Life / Finding medical oxygen, I live in Warsaw [2]

I need to find a source of medical oxygen. I live in Warsaw. I have a prescription for it from a polish doctor here but she was doubtful that I would be able to find the necessary equipment in Warsaw and I have no idea where to look. Anyone have any ideas? Ideally I would just rent an oxygen concentrator because I'm only in Poland until this summer, but I know almost zero medical vocabulary in Polish.

Life / what is a pedialyte alternative in Poland? [5]

My child is sick and I need to buy a rehydration solution. Something like Pedialyte sold in the United States. Does anyone know what that would be called in Poland?