cardiac arrest or heart attack?
It sounds obvious, but you should immediately call 911. The operator will help you or any bystander start CPR or employ a defibrillator if one is available until paramedics arrive.