It is generally accepted that early and specialized pre-hospital patient treatment improves outcome in terms of mortality and morbidity, in emergency cases. The focus of this paper is to present the implementation and the evaluation of an ambulance located telemedicine system for pre-hospital patient treatment. The primary emphasis is on the vital sign transmission from the accident site or the moving ambulance to the consultation site, using the GSM mobile telephony network. There, the experts evaluate the patient data, decides about the treatment protocol and provide directions to the ambulance’s medical staff concerning on the patient handling until the arrival to the hospital.
A. Project Design and Equipment. Emergency units such as ambulances, patrol cars and firevehicles are participating in this project. The operations are controlled by a small-scale trauma dispatch center, located in the University Hospital of Rion, Greece. All units are equipped with Global Positioning System (GPS) devices , able to transmit, via GPRS modems, the vehicle’s current position to the dispatch center, for vehicle control and management. A “clever mechanism”, installed both on vehicles and on controller in traffic intersections, forces in an indirect manner the transition to a “green light” when the ambulance is in a direction towards the corresponding traffic lights and in an adjustable radius. This capability makes possible the road to be free of traffic in the moving direction of vehicle. Additionally, each ambulance is equipped with: •special medical devices to acquire vital signs, such as electrocardiogram (ECG), Blood Oxygen Saturation (SPO2), Non Invasive Blood Pressure (NiBP), Temperature (Temp), from patients and transmit them to the dispatch center using the GSMnetwork  – . The data can be collected on the field of accident or en route to the hospital (Fig. 1), •a wireless LAN (IEEE 802.11) to transmit patient video or still images acquired by a wireless camera, from the ambulances to the dispatch center. In the trauma dispatch center is installed: •a Geographic Information System (GIS)  based street network data set, which is managed by a computer. The GIS operator can observe the exactly location and movement characteristics of all vehicles, •a server hosting still images or video transmittedfrom the ambulances’ wireless cameras, •a server hosting vital signs transmitted from the ambulances. B. Telemedicine equipment and transmission. The core of the telemedicine system is a portable device collecting and transmitting vital signs. Within this project, a market analysis has been performed evaluating diverse market available vital signs devices constructed by various manufacturers. The final decision has been based in the following specifications and restrictions: •fit to the small free space inside the ambulance, •light and portable, •a compact construction tolerant both to the bad mechanical and electromagnetic conditions, •waterproof, dustproof, oil proof, •built in transmission capability, easy connection to the patients body for vital sign collection, •user friendly, •communication over the GSM network, which has significant coverage in Greece, •secure data transmission, •no independent devices for each vital sign butmany devices integrated into a common package. Independent devices take up a lot of space, and need a lot of probes and cables for their installation and operation. Also, the operators need to spend alot of time to connect them to the patients. The other investigated category was the medical monitors. A medical monitor includes the measurement of many vital signs in a small cased device. But the usage onextreme conditions feeds the measured signal with artifacts, garbling the data. The result of the above market analysis led us to employ of a defibrillator device equipped with embedded vital signs amplifiers. This device allows the ambulance staff to: •measure and transmit of vital signs during the patient collection and transportation to the first aid center, and •defibrillate the patient if it needs so (after the experts advice), •carry the equipment in an accident area away fromthe ambulance. The selected defibrillator device handles the following vital signs: •Up to 12 lead ECG, •Blood Oxygen Saturation (SpO2), •Heart Rate (HR), •Non-Invasive Blood Pressure, •Temperature, •Invasive Blood Pressure (IP), •CO2 measurement. Code Shoppy
The implementation of the other part of the telemedicine system, the dispatch center, has been organized on the basis of the following specifications and restrictions: •Demonstration and modification of the patient demographic data, •Preview and measurements of the received medical data, •Archiving capabilities, •Capabilities for computer-assisted diagnosis, •Signaling of any new incoming incident, •Secure data reception and verification, •User friendly interface. The software running on any workstation of the dispatch center has to include a restricted number of different working windows (forms) demanding the minimal possible users actions. Figure 2,3 and 4 depict some working windows of the dispatch center. In Figure 2, the expert can see all events, alarms, the chronological list of the collected data, curvesrepresenting continuously recorded parameters, values in each point etc. In Figure 3, up to 12 lead electrocardiogram strips collected from the patient can be observed. Figure 4 shows the tools provided to the doctor in order to perform measurements on the ECG strips.
The aforementioned system was designed and implemented in order to assure that an emergency case will be served on the minimum time. So, if the vital sign collection and transmission starts being performed by the paramedics the time needed for in hospital evaluation willsignificantly decrease. Also, it is possible that the patient’s therapy begins during his transportation depending on patient’s health emergency level and the expert’s direction.