Uncontrolled severe bleeding is the primary cause of preventable death following traumatic injury. Immediate and effective intervention by bystanders is necessary to bridge the time gap before professional medical help arrives. The A-B-C framework provides a simple, memorable, and actionable structure for any person to respond confidently and potentially save a life. This standardized approach focuses on the rapid steps needed to control life-threatening hemorrhage, which can result in death within minutes.
A: Alert – Ensuring Safety and Summoning Aid
The first step in any emergency is to prioritize the safety of the person providing aid, as becoming a second casualty only worsens the situation. Before approaching the injured individual, assess the scene to confirm that the threat has been removed or neutralized, such as traffic or unstable structures. Once the scene is safe, immediately call for professional help by dialing 911 or your local emergency number.
Either make the call yourself or clearly direct a specific bystander to do so, ensuring the request for aid is activated without delay. When speaking with the dispatcher, provide clear and concise information, including the precise location of the incident, the number of victims, and the nature of their injuries. This early notification allows emergency medical services to coordinate their response and arrive quickly with the appropriate resources.
B: Bleeding – Identifying Life-Threatening Injuries
The next step involves a rapid assessment to locate the source of the hemorrhage and determine if the bleeding is severe enough to be life-threatening. Bleeding requiring immediate control is characterized by blood spurting rapidly from the wound or blood that pools on the ground. A clear sign of severe blood loss is clothing that is quickly soaking through with blood.
To accurately assess the injury and prepare for intervention, expose the wound completely by removing or cutting away any obstructing clothing. Injuries hidden beneath the body or clothing must be found, as any life-threatening bleed can quickly lead to shock and unconsciousness. Finding the source of the blood loss guides the subsequent decision on the most effective method of compression.
C: Compress – Immediate Manual Pressure
Compressing the injury is the most direct and universally available method to control external bleeding, often being the first intervention applied. Direct pressure works by physically compressing the damaged blood vessels, allowing the body’s natural clotting mechanisms to form a stable plug. Apply the pressure directly over the wound using the palm of a hand, a sterile dressing, or a clean piece of cloth or clothing.
The pressure must be firm, steady, and continuous, pushing down as hard as possible to achieve maximum effectiveness. If the initial material becomes soaked with blood, add additional layers of dressing or cloth on top, but do not remove the original material. Maintain this firm pressure without releasing it to check the wound, as doing so can dislodge any forming clot and restart the hemorrhage. This sustained manual compression must be held until professional responders arrive and take over care.
C: Compress – Utilizing Wound Packing and Tourniquets
When direct manual pressure alone fails to stop the bleeding, more aggressive compression methods are needed. For deep wounds in areas like the neck, shoulder, or groin—where a tourniquet cannot be applied—wound packing is the necessary technique. This involves quickly stuffing the wound cavity with gauze, specialized hemostatic gauze if available, or clean cloth, pushing the material deep into the wound to the source of the bleeding.
The purpose of packing is to create internal pressure against the bleeding vessel. Once the wound is completely packed, firm manual pressure must be applied directly on top of the packed material. For life-threatening bleeding on an arm or a leg, a tourniquet is the definitive tool to stop blood flow to the injured limb. Place the device high on the limb, two to three inches above the wound, avoiding placement directly over a joint.
The tourniquet must be tightened using the windlass rod until the hemorrhage completely stops, which will be painful for the patient but is necessary to save their life. Once applied, the time of application should be noted on the device, as this detail is important for subsequent medical care. Both wound packing and tourniquet use are necessary steps when initial pressure is insufficient to prevent catastrophic blood loss.