The “ABCs” of first aid represent the foundational order of assessment in any emergency, forming the primary survey used to identify and manage immediate life threats. This systematic approach ensures that the most critical functions necessary for life—Airway, Breathing, and Circulation—are addressed first. Stabilizing these three areas quickly can prevent further deterioration and buy valuable time until professional medical help arrives. This protocol provides a structured way for a layperson to prioritize actions.
The Primary Survey: Airway, Breathing, and Circulation
The first step, Airway, involves ensuring the passage from the mouth and nose to the lungs is clear of obstruction. In an unconscious person, the tongue can relax and fall back, blocking the throat. To counter this, the head tilt/chin lift maneuver is performed. This technique involves placing one hand on the forehead and the fingers of the other hand under the chin to gently tilt the head back, lifting the tongue away from the back of the throat. If a spinal injury is suspected, a jaw thrust without tilting the head is used instead.
Once the airway is opened, the second step is to assess Breathing, traditionally done using the “Look, Listen, and Feel” method. The rescuer should place their ear over the victim’s mouth and nose while looking down the chest for movement. For no more than ten seconds, they look for chest rise, listen for breath sounds, and feel for air movement on their cheek. It is important to distinguish between normal breathing and agonal gasps, which are ineffective, irregular breaths that signal a need for immediate intervention.
The final step in this traditional first aid sequence is Circulation, which primarily focuses on identifying and controlling severe external bleeding. Uncontrolled, heavy bleeding can lead to rapid shock and death, making immediate management a priority. The rescuer should apply direct pressure to any visible severe wounds, using a clean cloth or sterile dressing, to stem the blood flow. While checking for a pulse is a technical assessment, controlling life-threatening hemorrhage is the most important circulatory intervention for a layperson in trauma scenarios.
The Shift in Protocol: Why CAB is Used in CPR
For victims who are unresponsive and not breathing normally—a sign of sudden cardiac arrest—the American Heart Association (AHA) recommends a shift to the CAB sequence: Compressions, Airway, Breathing. This reordering emphasizes the immediate start of chest compressions, minimizing the delay in blood flow to the brain and heart. Since most adult victims of sudden cardiac arrest still have enough oxygenated blood circulating, prioritizing compressions ensures this remaining oxygen is delivered to the body’s sensitive organs.
Beginning with compressions also simplifies the initial action for bystanders, who may hesitate to perform the airway opening and mouth-to-mouth rescue breaths. Compressions should be delivered at a rate of 100 to 120 per minute, pushing down at least two inches on the center of the chest. The CAB protocol is applied when the heart has stopped, requiring cardiopulmonary resuscitation (CPR). The traditional ABC remains the standard assessment for general first aid and trauma where the victim is unresponsive but still breathing, or when the cause of arrest is likely due to lack of oxygen, such as in drowning.
Immediate Actions Following the Primary Survey
Once the primary survey is complete and immediate life threats like a blocked airway or severe bleeding are managed, the rescuer must immediately call for emergency medical services (EMS). Calling for help should occur as soon as unresponsiveness is determined, or directly after stabilizing the ABCs, depending on the situation. Continuous monitoring of the victim’s breathing and responsiveness is necessary until professional help arrives.
If the victim is unresponsive but is breathing normally, they should be carefully placed into the recovery position. This position involves turning the person onto their side, using gravity to help keep the airway open. It also allows any fluids, like vomit, to drain from the mouth. Maintaining a clear airway in an unconscious person prevents aspiration.
Following stabilization, the rescuer can begin the secondary survey, a thorough head-to-toe examination to identify non-life-threatening injuries, such as fractures or minor bleeding. This phase involves gathering information about the incident and the victim’s medical history. Throughout this process, the rescuer should also monitor for signs of shock, which include pale, cool, or clammy skin, and keep the victim warm by covering them with a blanket.