As we are all too often reminded in the wake of a mass shooting or other national tragedy, traumatic injuries can occur at any given moment. Whether it’s sustained from a bullet, an explosion, a car accident, or a shark attack, one question applies to all scenarios—what do you do to stop the bleeding?

Brigham and Women’s Hospital in Boston’s Chestnut Hill neighborhood offers a free course that addresses this issue. Called Stop the Bleed, it teaches proper bleeding control techniques, tourniquet application, and wound packing. It’s an initiative of the Hartford Consensus project, which “in April 2013, just a few months after the active shooter disaster … at Sandy Hook Elementary School in Newtown, CT … was convened by the American College of Surgeons (ACS) in collaboration with the medical community and representatives from the federal government, the National Security Council, the U.S. military, the Federal Bureau of Investigation, and governmental and nongovernmental emergency medical response organizations, among others.”

Stop the Bleed recently trained 500 people at Gillette Stadium in Foxboro. Those trained included employees in the concessions, parking, and security departments at the stadium.

Among the things taught at a Stop the Bleed event: Anyone who is at the scene of a trauma can act as a first responder until professional medical help arrives; a person can die from uncontrolled bleeding within five to 10 minutes; bleeding control and CPR training share two things—saving lives and ABCs, which for CPR training are Airway, Breathing, and Circulation, and for bleeding control are Alert, Bleeding, and Compress.

“All these people were trained if, God forbid, something happens in these places,” said Muhammad Ali Chaudhary, a research fellow at the Center for Surgery and Public Health at Brigham and Women’s. “There is someone who knows what to do. Someone who knows how to stop the bleed.

“The only thing more tragic than a death,” Chaudhary added, “is a death that could have been prevented.

“We’re trying to make this thing as common as we can so there [are] enough people … who can respond … at any given time at any given place if something happens.”

BONUS: Tips for saving lives that we picked up from Stop the Bleed

What do I do when I see someone bleeding? 

• One of the first things you do is call 911. If there are others nearby, another option is to establish direct communication with those around you. Command an individual to dial for help as you tend to the victim.

• Wounds in the lower trunk, like your abdomen, are much harder to pack and it is suggested to pack as best as you can and apply pressure. On an injured child, it is advised to apply direct pressure only. After packing the wound and once help arrives, wash your hands and let first responders know if you were injured, came in contact with exposed bones, or if there was transfer of fluids from an open wound you sustained. 

How can I tell if the person is bleeding a lot?

• The most crucial thing to do is to check the individual. Are they unconscious? How is their mental state? Are they confused? Dizzy? Are they drifting in and out of consciousness? If they show any of these signs, they already lost an excessive amount of blood, which will lead to shock.

• Shock is a life-threatening emergency. Our bodies need blood to hold our temperatures steady and deliver oxygen and nutrients to our cells. When our blood volumes are low, organs begin to fail.

• Another way to tell if an individual is bleeding profusely is to look for pooling. Has the blood spread? Is their clothing is soaked? If so, remove or open that article of clothing to get a better view of the wound. Again, is there pooling? Is there spurting? If blood spurts, it’s a high-pressure bleed. This means an artery or blood vessel is cut. This results bleeding to spray or come out at a faster rate.

How do I stop the bleeding?

• In the event of a mass shooting or a terrorist attack, wait until the threat is gone. Once you’ve assessed your safety and the safety of others around you, check for life-threatening bleeding. Then, look for a first aid kit. Grab a clean cloth or gauze and tend to the victim. If there is not a first aid kit in sight, use a clean article of clothing or something that is already being worn, like a sweater.

• There are three ways to contain bleeding until help arrives. 

• One is to apply direct pressure to the wound. Use your hands and fingers to apply pressure. Straighten your elbows and with your body weight, push down as hard as you can. Some areas like the neck and lower abdomen are tricky. For these areas, apply pressure by using hands or fingers. Do not use your body weight on someone’s neck.

• Second, apply a tourniquet. A tourniquet is a device used to stop the flow of blood through a vein or artery by compressing a limb. The most common tourniquet used is the Combat Application Tourniquet (CAT). It’s used in the military and is known for easy use. Note the tab to write down the time the tourniquet was placed, which gives EMTs and surgeons an idea of how long the individual wore it. When applying a tourniquet, place it one to two inches above the injury. Then, tighten as much as you can until the bleeding stops. Tourniquets are painful, but it is a life-saving device.

Muhammad Ali Chaudhary, a Research Fellow at the Center for Surgery and Public Health at Brigham and Women’s Hospital says in a US civilian setting, a person can wear a tourniquet for up to six hours after application before loss of limb. “They hurt,” Chaudhary says. “They hurt a lot, but pain doesn’t mean it was applied incorrectly.”

If needed, apply a second tourniquet—but never over the knee, elbow, or other joints. This will prevent compression. Do not apply a tourniquet to neck, shoulder, or groin injuries either. Common mistakes with tourniquets are failing to use one, waiting too long to apply one or a second one, and not tightening it enough. Chaudhary said that improvised tourniquets “seldom work.” 

• The last method to control bleeding is packing a wound and applying pressure. If the wound is deep, it’s best to take a clean piece of cloth or gauze and stuff the wound as much as it can go and apply pressure. Chaudhary says that if there is not a clean cloth or gauze available, remove an article of your clothing like a scarf or shirt and use that. “Infections can be treated,” he said.