New approach to defibrillation could improve cardiac arrest outcomes

Joshua Lupton, MD, has no memory of his own cardiac arrest in 2016. He knows only that first responders resuscitated his heart with an electric shock from a defibrillator, which ultimately led to his full recovery and puts him among the fewer than one in 10 people nationwide who survive cardiac arrest outside of a hospital.

He attributes his survival to the rapid defibrillation he received from first responders, but not everyone is so lucky.

Now, as lead author of a new observational study published in the journal Opening of the JAMA networkHe and his co-authors at Oregon Health & Science University say the study suggests that the position in which responders initially place the two defibrillator electrodes on the body can make a significant difference in whether spontaneous blood flow returns after a shock from a defibrillator.

“The less time you spend in cardiac arrest, the better,” said Lupton, an assistant professor of emergency medicine at OHSU School of Medicine. “The longer your brain is in a state of low blood flow, the less likely you are to have a good outcome.”

The researchers used data from the Portland Cardiac Arrest Epidemiology Registry, which comprehensively recorded defibrillation pad placement from July 1, 2019, to June 30, 2023. For the study, the researchers looked at 255 cases handled by Tualatin Valley Fire & Rescue where both pads were placed either front and side or front and back.

They found that placing the pads in the front and back was 2.64 times more likely to restore spontaneous blood flow, compared to placing the pads on the front and side of the person.

Health professionals are now convinced that whether the electrodes are placed on the front and side or on the front and back is equally beneficial in cases of cardiac arrest. The researchers cautioned, however, that their new study was an observational study and not a definitive clinical trial. Still, given the critical importance of getting the heart back to rhythm as quickly as possible, the results suggest that placing the electrodes on the front and side is beneficial rather than the front and side.

“The bottom line is you want energy to go from one pad to the other through the heart,” said lead author Mohamud Daya, MD, professor of emergency medicine at OHSU School of Medicine.

Placing the electrodes at the front and back can effectively “sandwich” the heart, increasing the possibility that the electrical current can be delivered more completely to the organ.

However, in many cases this is not possible. For example, the patient may be overweight or positioned in such a way that he or she cannot be moved easily.

“It can be difficult to move people,” said Daya, who is also the medical director for the Tualatin Valley Fire Department. “Emergency medical responders can often do it, but the general public may not be able to move a person. It’s also important to get power out as quickly as possible.”

In this regard, electrode placement is only one factor among many in the successful treatment of cardiac arrest.

Lupton survived his cardiac arrest and continued his medical studies at the hospital where he spent several days in intensive care, at Johns Hopkins University in Baltimore. The episode led him to shift his research focus to studying ways to optimize early care for patients who have suffered cardiac arrest.

The results of the new study surprised him.

“I didn’t expect to see such a difference,” he said. “The fact that we saw this difference might prompt the medical community to fund additional research to learn more.”