Adequate chest wall re-expansion following each compression during cardiopulmonary resuscitation (CPR) allows the heart to refill with blood. This full release of pressure on the chest creates a negative intrathoracic pressure, drawing blood back into the heart from the systemic circulation. Without it, the subsequent compression will primarily circulate the limited blood already within the heart, significantly diminishing the effectiveness of each chest compression. Imagine squeezing a sponge: if the sponge is not allowed to fully expand, subsequent squeezes will not expel much water.
The importance of this complete expansion cannot be overstated. It directly impacts cardiac output, the amount of blood the heart pumps per minute. Higher cardiac output translates to better perfusion of vital organs, increasing the likelihood of successful resuscitation and minimizing the risk of neurological damage. Historically, emphasis was placed primarily on the rate and depth of compressions. However, recognizing the critical role of allowing the chest to fully rise between compressions has led to refinements in CPR guidelines and training.
