Final answer:
A 'patient surrogate' for medical decisions is best described by a health care proxy, which is usually part of a power of attorney document focusing on healthcare decisions. A living will can also outline a person's health care wishes, including appointing a health care proxy or including a DNR.
Step-by-step explanation:
“Patient surrogate” in the event the patient is unable to make decisions for themselves best describes a health care proxy. This is a legal document that appoints a specific person to make medical decisions on behalf of the patient if they are unable to speak for themselves. Among the options given, the power of attorney would be the instrument that could include the designation of a health care proxy, which is not just limited to financial matters but can also extend to health care decisions.
Another important document is a living will, where a person outlines their healthcare preferences, including potentially appointing a health care proxy or listing a Do Not Resuscitate (DNR) instruction. Both the living will and the power of attorney for health care play crucial roles in ensuring that a person's medical care preferences are respected in cases where they cannot voice their wishes due to being incapacitated or terminally ill.