Cardiopulmonary Resuscitation (CPR) is a life-saving emergency procedure performed when someone’s heart has stopped beating effectively, a condition known as cardiac arrest. It involves chest compressions and rescue breaths to maintain blood flow and oxygen delivery to the brain and other vital organs. CPR is intended for situations where the heart is no longer functioning. This raises the question of what happens if chest compressions are performed on a heart that is still beating. Proper assessment before initiating CPR is important to avoid potential complications.
The Role of Chest Compressions in CPR
Chest compressions are a fundamental component of CPR, designed to artificially circulate blood throughout the body. When the heart stops, it can no longer pump blood to deliver oxygen to the brain and other organs. Compressions manually squeeze the heart between the sternum and the spine, pushing blood out to the rest of the body. This mechanical action creates a temporary blood flow, maintaining a supply of oxygen to tissues that would otherwise quickly suffer damage.
Compressions effectively take over the heart’s pumping function during cardiac arrest. They are delivered at a specific depth and rate to generate sufficient blood pressure and flow. The goal is to provide enough circulation to sustain the brain and heart until advanced medical care can restore the heart’s natural rhythm.
How to Determine if Compressions Are Needed
Before initiating chest compressions, a rescuer should perform a quick assessment to confirm that the person is in cardiac arrest. The first step involves checking for responsiveness by gently tapping the person and speaking loudly to them. If there is no response, the next step is to observe for normal breathing. This means looking for chest rise and fall, and listening for breaths for no more than 10 seconds; gasping or irregular breaths are not considered normal.
If the person is unresponsive and not breathing normally, chest compressions should be started immediately. While trained professionals may check for a pulse, lay rescuers are advised to bypass this step. This is because pulse checks can be unreliable for untrained individuals, potentially delaying life-saving compressions.
Potential Harms of Unnecessary Chest Compressions
Performing chest compressions on a heart that is still beating can lead to various physical injuries and physiological disruptions. One of the most common physical consequences is the fracture of ribs, which can occur in approximately 30% to 70% of CPR cases. Sternum fractures are less frequent, with estimates ranging from 1% to 8%. These injuries result from the significant force required to effectively compress the chest.
Beyond skeletal damage, internal organ injuries can also occur. The forceful nature of compressions can lead to lung contusions, or bruising of the lungs. Lacerations of organs such as the liver or spleen are also possible, particularly if hand placement is incorrect. In some instances, heart contusions or pericardial lesions, injuries to the heart muscle or its surrounding sac, have been observed.
From a physiological perspective, chest compressions on a beating heart can put undue stress on the cardiovascular system. Forcing blood flow when the heart is already pumping can create abnormal pressures and disrupt its natural rhythm. This interference might induce or worsen heart rhythm abnormalities, known as arrhythmias. While the risk of severe harm to the heart itself from compressions on a beating heart is considered low, the other potential injuries underscore the importance of proper assessment before starting CPR.