• Posted August 28, 2025

CPR In Space? Best Method Identified, Researchers Say

As humans begin to colonize space, it’s inevitable that some will suffer a cardiac arrest.

Space CPR conducted in weightlessness will be crucial to save their lives – and researchers say they’ve now come up with a better method.

Automatic chest compression carried out by a mechanical piston is expected to be more effective than emergency protocols now in place for the International Space Station, researchers reported Wednesday at the European Society of Cardiology’s annual meeting in Madrid.

Astronauts now are taught a “handstand” method of CPR, in which they brace their legs against a wall and perform a handstand on the patient’s chest, researchers said. In weightlessness, this has been the only viable option for creating the pressure needed for chest compressions.

But tests aboard a “flying laboratory” that re-creates weightlessness showed that this method likely doesn’t press deep enough to create life-sustaining blood flow, researchers said.

“Use of a particular type of automatic chest compression device was the only method that gave the depth that is recommended by international resuscitation guidelines to keep blood flowing to the brain in a real-life cardiac arrest,” lead researcher Nathan Reynette, a medical student at the University of Lorraine in France, said in a news release.

On Earth, CPR chest compressions use the rescuer’s weight to help keep blood flowing, but that’s not possible in microgravity, researchers said.

The research team used a modified civil aircraft provided by the French space agency, the National Center for Space Studies, to test different approaches for CPR on dummies.

The plane would climb high and then drop precipitously, accurately creating weightlessness for 22 seconds before pulling out of its dive. Each flight could create such conditions about 30 times.

The team tested the handstand method, a reverse bear hug and the Evetts Russomano method, in which a rescuer wraps their legs around the patient to prevent them from floating away.

None of these produced enough pressure to sufficiently pump blood in weightlessness, researchers said.

However, a standard mechanical piston device for CPR did achieve an average compression that could sustain a person’s life during cardiac arrest, results showed.

The piston device created compressions of about 53 millimeters in depth, compared to less than 35 millimeters from the handstand method, researchers said.

“It will be up to every space agency whether they want to include automatic chest compression devices in their emergency medical kit,” Reynette said. “We know they have other considerations beyond effectiveness, such as weight and space constraints.”

One consideration: “While cardiac arrest is a high danger event, that could even terminate a space mission, it is a relatively low risk for now,” Reynette said. 

“Most astronauts are young, healthy and physically fit individuals who have intensive medical monitoring, including scanning for chronic heart disease, before going into space," he said. “Nevertheless, longer lasting space missions in future and space tourism could increase the risks of a medical emergency occurring.”

These results aren’t just beneficial for astronauts, Reynette added. CPR piston devices also might be useful for responding to heart emergencies that occur in isolated environments on Earth.

“Further research could explore whether automated chest compression devices could prove useful to carry out CPR in environments such as submarines and Arctic bases,” Reynette said.

Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

More information

The American Heart Association has more on CPR.

SOURCE: European Society of Cardiology, news release, Aug. 27, 2025