After having gone through the descriptive checklists for ventilatory, gas exchange and circulatory limitations the reason(s) for a patient’s exercise limitation, if any, should be reasonably clear. However, one of the first questions that should be asked when reading an exercise test is what was the purpose of the test? Maximum safe exercise capacity for Pulmonary Rehab? Rule in/rule out exercise-induced bronchospasm? Pre-operative assessment? Dyspnea of uncertain etiology? What is the primary limitation to exercise (pulmonary or cardiac)? Is deconditioning suspected? The interpretation and summary should address these concerns.

I would like to re-emphasize the importance of the descriptive part of CPET interpretation. At the very least consider it to be a checklist that should always be reviewed even when you think you know what the final interpretation is going to be. After gas exchange, the next step in the flow of gases is circulation. The descriptive elements for assessing circulation are: What was the maximum heart rate?

I would like to re-iterate the importance of the descriptive part of CPET interpretation. At the very least consider it to be a checklist that should always be reviewed even when you think you know what the final interpretation is going to be. After ventilation, the next step in the flow of gases is gas exchange. The descriptive elements for assessing gas exchange are: What was the maximum oxygen consumption (VO2)?

I’ve always found interpreting CPET tests to be one of the more interesting (and enjoyable) things I’ve done. Interpreting a CPET test is both more difficult and easier than interpreting regular PFTs. More difficult because there are a lot more parameters involved and easier because determining test adequacy and the primary cause(s) of an exercise limitation tends to be clearer. I’ve found that you have to go back to basic physiology whenever you interpret CPETs and that always boils down to the flow of oxygen and carbon dioxide.