1. Header
     CDA Participant (Body) (2.16.840.1.113883.3.1937.777.11.10.134)
    1. Entry
       CDA Device (2.16.840.1.113883.3.1937.777.11.10.129)
    2. Entry
       CDA PlayingEntity (2.16.840.1.113883.3.1937.777.11.10.128)