Answer: Thank you for your question. You raise an excellent point. The truth is no one can clinically differentiate between the sound of them. It is really the rest of the clinical picture that helps us. It is often why we need imaging like a chest x-ray to help us. One can look at all the subtle cues like history of CHF or history of cough or fever etc. but ironically, patients with sepsis related to pneumonia actually need IV fluid yet would have crackles on exam, so you have identified the gap in the current medical directive. At the end of the day, use your best judgment and consider the entire clinical picture (does it sound like CHF or pneumonia based upon their clinical complaints) and treat accordingly.