A trust described in 42 U.S.C. 1396p(d)(4) is irrevocable if the terms of the trust prohibit the settlor from revoking it, whether or not the settlor's estate or the settlor's heirs are named as the remainder beneficiary or beneficiaries of the trust upon the settlor's death.
When certain trust is irrevocable
Ohio Rev. Code Ann. § 5804.18, under Chapter 5804 | Creation, Modification, Revocation, And Termination.
Ohio Rev. Code Ann. § 5804.18