New approach to defibrillation may improve cardiac arrest outcomes

He attributes his survival to the rapid defibrillation he received from first responders -- but not everybody is so fortunate.

Now, as lead author on a new observational study published in the journal JAMA Network Open, he and co-authors from Oregon Health & Science University say the study suggests the position in which responders initially place the two defibrillator pads on the body may make a significant difference in returning spontaneous blood circulation after shock from a defibrillator.

"The less time that you're in cardiac arrest, the better," said Lupton, assistant professor of emergency medicine in the OHSU School of Medicine. "The longer your brain has low blood flow, the lower your chances of having a good outcome."

Researchers used data from the Portland Cardiac Arrest Epidemiologic Registry, which comprehensively recorded the placement position of defibrillation pads from July 1, 2019, through June 30, 2023. For purposes of the study, researchers reviewed 255 cases treated by Tualatin Valley Fire & Rescue, where the two pads were placed either at the front and side or front and back.

They found placing the pads in front and back had 2.64-fold greater odds of returning spontaneous blood circulation, compared with placing the pads on the person's front and side.

The current common knowledge among health care professionals is that pad placement -- whether front and side, or front and back -- is equally beneficial in cardiac arrest. The researchers cautioned that their new study is only observational and not a definitive clinical trial. Yet, given the crucial importance of reviving the heartbeat as quickly as possible, the results do suggest a benefit from placing the pads on the front and back rather than the front and side.

"The key is, you want energy that goes from one pad to the other through the heart," said senior author Mohamud Daya, M.D., professor of emergency medicine in the OHSU School of Medicine.

Placing the pads in the front and back may effectively "sandwich" the heart, raising the possibility that the electrical current will be delivered more comprehensively to the organ.

However, that's not readily possible in many cases. For example, the patient may be overweight or positioned in such a way that they can't be easily moved.

"It can be hard to roll people," said Daya, who also serves as medical director for Tualatin Valley Fire & Rescue. "Emergency medical responders can often do it, but the lay public may not be able to move a person. It's also important to deliver the electrical current as quickly as possible."

In that respect, pad placement is only one factor among many in successfully treating cardiac arrest.

Lupton survived his cardiac arrest and went on to complete medical school at the very hospital where he spent several days recovering in the intensive care unit -- Johns Hopkins University in Baltimore. The episode led him to alter the focus of his research so that he could examine ways to optimize early care for cardiac arrest patients.

The results of the new study surprised him.

"I didn't expect to see such a big difference," he said. "The fact that we did may light a fire in the medical community to fund some additional research to learn more."

The research was supported by the Zoll Foundation, grant award 1018439; the Society for Academic Emergency Medicine Foundation, grant award RE2020-0000000167; and the National Institute of Neurological Disorders and Stroke of the National Institutes of Health, award U24NS100657 and National Center for Advancing Translational Sciences, award UL1TR002369. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.