Effective emergency mobile telemedicine and home monitoring solutions are the thrust areas discussed in this study. Ambulances, Rural Health Centers (RHC) or other remote health location such as ships navigating in wide seas are common examples of possible emergency sites, while critical care telemetry and telemedicine home follow-ups are important issues of telemonitoring. In order to support the various growing application areas explained above a combined real-time store and forward facility that consists of a base unit and a telemedicine (mobile) unit is used. This integrated system can be used when handling emergency cases in ambulances, RHC or ships by using a mobile telemedicine unit at the emergency site and a base unit at the hospital-expert’s site. This enhances intensive health care provision by giving a mobile base unit to the ICU doctor while the telemedicine unit remains at the ICU patient site and enables home telemonitoring, by installing the telemedicine unit at the patient’s home while the base unit remains at the physician’s office or hospital. The system allows the transmission of vital bio signals (ECG, SP02, NIBP, IBP, Temperature) and still images of the patient. The transmission is performed through GSM mobile telecommunication network, through satellite links (where GSM is not available) or through Plain Old Telephony Systems (POTS) where available. Using this device a specialist doctor can telematically “move” to the patient’s site and instruct unspecialized personnel when handling an emergency or telemonitoring case.
Mobile telemedicine is defined as the delivery of health care and sharing of medical knowledge over a distance using telecommunication means. Thus, the aim of telemedicine is to provide expert-based health care to understaffed remote sites and to provide advanced emergency care through modern telecommunication and information technologies. This integrated system can be used when handling emergency cases in ambulances, rural health centers (RHC) or ships by using a mobile telemedicine unit at the emergency site and a base unit at the hospital-expert’s site. This enhances intensive health care provision by giving a mobile base unit to the ICU doctor while the telemedicine unit remains at the ICU patient site and enables home telemonitoring, by installing the telemedicine unit at the patient’s home while the base unit remains at the physician’s office or hospital. The system allows the transmission of vital bio signals and still images of the patient. The transmission is performed through GSM mobile telecommunication network, through satellite links (where GSM is not available) or through Plain Old Telephony Systems (POTS) where available. Using this device a specialist doctor can telematically “move” to the patient’s site and instruct unspecialized personnel when handling an emergency or telemonitoring case. Today, mobile telemedicine systems are supported by State of the Art Technologies like Interactive video, high resolution monitors, high speed computer networks and switching systems, and telecommunications superhighways including fiber optics, satellites and cellular telephony
Critical care telemetry is another case of handling emergency situations. The main point is to monitor continuously intensive care units’ (ICU) patients at a hospital and at the same time to display all telemetry information to the competent doctors anywhere, anytime. In this pattern, the responsible doctor can be informed about the patient’s condition at a 24-hour basis and provide vital consulting even if he’s not physically present. This is feasible through advanced telecommunications means or in other words via telemedicine. Another important telemedicine application area is home monitoring.
TRENDS AND NEEDS OF MOBILE TELEMEDICINE SYSTEMS
Telemedicine system is able to handle different critical problems in the area of distant medication like:
- Emergency health care provision in ambulances, Rural Hospital Centers (or any other remote located health center) and navigating Ships
- Intensive care patients monitoring
- Home telecare, especially for patients suffering from chronic or permanent diseases (like heart disease).
Mobile telemedicine is a “Multi-purpose” system consisting of two major parts: a) Telemedicine unit and b) Base unit or doctor’s unit
Figure 1 describes the overall system architecture. The Telemedicine unit is located at the patient’s site, whereas the base unit (or doctor’s unit) is located at the place where the signals and images of the patient are sent and monitored. The Telemedicine device is responsible to collect data (bio signals and images) from the patient and automatically transmit them to the base unit. The base unit is comprised of a set of user-friendly software modules, which can receive data from the Telemedicine device, transmit information back to it and store important data in a local database. The system has several different applications, according to the current healthcare provision nature and needs.
Before the system’s technical implementation, an overview of the current trends and needs in the aforementioned Telemedicine applications was made, so that the different requirements are taken into account during design and development, thus ensuring maximum applicability and usability of the final system in distinct environments and situations. Table provides the results of this overview, which was done towards a predefined list of criteria that usually influence a Telemedicine application implementation (cost, portability, autonomy, weight and size of Telemedicine device, type and quality of PC and camera, communication means used).
SYSTEM DESIGN AND TECHNICAL IMPLEMENTATION
As mentioned above, the system consists of two separate modules (Figure 1): a) the unit located at the patient’s site called “Telemedicine unit” and b) the unit located at doctor’s site called “Base Unit”. The doctor might be using the system either in an emergency case or when monitoring a patient from a remote place. The design and implementation of the system was based on a detailed user requirements analysis, as well as the corresponding system functional specifications. The Telemedicine unit is responsible for collecting and transmitting bio signals and still images of the patients from the incident place to the doctor’s location while the doctor’s unit is responsible for receiving and displaying incoming data.
The information flow between the two sites can be seen in Figure 2. The software design and implementation follows the client server model. The Telemedicine unit site is the client while the Base unit site is the server. Communication between the two parts is achieved using TCP/IP as network protocol, which ensures safe data.
The Telemedicine unit mainly consists of four modules, the bio signal acquisition module, which is responsible for bio signals acquisition, a digital camera responsible for image capturing, a processing unit, which is basically a Personal Computer, and a communication module (GSM, Satellite or POTS modem).
The bio signals collected by the patient (and then transmitted to the Base Unit) are:
- Oxygen Saturation (Sp02).
- Heart Rate (HR).
- Non-Invasive Blood Pressure (NIBP).
- Invasive blood Pressure (IP).
- Temperature (Temp)
- Respiration (Resp)
Data interchange is done using the TCP/IP network protocol, which allows operation over several communication means. The PC is equipped with the proper modem for each case, i.e. GSM, Satellite or POTS. The design was done for standard Hayes modems. Several modems types were used for testing: GSM 900 modem-for GSM NW POTS modem 56K-for telephone nw
The Telemedicine unit is also responsible for the collection and transmission of images of the patient to the base unit,a digital camera responsible for image capturing. Several cameras were used while testing the system:
- ZOOM digital camera connected to the PC’s parallel port model 1585.
- ZOOM digital camera connected to the PC’s usb port model 1595.
- Creative camera connected to usb .
The control of the Telemedicine unit is fully automatic. The only thing the telemedicine unit user has to do is connect the bio signal monitor to the patient and turn on the PC. The PC then performs the connection to the base unit automatically. Although the base unit basically controls the overall system operation, the Telemedicine unit user can also execute a number of commands. This option is useful when the system is used in a distance health center or in a ship and a conversation between the two sites takes place.
BASE UNIT (OR DOCTOR’S UNIT)
The base unit mainly consists of a dedicated PC equipped with a modem, which is responsible for data interchange. In addition the base unit pc is responsible for displaying incoming signals from the Telemedicine unit. When an expert doctor uses the base unit located outside the hospital area, a portable PC equipped with a GSM modem or a desktop PC equipped with a POTS modem is used. When the base unit is located in the hospital, a desktop PC connected to the Hospital Information Network (HIS) equipped with a POTS modem can additionally be used; the expert doctor uses it as a processing terminal.
The user is able to monitor the connection with a client (telemedicine unit), send commands to the telemedicine unit such as the operation mode (bio signals or images) Figure 4. In cases were the base station is connected to a Hospital LAN the user can choose to which of the telemedicine units to connect to, as shown in Figure 5 the user of the base unit is able to choose and connect to anyone of the telemedicine units connected on the network.
Figure 6 presents a typical bio signal-receiving window (continuous operation). When the system operates on still image mode, the doctor can draw-annotate on the image and send the annotations back to the Telemedicine unit. When operating on bio signal mode (Figure 6), the transmission of vital bio signals can be done in two ways, continuous way or store and forward way, depending on the ECG waveform channels which are transmitted and the telecommunication channel data transfer rate. In continuous operation, the Base Unit user can send commands to the Telemedicine Unit monitor, such as lead change or blood pressure determination; the user can also pause incoming ECG, move it forward or backward and perform some measurements on the waveform.
Images captured by the Telemedicine unit’s camera have resolution 320 * 240 pixel and are compressed using the JPEG compression algorithm; the resulting data set is approximately 5-6 KB depending on the compression rate used for the JPEG algorithm .
Two major portable monitors firms were used in this study, which can provide three to twelve leads waveform of ECG and numeric data from other bio signals (HR, Sp02, NIBP, IP, Temp). The first of the monitors used, CRITIKON DfNAMAP PLUS Monitor has a digital output of a continuous one channel ECG plus bio signals such as NIBP, Sp02, HR, IP and data concerning monitor alarms etc.
The second of the monitors used, PROTOCOL Propaq Monitor has a digital output of a continuous one (model lxx) or two (model 2xx) channels ECG, plus another waveform such as Sp02 or Co2; plus bio signals trends such as NIBP, Sp02, HR, IP and data concerning monitor alarms etc. All above information can be transferred using up to 2400 BPS for one channel ECG, up to 4400 for two channels of ECG or up to 5400 for two channels of ECG plus another waveform (Sp02 or Co2). For this reason, the continuous transmission of signals from this monitor can be done when using GSM and POTS but only one lead ECG when using 2400 BPS satellite links.
COMPRESSION & ENCRYPTION
In order to decrease data size, a lossless ECG compression algorithm based on Huffman coding algorithm is implemented in the system and can be applied on transmitted signals, when needed by the Base Unit user.
An encryption algorithm was implemented in the system and can be used when needed by the hospital unit user. The system can encrypt interchanged data using the Blowfish cipher algorithm . The use of encryption is optional and can be selected by the user; authentication and connection between base and telemedicine units is done using encrypted messages.
The system has been clinically tested through installation and extended validation of the system in a number of distinct demonstration sites across Europe. More specifically the use of the developed system in emergency cases handling in ambulances has been extensively demonstrated in Greece, Cyprus, Italy and Sweden. The initial demonstration of the system for ambulance emergency cases was performed on 100 emergency cases for each hospital.
The use of system in Rural Health Centers has been tested extensively tested in Cyprus. The use of the system in a Ship is currently being used in Athens Greece and finally the use in home telecare is also being tested in Athens Greece. The system is currently installed and being used in two different countries, Greece and Cyprus.
Current technology has severe inadequacies that need addressing. Firstly the capability of current system is limited by the bandwidth availability of the data transmission tools like GSM. Future work would concentrate on improving the message transmission making the system response fast. This would enhance the current technology to reach people at a much larger scale.
We have developed a medical device for telemedicine applications. The device uses GSM mobile telephony links, Satellite links or POTS links and allows the collection and transmission of vital bio signals, still images of the patient and bi-directional telepointing capability. The advance man-machine interface enhances the system functionality by allowing the users to operate in hands-free mode while receiving data and communicating with specialists. The final system is currently installed and used in two different countries Greece and Cyprus. Results from the system use are very promising thus encouraging us to continue the development and improvement of the system in order to be able to cover additional future needs.