There is no situation in medicine where seconds matter more than they do in a cardiac arrest. Every second that CPR and defibrillation are delayed is time that the brain, kidneys, and other vital organs are not being perfused. As our post-arrest interventions – hypothermia, balloon pumps, and so on – get ever more complex, its widely acknowledged that the most potential for improving outcomes is finding ways to initiate BLS faster.

Increasing the number of citizens trained in BLS and installing AED’s in public areas across the country are two ways in which public health officials have to tried to accomplish this goal. Despite these efforts, the life of the patient experiencing the arrest still depends on the hope that a BLS trained bystander sees the arrest and is willing to act. A group in Stockholm is trying to increase the likelihood of that happening by using smartphones to alert volunteers of a nearby arrest, leveraging a large group of good samaritans in the hopes getting help to cardiac arrest victims faster.

The study utilized a custom mobile phone based system integrated with the local emergency response system. When a suspected cardiac arrest call was received, operators would simultaneously activate EMS and the “Mobile Lifesaver Sytem” (MLS). Volunteers within the MLS carried mobile phones whose locations were tracked. When the Mobile Responder (MR) was within 500 meters of the arrest, a text message and automated call alerted this BLS-trained individual.

The results were pretty dramatic. A total of 92 activations occurred and in 45% of those, the MR beat EMS to the scene. In the true cardiac arrests (40%), the MR beat EMS to the scene 56% of the time. Among these, the MR initiated CPR 30% of the time, which amounted to 17% of all true cardiac arrests.

Unfortunately, the researchers did not track how much time was actually saved in the cases that an MR initiated CPR before EMS arrival, though I suspect even thirty seconds could warrant the investment in these kinds of systems. Another important question is why, when an MR beat EMS to the scene of a true cardiac arrest, only 30% initiated CPR.

The fact that the study was conducted in a highly populated city suggests these results, if further validated, could be replicated in many other urban environments and get help to cardiac arrest victims faster. It may also offer hope for in-home arrests, where previous data has shown that interventions like home AED’s don’t work. And while this pilot system relies on a custom system, its design is quite scalable as it lends itself very well to a downloadable app that could work on any iPhone, iPad, Android, or other mobile device.

For the actual study, click here.