1. Converting HL7v2.6 to FHIR
Mattes Rhein1, Stefan Schlichting2, Josef Ingenerf3
1Medizinische Informatik, Universität zu Lübeck
2Drägerwerk AG, Lübeck; 3Institut für Medizinische Informatik, Universität zu Lübeck
Motivation
Within the scope of medical messaging there is a diversity of various medical messaging standards and occasionally it is needed to convert from on standard to another. In this work converting PCD-01 Message to a FHIR conform resource is shown. FHIR aims to solve the problem of diversity by defining a framework for extending and adapting the existing resources. PCD is defined by the “Integrating the Healthcare Enterprise initiative”. It deals with use cases in which at least one participant is a controlled patient-centric point-of-care medical device that aims to communicate with, at least, one other participant like a medical device or an information system [1]. PCD-01 is used to transmit patient care device data between systems. The PCD-01 message is written in HL7v2.6 syntax. HL7v2 is a messaging standard which allows the exchange of clinical data between systems. It is designed to support a central patient care system as well as a more distributed environment where data resides in departmental systems and is arguably the most implemented medical messaging standard worldwide [2].
In Figure 1 the conceptual idea of the project is shown. The goal is to receive a PCD-01 message from the company intern network or a medical device and convert it to a FHIR conform resource, which is than written on a FHIR server and available for further processing.
The server on which the converter writes the resource is a Furore Spark
Server. It is written in C# and is build for FHIR DSTU 2 [3]. The server and the converter are running on the same Windows Server 2012 R2 system which is operating in a virtual machine with an Intel Xeon E CPU with 2.5GHz and 16GB RAM. The converter is written in Java 1.8u66 and developed with Eclipse Mars.
Table 1 describes the mapping of the PCD segments to the FHIR resources.
While the PID segments gets written completely in the patient resource,
the OBR (observation request) and the OBX(observation result) are mapped
depending on their content.
Fig. 2: Used PID Segment from the PCD Message, with the Patient Identifier, Name and an undefined Gender
Medical Device
PCD-01 Message
Converter
FHIR Ressource
FHIR Server
Fig. 1: Conceptual Idea: PCD-01 Message is send from the Medical Device to the Converter and there transformed to a FHIR Resource. Subsequently, the resource is send to the FHIR Server
Fig. 3: To the PID Segment, shown in Fig. 2 corresponding FHIR resource with the Patient Identifier, Name and the Gender converted from Undefined to “other”
Methods
The PCD-01 message contains, besides the device data, information about the patient which the device is taking care of. The information about the patient is stored in the PID segment of the message which is shown as a converting example. The implemented converter receives a PCD-01 message from the network. Then, the converter reads the message and writes it in a txt file. After the txt file is written the converter reads this txt file and converts the content to a FHIR resource. Before writing the resource, the converter checks if the resource is already written on the server. If so the converter just updates the resource with the new values, if not the converter creates a new resource with the given values.
In Table 1 it is simplistically shown how the content of the message is mapped to the destined FHIR resource. Figure 2 depicts the used PID Segment from the PCD-01 Message and Figure 3 the converted and written FHIR resource.
Evaluation
Since FHIR is still under development it is not completely bug free. While implementing a major bug was found, which doesn’t allow to search for a device component, that is a part of a medical device, on the basis of its identifier. Since FHIR is still in development it is assumable that this bug is going to be fixed.
The given PCD message contained 1 MSH, 1 PID, 1 OBR and 28 OBX segments. The converter needs 30,4 seconds to read the txt file, convert the content, decide if the converted resource was written before and then write or update the resources.
Results and Perspective
The final resource is shown in Figure 2. This result was achieved with the
programmed converter. The next step should be, to implement the converting of the FHIR resource to a PCD-01 message and sending the
message to a medical device or an administrative system. Additionally, the converter needs further optimization for faster converting. If the discovered bug is fixed in the framework, the converter could be running faster when the method for finding already existing device components is changed in a way, that it can search with the identifier.
PCD Segment
FHIR Resource
MSH
MessageHeader
PID
Patient
OBR
Observation, Device, DeviceComponent, DeviceMetric (depending on the segment part)
OBX
Acknowledgment
I would like to express my gratitude to Stefan Schlichting for his trust and for giving me the chance to work on this project.
Tab. 1: Mapping overview for PCD to FHIR
Literatur: [1] IHE, IHE Patient Care Device(PCD) Technical Framework Volume 1 IHE PCD TF-1 Profiles, 2014.
[2] HL7, “HL7 version 2 productsuite. ”
[3] Furore, “Spark fhir server.”
Janurary 2016.