The A17 is used when it is decided that two patients will exchange beds. The patient ID and visit data are repeated for the two patients changing places. See Section 3.5.1, "Swapping a patient" for a discussion of issues related to implementing this trigger event.
ADT ADT Message Chapter
MSH Message Header 2
EVN Event Type 3
PID Patient (1) Identification 3
[PD1] Additional Demographics 3
PV1 Patient (1) Visit 3
[ PV2 ] Patient (1) Visit - Additional Info. 3
[ { DB1 } ] Disability Information 3
[ { OBX } ] Observation/Result (1) 7
PID Patient (2) Identification 3
[PD1] Additional Demographics 3
PV1 Patient (2) Visit 3
[ PV2 ] Patient (2) Visit - Additional Info. 3
[ { OBX } ] Observation/Result (2) 7
ACK General Acknowledgment Chapter
MSH Message Header 2
MSA Message Acknowledgment 2
[ ERR ] Error 2