Chest compressions are indicated when the baby’s HR remains < 60 bpm after 30 seconds of PPV that effectively moved the baby’s chest. When effective PPV fails to resuscitate the baby, the newly born may have significantly inadequate oxygen saturation, significant acidosis, and/or decreased cardiac perfusion. These conditions diminish cardiac function. Therefore, chest compressions are needed to improve blood flow and restore function to the heart.

The coronary arteries supply blood to the myocardium via the aortic root. When the heart is beating normally, myocardial perfusion happens during diastole. In cardiac arrest, coronary blood flow stops because no more blood flows into the aorta. Chest compressions are directed toward the lower one-third of the sternum and compress the heart toward the spine. This compression causes an increase in aortic pressure and right atrial pressure.

When the chest decompresses with full chest recoil, the right atrial pressure decreases faster than the aortic pressure. The resulting pressure gradient causes blood to flow into the coronary arteries, and the myocardium perfuses with oxygenated blood.