1 Teleneurology and requirements of the Medical Devices Directive (MDD) written by Dipl. Ing. Armin Gärtner Teleneurology represents a procedure for the improvement of medical treatment of neurological patients at distant locations using information and communication technologies (ICT). At smaller hospitals without any own neurology department, patients suspected apoplectic stroke or others can be cared for by a teleneurologist of a neurological center who advisorily supports his internal specialist on the spot. This is guaranteed by a video conference technology adapted for medical engineering. Since according to definition components applied in teleneurology represent medical devices, safety standards according to the Medical Devices Directive and all relevant standards considering the third edition of the IEC for teleneurology will be presented in the following from the technical point of view. 1. Purpose of Medical Devices Directive (MDD) The Medical Devices Directive regulates the development, manufacture, putting into circulation and operation of medical devices. Based on these regulations, the law pursues the objective to provide for the safety, suitability and performance of medical devices as well as the protection required for patients, users and third parties. The scope of regulation of the Medical Devices Directive comprises any kind of medical devices, mechanical as well as electrical, and for this reason does not exclusively deal with x ray machines, saline drips, but also with software, dental products as well as dentist s chairs and many more, because the Medical Devices Directive says: Medical devices are all instruments, apparatuses, appliances, substances and preparations made from substances or other devices, applied both individually or in combination, including the software used for the medical device s proper application, intended by the manufacturer to be used for the diagnosis, prevention, monitoring, treatment or abatement of diseases, injuries etc.... This means that telemedical devices and systems and the required technical components of the video conference technology along with the transmission network are subject to the Medical Devices Directive as well. For this reason, a manufacturer of a telemedical system such as for example for teleneurology, is required to determine the medical purpose following para. 3 clause 10 Medical Device Directive carry out the risk classification and risk management (DIN EN 14971) and to completely meet the requirements (MDD, annex I) and to process the conformity evaluation procedure These sub processes represent the prerequisite that the manufacturer of a medical device proves and explains (declaration of conformity) the conformity of a medical device with the appropriate directive such as MDD 93/42 EWG (Medical Device Directive). The demands on medical devices in the sense of the MDD are far beyond the demands on medicaltechnical devices as described in standards (DIN EN , DIN EN , DIN EN X and others). The harmonized standards published in the official gazette of the EC are considered as the so called Rules of Technology and are taken as a reference to prove conformance with the state of technology and the respectively applying fundamental requirements of annexes of the European guidelines. Standards e.g. deal with constructional demands on mechanical and electrical safety, on ergonomics, EMC compatibility and further safety criterions for (medical )technical devices.
2 However, medical devices are not just subject to the MDD, but the provisions of the Atomic Energy Act (Atomgesetz), the Radiation Protection Ordinance (Strahlenschutzverordnung), the X Ray Ordinance (Röntgenverordnung) and the Act on the Prevention of Radiation (Strahlenschutzvorsorgesetz), the Chemicals Act (Chemikaliengesetz), the Dangerous Substances Ordinance (Gefahrstoffverordnung) as well as the legal provisions on secrecy and data protection and others shall apply and be stuck to as well. 2. Teleneurology Teleneurology is applied for neurological acute expertise, for more difficult neurological examination stati, particularly in the field of brainstem symptomatology and differential diagnostics. The systemic fibrinolysis on the spot, requiring an internist and a neurologist, contains a further application area. According to picture 1, teleneurology represents a procedure in which a video conference connection between the examining doctor, the patient and the distant diagnostician is provided for the transmission of video and audio recordings between the persons involved. The teleneurologist e.g. asks the patient for certain reactions, observes his pupil motor activity and may assist the examining doctor in diagnostics by using a mobile telemedical system (also called mobile examination unit or mobile video trolley) with a special camera and microphone as well as the required flat screens, computers, software and network connection. Picture 1: Procedure of teleneurology Picture 2 shows a mobile telemedical system that can be rolled to the patient s bed as a mobile tool trolley for sending video and audio recordings of the patient as well and of the examining doctor to a distant neurological center via a wideband line, where a teleneurologist at a special work station according to picture 3 can communicate with the patient and his collegue on the spot via the used communication technology. The system shown in picture 2 is categorized as a medical device of the risk class 1 and is placed into circulation as a medical device system.
3 Picture 2: Example of a mobile telemedical system (source company Meytec) A telemedical system as illustrated in pictures 1 3 thus represents a system according to para. 10 clause 2 MDD. It may be composed of medical devices and non medical devices and moreover covers a wideband connection between distant locations. This system represents a video conference technology specially adapted for (medical) technology and as a whole put in circulation as a medical device. This means the system inclusive of all its components shall be subject to the operator s ordinance as well, requiring in para. 2 clause 1...that medical devices are only allowed to be exclusively established, operated, applied and maintained according to their purpose, in compliance with the generally approved regulations of technology as well as industrial safety and accident prevention regulations. As a consequence, the operator is required to observe and comply with e.g. the standards and and VDE 0751 concerning electrical safety.
4 Picture 3: Work station of the teleneurologist (source company Meytec) Picture 3 shows an exemplary work station at which the teleneurologist is sitting in the event of a call, and via the connection he can see the patient and his internal medical colleague on the spot and speak to them. 3. Formal legal safety Telemedicine from the MDD s point of view and the operator s ordinance All kinds of telemedical applications are subject to the requirements of the Medical Devices Directive, should they be used for supporting diagnosis and therapy (teleconsultation, second opinion, assessment of diagnostic findings etc.). Picture 4 represents a diagram of the functioning of a system between different houses.
5 Picture 4: Functioning of a teleneurological system Picture 2 shows a product of the risk class 1 (Medical Devices Directive) as a mobile tool trolley. Commercial solutions are usually categorized as a class I medical device according to the MDD 93/42/EWG directive, since they are operated neither immediately at nor in physical contact with the patient. They represent a technical system for the assistance during diagnostic work as well as the usage of consiliary services of other doctors and clinics involved. Mobile systems are usually rolled into the immediate environment of the patient (following DIN EN ) and are required to accordingly comply with the safety requirements resulting thereof. In teleneurology, from the Medical Devices Directive point of view, a network based connection between distant hospitals is built up. Within the scope of admissal a manufacturer of commercial systems is therefore required to carry out the risk assessment for a network connection as well by analyzing and assessing which risks are likely to arise and how the user/operator could e.g. protect the patient against a possible damage in the event of a sudden breakdown of the network connection. As an example, the assigned purpose prescribed according to para. 3 clause 10 MDD could be defined as follows: The system is a mobile telediagnosis system and serves as an aid for the assistance during diagnostic work as well as the usage of consiliary services of other doctors and clinics involved. The risk assessment in the event of an interruption of the connection or the network e.g. could be as follows: Actions in the event of a system s breakdown or breakdown of parts of the system A connection fails, a connection is interrupted. A consiliary assistance is impossible, building up a new connection, if required at another location.
6 Image transmission failed, continuation of consultation only by voice connection. Image and voice failed, establishing a new connection. Voice failed, establishing a new connection. Image files not available, sending and/or receiving malfunctioning, new selection and calling/sending of data set. Total breakdown: The system does no restrict the self dependent actionalibility of the doctor on the spot. The doctor being with the patient decides self dependently on the further progress of the examination. If necessary, it may be required to establish another alternative communication line or to transfer the patient to another ward. The analysis of images gained from other modalities shall be carried out at the location of creation and/or storage. The results shall be communicated to the treating doctor. In house production (new: own production) according to para. 12 MDD Should an operator himself establish a telemedical connection of conventional components by which he supports or even carries out diagnosis and interpretation of findings, he builds up a system in the form of an in house production following para. 12 MDD and is required to carry out and prove a simplified conformity assessment procedure for this. It is dealt with in house production whenever an operator himself establishes a device or a system used for diagnosis and/or therapy. The in house production of medical devices is regulated by legislation in the third MDD Amendatory Act according to which para. 12 shall exclusively apply to devices or systems established at the place of operation where they are exclusively used. However, this means that according to regulations the manufacturer as well as the operator must not put these devices and systems into circulation on the Single European market and not hand them over to third parties either. A simplified conformity assessment procedure means the operator is not required to issue any declaration of conformity or to intervene any notified body, but to be able to prove compliance with fundamental requirements inclusive of the clinical assessment, risk management and documentation requirements. Due to the restriction of in house production to the place of operation, the operator himself for this reason cannot establish any telemedical system in the form of in house production, since he is always required to build up a connection between the actual place of operation (hospital I) and a second location (hospital II, outside his location). And this is no longer an in house production which means the procedure of the simplified conformity assessment cannot be applied in this situation. An in house production of a telemedical system in the sense of the MDD is only possible between different buildings at one and the same location. (Remark: In the draft of the third MDD Amendatory Act of September 2005 the current regulation of the in house production is further restricted and modified.) Medical Devices Operator Ordinance (German: MPBetreibV) In the Medical Devices Operator Ordinance, the establishment, operation, usage and maintenance of medical devices according to para. 3 Medical Devices Directive is regulated. This includes e.g. all x ray systems, their related components for the interpretation of findings and distribution of digital images such as findings workstations, PACS systems etc. For the purposes of processing as a medical device, telemedical systems are subject to the operator s ordinance. As a consequence, all requirements of the operator s ordinance regarding inventory listings, starting up formalities, documentation, instruction and maintenance shall apply for a
7 telemedical system as presented in the pictures 1, 2 and 3 based on the example of teleneurology. This concerns the mobile telemedical system at the sending end as well as the components at the receiving end in the form of the teleneurological work station. 4. Technical safety Electrical safety of a mobile teleneurology system A mobile, teleneurological examination unit (see picture 2) supports diagnosis and therapy, represents a system of different components and as a result is put into circulation as a medical devices system according to the Medical Devices Directive. Among others, such a system is required to comply with the requirements of DIN EN (general provisions for the safety collateral standard: Electromagnetic compatibility requirements and tests) and the EN standard: (Limit values and measuring methods for radio shielding of industrial, scientific and medical high frequency units (ISM devices) class A). Since such a mobile unit is moved into the so called patient s environment (according to DIN EN and DIN EN , third edition) (radius of 1.5 meters around the bed or patient s chair), it requires an isolating transformer for the limitation of leakage current and a galvanic isolation of the connections to the hospital network, if non medical technical components such as PC, monitors etc. are integrated. From the DIN EN standard point of view, a mobile telemedical system according to picture 2 represents a medical electrical system (MES), since it is made up to a system of different components such as PC, software and others. For this reason, the mobile examination trolley is required to comply among others with the demands on safety according to DIN EN From the current DIN EN standard and the new IEC and the future DIN EN (third edition) point of view, such a system is called PEMS (Programmable Electrical Medical System). Such an examination unit is operated with supply voltage 230 V and is categorized as protection class 1. If the mobile unit is moved into the patient s environment, the medical device mobile unit shall comply with the following safety requirements of the standards: Limitation of admissible leakage current Inclusion in the so called additional potential equalization Following DIN EN (third edition) the so called patient s environment represents the area of a radius of 1.5 meters around the patient, in which a system consisting of medical technical and nonmedical technical components is considered as a coherent, medical technical device. Under normal condition, the medical technical system must not exceed a leakage current of up to 0.5 ma (n.c. = normal condition), and in the first event of an error (s.f.c. = single fault condition) of up to 1 ma.
8 Picture 5: Patient s environment according to DIN EN third edition The mobile telemedical system consists of different components such as monitor, computer, video camera, microphone and amplifier, loudspeaker as well as related software (conference software, operating system etc.). As a computer, a so called medical PC is used in the mobile unit according to picture 6, built according to DIN EN , sticking to the admissible leakage current according to standard, having a potential equalization pin and which is determined and suitable for being used in the immediate patient s environment. Picture 6: Mobile telemedical system in patient s environment
9 Compliance with these requirements as described in the system standard DIN EN is one of the fundamentals for the conformity assessment procedure of the system. Moreover, picture 6 shows that the connection between the mobile examination unit and the network connection is required to be galvanically isolated, to avoid any interference or equalizing current that may flow e.g. via metallic conductors or shielding getting on the examination unit via the network connection and as a consequence into the patient s environment. Additional potential equalization Since the housing of the mobile unit consists of touchable, conductible parts (metal) etc., all parts and devices of the trolley, as far as categorized as protection class 1 and having touchable, conductible housing parts, are required to be provided with an additional potential equalization and to be included in the overall potential equalization. Consequentially, the mobile unit shall have a central potential equalization pin, by which the operator must connect the mobile unit while in operation via an additional potential equalization with the potential equalization of the room. Picture 7: Example of additional potential equalization pin at a mobile video trolley
10 The additional potential equalization serves for the limitation of possible potential differences between different conductible parts of a system within the patient s environment. Thus, it represents a safety philosophy that understands to preventively avoid voltage drops and differences between conductible formations as a driving force for equalizing current with risk potentials for the patient and the user. Even if the mobile examination unit presented in picture 2 according to regulations is not connected with the patient, a touch by the patient and/or the doctor or nursing staff is nevertheless possible. Galvanic isolation Since according to regulation the mobile unit is provided for sending and transmitting data, a galvanic isolation according to picture 8 between the transmitter unit and the hospital network is required, in order to avoid any stray current flowing from the network on the movable unit via the network cable. Picture 8: Example for a galvanic isolation between the network connection and the mobile examination unit (Source: Baaske Datentechnik, Space group according to VDE 0100 Part 10 VDE 0100 Part 710: Establishment of low voltage plants, medically used areas contains demands on voltage supply at hospitals and other institutions of the public health system. It defines medically used areas and divides them, according to the scope of application, in the space groups 0, 1, and 2. Mobile teleneurological examination units are applied in space group 1 (ambulance rooms) as well as in space group 2 (intensive care etc.). Radiation Control Law After evaluation of findings by a radiologist, CT images taken of stroke patients if necessary are placed at the teleneurologist s disposal via a corresponding line with an appropriate bandwidth, since usually interpreted images are sent in DICOM quality. As the teleneurologist does not carry out any evaluations of findings of radiologic images, but receives images and findings from a radiologist, the connection between the radiologist carrying out the evaluation of findings and the teleneurologist
11 does not represent any teleradiology connection subject to authorization in the sense of the Radiation Control Law. 5. DIN EN (3 rd edition) and telemedicine The standard existing as a IEC version since 12/2005 also deals with the connection of medical devices with networks like an imaging modality with a PACS system. In July 2007, the standard came into force as DIN EN standard. For an operator, a standard primarily does not have any normative or legal obligation. Standards represent regulations of technology where it is referred to and which are applied. Standards are developed in a partially tedious and elaborate approval process and regulate and standardize only general, fundamental requirements. Due to these time consuming prozesses, standards usually cannot represent the (latest) state of the art. The obligation to pay attention to, to comply with and to realize the state of the art such as e.g. DIN EN and other standards in the field of medical technology, results from the Medical Devices Directive (MDD 8) and der Medical Devices Operator Ordinance. The following obligation is described in para. 2 clause 1 (generel requirements) of the Medical Devices Operator Ordinance (MPBetreibV) which is based on the MDD: Para. 2 (1) Medical devices may be built up, operated, applied and maintained exclusively according to their assigned purpose and according to the provisions of this ordinance, the generally approved regulations of technology (standards) as well as the regulations for industrial safety and accident prevention. This paragraph involves the nexus between the Medical Devices Directive and standards, i.e. this applies for the third edition of the DIN EN with its requirements for telemedicine as well. The third edition has been reviewed over the past five years (since about 2000): Explicite descriptions, requirements and regulations regarding telemedicine naturally cannot be found in this standard, since on the one hand a standard always regulates general requirements and on the other telemedicine has not been and is not yet the focus of attention of this standard at the time of completion of the draft standard. The 3 rd edition of the IEC came into force as DIN EN standard in July 2007 and has replaced the 2 nd edition. The current designation (October 2006) is: DIN EN (VDE 0750 Teil 1) Medical electrical devices part 1: General definitions for safety inclusive of substantial characteristics (approved as IEC already in 2005). The new 3 rd edition has an impact on telemedicine as well. Chapter of the standard deals with the connection between a Programmable, Electrical Medical System (PEMS) and other devices by network and data communications network. A telemedical connection (teleneurology) provides such a connection as described in DIN EN in paragraph
12 This section of the standard describes the information a manufacturer/suppler is required to include in this technical descriptions for an operator, if a PEMS is connected with other devices by a network or data interconnections, that are beyond the PEMS manufacturer s responsibility. The following information shall be contained in the technical description: &nb The manufacturer shall specify the features of the network or data interconnection required by the PEMS to achieve its intended use and to comply with the assigned purpose following 3 clause 10 MDD. The manufacturer shall list all possible risks resulting from the fact that the network or the data interconnection is no longer in the position to provide the features specified. The standard requires the manufacturer to draw the responsible organization s, i.e. the operator s (hospital, medical practice) attention to the following risks specified in the technical description: The connection of a PEMS with a network or a data interconnection enclosing other devices may lead to previously unknown risks for the patient, operator or third parties. The operator (hospital, medical practice) should determine, analyse, assess and control these risks. (The suitable instrument for this represents the risk management according to DIN EN as described in chapter 5.3). The operator s attention shall be drawn to the fact that the following amendments of the network or data interconnection could involve new risks and therfore require new analyses. Amendments at the network or data interconnection may comprise the following measures: Connection of additional devices with the network or data interconnection Removal of devices from the network or data interconnection Devices connected with the network or data interconnection shall be brought up to date Improvements of devices connected with the network or data interconnection. Which consequences and meanings do these requirements of the 3 rd edition finally have on telemedicine and the operator? A separation between medical technology (medical device) and IT technlogy (network or central data storage on a server) is functionally and technically no longer possible. The standard defines the information transmitted as a part of the network or data interconnection as that one determined by the manufacturer for transmission. 5.1 Responsibility for the system integration The operator of ME devices and ME systems (ME = medical electrical), such as telemedical applications, is required to appoint a so called system integrator who shall responsibly care for the tasks resulting from the standard. The standard justifies this demand by the fact that ME devices are applied as well that primarily have not been developed for cooperating with other ME devices or MEsytems. For this reason the standard demands a position as a system integrator, in practice called system administrator as well, who is responsible for seeing to it that all individual ME devices satisfactorily cooperate in an integrated system as well. The system integrator shall perform the following tasks and have the following know how: How is the integrated system intended to be used? What are the demands on performance of the integrated system?
13 How is the planned system configuration intended to look like? Which restrictions are likely to occur regarding the expandability of the system Documents about the specifications of all ME devices and other devices to be integrated Which performance does each ME device and other devices represent? How does the information flow within and around the system take place? Manufacturers usually cannot take on the task of a system integrator at the hospital since they have not the complete information and data recorded in advance. The standard restricts the manufacturer s responsibility to the provision of the required information via his device; it cannot be divided between different manufacturers either. Of course, an operator such as a hospital or a medical practice may instruct a manufacturer or perhaps even a service provider to integrate their system. In this case, the overall system becomes a ME system from which the manufacturer s or service provider s responsibility may be derived to establish a correctly integrated system. The system integrator should have the competence and experience for naming and assessing risks likely to result from the integration of a system and guarantee that remaining, possible (residual) risks are detected during operation of the system. For the job definition of a system integrator, this means that he is required to plan the integration of all ME devices or ME systems and non medical devices in compliance with the instructions of different manufacturers, has to carry out the risk management at the integrated system shall forward all manufacturer s information to the operator, i.e. the hospital or the medical practice requiring it for a safe operation of the integrated system. The standard requires such manufacturer s information including pointers and warnings about risks as well that could arise because of configuration changes (upgrades, updates). This takes for granted that manufacturers inform the named system integrator about all software updates and upgrades, but hardware modifications as well. Ideally, the operator should prepare a complete documentation about network connected systems, so also telemedical systems, and document or update modifications (technical modifications, software modifications, upgrades etc.) accordingly. For this task, the system integrator is required to be aware of and apply the risk management standard DIN EN Considerations for building up a network or data interconnection with risk management in compliance with DIN EN The standard explains that from a PEMS manufacturer s point of view any kind of network or data interconnection represents a source of additional reasons for risks. Conversely, this means that no network or data interconnection beyond the manufacturer s control may be considered as reliable.
14 Picture 9: Networked connection of modalities in a radiology department The following possible reasons for risks in a network or data interconnection may arise: data loss inappropriate data exchange data corruption inappropriate temporal data matching unexpected data reception unauthorized access to data destructive data. Examples for ME devices and ME systems in the network and data interconnection: Networked connection of modalities at PACS and WEB based electronic image distribution according to picture 9 Server based database for longtime ECG devices Telemedical applications WLAN connection of patients monitors and others
15 Picture 10: Telemedical connection Annex A of the DIN EN contains questions about the identification of characteristics of a medical device that could have an impact on safety. Following DIN EN the application of this annex with regard to reasons and risks of networks and data interconnection among others should at least include and consider the following considerations and risk reasons and risk potentials: Teleservice and telemedicine with external access to the internal network or data interconnection of an operator (hospital or others) Remote service of modality manufacturers Compatibility of operating systems Modifications and upgrade of the software (operating system, applications etc.) Impacts and consequences of patch management Interface management (example incompatibility of 10 MB network interface cards with a 100 MB Ethernet network or others) Connections (modification of hardware, network plug) Protocols such as DICOM, HL7 in the network or data interconnection Structure of packet address and bandwidth Heterogeneous network topology Normal network load and bandwidth required Top network load Safety and long term readability of data media Safety with regard to destructive software, non authorized software updates or upgrades Maximum permissible response time Permissible error rate of the network or data interconnection Availability in the event of scheduled and non scheduled maintenance Inconsistency of interfaces and formats likely to involve losses of accuracy during data transmission
16 etc. Annex D of the DIN EN describes exemplary risks and other factors in connections between a ME device and network or data interconnection: Which foreseeable abuse may arise? Is the connection with the network or data interconnection carried out in compliance with its use or purpose in accordance with the regulations of para. 3 clause 10 of the Medical Devices Directive or does it contravene? May an incorrect data flow to or from any connected or involved PEMS arise? What shall the medical data transmitted via the network or data interconnection achieve and what is intended to happen to it? What happens in the event of a breakdown of the network or data interconnection during data transmission? May variances of stipulated operating features of any PEMS involved occur? Which characteristics and operating features does a PEMS have and how and in which form may they be influenced by the network or the data interconnection? Does there exist a complete description of the parameters of the network or the data interconnection such as network topology, configuration, parameters, bandwidth (100 MB Ethernet, 1GB Ethernet etc.) etc.? Is it possible that an overload of the network or the data interconnection may occur in the network nodes? Is the network load resistant? Is the planned number of network nodes sufficient? Are there any redundancies? Is there a structured network cabling? Does there exist the risk of user errors and if there is any, which one? Which vocational training and skills is the operator required to have to appropriately operate and administrate the network? How are the configuration and patch management of the network and connected PEMS made? May regular service work change the features and characterstics of the network or data interconnection e.g. in the event of remote service? Which impact do remote service, patch management etc. have on connected PEMS such as modalities and others? Does the system administrator care for the approval and admission of patches at operating system level, antivirus protection etc. and does he check the consequences on PEMS and network? Does the medical data arrive completely at the correct place at the correct receiver? Are there any unforseeable modifications likely to occur which the user diagnoses in time? Are there sufficient documentations for all hard and software components as well as for the software with all updates available at any time? IEC classifies networks and data interconnection according to picture 11 in compliance with the criterions A, B and C, to achieve a statement about consequences as well as required response times. With regard to the connection of PEMS with a network or a data interconnection, response time means the time delay between the occurrence of an error in the network or data interconnection and the occurrence of an impairment of the patient. Table 1 contains possible risks according to severity and response time in the event of data loss or data modification in a network or data interconnection.
17 Severety Response time Network class Examples Death or severe injury Second(s) A Infusion (closed loop), operation robot, controlling error Minute(s) A Unavailable transmission of alarm signals of an intensivemedical network Hour(s) A/B Defective therapy data at dialysis machine or respirator Medium injury Second(s) A Defective transmission of alarm signals, operation robot, robot controlling error Minute(s) A/B Defective transmission of alarm signals, operation robot, robot controlling error Hour(s) B Image falsification, loss of a therapy protocol Minor injury Second(s) B Minute(s) B Loss of image of an x ray Hour(s) B/C Failure of a telemedical connection Insiginificant Second(s) C Minute(s) C Hour(s) C Breakdown of a telemedical connection Table 1: Possible risks according to severity and response time in the event of data loss or interferences in the network or data interconnection
18 Picture 11: Classification of a network or data interconnection in the categories A, B and C Class C network or data interconnection Class C contains all time critical processes and applications whose malfunction or interruption may involve a time critical situation for a patient, such as regarding an intensive medical network in intesive care. Such a network should not be connected with the general hospital network since such a connection may cause uncontrolled dangers. The availability of such an isolated (floating) network is required to be very high, interruptions should not take place often. Such a network is exclusively subject to the manufacturer s/supplier s responsibility, who defines the demands on the used network nodes as well. Remark: In practice, such an isolation of networks at hospital may be achieved only with a high technical effort or not at all. According to manufacturer, x rays, laboratory data and other patientrelated information is shown on the patients monitors of intensive medical systems as well; this requires a connection between the intensive medical network and the general hospital network in order to transfer data such as x rays from the PACS. In this case, however, the responsiblity for the operation of such networks is definitely shifted to the operator by legislation. Class B network or data interconnection This category of networks or data interconnections contains all non time critical applications or processes dealing with therapeutic or diagnostic patient data. Via a defined and controllable or secured interface, such a network may be connected with another network like e.g. a hospital network. The demands on availability of such a network are high, so that interruptions should take just short periods.
19 The responsibility for such networks is either assigned to the manufacturer or the system administrator appointed by the operator. Since such class B networks usually are radiologic network, the assignment of responsibility always becomes problematic if modalities of several manufacturers for such a network are placed at disposal. Class A network or data interconnection The general hospital network may be taken as a class A example; this is a network or data interconnection where general applications inclusive of administrative or demographical patient data run in. The standard considers a longer shortfall of availability as acceptable, since usually the hospital provides for alternatives. The responsiblity for such a network is placed on the system administrator appointed by the operator. In practice, such a closed or clear categorization/classification will hardly be possible. The following example shall explain why in practice there is always a mixture of the three classifications: A class B radiology network sends pictures and findings data of the radiology network to a PACSserver (Picture and Communication System) via the general class A hospital network. Then the radiologic pictures are available to all users and can be accordingly called up in the respective operating rooms, intensive care units etc. via a WEB distribution. Some manufacturers of intensivemedical monitoring systems categorized class C proposed by standard offer the possibility to show x rays on the bedside monitor of the intensive care unit. In the professional hospital routine, there is a clear mixed operation of the three network classes mentioned. It is decisive that the third edition of the DIN EN is now dealing with the increasing networking of medical technical devices with networks and server based databases and with the required system administrator and risk management according to DIN EN and proposes to cover complexity and potential risks of telemedical approaches and techniques from the safety related point of view. Telemedicine is not yet explicitely described in this third edition of the DIN EN , but the chapter about network and data interconnection contains the approaches described to deal with this development. The standard assumes that if using a network or data interconnection with the objective of a data exchange between PEMS and PEMS or with other IT devices (e.g. server and databases) the manufacturer and operator have the know how required for building up, controlling and consequently know such networks together with all their related processes and functions. As an example, the standard obliges manufacturers or suppliers of PEMS and/or networks and data interconnections to choose the configuation of their products to such an extent that they comply with internationally known network standards such as Ethernet, Fast Ethernet, GigaBitEthernet, FDDI and others and to appropriately use the available bandwith according to the use in accordance with the regulations and the purposes of processing following para. 3 clause 10 MDD and to achieve the optimal performance for their application. The third edition of the DIN EN requires that a hospital as an operator, represented by a system integrator, and PEMS manufacturers come to an agreement about all important technical parameters in order to guarantee a reliable installation of PEMS operated in a network or in a data communications network. This procedure is called for in order to possibly avoid unacceptable risks.
20 Table H.4 of the standard e.g. contains a listing of parameters required for the description of a network or for the description, documentation and determination of a data communications network. However, this listing just represents a draft that should be considered as the beginning of a comprehensive documentation. 6. Summary For ensuring a top quality and safe patient care, the operation of telemedical systems such as among others in teleneurology requires observing and keeping to the Medical Devices Directive and safety standards as described in the regulations of technologies (standards). Particulary the third edition of the DIN EN is substantially stronger directed to the operator of telemedical connections than the second edition. For the operation of a safe and top quality telemedicine such as teleneurology, compliance with the safety standards described is indispensable. Author: Herr Dipl. Ing. Armin Gärtner ö.b.u.v. Sachverständiger Edith Stein Weg Erkrath online.de Literature and list of references 1. Gärtner, A.; Telemedicine and computer based medicine, series Medizintechnik und Informationstechnologie TÜV Media Verlag 2006, ISBN DIN EN ; VDE : , Medical Electrical Devices part 1: General Safety Regulations (IEC : A1: A2:1995); German version EN : A1: A2: DIN EN VDE 0750 part 1 2 Medical Electrical Devices Part 1 2: General Safety Regulations Collateral standard: Elektromagnetic compatibility requirements and tests 4. DIN EN ; Medical Electrical Devices Part 1 4: General Safety Regulations; Collateral standard: Programmable electrical medical systems (IEC : A1:1999); German