Thanks for your question on Healthcare Magic. I can understand your concern. Breathlessness in patients with dialysis and active smoking can be due to fluid overload, pulmonary edema and COPD (chronic obstructive pulmonary disease). So better to get done chest x ray and PFT (pulmonary function test). If chest x ray is suggestive of pulmonary edema then she will need diuretics. If PFT is showing obstructive Airway defect then she will need inhaled bronchodilator and inhaled corticosteroids (ICS). In any case smoking cessation should be done first. About potassium level, if she is having low potassium level then banana should be given. Actually kidney patients are having high potassium level in the blood due to decreased urine output. But due to dialysis, some patients develop low potassium level. So in such patients, you should give banana to supplement potassium. Hope I have solved your query. I will be happy to help you further. Wishing good health to your grand mother. Thanks.