Cardiopulmonary resuscitation (CPR) is a life-saving technique used when someone’s breathing or heart stops, most often during a sudden cardiac arrest. Modern guidelines use the acronym CAB to organize the sequence of actions and guide rescuers. This structure ensures that time-sensitive actions are performed without delay. The acronym CAB is the current standard for adult CPR, and understanding what it stands for is the foundation of modern resuscitation efforts.
Defining the CAB Acronym
The acronym CAB in CPR stands for Compression, Airway, and Breathing. This sequence represents the three primary interventions a rescuer must perform on an unresponsive person who is not breathing normally. Compression involves manually circulating blood through the body to keep vital organs perfused. Airway focuses on ensuring an open passage for air to move into the lungs. Breathing refers to the delivery of rescue breaths to provide oxygen to the person’s blood.
The Rationale for Prioritizing Compressions
The current CAB sequence replaced the former ABC (Airway, Breathing, Compressions) standard in 2010. This shift occurred because most sudden cardiac arrests in adults result from a primary heart problem, not a lack of oxygen. The blood already contains a sufficient amount of oxygen for the first few minutes after collapse. The priority became minimizing the time delay before starting chest compressions to move this existing oxygenated blood to the brain and heart. Initiating compressions first ensures that circulation is rapidly established, which is the most time-sensitive action for preserving neurological function.
Practical Steps for Performing the CAB Sequence
The CAB sequence begins with Compression, requiring the rescuer to place the heel of one hand on the center of the person’s chest, with the other hand placed directly on top. The compressions must be delivered hard and fast, pushing straight down on the chest to a depth of at least 2 inches (about 5 centimeters) but no more than 2.4 inches (6 centimeters) in an average adult. The required pace is between 100 to 120 compressions per minute.
After a cycle of 30 compressions, the rescuer moves to Airway, opening the passage using the head-tilt/chin-lift maneuver. This involves gently tilting the head back while lifting the chin to move the tongue away from the back of the throat.
Once the airway is open, the rescuer proceeds to Breathing, delivering two rescue breaths. The rescuer pinches the person’s nose shut and makes a complete seal over the mouth with their own, blowing steadily for about one second to make the chest visibly rise. If the chest does not rise with the first breath, the rescuer repositions the head using the head-tilt/chin-lift maneuver before attempting the second breath. The rescuer then returns immediately to chest compressions, continuing the cycle of 30 compressions followed by two breaths until professional help arrives or the person shows signs of movement.