8/10/2019 Poster Biotelemetry - HL7

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Celso Figueiredo

Paulo Mendes

niversity of Minho

hool of Engineering

epartment of Industrial Electronics

Biotelemetry – HL7

This project attempts the creation of client and server applications for real time communication of a biomedical signal, using a standardized protocolfor the syntax of medical messages, the HL7 (Health Level 7). HL7 is an application layer protocol whose primary goal is to provide globalspecifications for the exchange of data between healthcare computer applications, altering the actual scene of local applications in each healthcareestablishment.

The language used for the application programming was the “G” language, which is the graphical language of the LabView software of NationalInstruments.

The created client application allows the user to send a message containing a waveform (like an ECG) in its text to a remote computer, using theTCP/IP protocol. The user can adjust parameters such as the sampling frequency and the number of samples per message. The server application hasthe ability to parse the received message and to extract the waveform allowing graphic visualization on real time.

Summary

HL7 stands for “Health Level 7”. The “Level 7” designation refers to the highestlayer of the Open Systems Interconnection (OSI) model of the InternationalOrganization for Standardization (ISO) as the HL7 Standard is primarily focusedon the issues that occur within the seventh (or application) level. These are thedefinitions of the data to be exchanged, the timing of the exchanges, and thecommunication of certain application-specific errors between the applications.

The Standard currently addresses the interfaces among various systems thatsend or receive patient admissions/registration, discharge or transfer (ADT)data, queries, resource and patient scheduling, orders, results, clinicalobservations, billing, master file update information, medical records,scheduling, patient referral, and patient care.

It does not try to assume a particular architecture with respect to the placement

of data within applications but is designed to support a central patient caresystem as well as a more distributed environment where data resides indepartmental systems. Instead, HL7 serves as a way for inherently disparateapplications and data architectures operating in a heterogeneous systemenvironment to communicate with each other. However, HL7 does not currentlyprovide the interfaces definition for real time data communication in betweenmedical devices like ECG or EEG and the control unit.

The Health Level 7 Protocol Implementation - Block Diagram

Results and Conclusions

Real time reception of a ECG signal bythe server application

The biomedical signal and additional information were successfully transmitted atdifferent sampling frequencies, beyond the 2000 Hz frequency, which is therecommended sampling rate for a high-resolution ECG. This results assure thefunctionality of the created application.

The use of a graphical programming language has brought many advantages overthe text based languages, given the possibility of creating an application in a block

diagram display.

This project has shown a gap concerning the specifications of the HL7 protocol, inreal-time data communication. This impediment has been overcome by sendingmessages at regular intervals, which are determined by the sampling frequency andthe number of samples per message. The server application has the ability ofdecoding messages right after their reception, allowing graphical visualization of thewaveform on real time.

Biomedical

Signal

Server ApplicationPatient and Institutional Data

HL7 MessageReception via TCP/IP

HL7 MessageParsing

InformationExtraction

Client ApplicationSampling Frequency and

Number of Samples

Patient and

Institutional Data

Acquisition ofBiomedical Signal

HL7 MessageEncoding

Shipment of the HL7Message via TCP/IP

Signal

Patient

DataAcquisition Client Application

HL7

Message

TCP/IP Server Application

Implementation - Illustration

HL7 Message

ExtractedWaveform