Which factor has been most associated with improved survival in patients experiencing cardiac arrest?

Immediate high-quality CPR is the factor most associated with improved survival in patients experiencing cardiac arrest because it serves as a critical intervention that maintains blood flow to vital organs until more advanced medical care can be provided. High-quality CPR involves several key components, including a high rate of chest compressions, adequate depth, allowing full chest recoil, and minimizing interruptions. These elements help to maintain coronary and cerebral perfusion pressure, thereby increasing the chances of restoring a perfusing rhythm when a defibrillator is available.

Research has consistently demonstrated that the chances of survival and favorable neurological outcomes drop significantly with delays in initiating CPR. Effective bystander CPR can double or triple a victim's chance of survival. Additionally, CPR performed in conjunction with early defibrillation further enhances outcomes, reinforcing the importance of immediate action in the face of cardiac arrest.

In contrast, delayed medical responses or reliance on advanced life support interventions alone, without immediate CPR, do not provide the same survival benefits. The patient's age can also influence the outcome in a cardiac arrest scenario but is not as directly modifiable as the execution of immediate high-quality CPR. Hence, while several factors play a role in survival, the immediacy and quality of CPR have the most profound impact.