42 CFR § 422.113(c)(2-3)

(2) The MA organization –

(i) Is financially responsible (consistent with Sec. 422.214) for post-stabilization care services obtained within or outside the MA organization that are pre-approved by a plan provider or other MA organization representative;

(ii) Is financially responsible for post-stabilization care services obtained within or outside the MA organization that are not pre-approved by a plan provider or other MA organization representative, but administered to maintain the enrollee’s stabilized condition within 1 hour of a request to the MA organization for pre-approval of further post-stabilization care services;

(iii) Is financially responsible for post-stabilization care services obtained within or outside the MA organization that are not pre-approved by a plan provider or other MA organization representative, but administered to maintain, improve, or resolve the enrollee’s stabilized condition if –

(A) The MA organization does not respond to a request for pre-approval within 1 hour;

(B) The MA organization cannot be contacted; or

(C) The MA organization representative and the treating physician cannot reach an agreement concerning the enrollee’s care and a plan physician is not available for consultation. In this situation, the MA organization must give the treating physician the opportunity to consult with a plan physician and the treating physician may continue with care of the patient until a plan physician is reached or one of the criteria in Sec. 422.113(c)(3) is met; and

(3) End of MA organization’s financial responsibility. The MA organization’s financial responsibility for post-stabilization care services it has not pre-approved end when –

(i) A plan physician with privileges at the treating hospital assumes responsibility for the enrollee’s care;

(ii) A plan physician assumes responsibility for the enrollee’s care through transfer;

(iii) An MA organization representative and the treating physician reach an agreement concerning the enrollee’s care; or

(iv) The enrollee is discharged.