Very few Americans have taken a first aid course in the last two years, and those who did probably didn't get taught to control bleeding, a U.S. survey suggests.

The findings come amid a push by doctors and emergency responders to eliminate deaths in mass shootings and disasters that might be avoided with proper bleeding control at the scene. A national protocol known as the Hartford Consensus calls for strangers and bystanders to step in and assist the wounded before emergency medical service (EMS) workers arrive.

"The most critical issue in major bleeding from any source is time," said lead study author Dr. Lenworth Jacobs, a surgery researcher at the University of Connecticut and chairman of the Hartford Consensus.

"It is essential that the average person understands the concept of using their hands to apply pressure to the bleeding site, which will stop the bleeding," Jacobs said by email.

To assess how willing and able ordinary people might be to help a bleeding patient in an emergency, Jacobs and colleagues surveyed 1,051 people by phone in English and Spanish.

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Overall, 47 percent of respondents said they had ever taken first aid training. About half of these said their training had happened more than five years ago. Only 13 percent of respondents said their training took place within the past two years.

Among 941 individuals who said they were able to give first aid, 98 percent said they would be at least somewhat likely to try to stop bleeding for a family member with a severe leg wound. Most would use compression or pressure, while about a third would apply a tourniquet.

About half of those who could give first aid were randomly asked what they would do after a car crash; 92 percent said they'd be at least somewhat likely to try to stop bleeding for an injured stranger.

Regarding a mass shooting, 75 percent of people randomly selected to consider this scenario said they would try to give first aid if it seemed safe to do so, according to a report in the Journal of the American College of Surgeons.

It's possible, the authors admit, that respondents expressed more willingness to help then they would in a real-life emergency.

Even so, the findings highlight the willingness of ordinary citizens to intervene when strangers are severely injured, as well as the need for more widespread first aid training that includes lessons on bleeding control, said Dr. Peter Pons, an emergency medicine physician and a researcher at the University of Colorado School of Medicine.

"While it is a sad reality of our time that incidents such as the Tucson shooting, the Planned Parenthood shooting in Colorado Springs, the Boston Marathon bombings, the attacks in Paris and Belgium, and numerous others occur resulting in large numbers of casualties, injury also occurs intentionally in the home, in the workplace and during leisure activities," Pons said by email.

"For all of these reasons, it is essential that hemorrhage control join CPR as an appropriate component of every citizen's knowledge base," added Pons, who wasn't involved in the study.

Even without formal training, just about anyone can help in an emergency, said Jonathan Epstein, senior director of science and content development for the American Red Cross.

"Anyone can help to stop severe bleeding with little to no formal training by using their hands and applying direct pressure over the wound while waiting for EMS to arrive with no significant complications," Epstein, who wasn't involved in the study, said by email.

"When a person is bleeding severely it is more important to have someone willing to act than being worried about causing harm by putting pressure on the wound," Epstein added. "A person who may not have the confidence to help in an emergency and thus be unwilling to help is far worse than someone willing to step in and do something in a lifesaving situation."