oxygen machine in Italy

I believe you're talking about a CPAP machine? Questions about those come up pretty regularly on the forum but mostly about bringing one's own. I can't remember anyone asking about renting one. Anyway, browse the forum for threads about these even if renting isn't the topic? Here are a couple of examples:

https://community.ricksteves.com/travel-forum/general-europe/trave-ling-with-a-cpap-machine

https://community.ricksteves.com/travel-forum/packing/travel-cpab-machines

I take my machine every year. As it is medical equipment, you carry it on board like a purse. The hardest problem is finding a pharmacy to buy the distilled water. In some places the only extra socket is across the room. but our hotel had an extension cord. My machine is the newer one too. Don't forget your adapter plug.

Regarding distilled water:

https://community.ricksteves.com/travel-forum/italy/cpap-machine-baa3ecd3-4754-42c5-9d3b-c40229d6b5ba

Are you referring to a CPAP machine for sleep apnea, or an oxygen concentrator for COPD, similar to the model shown on this website - http://www.inogen.com/resources/oxygen-therapy-treatment/oxygen-therapy-for-lung-disease/ .

I don't know if it's possible to rent one as I've never had occasion to check that. You might want to check with your Mom's Physician to see what h/she recommends.

This may help? Or perhaps they can direct you to someone who can

http://www.specialneedsatsea.com/about-us/frequently-asked-questions-faq/

I've taken my CPAP to Italy three times in 7 years, no problem. Hope yours is not a big one--I have upgraded my machine over the years specifically for smaller size for travel purposes. But even if it is big, it's not supposed to be counted as a carry-on. One caveat--DO NOT CHECK IT THROUGH!

What did the trick for me at security is a laminated badge/tag that hooked onto the carry bag for the machine that said 'Medical Equipment'. Just to be safe, I did have a letter from my sleep doctor verifying that, in fact, I was qualified to have this CPAP for my sleep apnea. Never had to produce it, however.

While these machines are still checked thoroughly at airports, they fly through security no problem.

I would not try to set up a rental--too many variables--but that's up to you.

My friend uses a cpap machine. According to him, you need physician approval to purchase one. If this a requirement in Italy then you may need to visit a doctor there.`

I wish the OP would come back and answer questions. I think she is probably talking about a true oxygen machine. A CPAP does not deliver oxygen, it uses controlled pressure to keep airways open.

""".....uses a oxygen machine at night for sleep apnea"""

It is a bit unclear just what she is looking for. An O2 generator or a CPAP ?

Hard to help someone find something when "what" it is, is unclear.