Out-of-hospital cardiac arrest (OHCA) is a medical emergency that requires immediate cardiopulmonary resuscitation (CPR) to maximise survival chances.
New research presented at this year’s ESC Acute CardioVascular Care congress in Florence, Italy, sheds light on the evolving role of bystanders in providing CPR. The study finds that while the proportion of bystanders performing CPR has increased significantly over the past two decades, the most critical factor in survival remains how quickly CPR is initiated—not who performs it.
The study highlights a promising trend: the proportion of layperson rescuers has steadily risen over time. However, with 80% of OHCAs occurring in residential settings, the findings emphasise the urgent need for broader public education and Basic Life Support (BLS) training to improve survival rates.
Findings show that rapid return of spontaneous circulation (ROSC) was crucial for in-hospital survival, regardless of rescuer type. Additionally, long-term survival rates were similar between patients who initially received CPR from laypersons and those treated by emergency medical services (EMS). These findings highlight the importance of immediate resuscitation and reinforce the need for public awareness and BLS training to further enhance survival outcomes.
The research team analysed data from 3,315 patients admitted with ST-elevated myocardial infarction (STEMI) at University Hospital Trieste between 2003 and 2024. Of these, 172 patients experienced OHCA, with 44 receiving bystander-initiated CPR during the study period.
When analysing trends across five time intervals (2003–2007, 2008–2011, 2012–2015, 2016–2019, and 2020–2024), the researchers found that the percentage of patients receiving bystander CPR rose significantly from 26% (2003–2007) to 69% (2020–2024). The median time to ROSC was 10 minutes overall, but significantly longer for patients who received bystander CPR (20 minutes) compared to those treated by medical professionals (5 minutes). Patients who received bystander CPR were more likely to undergo endotracheal intubation (91% vs. 65% for EMS CPR).
Despite improvements in bystander intervention, 25.6% of patients died during hospitalisation. Factors associated with higher in-hospital mortality included older age (67 years vs. 62 years among survivors), more comorbidities, longer time to ROSC and lower left ventricular ejection fraction (LVEF).
Findings show that every 5-minute delay in ROSC increased mortality risk by 38%. A 5% drop in LVEF corresponded to a 38% higher mortality risk. Every 5-year increase in age raised the risk of death by 46%.
During a median follow-up of seven years, 14% of patients died, but long-term survival did not differ based on whether CPR was initiated by a bystander or EMS.
These findings reinforce that the time to CPR initiation is the most critical factor in OHCA survival. While more people are stepping in as rescuers, widespread public CPR education and training remain essential—especially given that most cardiac arrests occur at home.
By improving awareness and access to BLS training, more lives can be saved through early intervention—regardless of whether CPR is performed by a trained bystander or a medical professional.
Source: European Society of Cardiology
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