Who has the authority to consent to medical treatment for an unconscious adult client without advance directives?

When an adult client is unable to consent due to incapacity and has no advance directive identifying a healthcare proxy, state law establishes a hierarchy of surrogate decision-makers. The typical order: spouse, adult children, parents, adult siblings, other relatives, close friends, court-appointed guardian. The exact order varies by state. The surrogate decision-maker is expected to apply 'substituted judgment' — making the decision the client would have made if able. In an emergency where consent cannot be obtained and delay would be life-threatening, 'emergency consent' (implied consent) allows necessary treatment to proceed. For non-emergency situations where surrogates cannot agree or are unavailable, courts may appoint a guardian. Healthcare facilities have ethics committees that consult on complex consent situations. The nurse documents the consent process carefully, including who consented, their relationship, and the basis for their authority.