### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
My mother is on oxygen and has congestive heart failure.  Does people with 20% heart functioning usually have to go on oxygen or could there be other problems with her.  She can barely get around without getting out of breath.  Oxygen is the only thing that seems to help her.

### output:

Hello. Welcome to Chat Doctor, and thank you for your question. I carefully read your query. Supplemental oxygen always helps in congestive heart failure patients. Some of these patients need it with higher percentages of ejection fraction and some with lower. A congestive heart failure patient with a 20% function of the left ventricle is advised to be confined only to every-day duties and not various strains of a healthy heart or a slightly decreased heart function. A 20% functioning heart means that 80% of its content remains in the left ventricle (normal being 30-45%) in every cardiac cycle. This means that blood coming from the pulmonary circulation does not have space to empty, and all of this is interpreted as a raised pressure in this circulation. This produces fluid build up in lungs and difficulty to breath (dyspnea). Therefore, the lower the heart function percentage, the higher and the more often the need for supplemental oxygen. Besides oxygen, a good support to lowering the above-mentioned pulmonary circulation high pressure, are the diuretics, and in these figures, I would recommend a loop diuretic and a potassium-sparing diuretic to her therapy. No salt should be used in her diet, whatsoever, because it retains the water and further raises the pulmonary pressure. I hope I was helpful with my answer. Take care. Best regards, 