From the Guidelines
Survival rates after cardiac arrest decrease significantly with each minute of downtime, with a 7-10% decrease in survival rates per minute without CPR, as reported in the 2010 American Heart Association guidelines 1. The relationship between downtime and survival is influenced by factors including initial cardiac rhythm, age, comorbidities, and whether the arrest was witnessed.
- Key factors that influence survival rates include:
- Initial cardiac rhythm: Ventricular fibrillation is the most common initial rhythm in out-of-hospital witnessed cardiac arrests, and its treatment is defibrillation.
- Age and comorbidities: These factors can affect the likelihood of survival and the quality of life after cardiac arrest.
- Witnessed arrest: Cardiac arrests that are witnessed have a higher chance of survival, especially if CPR is started immediately. For the best chance of survival, CPR should begin immediately and defibrillation should occur within 3-5 minutes of collapse.
- The quality of CPR matters significantly, with proper chest compressions at 100-120 per minute and minimal interruptions being essential. After 10 minutes without intervention, survival probability drops below 5% 1.
- For witnessed ventricular fibrillation arrests with immediate CPR, survival rates can reach 50-70%, but fall to 10-30% for unwitnessed arrests or those with non-shockable rhythms. Post-resuscitation care, including targeted temperature management (33-36°C for 24 hours) for comatose survivors, can improve neurological outcomes 1.
- The use of automated external defibrillators (AEDs) in public places, such as health/fitness facilities, can significantly improve survival rates by reducing the time to defibrillation.
From the Research
Cardiac Arrest Downtime vs Survival Rates
- The relationship between cardiac arrest downtime and survival rates is complex, with multiple factors influencing outcomes 2, 3, 4, 5, 6.
- Early recognition and high-quality cardiopulmonary resuscitation (CPR), early defibrillation of ventricular fibrillation (VF), and subsequent care in a specialist center can improve survival rates with good neurological outcomes 2.
- The use of automated external defibrillators (AEDs) can significantly improve survival rates following out-of-hospital cardiac arrest, especially when used promptly and correctly 4.
- Factors promoting survival after prolonged resuscitation attempts include immediate good quality CPR, high level premorbid function, reversible cause of arrest, and rapid access to advanced care such as extra-corporeal membrane oxygenation (ECMO) 5.
- Delaying CPR to perform rhythm reanalyses, stacked shocks, and postshock pulse checks can have a low yield for achieving or detecting return of a pulse, and may negatively impact survival rates 6.
Key Factors Influencing Survival Rates
- Early defibrillation and use of AEDs can improve survival rates 2, 4.
- High-quality CPR, including adequate chest compressions, can improve survival rates 3.
- The timing of epinephrine administration may affect patient outcome, but basic life support measures are the most important aspect of resuscitation and patient survival 3.
- The use of supraglottic airway devices and tracheal intubation should be attempted only by skilled rescuers 2.
- Care after cardiac arrest, including controlled reoxygenation, therapeutic hypothermia, and percutaneous coronary intervention, can improve survival rates and neurological outcomes 2, 5.