A MEDICAL INFORMATION CONCENTRATOR

Acquisition Biosignals Module for a Mobile Telemedicine System

Ediana Sutjiredjeki

Department of Electrical Engineering, Politeknik Negeri Bandung, Desa Ciwaruga, Bandung, Indonesia

Kastam Astami, Soegijardjo Soegijoko, Tati R. Mengko, Suhartono Tjondronegoro

School of Electrical Engineering and Informatics, Institut Teknologi Bandung, Jl. Ganesha 10,Bandung, Indonesia

Keywords: Interface array, Concentrator, Low-cost medical instrumentation, Mobile telemedicine system.

Abstract: This paper describes the development of medical information concentrator to be used for a telemedicine unit

in a mobile telemedicine system. The concentrator contains of an interface array which function to obtain

biosignals coming from several medical instruments, such as ECG monitor, NIBP device, etc. The number

of medical instruments connected to the concentrator can vary, though there must be a swap between the

user’s requirement and the design complexity to optimize the design implementation. This concentrator

provides connection of low-priced medical instruments which previously are incapable of directly link up to

the necessary computer in a telemedicine unit. Hence, the cost for building a mobile telemedicine can be

more economically. Comprehensively test of the concentrator has been conducted in a whole mobile

telemedicine system. Results show recorded biosignals can be displayed by parts or collected beforehand as

a medical record which may be sent to the doctor who stays alert in the hospital as the base unit.

1 INTRODUCTION

Community healthcare services in rural areas are

often impeded by the scarcity in transportation

infrastructure, inadequate service facilities,

insufficient number of medical experts, and limited

availability of communication means. To alleviate

these problems, a mobile telemedicine system is

believed to be an alternative solution (Martinez

et.al., 2004) (Satyamurthy, 2007). Unfortunately, to

extend the system will involve high-priced

investment to procure medical devices and

supporting equipments both hardware and software

(Norris, 2002).

This paper presents the development of a

medical information concentrator as a module to

acquire various biosignals in the telemedicine unit of

a mobile telemedicine system. The medical

information concentrator is an interface array for

various medical instruments used within a mobile

telemedicine system, such as an ECG monitor,

NIBP, and oxygen saturation SpO2. For each of

medical instruments we have developed a dedicated

interface, since the medical instrument selected are

incapable of direct connectivity to the necessary

computer, also each of the devices must be operated

individually according to a previously decided set of

procedures. So, we apply a multiprotocol interface

within the concentrator.

In designing of the medical information

concentrator, the compatibility between hardware

and software is very important, and needs special

consideration. To cope with this, the hardware-

software co-design method is used on the design by

considering the complexity that the system has.

This concentrator provides different medical

instrument with relatively inexpensive may be

applied for building a mobile telemedicine system.

Therefore, it may reduce the venture to get hold of

medical devices. The rest of the paper is organized

as follows. In the section two, the method and the

implementation of the medical information

concentrator is explained. The test of the

concentrator that has been integrated into a mobile

telemedicine unit is also discussed in this section.

Finnaly, section three is a summary of the paper,

and it also presents the future works as the closing

remark.

Sutjiredjeki E., Astami K., Soegijoko S., R. Mengko T. and Tjondronegoro S. (2010).

A MEDICAL INFORMATION CONCENTRATOR - Acquisition Biosignals Module for A Mobile Telemedicine System.

In Proceedings of the Third International Conference on Biomedical Electronics and Devices, pages 59-63

DOI: 10.5220/0002697000590063

 SciTePress

2 METHOD AND

IMPLEMENTATION

For monitoring a patient in a mobile telemedicine

system we need the measurements of biosignals,

including vital sign for instance ECG signal, blood

pressure, etc. (Jung et al., 2005). In general to

conduct the vital sign measurement, the mobile

telemedicine system applies medical devices which

already has a digital output for instance a continuous

one channel ECG, plus another biosignals, viz.

NIBP, SpO2, HR etc., in one package. Also, such

kind of equipment is costly. Usually, user has no

flexibility to choose a medical device that may suit

her/his ability. In addition, since the devices are

already in one compact package, it is difficult to be

expanded.

The medical information concentrator offers a

user to select and to use a low-cost individual

medical device to be linked up with a mobile

telemedicine system. The kind and the number of

medical instruments to be connected to the system

can be decided by the user according to her/his

financial ability, and a clinical situation.

Figure 1 depicts the block diagram of the

medical information concentrator. Each of medical

instrument is served by a dedicated interface that is

connected to the data buffer which stores measured

biosignal to be processed and transmitted to the

communication manager. The communication

manager is a module to manage data transaction and

communication within units in a mobile

telemedicine system.

Figure 1: Block diagram of the medical informational

concentrator.

Every instrument is operated and controlled by

the interface program controller that is a specific

software which has been developed during this

research.

The number of medical instruments may be

attached to the medical information concentrator is

flexible, depends on the user’s need to cover a

certain clinical situation. Although, there must be a

trade off between the user requirement and the

design complexity to optimize the realization. It is

suggested that the number of the medical instrument

is less than 16. If the number of medical devices is

bigger will degrade the performance of the whole

system dramatically.

Since all instruments have unique characteristics

according to its measured biosignal feature,

therefore the medical information concentrator is

developed in a modular way both hardware and

software. Each interface is designed specifically that

includes the data transfer rate, the format of the file,

and the assembler programming.

2.1 Design Implementation

In this research, the design of the medical interface

concentrator has been implemented to serve four

medical instruments, i.e. ECG monitor 12 leads,

NIBP, temperature, SpO2, and FHR monitor. The

block diagram of realized concentrator is shown in

Figure 2.

Figure 2: A realized medical information concentrator

block diagram.

Functionally, the medical information

concentrator can be divided into two sections, i.e.

interface array section, and the interface

concentrator section. The number of interface within

the interface array section depends on the number of

medical devices will be related to the system. In the

interface concentrator, the software is developed

using plug-in concept, to solve the problem of

flexible functionality in many applications (Stapic

et.al., 2008).

BIODEVICES 2010 - International Conference on Biomedical Electronics and Devices

Every instrument is supported by one interface

which is microcontroller based. Hence, the medical

information concentrator consists of four interfaces,

viz. ECG interface, BP and temperature interface,

SpO2 interface, and FHR interface.

2.1.1 ECG Interface

The ECG interface is specialized design for ECG 12

leads Cardimax 2111. As the core of the interface is

a microcontroller PIC16F87A from Microchip. The

interface has specification as following:

 Input: serial data format;

 Clock data transfer: 500 KHz;

 Output: 8-bit parallel data format;

 Data transfer rate: 500 Kbit/second;

 Power supply: 5.3 volts.

2.1.2 BP and Temperature Interface

The BP interface is designed to a universal interface

that means the interface can be connected to any

digital blood pressure without regarding the product

manufacture (Sutjiredjeki and Soegijoko, 2006). The

microcontroller PIC16F87A from Microchip is still

used as the core of the interface. The temperature

interface is designed to be integrated with the BP

interface by using A/D converter within the

microcontroller. The specification of the interface is

as following:

 Programmable;

 Range of measurement: (0 – 280) mmHg;

 Accuracy: ± 3 mmHg;

 Power supply: 5 volts.

2.1.3 SpO2 Interface

The core of SpO2 interface is a microcontroller

ATMega8 from ATMEL. It is specialized design for

common oximeter, and the interface has

specification as following:

 Range of measurement: (0 – 100)%;

 Resolution: 8 bit;

 Output: 8-bit parallel data format.

2.1.4 FHR Interface

To simplify the design, we used a sound card as the

FHR interface. The interface connects an

inexpensive FHR doppler monitor to a PC. The

range of measurement is for typical ultrasonic

frequency of 2 Mhz.

2.1.5 Biosignals Display on the Concentrator

To prevent a conflict between the various medical

instruments which may cause a reading error, each

time only one instrument is allowed to detect a

biosignal according to its function.

The measured vital signs can be displayed by

parts or collected and presented as a medical record

which can be sent to the doctor in the hospital or

health centre. An example of displays on the

medical information concentrator is showed in

Figure 3. This figure describes the result of BP

measurement, temperature, and oxygen saturation

SpO2. In addition, the patient’s data demographic is

also included in the medical record.

Figure 3: Example of measured vital signs display on the

medical information concentrator.

If the biosignals are aimed to display partly or

individually, it can be done as illustrated in Figure 4.

Figure 4: Recorded ECG biosignal from lead V4.

2.2 Test Results

The medical information concentrator is integrated

into a mobile telemedicine unit of a mobile

telemedicine system. Figure 5 depicts the block

diagram of the mobile telemedicine unit. This unit

is located at a patient’s site, and comprises of the

following:

 Medical instruments: ECG, NIBP, SpO2, FHR,

and thermometer;

 Medical information concentrator;

 Data processing unit;

A MEDICAL INFORMATION CONCENTRATOR - Acquisition Biosignals Module for A Mobile Telemedicine System

 Communication manager module;

 Communication devices: GSM/GPRS and

CDMA.

Figure 5: A mobile telemedicine unit block diagram.

The mobile telemedicine unit is realized in the

form of a portable telemedicine unit which can be

easily carried and placed in an ambulance or a

remote community healthcare centre (Sutjiredjeki

et.al., 2008). The unit is equipped with a Core 2

Duo CPU, 1 GB memory, and 120 GB hard disk. All

components are placed in a water-proof case which

also protects it from impact and vibration as shown

in Figure 6.

By having the medical information concentrator

inside, the portable telemedicine unit is able to

acquire a number of vital signs coming from various

inexpensive medical devices which formerly have

no links up to the computer. These signals are

directed into the computer via a standard RS232.

In the computer, the measured biosignals are

processed to find the parameter values and

displayed. Figures 7 describes the recorded

biosignals using the medical information

concentrator that has been realized.

As illustrated in Figure 7, all the measured vital

signs, i.e. 12 leads ECG, NIBP (systolic and

diastolic values), SpO2, HR, temperature, and

patient’s data can be exhibited at once.

Figure 6: A portable telemedicine unit.

Figure 7: Recorded biosignals as a result of the medical

information concentrator.

Currently, the mobile telemedicine system

included the medical information concentrator is

operated at local general hospital, RSUD Syamsudin

in Sukabumi, West Java. The system is applied for

recording and reporting patient’s medical record,

and teleconsultation. The portable telemedicine unit

is placed in a moving ambulance. The recorded

biosignals from the ambulance is transmitted via

multi communication links, viz. GSM/GPRS and

CDMA to the base unit which is located in the

hospital. In addition, the tests also have been

conducted in three community health centres in

Sukabumi, i.e. Parungkuda, Cikembar, and Surade.

Most of times, the system is used for

teleconsultation in particular.

Based on the user evaluation, the acquired

biosignals from the medical information

concentrator are clear, and they can be applied for

supporting patient’s diagnose. Specially, for health

centres in a rural area the mobile telemedicine

system has been very demanding to improve

healthcare services.

3 CLOSING REMARKS

The development of a medical information

concentrator has been presented. The concentrator

is applied to acquire biosignals coming from several

medical devices that works individually. By

providing the concentrator in the mobile

telemedicine unit leads to low-priced medical

instruments may be connected into a mobile

telemedicine system. As a result, the cost of

investment on medical instruments for building a

mobile telemedicine system may be reduced.

At present each one of medical instruments is

provided with one dedicated interface by using

BIODEVICES 2010 - International Conference on Biomedical Electronics and Devices

individual microcontroller. For future works, the

interface array need to be redesigned and

implemented in a single board in order to further

reduce the size and the cost. Plug and play

approach should also be considered to improve

flexible functionality of the concentrator, so the

system may be up-gradeable.

ACKNOWLEDGEMENTS

The authors would like to thank Engineers at System

Application Laboratory of Microelectronics Centre ITB

for their support, and Biomedical Engineering Research

Group ITB. We also very grateful to the Director and

staffs of RSUD Syamsudin Sukabumi, for their

cooperation while conducting this research.

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A MEDICAL INFORMATION CONCENTRATOR - Acquisition Biosignals Module for A Mobile Telemedicine System