Compression depth in cardiopulmonary resuscitation (CPR) refers to how far the chest wall is depressed during each compression. This action circulates blood manually throughout the body. Appropriate depth significantly impacts patient outcomes during a cardiac arrest event. CPR’s effectiveness relies on this parameter to support life until professional medical help arrives.
Recommended Depths for Different Ages
Compression depths vary based on the age of the individual receiving CPR. For adults, guidelines from major resuscitation organizations recommend a compression depth of at least 2 inches (5 cm). However, this depth should not exceed 2.4 inches (6 cm) to balance effectiveness with safety.
For children, the recommended depth is approximately 2 inches (5 cm), about one-third of the chest’s anterior-posterior diameter. For infants, the depth is about 1.5 inches (4 cm), also roughly one-third of the chest’s diameter. These measurements maximize blood flow while minimizing injury risk to younger patients.
The Importance of Proper Depth
Correct compression depth directly influences the amount of blood pumped to vital organs. Adequate depth creates sufficient intrathoracic pressure to force blood from the heart into the arterial system. This pressure ensures oxygenated blood reaches the brain and heart muscle, which are susceptible to oxygen deprivation.
Proper depth facilitates venous return to the heart, allowing it to refill with blood between compressions. This cycle of compression and recoil maintains systemic circulation. Effective blood flow to the brain helps prevent neurological damage, while coronary perfusion supports the heart’s ability to regain its own rhythm. Correct compression depth significantly improves survival and neurological outcomes for individuals experiencing cardiac arrest.
Consequences of Wrong Depth
Compressions that are too shallow are largely ineffective in generating adequate blood flow to the brain and other organs. When the chest is not compressed deeply enough, insufficient pressure means oxygen and nutrients do not reach the tissues. This can lead to continued organ damage and reduced chances of successful resuscitation.
Conversely, overly deep compressions can cause injuries, though CPR’s benefits generally outweigh these risks. Excessive force can lead to rib fractures, sternum fractures, or internal organ damage, such as lung contusions or liver lacerations. While these injuries are concerns, the primary focus during cardiac arrest remains on providing adequate circulation to save a life.
How to Ensure Correct Depth
To achieve and maintain the correct compression depth, rescuers should focus on proper body mechanics. This involves kneeling beside the person, placing the heel of one hand in the center of the chest, and placing the other hand on top, interlocking fingers. The rescuer’s arms should be straight, with shoulders directly over the hands, allowing body weight to contribute to the force of compressions.
Full chest recoil after each compression is also important; allowing the chest to fully re-expand ensures the heart can refill with blood. In training and some real-life scenarios, feedback devices on automated external defibrillators (AEDs) or manikins can provide real-time guidance on compression depth. These tools help rescuers adjust their technique to meet the recommended depth parameters.
References
American Heart Association. (2020). Highlights of the 2020 American Heart Association Guidelines for CPR and ECC.