As part of the v2-to-FHIR project we are mapping commonly used fields in key v2 messages to FHIR resources so that messages can be transformed into bundle of FHIR resources. PD1-7 is the Living Will Code field but there is no cognate existing data element in FHIR. We suggest that a standard extension to Patient be created to allow exchange of this concept. 

We suggest a CodeableConcept value using value set http://terminology.hl7.org/CodeSystem/v2-0315 with a binding other than Required (as table 0315 is user defined and the v2 values are suggestions only).

The v2 description can be reused as part of the extension narrative:

This extension indicates whether or not the patient has a living will and, if so, whether a copy of the living will is on file at the healthcare facility.  If the patient does not have a living will, the value of this field indicates whether the patient was provided information on living wills.