What is Cardiopulmonary testing?
Cardiopulmonary exercise testing, often abbreviated as CPX, CPEX or CPET, is now the 'gold standard' objective tool for the evaluation of cardiopulmonary function and fitness. It is a non-invasive and objective method of assessing exercise capacity or fitness and looks at the heart, lungs, blood vessels and muscle systems.
Why is it done?
Diseases that affect the heart, lungs, circulation or blood may cause an abnormal response to exercise. CPX is used to simultaneously measure many parameters that can then be used to help with a diagnosis or to reassure you as to the cause of your symptoms.
In particular we use the test to assess fitness levels for people undergoing major surgery and this can be used to assess your risk of complications and identify any special measures that we may undertake to reduce the risk, including things that you may be able do including smoking cessation and exercise. It can also be used to identify if a higher level of care on the high dependency or intensive care unit is required.
How is the test performed?
The test will be performed by a doctor or trained clinical physiologists, who will explain the test and answer any questions. Your height and weight will be recorded and a few baseline questions will be asked to assess your background history. You will then perform a baseline non-invasive breathing test to assess your resting lung function. You will have sticky electrodes will be applied to your chest to monitor your heart rate and rhythm during the test so if you can wear a front buttoning top that would be helpful.
Following this your breathing will be measured by a soft neoprene facemask and mouthpiece attached to the CPET machine. Once you are ready, you will be assisted onto the stationary bicycle which can be electronically adjusted to your height. Your resting breathing will then be assessed. You will then be required to exercise whilst breathing through the facemask / mouthpiece. The exercise will begin very easy, and become progressively harder. You will be encouraged to continue for as long as you can. The test will probably last for fifteen minutes with the exercise component lasting for 5-12 minutes depending on your level of fitness.
When you indicate that you want to stop, the exercise will rapidly become very easy again so that you can ease down. Measurements will continue to be taken until they have returned to normal. On occasions, it may be necessary to stop the test earlier than you feel you need, if all the important information has been acquired. Equally, if you feel unwell or there are changes on your heart tracings the physiologist/doctor may decide to stop the test.
If you having the test as part of your pre-operative assessment visit you will then have the results and their meaning discussed with you by the anaesthetic doctor in clinic.