Plain version: Part A pays the hospital's bill for an inpatient stay (a semi-private room, meals, general nursing), not the doctors' bills. The surgeon's and other physicians' charges fall under Part B, which generally pays 80% of the Medicare-approved amount.
Benefit period: it starts when the beneficiary first receives inpatient hospital or skilled nursing facility care and ends once the person has gone at least 60 consecutive days without inpatient care in either setting. It is not a calendar year, and discharge alone does not end it. Example: home on May 1 and readmitted on June 10 (40 days), so it is the same benefit period and no new deductible.
Hospital deductible: the CDI outline calls it the "hospital admission annual deductible." Under current rules (42 CFR §409.82) the deductible is charged once per benefit period, at a dollar amount set for each calendar year, so a person with two benefit periods in one year can pay it twice.
Long stays within one benefit period:
Days 1–60: no daily charge once the deductible is paid.
Days 61–90: daily coinsurance of one-fourth of the inpatient deductible.
Lifetime reserve days: 60 extra days for life, used after day 90, with daily coinsurance of one-half of the deductible. The 90 regular days renew with each benefit period; reserve days, once used, never come back.
When the reserve days are exhausted, Part A stops paying after day 90 and there is no out-of-pocket maximum: the person pays all costs unless supplemental coverage applies.
Home health care and hospice: the outline says these may be covered following a hospitalization. Under current rules neither requires a prior hospital stay.
Home health: the person must be homebound, under a doctor's or allowed practitioner's plan of care, need intermittent skilled services and use a Medicare-approved agency. Care that is only custodial does not qualify.
Hospice: requires Part A, certification of terminal illness with a life expectancy of six months or less, choosing comfort care instead of curative care, and a signed election statement.
Mental health: inpatient care in a freestanding psychiatric hospital has a 190-day lifetime maximum. It does not renew with a new benefit period, and Medicare.gov says it does not apply to a psychiatric unit within an acute care hospital.