Вроде в ИТ это не относится)

Похоже, что Discharge/end visit - это Выписка и/или Завершение приема

http://hl7.cgmpolska.pl/HL7/ch300005.htm
3.2.3 ADT/ACK - discharge/end visit (event A03)
An A03 event signals the end of a patient’s stay in a healthcare facility. It signals that the patient’s status has changed to "discharged" and that a discharge date has been recorded. The patient is no longer in the facility.

For non-admitted patients, an A03 event signals the end of a patient’s visit to a healthcare facility. It could be used to signal the end of a visit for a one-time or recurring outpatient who is not assigned to a bed.

http://hl7.cgmpolska.pl/HL7/ch300015.htm
The A13 event is sent when an A03 (discharge/end visit) event is canceled, either because of erroneous entry of the A03 event or because of a decision not to discharge or end the visit of the patient after all.

"An A03 event signals the end of a patient’s stay in a healthcare facility... For non-admitted patients, an A03 event signals the end of a patient’s visit to a healthcare facility. It could be used to signal the end of a visit for a one-time or recurring outpatient who is not assigned to a bed".

https://www.google.com.ua/url?sa=t&rct=j&q=&esrc=s&source=we...

Если пациент был помещён в больницу, то событие А03 (A03 event) означает выписку. Если же пациент не был помещён в больницу, но ему предписывалось регулярно туда приходить (на осмотр, обследование, сдачу анализов), тогда событие А03 - это последний визит.

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Note added at 18 час (2017-09-08 08:23:20 GMT)
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Соответственно:
discharge - выписка
end visit - последний визит