Cardiopulmonary Resuscitation (CPR) is an emergency procedure performed during cardiac arrest when someone’s heart stops beating. Effective chest compressions are the most important part of CPR, manually circulating oxygen-rich blood to the brain and vital organs until professional medical help arrives. The quality of these compressions, including hand placement and depth, directly influences the chances of survival. Proper technique involves a precise application of leverage and body mechanics to maximize blood flow.
Locating the Compression Site
The correct location for chest compressions on an adult is the lower half of the sternum (breastbone), centrally located in the chest. Placing hands here ensures force is applied over the heart and minimizes the risk of injury to structures like the ribs. A common guideline for finding this spot is to target the center of the chest, roughly between the nipples.
This central point is situated directly above the heart, between the sternum and the spine. The target is just above the xiphoid process, the small cartilage tip at the bottom of the sternum. Identifying this landmark is the first step to delivering safe and effective compressions.
Specific Hand Placement Technique
The technique for placing hands focuses the force onto a small, strong area of the breastbone. The rescuer should first place the heel of one hand directly onto the center of the person’s chest. The heel of the second hand is then placed directly on top of the first hand.
To avoid applying pressure to the ribs, the fingers of the hand touching the chest must be interlocked with the top hand or lifted completely off the chest surface. This stacking ensures all compression force is channeled through the heel of the bottom hand and directly onto the sternum. Maintaining this precise alignment helps achieve the required compression depth without causing unnecessary trauma.
Body Mechanics for Effective Compressions
Proper body positioning is essential for delivering the hard and fast compressions required for effective circulation. The rescuer should kneel beside the person and position their shoulders directly over their hands. This alignment allows the rescuer to push straight down, using their upper body weight rather than just arm strength.
The arms must be kept straight and the elbows locked throughout the compression cycle to create a rigid column for the force. Leaning from the hips and using core muscles helps generate the necessary force to compress the chest by at least 2 inches, but no more than 2.4 inches, for an average adult. This technique conserves the rescuer’s energy while maintaining the sustained rate of 100 to 120 compressions per minute.
Adjustments for Different Age Groups
The basic principles of hand placement change significantly when performing CPR on children and infants due to their smaller, more fragile anatomy.
For children generally aged one year to the onset of puberty, the hand position remains in the center of the chest, but the amount of force applied is reduced. Rescuers may use only the heel of one hand to achieve a compression depth of about 2 inches, or approximately one-third the depth of the child’s chest.
For infants under one year old, the standard technique involves a much smaller contact area to avoid overwhelming the chest cavity. The recommended method uses two fingers, typically the index and middle fingers, placed just below the nipple line in the center of the chest.
Infant compressions should aim for a shallower depth of about 1.5 inches, or one-third the depth of the chest, applied at the rate of 100 to 120 times per minute. A two-thumb encircling technique is an alternative method often used by two rescuers, where both thumbs are placed side-by-side on the sternum while the hands wrap around the infant’s back for support.