Cardiopulmonary resuscitation (CPR) is a life-saving technique used when a person’s heart has stopped beating. It combines chest compressions and rescue breathing to manually maintain blood flow and oxygen supply to the brain and other vital organs. Compression depth, the distance the chest wall is pushed inward, is fundamental to effective resuscitation. Achieving the correct depth is a precise balance, ensuring enough force is applied to circulate blood without causing unnecessary harm.
Defining the Ideal Adult Range
Current guidelines establish a specific target for chest compression depth in adult patients. The ideal depth is at least 2 inches (5 centimeters), but compressions should not exceed 2.4 inches (6 centimeters). This narrow range is rooted in the physiology of blood circulation during cardiac arrest.
Compressing the chest manually creates the pressure needed to force blood out of the heart and into the body’s vascular system. This action maintains perfusion, the flow of oxygenated blood to the brain and heart muscle. The 2-inch lower threshold is the minimum force needed to generate sufficient blood flow to vital organs. Limiting the depth to 2.4 inches minimizes the risk of complications associated with excessive force.
The Consequences of Incorrect Depth
Missing the established target range for compression depth significantly reduces the chances of a positive outcome. If compressions are too shallow, they fail to generate enough pressure to circulate blood effectively. This inadequacy means oxygen-rich blood may not reach the brain and heart, leading to a poorer prognosis.
Conversely, compressing the chest too deeply substantially increases the risk of serious injury. Compressions exceeding 2.4 inches are associated with a higher likelihood of trauma, such as fractured ribs or a broken sternum. Excessive depth can, in rare cases, lead to damage to internal organs like the lungs or major blood vessels. The goal is to maximize circulatory benefit while minimizing injury.
Adjusting Compression Depth for Children and Infants
Compression depth must be modified when performing CPR on pediatric patients due to their smaller anatomy. For children (ages one year to puberty), the recommended depth is approximately 2 inches (5 centimeters). This depth is often described as compressing the chest to about one-third of its total anterior-posterior depth. The force used should be adjusted based on the child’s size, using one or two hands as necessary to reach the proper depth.
Infants, who are less than one year old, require the least compression depth. The proper technique is to compress the infant’s chest by approximately 1.5 inches (4 centimeters). This measurement also corresponds to about one-third of the infant’s chest depth. The infant’s smaller chest cavity and fragile internal structures necessitate this reduction in force to ensure effectiveness while avoiding serious injury.
Practical Techniques for Achieving Consistency
Maintaining the correct compression depth requires proper body mechanics from the rescuer. Rescuers should position their shoulders directly over their hands and keep their arms straight. This alignment allows the rescuer to use upper body weight to deliver compressions, which is more sustainable than relying solely on arm strength.
A fundamental technique for maximizing the benefit of each compression is ensuring full chest recoil. After each push, the rescuer must completely remove all pressure, allowing the chest to return to its normal, resting position. Full recoil allows the heart to refill with blood before the next compression, ensuring maximum volume is pumped. Rescuers should also consider using CPR feedback devices, which provide real-time data on compression depth and rate, helping adjust technique to maintain high-quality performance.