Wildfire smoke could increase out-of-hospital cardiac arrests

A new study published in April found that exposure to heavy smoke during recent California wildfires raised the risk of out-of-hospital cardiac arrests by up to 70%. This has serious implications in Oregon which has active wildfires across the state. Combined with the fact that heart conditions are a main underlying condition in COVID-19 deaths means it’s especially important to do what we can to prevent unintentional fires, especially to protect at-risk populations.

The research was published in the Journal of the American Heart Association, which focused on out-of-hospital cardiac arrests which occur when the heart malfunctions and suddenly and unexpectedly stops beating. This differs from a heart attack, an event when blood flow to the heart is blocked.

Out-of-hospital cardiac arrests are more dangerous because they can cause death within minutes if no one performs cardiopulmonary resuscitation (CPR) or uses a defibrillator to shock the heart into normal rhythm, according to the study.

Researchers wanted to learn more about the health effects caused by large-scale wildfires that expose rural and urban communities to more wildfire smoke.

“In recent decades, we experienced a significant increase in large-scale wildfires, therefore, more people are being exposed to wildfire smoke,” said study author Ana G. Rappold, Ph.D., a research scientist at the U.S. Environmental Protection Agency’s Center for Public Health and Environmental Assessment in the Office of Research and Development. “In order to respond properly, it is important for us to understand the health impacts of wildfire smoke exposure.”

The study examined cardiac arrests during 14 wildfire-affected counties in California between 2015 and 2017 with varying degrees of smoke exposure. They found that cardiac arrests increased on heavy smoke density days and persisted for several days afterwards. The second day after smoke exposure caused the highest risk, which was 70 percent higher than days with no smoke.

“Particulate matter from smoke that is inhaled can penetrate deeply into the lungs, and very small particles may cross into the bloodstream,” Rappold said of the findings. “These changes can lead to disturbances in the heart’s normal rhythm, blockages in blood vessels and other effects creating conditions that could lead to cardiac arrest.”

Researchers also found an increased risk among people living in lower-income communities, which might reflect less access to strategies to reduce exposure. Previous studies have shown that there are more respiratory problems in lower-income communities and worsening congestive heart failure in response to wildfire smoke exposure.

Furthermore, the study found that it’s not just older adults who are negatively affected. “We also observed elevated effects among middle-aged adults (aged 35-64). It is possible that this population may not be aware of their risk and may not have flexibility to discontinue activities that involve exertion and exposure during wildfire smoke episodes,” concluded Rappold.

What can you do to reduce your exposure? Researchers advise people to stay indoors with doors and windows closed, use high-efficiency air filters in air conditioning systems, avoid exertion, and to seek shelter elsewhere if the home does not have air conditioning and it’s too warm to stay inside.