As you know, Original Medicare, Medicare Advantage and Med Sup plans do not cover all your Medicare Expenses. Hospitals are now using "Observation" instead of "Admitting" to the hospital at times. Observation is not covered by most plans.
Due to this you might want to look into "Gap" or "Indemnity" plans which offer lump sum payouts to help cover items that you might have to pay via co-pay, co-insurance and deductibles...all adding up to your Max Out of Pocket.
Keep in Mind:
1) Indemnity plans pay out no matter what. They do not care what other insurance you have in place Hospitals are now using “Observation” instead of admitting more often than not. Medicare does not usually pay for Observation…it only pays out for when you are “Admitted” to the hospital. Most Hospital Indemnity plans will pay out cash, in a lump sum, to help cover your Observation charges, which Medicare will not.
2) You can use the money paid out for WHATEVER you want...house payment, medical bills, auto payments, health insurance premiums.
3) Some plans offer Riders which help pay for ambulance (up to $250 on some Medicare Advantage plans), Chiropractic services (not covered on many plans), Skilled Nursing, Outpatient Surgery, Lump Sum Cancer, and Urgent Care...just to name a few.
Now is the time to purchase an Indemnity plan, not when you need it.
1/15/2020 UPDATE: Some Medicare plans for 2020 have decided to pay for Observation at their Emergency Room rate. This is good news!