How are computers used in hospitals?

Application systems in medicine

What are application systems?

Application systems in medicine are computer programs that support the people involved in medical tasks in the context of patient care. The spectrum ranges from software that enables the search in a drug directory to complex systems for all tasks in the practice of a general practitioner. Application systems are used to provide and process information. That is why one speaks of computer-aided Information systems.

Application systems in the hospital


The services of a hospital, i.e. the quality of patient care, depend to a large extent on the availability and quality of information. It is important that the right information is available in the right form at the right time in the right place (information logistics). In order to achieve this goal, be Hospital information systems designed and built.

It should be noted that not all information processing tasks are (can) carried out with the help of computers, i.e. there are also information systems that have to get along without computer support. So it's not about using as many computers as possible, but also about using them not automatable Procedures for obtaining and processing medical information must be taken into account in an overall concept.

Example: A conventional patient record archive is an information system without computer support.

Computers have been used in hospitals for around 30 years. For a long time, the focus was on administrative tasks. This includes patient data management, billing, accounting, inventory management, telephone billing and other procedures. It is only in the last few years that computers have also been used increasingly in the clinical sector. This imbalance is due to the fact that the administrative functions i.a. can be easily automated and non-hospital-specific software can be used for this (e.g. for bookkeeping). On the other hand, there are many difficulties and reservations in the clinical area, which have their origin in the special handling of information in medicine.

Today you can Hospital information systems (HIS) that claim to support all essential, automatable tasks in the hospital. On closer analysis, however, it turns out that such systems are only suitable for small hospitals with few beds and only a few specialist departments. For large hospitals the maximum care are used today distributed Hospital information systems designed and built. They are made up of many Subsystems together, which guarantee that the information processing procedures in the individual departments and functional areas are largely independent. This is the only way to take the different requirements and needs into account.

Distribution does not mean that there is no longer a central office. Rather, in a distributed HIS, both the data and the tasks are distributed centrally and decentrally. It is based on the so-called Client-server principle, i.e. there are application systems in the HIS that provide certain services (= servers) and application systems that use these services (= clients). There are, for example, the following types of servers:

  • Data serverthat manage data in the form of databases and make it available to clients. The patient database is usually kept on such a data server.
  • Application serverwho manage programs and make them available to clients. This means that all programs do not always have to be saved on all computers; This also ensures that all clients use the same version of the software. For example, the programs for admitting, relocating and discharging patients can be stored on an application server. From there, they are loaded onto the client computer and executed decentrally.
  • Communication server handle and control the data transfer between the application systems (see next section).
  • Information server provide important information for direct access to clients.

The distribution takes place according to the following principle: decentralized as much as possible (to stick to data and programs) and central only as much as is absolutely necessary. The decision as to where which data should be stored and managed also influences data security and data protection. If, for example, the same data can be changed centrally and decentrally, it becomes difficult to change the Data consistency to ensure, i.e. you no longer know what the latest status and what content is valid.

Communication structure


This concept implies a powerful Communication infrastructure ahead, i.e. the possibility of exchanging information between the subsystems as required. One speaks therefore also of information and Communication systems. In terms of hardware, the system is implemented by a computer network. A distinction is made between two levels of communication: the transport level and the application level.

The Transport level initially includes the cable network and other hardware components, so-called network computers. For large hospitals that are spread over a larger area in several buildings, a central ring or Backbone created, on the so-called in the individual buildings and departments. Subnets connected. High transmission speeds are required, for example, for the exchange of images or video sequences.

In the Application level so-called higher protocols are defined for the exchange of data between the individual application systems. The best known higher protocol is HL7 (Health Level 7). It was developed and standardized in the USA (ANSI) and is now also used in other countries. The name should indicate that this is a protocol for level (layer) 7 (in the picture Application) in the ISO / OSI reference model acts. The following figure shows the model projected in two application systems with the corresponding communication links. Layers 1 to 4 (gray in the picture) correspond to the transport level and layers 5 to 7 to the application level.

HL7 defines at what point in time which data is transmitted in which form between the application systems in a hospital information system. The exchange takes place depending on events. The messages to be transmitted and their form are precisely defined for each event.


event source message aim
admission Patient data management Patient master data Laboratory information system

When a patient is admitted, the master data (surname, first name, gender, date of birth, I-number, etc.) are automatically transferred from the “patient data management” application system to the “laboratory information system” application system. Corresponding HL7 interfaces must be programmed in both systems for this.

If the HIS consists of a large number of application systems, it makes sense to have your own for the implementation and coordination of the numerous and complex communication processes Communication server to use. It takes the messages from the sending subsystem, converts them (i.e. recoding, changes in the record structure, conversions) and forwards them to the intended recipient. It is also possible to send a message to several recipients or messages from different application systems to one recipient. At the same time, all communication processes are monitored (automatic and manual monitoring).

Examples of application systems

Depending on the area of ​​application and range of functions, a distinction is made between different classes of application systems in hospitals.

Clinical workplace systems for wards
The ward is the most important service point in the hospital for patient care. The use of software in this area is intended to improve inpatient health care while at the same time relieving the medical and nursing staff.

Clinical workstation systems offer the following functions:

  • Medical documentation support. The system offers help with the acquisition, control, storage, retrieval and presentation of all data that arise during medical activity (anamnesis, examinations, diagnoses, therapies, other measures).
  • The nursing documentation (nursing history, nursing needs assessment, nursing planning and nursing measures) is also supported in a corresponding manner.
  • All services performed on the ward should be recorded and saved on a case-by-case basis and on a patient-specific basis. As far as possible, the recording is to be automated (e.g. deriving services from the diagnoses).
  • Maintaining the electronic patient record (see section Medical Documentation in the Hospital, with illustrations). This means that the patient file or parts of it (e.g. the diagnoses and findings) are saved in this system.
  • Mobile data acquisition can optionally be considered, i.e. data acquisition and data presentation at the bedside with portable computers.
  • The preparation of medication and infusions can be made easier by displaying or printing out the prescriptions. This procedure assumes that all regulations are recorded (curve guidance).
  • The administrative patient data are usually recorded separately by the patient data administration. They can be transferred to the clinical workstation system with the aid of the communication system and administered locally there. It must be ensured that any changes and additions are reported back to the patient database (preservation of data consistency).
  • Interactive access to other procedures in the hospital information system (e.g. to order materials or food) should be possible within the routinely used user interface.
  • The planning of measures, including scheduling, and the performance requirements for service departments (e.g. radiology or endoscopy) should be supported. This eliminates the need for time-consuming coordination and filling out forms.
  • Correspondingly, the findings or results are automatically adopted by the service centers and presented on demand.
  • For the medical staff it is very important that the doctor's letter writing is supported by the transfer of the data from the medical and nursing documentation and thus the time between discharge and writing is shortened. Research has shown that doctors' letters can be standardized to a large extent. These sections can be given as a framework and supplemented by individual, free-text formulations. Text systems are used for this. The organization, i.e. the coordination between doctor and typist, must be adapted accordingly.
  • Retrieval and output of simple evaluations.

There are commercially available systems for these applications, which, however, have to be adapted to the organizational processes and needs of the individual hospital.

Clinical workplace systems for outpatient departments
In addition to the wards, some of the services of a hospital are provided in outpatient departments. In terms of health policy, outpatient services are even to be expanded so that expensive inpatient treatment can only be used when all other options have been exhausted. For this reason, day-care as well as pre- and post-inpatient treatment and outpatient surgery were introduced as new forms of patient care.

The following functions, among others, are required in the clinical workplace systems for outpatient departments:

  • Reading the health insurance card, transferring the data to the system and managing the patient master data is the basis for all other functions.
  • Medical documentation support. The system offers help with the acquisition, control, storage, retrieval and presentation of all data that arise during medical activity (anamnesis, examinations, diagnoses, therapies, other measures).
  • All services provided in the outpatient department should be recorded and saved in relation to the patient. The performance recording based on the data of the medical documentation needs to be automated even more than on the wards.
  • Management of the master data of the outpatient clinic, including e.g. names of the cash registers, addresses, diagnosis catalogs, abbreviations, medication, fee schedules, service figures and point values.
  • An important function is the support in planning, ordering and making appointments.
  • It must be possible to print forms such as prescriptions, certificates of incapacity for work, etc. in a simple manner.
  • KV billing with data carrier exchange. As with resident doctors, the services of the outpatient clinics are not billed directly to the payers, but via the Association of Statutory Health Insurance Physicians (KV). These settlements take place with data carrier exchange (CD) or the data are transferred directly from computer to computer.
  • In a similar way as on the wards, the performance requirements at service points must be supported.
  • Correspondingly, the findings or results are automatically adopted by the service centers and presented on demand.
  • In contrast to the wards, where the entire stay is shown in a doctor's letter, only short letters are created in the outpatient departments. These messages can be standardized and can be drafted relatively easily by taking over the data from the ambulance documentation.

In principle, the clinical workstation systems have the same range of functions as Medical practice systemsthat are used by general practitioners. In the outpatient area, performance requests and reports on findings (e.g. with laboratories or radiologists) are also increasingly computer-aided.

Systems for service centers
In the hospital there are a number of non-bed service centers that provide individual services across the entire spectrum of health care. These include the operational areas for performing operations, the clinical laboratories, imaging service centers such as radio diagnostics, nuclear medicine and magnetic resonance imaging, pathology, microbiology, hemostaseology and blood bank, endoscopy, etc. The application systems installed there are then called, for example, laboratory information system (LIS) or radiology Information system (RIS).

The process of requesting services, providing services and transmitting results basically follows a fixed scheme. It makes no difference whether the service center receives material (blood, tissue or the like) or the patient himself has to be present at the service center. Conventionally, the performance request is made with forms and the results are reported in the form of information on paper.

Certain basic functions can be defined independently of the special requirements of individual service units:

  • Automatic transfer of the performance requirements and transfer of the associated patient data. For service centers where the patient has to be present for the planned measure, it should be possible to schedule an appointment, i.e. the requesting center receives a confirmation with an indication of the date.
  • The assignment of patient to material must be checked. While the request is sent via the network in an automated process, the material must be sent conventionally (e.g. by pneumatic tube). Machine-readable labels are often used for this, which are created when the patient is admitted and made available to the ward. The label contains data that identifies the patient. This ensures the clear assignment in the service center.
  • When the requirements are met, work lists can be created.
  • Process control and quality assurance in the service center should be supported. For example, quality control in the clinical laboratory can be largely automated.
  • Direct connection of measuring devices must be possible in laboratories.
  • All services provided must be recorded and documented on a case-by-case and patient-specific basis and included in the performance statistics.
  • How far the diagnosis itself can be supported depends on the individual task. In any case, it should be possible to simply write findings reports with integration of the automatically determined partial results. This also includes digital dictation or automatic speech recognition (see section on data acquisition).
  • The findings and results must be transmitted to the client after the order has been carried out. As far as text is concerned, that's no problem. The transmission of the results of imaging procedures is more difficult if the images (and not just the findings) are to be forwarded.The transmission requires a powerful network and then requires an adequate presentation.
  • Support for local archiving (e.g. of images or preparations) should be possible.

Schematic process of performance request and reporting of findings:

Archiving systems
The archiving of patient files plays an important role, as the amount of information that arises in patient care is constantly increasing and at the same time retention periods have to be adhered to. In addition to the conventional procedures (hanging patient files in register cabinets), computer-aided procedures are also increasingly being used. The systems must allow the filing of all documents in the form of paper, data carriers, gray-scale images, video images, sound and voice. In addition to the secure storage (storage) must be accessible at all times (Retrieval) be possible for these documents while maintaining data protection. For effective use is also adequate presentation of the retrieved documents, for example within the electronic patient file.

Information services
This means the provision of information in the workplace. There is hardly any local access to the hard drive or CD, but rather to servers in the Internet or intranet.

A distinction is made according to the type of information, its storage and its presentation:

  • Fact databases: These can be, for example, drug directories ("Red List"), encyclopedias, software directories, timetables or postal code directories. Most databases present the information in the hypertext format familiar from the Internet (like this tutorial!). In a broader sense, this also includes literature databases such as MEDLINE.
  • Knowledge bases: This is the storage of knowledge in electronic form. Knowledge is information as presented in a textbook, for example. In the medical field there are now many textbooks also in electronic form. The most common type of presentation chosen is Hypertext. This is text in which individual words or pieces of text are specially marked (e.g. in color), which can be used like references in a lexicon (ä). Click with the mouse on the marked text and you will see a new piece of text on the screen that provides details on the selected reference. The principle works in the same way with buttons or icons.
  • Remote information databases: The information is also prepared in hypertext form on the World Wide Web (WWW). There are many servers in this network that hold information in so-called pages. Pages are multimedia, i.e. information can be in the form of text, graphics, sound, images or moving images. Each server has a home page that is shown when it is selected. There are links to other pages on this server or somewhere in the network. The WWW thus represents a gigantic information database.
    In order to be able to access the information on the WWW, you need a program for the PC or workstation you are working on, with the help of which the multimedia information can be fetched and displayed. Such programs are called Browser. You choose the server from which you want to get information, and the so-called main page is displayed. From there you branch to other pages by clicking on the links. Browsers can also play sound sequences and display images.
  • Tutorials serve not only to look up information, but also to provide interactive knowledge transfer. They are mostly set up as multimedia hypertext systems, but also have special mechanisms, e.g. questions to the user or the creation of user profiles for self-monitoring. So far, some learning programs have been kept on their own servers and accessed from there in computer classrooms. Many learning programs (possibly chargeable) can already be accessed on the WWW and thus partially replace conventional forms of imparting knowledge.
    Example: ILIAD is a learning system ("expert system") for internal medicine that was developed in the USA. Unfortunately, the program is no longer being developed and sold. Nevertheless, it is briefly introduced here in order to illustrate the essential functions of a program for diagnostic support.
    The stored knowledge comes from three different sources: current patient data from hospitals (around 500,000 cases over 12 years have been evaluated), knowledge from medical experts and from specialist medical literature. The current version contains around 2,400 clinical pictures and 10,000 symptoms, which also come from the fields of neurology, psychiatry and pediatrics. ILIAD also has some images, but the multimedia capabilities of the program could be better.
    There are four different ways of working:
    Consultation: After entering a patient's symptoms and findings, the program calculates possible diagnoses and lists them according to probabilities. The list is based on the values ​​stored in the database for the sensitivity and specificity of certain findings. The decision rules used are displayed.
    Self-control: A work diagnosis or a hypothesis is given and the program requests information on symptoms and / or complexes of findings. The processing of this information by the program is the same as for the consultation and enables a critical evaluation of one's own hypotheses in comparison with the diagnosis list.
    Simulation: The program presents a case with its symptoms and findings and the user should find out the associated diagnosis. The dialogue carried out depends on the prior knowledge and experience of the user.
    Look up: One uses the knowledge base of the program for looking up.

Administrative systems
Administrative systems offer both hospital-specific and general functions. The hospital-specific functions include patient data management and the administration of a Patient database, inpatient and outpatient Service accountingManagement of master data, information and reporting, provision of organizational resources, procurement and maintenance management for medical devices.

General functions are financial accounting, accounts payable and accounts receivable, asset accounting, cost and performance accounting, controlling, materials and warehouse management, human resources, payroll accounting, office functions and support for so-called Supply systems like kitchen or driving service. Most of these functions can be performed with conventional business application systems.

Medical network
Various institutions work together to provide health care for the population (see figure). This collaboration requires intensive communication. The exchange of information is increasingly taking place via the Internet. Special security precautions are necessary because personal data is transferred. This creates an internet-based one medical network with the aim of increasing the quality of care, strengthening the patient's personal responsibility, being able to introduce new forms of treatment (e.g. "shared care") and - last but not least - reducing costs (e.g. by avoiding double examinations). The following figure shows the institutions involved and possible communication relationships.

A number of projects have already been implemented at the application level, e.g. electronic prescriptions or transmission of accounting data to the cost units. In addition, concepts for a cross-institutional electronic patient record (electronic health record (EGA)) developed. All treatment-relevant data - from medication to diagnostic image data - are no longer just in patient files and archives of hospitals or in the files of doctors in private practice, but are available in electronic form in the medical network.

The EGA has the following advantages for patient care:

  • The better the attending physicians are informed about the diagnosis results and the therapy status of their patients, the better they can tailor their treatment to the medical requirements. Findings, therapy information and much other necessary medical information can be called up quickly where it is needed (with the consent of the patient).
  • The tedious search for previous medical findings is no longer necessary. The data can be made mutually accessible to doctors in clinics and outpatient practices. This means that outpatient and inpatient treatment processes are better interlinked.
  • Multiple examinations, which put additional stress on the patient, can be reduced. This is not only in the interest of the patient, who receives better coordinated care, it also saves the resources of the health system and contributes to more efficient care.

Cooperation in the German health system is thus promoted and improved overall.

Sufficient data security should be achieved with two different chip cards. The patient receives one instead of the current health insurance card Health card, on which personal and administrative data is stored and which is secured with a personal identification number (PIN). With this card he allows access to his electronic health record, some of which is stored on the card itself or in specially secured servers. Which data is actually stored there is solely the responsibility of the patient. For example, information about drugs taken, emergency information such as risk factors and allergies, medical documents such as doctor's letters or reports, and living wills are provided.

Access to the stored data is also usually under the control of the patient. Healthcare professionals need to use a second card (Health Professional Card, HPC). A digital signature is also possible with this card. Access is only possible with the HPC in exceptional situations and emergencies. All accesses are logged.

The health card and HPC are currently being tested in large pilot projects in order to solve all technical and organizational problems before they are introduced across the board. For example, wherever there is patient contact, appropriate Card reader be installed. In addition, a "foolproof" handling of the cards must be ensured and any misuse must be excluded.

The transmission of medical data over a computer network is often called Telemedicine designated. Accordingly, the medical network is a telemedical application. However, it makes sense to limit the term telemedicine to the transmission of data in direct patient care. This includes, for example Teleconsultationif radiological images are transmitted from the place of origin to a doctor who will carry out the diagnosis, or the Telesurgerywhen a doctor remotely controls an operating room robot. The more general term of Telematics in healthcare then also includes tele-training in medical teaching, as well as applications in medical research and health management.