PCPR- Lesson 3- Chest Compressions

There are two techniques for performing chest compressions. It has been shown that even the best-performed compressions only produce 30% of the normal stroke volume in the animal. The primary goals of chest compressions are to replace the function of the left and right ventricles, provide blood flow to the lungs, and oxygenate the tissues.

Thoracic Pump Theory- (most dogs and barrel-chested dogs) recoil of the chest between compressions causes negative pressure within the chest, drawing blood into the blood vessels and into the heart.

Cardiac Pump Theory- (cats, keel chested dogs) left and right ventricles of the heart are directly compressed between the sternum (breastbone) and the spine when compressions are done in the barrel chested position or between the ribs on the opposite sides of the chest when in lateral recumbence (laying on their right side).

Compression Rate- Regardless of size chest, compressions should be done at a rate of 100-120 compressions per minute. Because cardiac output is the product of heart rate and stroke volume, lower compression rates result in reduced cardiac output, leading to lower survival rates. Higher compression rates also reduce cardiac output because they do not allow for full recoil of the chest, reducing the return of blood to the heart. Perform chest compressions in cycles of 2 minutes without interruption.

It takes approximately 1 minute of chest compressions for aortic blood pressure to reach a level that provides perfusion to the heart and tissues.

Compressor Position- The shoulders of the compressor should be directly above the hands. If the height of the table makes it impossible to keep the elbows locked while doing compressions, the compressor should use a stool, climb on the table with the animal or place the animal on the floor. Always lock your elbows and use your core muscles rather than your biceps or triceps. This will reduce fatigue and maintain optimal compression force. Hands should be placed one over the other, locking fingers if need be. [4]