shall communicate the response to the prescribing practitioner (as so defined by the Secretary) making the prior authorization request and to the supplier designated on the certificate of medical necessity. (V) A prior authorization approved under the process shall be deemed to constitute medical necessity for coverage and payment under this title but shall not eliminate the proof of delivery documentation requirement under section 424.57(c)(12) of title 42, Code of Federal Regulations. (VI) A supplier of home respiratory therapy shall not be required to provide such therapy if a prior authorization request under this subparagraph for such therapy has not been approved. (iii) Effect of prior authorization The approval of a prior authorization request under this subparagraph shall constitute a finding of medical necessity. The Secretary may not subject claims with such a prior authorization to pre- or post-payment audit for the purpose of determining medical necessity or improper payment reviews as they relate to documenting medical necessity. (iv) Implementation The Secretary may carry out this subparagraph through notice and comment rulemaking or by interim final rule with comment period. In establishing and implementing the process under this subparagraph, the Secretary shall consult with stakeholders through formal and informal mechanisms. (v) Home respiratory therapy defined For purposes of this subparagraph, the term home respiratory therapy means— (I) equipment, supplies, and services for home oxygen, home sleep, and mechanical ventilation