What is CPET?

What is CPET?

CPET is short form for cardiopulmonary exercise testing. Cardiopulmonary means related to the heart and lungs. Most of you will be familiar about treadmill exercise test which is done to assess deficits in blood flow to the heart muscle by exercise ECG. CPET includes an exercise test with ECG monitoring as well as analyzing the breath for usage of oxygen and expulsion of carbon dioxide from the body. Though treadmill can be used for CPET, most often it is another exercise machine known as bicycle ergometer which is used for CPET. Bicycle ergometer is a static cycle which can be used for graded exercise up to the maximum effort tolerance of the individual.

Blood pressure is monitored using non-invasive blood pressure equipment connected to the CPET console. Facemask is connected to the breath gas analyzer machine which is part of the CPET equipment. A volume sensor in the mask senses the volume of air which is breathed in and out. Fast responding oxygen and carbon dioxide sensors in the system acquire information on a breath-to-breath basis, analyzes and displays continuously in the monitor. ECG, the recording of the electrical activity of the heart is also displayed simultaneously on another screen to check whether there is any abnormality which requires early termination of the test, as in usual exercise ECG testing. Pulse oximeter kept on the ear lobe, finger or forehead monitors the oxygen saturation in blood during exercise.

Highest level of oxygen consumption achieved during CPET is an important measure of the exercise capacity. Peak oxygen consumption (VO₂) is correlated with the severity and outcome of heart failure. Another important measure is the carbon dioxide production (VCO₂). Volume of air breathed in a minute is the minute ventilation (VE). The slope of the graph displaying VE/VCO₂ is another important measure. The slope is taken from the resting level to the peak exercise level.