IHE Profiles

ITI-8 (Patient Identity Feed) IHE Profile

ITI-8 is the HL7v2 format of ITI-44. Both ITI-8 and ITI-44 performs same action (i.e) Sending Patient Identity Feed. Some HIE expects ITI-8 (HL7v2 format) format and some HIE expects ITI-44 (HL7v3 format).

EHR – HIE Communication:
ITI-8 Communication from EHR to HIE can happen in two ways:

  1. EHR can send data to HIE via VPN IP/PORT socket.
  2. EHR can send SOAP based webservice data. (In this case HL7 message will be bind within the SOAP request)

EHR – HIE USE CASE Relevance:
This ITI-8 message is a transaction between EHR to HIE.

  1. EHR is described here as Patient Identifier Cross-Reference Consumer.
  2.  HIE is described as Patient Identifier Cross-Reference Manager as well as Document Registry.
  3. Even though the working of  Patient Identifier Cross-Reference and Document Registry are not the same.

iti-8_message_specification

ITI-8 Document Registry:

  1. The Document Registry is an Actor that actually a software/Database.
  2. Meta-data of each registered document or patient record is maintained here. Note, that it maintains only meta-data (index of main data).
  3. The Document Registry responds to queries asked to it regarding documents meeting specific criteria.

What is Patient Identifier Cross Referencing (PIX) :

Patient identifier cross referencing also known as  (PIX) is a concept where patient identifier information (patient id) is transmitted from patient identifier source (EHR in our scenario) to the patient identifier cross reference manager (a.k.a PIX Manager)

What is PIX Manager:
The Patient Identifier Cross Reference Manager is called as PIX MANAGER.
It is a software that receives data from any patient identity source and gives the data to document registry for performing query operations.

iti_8-actors_definition

Actions performed in ITI – 8 :

The EHR will send the HL7 ADT messages to the HIE to do the following activities:

  1. ADT^A01 – Patient Admit Message
  2. ADT^A04 – Patient Registration Message
  3. ADT^A05 – Patient Pre-Admission Message
  4. ADT^A08 – Patient Update Message

iti-8_actions_performed

HIE don’t really needs to adhere to IHE profiles.

Why Adhering IHE Profiles is difficult:

Logical understanding of IHE profile with HL7 specs is difficult

A04 :

Is a “Patient Register” message (A04 event) .This message contains the information of patient as well as other information like next of kin, insurance or guarantor information as well.

A08 :

Whenever any important information related to the patient is updated then this will be communicated as A08 message (for eg: visit information of patient, name, date of birth, or any information related to the patient).

Scenario :1
consider this scenario.

Where a patient named zzzz is registered to a hospital and his details were sent to the HIE in the form of ADT A04 message.
Now, no demographics information of a patient zzzz is changed except his physical location upon which he was admitted. Like he is moved from Bed Number 305 to 405.

What Message to be sent for ITI-8:

In this case, it does not make sense to send this message as patient update (A08) as all the demographics fields are intact and same.
It is good to send an A02 message a Patient Transfer Message instead of Patient Update Message.

Why Sending A02 Makes Sense:

Sending A02 makes more sense. Because this message contains change in assigned patient location in PV1-3 segment. While the old patient location appears in PV1-6-(prior patient location) and other demographic changes will be same.

How HL7 Specs Differs:

As per HL7, when only patient location changes happens EHR sends a A02 event type. But if the location change and demographic change both happened, then EHR should send an A08.

 But never both the messages i.e both A08 and A02 shouldn’t be sent.

Reference : http://www.hl7.eu/refactored/ch03.html

Similarly, If the patient is going to a temporary location (such as the O/R, XRAY, LIMBO, the HALLWAY) it is recommended that the A09 (patient departing tracking) and A10 (patient arriving tracking) events be used instead of A02.

But in the diagram provided above is IHE profiles suggested as per the document Vol2a there is no ADT A02 specified. Which makes this topic even more debatable.

Scenario 2:

Consider a scenario, where patient’s mother name is updated here patient’s mother is a Next of Kin, basically NK1 segment is changed. According to the above diagram, we have to send this as ADT^A31 message.

ADT^31 By Specification:

By the definition of ADT^A31 it is shown that it is “An update of any person information & the person need not be patient”. Which means it can be a patient as well. Now, to send the change of mother name, the EHR have the license to send either A31 or A08.

Reference : http://www.hl7.eu/refactored/ch03.html

HL7 Specs about A08:

“An A08 (update patient information) event should be sent and/or negotiated as necessary to provide for implementation and application specific needs.”

It is always advised to get right information from both EHR as well as HIE team to proceed further with ITI-8 profiles.

A01 :

The ADT A01 message will be used only for Inpatients. In other words this message is for ‘admitted patients only’. Not for clinic visits or outpatients.

A05 :

The ADT A05 is a pre-register message, if the patient is scheduled for an operation, then the operation theater, setup and post-operation bed setup all information will be sent in this message.

 

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