Reinhold Haux Alfred Winter Elske Ammenwerth Birgit Brigl Strategic Information Management in Hospitals An Introduction to Hospital Information Systems 3 3 What do Hospital Information Systems look like? 3.1 Introduction A hospital information system (HIS) was previously defined as the subsystem of a hospital, which comprises all information processing as well as the associated human or technical actors in their respective information processing roles. We will now take a closer look at what hospital information systems look like. We will then present typical functions and processes of hospitals. We will discuss how to describe hospital information systems using appropriate modeling methods. We will in detail describe the three layer graphbased metamodel to describe HIS. Finally, we will discuss typical architectures of hospital information systems. After this chapter, you should be able to answer the following questions: • Which typical hospital functions exist? • Which metamodels exist for modeling which aspects of HIS? • What is the three layer graphbased metamodel (3LGM)? • Which typical information processing tools exist in hospitals? • Which architectural styles of HIS exist? 3.2 Hospital functions In this chapter, typical hospital functions will be presented in greater detail. Patient admission Patient admission (see Figure 26) aims at recording and distributing those patient data which are relevant for patient care and administration. In addition, each patient must be correctly identified, and a unique patient and case identification must be assigned. Subfunctions are: • Appointment scheduling: The hospital must be able to schedule an appointment for a patients visit. In addition, unplanned admissions must be possible (e.g., in case of emergencies). Figure 26: A patient being admitted in a patient admission department. 34 Strategic Information Management in Hospitals Figure 27: Typical organizational media. • Patient identification: A unique patient identification number (PIN) must be assigned to each patient. This PIN should be valid and unchangeable lifelong (i.e. the PIN should not be based on changeable patient’s attributes such as name). The PIN is the main precondition for a patientoriented combination of all information arising during a patients stay. Before a PIN can be assigned, the patient must be correctly identified, usually based on available administrative patient data. If the patient has already been in the hospital, she or he must be identified as recurrent, and previously documented information must be made available (such as previous diagnoses and therapies). If the patient is in the hospital for the first time, a new PIN must be assigned. In addition, the hospital must be able to distinguish between different cases or hospital stays of a patient. Therefore, in addition to the PIN, a case identification is usually assigned. • Administrative admission: Administrative admission starts following patient identification. For example, insurance data, type of admission, details about special services, patients relatives, admitting physician, and referral diagnoses must be recorded. The patient is assigned to a ward and a bed. Some of the administrative data must be made available to other hospital functions through the help of certain organization media (such as labels and magnetic cards, see Figure 27). Administrative data form the backbone of information processing. In case of changes, patient data must be maintained and communicated. If the admitting physician has communicated relevant information (e.g. previous laboratory findings), this information must be communicated to the responsible physician in the hospital. Administrative admission is usually either done in a central patient admission, or directly on the ward (for example, during emergencies or on the weekend). • Clinical admission: The responsible physician and nurse will proceed with the medical and nursing admission. This typically comprises the anamnesis (both by physician and nurse), and the introduction of the patient to the ward. These basic data have to be available for Figure 28: Information of patient’s relatives at a ward. 3. What do Hospital Information Systems Look Like? 35 each of the following hospital functions. • Information: The hospital management must always have an overview of the recent bed occupation, i.e. about the patients staying at the hospital. This is, for example, important for the porters which must be able to inform relatives and visitors correctly (see Figure 28), and also for some general hospital management statistics. Planning and organization of patient treatment All clinical procedures of health care professionals must be discussed, agreed upon, initiated, and efficiently planned. In contrast to patient admission, the management of patient treatment is a continuous task which is initiated each time new information is available. Subfunctions are: • Presentation of information and knowledge: Staff members must be able to access all relevant patient data specific to a situation, in addition to general clinical knowledge (e.g., guidelines and standards) supporting patient care (see Figure 29). • Decision making and patient information: Responsible team members must decide upon the next steps such as certain diagnostic or therapeutic procedures (see Figure 30). Depending on the complexity of a diagnostic or therapeutic decision, they should be able to consult internal or external experts (e.g., in specialized hospitals) to get a second opinion (e.g., about the question if a patient can be transported by exchanging CT images). In this context, (tele)conferences may be useful. Decisions about clinical procedures must be documented. The patient should be included in the decision making process, and his informed consent must be documented as well. • Care planning: The next steps now have to be planned in detail. For each procedure (such as an operation or a chemotherapeutic treatment), the type, extent, duration and responsible person have to be fixed. In nursing, treatment planning is documented in nursing care plans, containing nursing problems, nursing goals, and planned nursing procedures. If necessary, other health care professionals are ordered to execute the planned clinical Figure 29: Infrastructure to access medical knowledge. Figure 30: Regular meeting of health care professionals to discuss care plans for patients. 36 Strategic Information Management in Hospitals procedures (e.g., medical bandaging orders which have to be executed by a nurse). Order entry and communication of findings Diagnostic and therapeutic procedures must often be ordered at specialized service units (e.g., laboratory, radiology, or pathology). These units execute the ordered procedures and communicate the findings or results back to the ordering department. Subfunctions are: • Preparation of an order: Depending on the available service spectrum offered by a service unit, which may be presented in the form of catalogs, the physician or nurse selects the adequate service on an order entry form (see Figure 31). Patient and case identification, together with relevant information such as recent diagnoses, the concrete questions, the service ordered (e.g. laboratory, radiology), and other comments (e.g. on special risks) are documented. An order should only be initiated by authorized persons. • Taking samples or scheduling appointments and procedures: Depending on the type of order, specimens which must be unambiguously assigned to a patient are submitted (e.g., blood samples), or patient’s appointments must be fixed (e.g., in radiological units). During scheduling, the demands of all parties must be fairly balanced (e.g. ordering physician, service unit, patient, transport unit). • Transmission of the order: The order must quickly and correctly be transmitted to the service unit. If a specimen is transferred, it must be guaranteed that the order and specimen can be linked to each other at the service unit. If necessary, modification to already transferred orders by the ordering physician or nurse should be possible. • Reporting of findings: Findings and reports must be transmitted (as quickly as necessary) back to the ordering unit on time and presented to the responsible health care professional. They must be unambiguously assigned to the correct patient. The responsible physician should be informed about new results, and critical findings should be highlighted. Figure 31: Example of an order entry form for laboratory testing. Figure 32: Clinical examination at a pediatrician. 3. What do Hospital Information Systems Look Like? 37 Execution of diagnostic or therapeutic procedures The planned diagnostic, therapeutic or nursing procedures (such as operations, radiotherapy, radiological examinations, medication) must be executed (see Figure 32). The hospital must offer adequate tools and resources (e.g. staff, room, equipment) for necessary procedures. It is important that changes in care planning which may be due to new findings are directly communicated to all involved units and persons, enabling them to execute them as quickly as possible. Clinical documentation The goal of clinical documentation is to record all clinically relevant patient data (such as vital signs, orders, results, decisions, dates) as completely, correctly and quickly as possible. This supports the coordination of patient treatment between all involved persons, and also the legal justification of the actions taken. Data should be recorded in as structured a form as possible. It is important that data can be linked by patient and case identification, even when data originate in different areas (such as ward, service unit, outpatient unit). Usually, the hospital has to fulfill a lot of different legal reporting (such as epidemiological registers) and documentation requirements. Often, data must be adequately coded (for example, using the International Classification of Diseases, ICD10 18 , for diagnoses codes). The content of clinical documentation depends on the documenting unit and the documenting health care professional group (such as documentation by nurses or physicians, documentation in outpatient units or in operation rooms). Clinical information should be available for other purposes such as accounting, controlling, quality management, or research and education. Subfunctions are: • Nursing documentation (see Figure 33) comprises the documentation or the nursing care process (nursing anamnesis, care planning, procedure documentation, evaluation and reports writing), together with documentation of vital signs, medication, and other details of patient care. 18 World health organization (WHO): Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems (ICD10). http:www.who.intwhosisicd10 Figure 33: Nursing documentation on a ward. 38 Strategic Information Management in Hospitals • Physician documentation comprises the documentation of medical anamnesis, diagnoses, therapies and findings, and also documentation for special areas (such as documentation in intensive care units) or special purposes (such as clinical trials). It also comprises order entry for service units and for other health care professional groups (such as nurses). Administrative documentation and billing The hospital must be able to document all services carried out in a correct, complete, quick and patientoriented way. Those data are then the basis for the hospitals billing. The administrative service can also be used for controlling, cost center accounting and internal budgeting, cost responsibility accounting (i.e. the presentation of costs with regard to the source, for example a patient), and for other economic analysis. In addition, some of the data must be documented and communicated due to legal requirements. During administrative documentation, diagnoses and procedures are recorded in a standardized way, and then processed. Administrative documentation should be at least partly derivable from clinical documentation. To support administrative documentation, adequate catalogs must be offered and maintained, containing lists of typical diagnoses and procedures relevant for a unit or a hospital. Patient discharge and referral to other institutions When patient treatment is terminated, the patient is discharged and referred to other institutions (e.g., a general practitioner, or a rehabilitation center). Administrative patient’s discharge contains the initiation of final billing and the fulfillment of legal reporting requirements (e.g. statistics on diagnoses and procedures). Clinical and nursing patient’s discharge comprises the completing of documentation and writing of a discharge report. The hospital must be able to transmit this and other information (e.g., radiological images) to the other institutions as quickly as possible. To speed up this process, a short report (i.e., physicians discharge letter) is often immediately communicated to the next institution, containing for example the diagnoses and therapeutical propositions, which is then later followed by a more detailed report. Handling of patient records Relevant data and documents must be created, gathered, presented and stored such that they are efficiently retrievable during the whole process of patient treatment. This storage is primarily done in patient records. Usually, a certain amount of legal requirements must be considered. Subfunctions are: • Creation and dispatch of documents: Medical documents, such as physician letters and surgical reports, should be easy to create, be available on time and be patientoriented. Already documented information should be reusable as much as possible (e.g. laboratory results and coded diagnoses should be 3. What do Hospital Information Systems Look Like? 39 reusable for the discharge report). All documents should be signed with author and date of generation. • Management of documentation for special areas or special purposes and clinical registers: They should by easy to create and maintain, for example, to support quality management, research, or individual departments. Already documented data (e.g. from clinical documentation) should be reusable as much as possible. Queries for a given subset of patients should be possible. • Coding of diagnoses and procedures: Basic medical data such as diagnoses and procedures should be easy to document in a structured way. Basic dataset documentation serves for the internal hospital reporting structure as well as for the fulfillment of legal requirements. • Analysis of patient records (see Figure 34): All data from patient records (whether computerbased or not) should be available on time and in an easy, comprehensive and structured way. Therefore, a uniform structure for the patient record is useful. Healthrelated data are very sensitive, the hospital must, thus, guarantee data protection and data security. • Archiving of patient records: After discharge of the patient, patient records must be archived for a long time (e.g. for 10 or 30 years, depending on the legal regulations). The archive must offer enough space to allow the longterm storage of the created patient records. Their authenticity and correctness can be proven more easily, e.g. in case of civil actions, when they are archived in accordance to legal regulations. • Administration of patient records: The hospital archive must be able to manage patient records and make them available upon request within a defined timeframe. The exact location of each record should be available (e.g. in which archive, on which shelf). Lending and return of records (e.g. for recurring patients) has to be organized (see Figure 35), while respecting different access rights which depend on the role of the health care professionals in the process of patient care. Figure 34: Analysis of the patient record. Figure 35: Documenting the lending of patient records which have been ordered by clinical departments. 40 Strategic Information Management in Hospitals Work organization and resource planning The hospital must offer sufficient and wellorganized resources for patient care. This is true for wards (ward management), outpatient units (outpatient management), and service units (department management). Subfunctions are: • Scheduling and resource allocation: Resources needed for patient care are, for example, staff, beds, rooms and devices. Resource management, therefore, comprises staff planning, bed planning, room planning and device planning. All resource planning activities must be harmonized with each other. When procedures are scheduled, the interests to decide on the appointment of both the service unit and the ordering unit must be harmonized. Request, reservation, confirmation, notification, postponement and cancellation must be supported. All involved staff members and the patients should be informed about the next relevant appointments. Postponement and cancellations should be communicated in time to all involved persons. • Materials and pharmaceuticals management (see Figure 36 and 37): Supply and disposal of materials, food, drugs and so on must be guaranteed. All departments of the hospitals should be able to order them, based on uptodate catalogs. The corresponding service units (stock, pharmacy, kitchen) must be able to deliver correctly and on time. • Management and maintenance of equipment: Various medical devices are used in hospitals. They must be documented and maintained according to legal legislation. • General organization of work: An efficient process organization is extremely important for hospitals, for example in outpatient units or service units. This can be supported, for example, by offering working lists, by reminding of next appointments, or by visualizing optimal processes. • Office communication support (see Figure 38): The hospital must be able to support communication between all persons involved in patient care. This comprises synchronous (e.g., telephone) and asynchronous (blackboards, brochures, email) communication. Staff members must be contactable within a definite time. Figure 36: The stock of drugs on a normal ward. Figure 37: In the central pharmacy of a hospital. Figure 36: The stock of drugs on a normal ward. 3. What do Hospital Information Systems Look Like? 41 • Basic information processing support: The hospital must support basic information processing tasks such as writing letters or calculating statistics. Hospital management Hospital management supports the organization of patient care and controls the financial issues of the hospital. One of the main tasks is recording and billing of all accountable services. Subfunctions are: • Quality management: Quality management supports a definitive quality of structure, process and outcome of the hospital. This covers, for example, internal reporting containing quality indices. Quality management requires information about patients and treatments as well as knowledge about diagnostic and therapeutic standards. • Controlling and budgeting: The hospital must be able to gather and aggregate data about the hospitals operation in order to control and optimize it. This covers, for example, staff controlling, process controlling, material controlling, and financial controlling. • Costperformance accounting: For controlling purposes, it is necessary to keep track of services, their costs and who has received them. This covers for example, accounting of cost centers, cost units and process cost. • Financial accounting: All hospitals operations which deal with companies values (for example, money, values, fortune, debt) have to be systematically recorded according to legal requirements. Financial accounting comprises, for example, debtor accounting, credit accounting, and facility accounting. • Human resources management: This contains all tasks for the development and improvement of the productivity of staff. It comprises, for example, staff and position planning, staff recording, staff scheduling and staff billing. • General statistical analysis: The hospital must support general statistical analysis, for example calculation and analysis of economic data. Examples {Example for an index of hospital functions?} Figure 38: A physician communicating by phone with a general practitioner. 42 Strategic Information Management in Hospitals Exercises Exercise 3.2.1 Differences in hospital functions Please have a look at the hospital functions presented in this chapter. Now imagine a small hospital (for example, 350 beds) and a big university medical center (for example, with 1,500 beds). What are the differences between both hospitals with regard to their functions? Please explain your answer. Exercise 3.2.2 Different health care professional groups and hospital functions Please have a look at the hospital functions listed in this chapter. Analyze the relationships between the hospital functions and the different health care professional groups (physicians, nurses, administrative staff, others) working in a hospital. Which hospital functions are performed by which health care professional group? Please create a table with health care professional groups as columns, hospital functions as rows, and the following symbols as content in the boxes: ’++’ = hospital function is primarily performed by this profession; ’+’ = function is also performed by this profession; ’‘ = function is not performed by this profession; ‘.’ = neither ‘++’, ‘+’ nor ‘‘. Summary Typical main hospital functions are • patient admission with appointment scheduling, patient identification, administrative admission, clinical admission, and information processing; • planning and organization of patient treatment with presentation of information and knowledge, decision making and patient information, and care planning; • order entry and communication of findings with preparation of an order, preparation of specimen or scheduling of appointments and procedures, transmission of the order, and reporting of findings; • execution of diagnostic or therapeutic procedures; • clinical documentation with documentation performed by physician’s and nurses; • administrative documentation and billing; • patient discharge and referral to other institutions. These hospital functions are typically supported by functions such as • handling of patient records with creation and dispatch of documents, management of documentation for special areas or special purposes and 3. What do Hospital Information Systems Look Like? 43 clinical registers, coding of diagnoses and procedures, and analysis, archiving and management of patient records; • work organization and resource planning with scheduling and resource allocation, materials and pharmaceuticals management, management and maintenance of equipment, support in the general organization of work, office communication support, and basic information processing support; • hospital management with quality management, controlling and budgeting, costperformance accounting, financial accounting, human resources management, and general statistical analysis. 3.3 Modeling hospital information systems Modeling HIS is an important precondition for their management: What we cannot describe, we usually cannot manage adequately. We will present some types of information system metamodels, describing different aspects of HIS, and present some smaller examples of HIS models. HIS models and metamodels A model was defined in chapter 2.3 as a description of what the modeler thinks to be relevant of a system. The significance of models is based on their ability to present a subset of the (usually complex) reality and to aggregate the given information in order to answer certain questions or to support certain tasks. That means that models should present a simplified, but appropriate view of a HIS in order to support its management, and operation. Models should be appropriate for respective questions or tasks. Examples of questions or tasks which are important with regard to hospital information systems could be: • Which hospital functions are supported by a HIS? • Which information processing tools are used? • What are the steps of the business process of patient admission? • What will happen if a specific server breaks down? • How can the quality of information processing be judged? A model is only good when it is able to answer given questions or can support a given task (such as detection of weaknesses, or planning the future state of HIS). The better you can see a HIS, and the better a model assists you in managing it (e.g. in identifying good or also critical parts of HIS), the better the model is. Thus, the model you select depends on the problems or questions you have. When looking at the amount of possible (and important) questions and tasks, it is clear that a large number of different classes of models exists. The class of a model is described by its metamodel We can distinguish some typical metamodelswhich each describe a class of similar models. Metamodels describe the modeling framework which consists of: 44 Strategic Information Management in Hospitals • modeling syntax and semantics (the available modeling objects together with their meaning), • the representation of the objects (how the objects are represented in a concrete model, e.g. often in a graphical way), • the modeling rules (e.g. the relationships between objects), • and (sometimes) the modeling steps. Just as different architectural views on HIS exist, there also exist various metamodels. Typical types of metamodels for HIS are: • functional metamodels, focusing on hospital functions which are supported by the information system, i.e. on the functionality of a HIS; • technical metamodels that are used to built models describing the information processing tools used; • organizational metamodels that are used to create models of the organizational structure of HIS; • data metamodels, used for building models of the structure of data processed and stored inside a HIS; • business process metamodels, focusing on the description of what is done in which chronological and logical order; • enterprise metamodels, that combine different submodels to an integrated, enterprisewide information system model. Business process metamodels are also referred to as dynamic metamodels in contrast to the other more static metamodels. The art of HIS modeling is based on the right selection of a metamodel. Thus, for HIS modeling, you should consider the following steps: 1. Define the questions or tasks to be supported by the HIS model. 2. Select an adequate metamodel. 3. Gather the information needed for modeling. 4. Model the information in a model (e.g., in a graphical way) 5. Analyze and interpret the model (answer your questions). 6. Evaluate if the right metamodel was chosen, i.e. if the model was adequate to answer the questions. If not: proceed with step 2. In the next paragraphs, we will focus on some typical metamodels. We will answer the following questions for each metamodel: • What elements does the metamodel offer? • Which relationships between the elements can be modeled? • Which questions can be answered by using this metamodel? • What could a typical model look like, when derived from this metamodel? Functional modeling Functional metamodels are used to build models which represent the functionality of a hospital (what is to be done). The elements they offer are the hospital functions which are supported by the hospital information system. The relationships of the hospital functions can, for example, represent the 3. What do Hospital Information Systems Look Like? 45 information exchange between them. In addition, functions are often described in a hierarchical way, comprising more global functions (such as patient management) and more specific (refined) functions (such as patient billing). Typical questions to be answered with models derived from functional metamodels are: • Which hospital functions are supported by which HIS components? • Which specific hospital functions are part of which global hospital function? • Which hospital functions share the same data? • Does the functional model correspond to a reference model? Typical representations of functional models are (hierarchical) lists of functions, as well as graphical presentations of the hospital functions. Table 2 presents an extract from a threelevelhierarchy of hospital functions for information processing in nursing: Documentation of patients resources Documentation of nursing goals Planning and documentation of nursing tasks Writing of nursing reports Nursing documentation ... Documentation of orders Documentation of findings Management of the patient record Physician’s documentation relevant for nursing ... Admission of a patient Discharge of a patient Patient management ... Patientrelated ward organization Generation of organizational tools .... ... ... ... Table 2: An extract from the functional HIS model, describing some nursing hospital functions at the Plötzberg Medical Center and Medical School (PMC). 19 Technical modeling Technical metamodels are used to build models which describe the information processing tools used. As elements, they typically use physical data processing components (e.g., computer systems, telephones, forms, pagers, records) and application components (application programs, working plans). As 19This example is an extract from: Ammenwerth E, Haux R. A compendium of information processing functions in nursing development and pilot study. Computers in Nursing 2000; 18(4): 18996. 46 Strategic Information Management in Hospitals relationships, they describe the data transmission between physical data processing components (e.g., network diagrams), or the communication between application components. Typical questions which can be answered with models derived from technical metamodels are: • Which information processing tools are used? • Which application components communicate with each other? • What are the data transmission connections between the physical data processing components? • What does the network technology look like? • What technical solutions are used to guarantee security and reliability of information processing components? • Technical models are typically presented as lists (e.g., lists of information processing tools used) or as graphs (e.g., graph of the network architecture of computer systems). Examples for graphical models are presented in Figures 39 and 40. Storage Area Network Switch inf001S 2x50 GB data inf002S 2x50 GB data inf003S 2x50 GB backup inf004S 2x50 GB backup Figure 39: An extract of a technical HIS model with some physical data processing components and their data transmission links of the hospital information system of the Plötzberg Medical Center and Medical School. 3. What do Hospital Information Systems Look Like? 47 Organizational modeling Organizational metamodels are used to build models which describe the organization of a unit or area. For example, they may be used to describe the organizational structure of a hospital (e.g., consisting of departments with in and outpatient units). In the context of HIS, they are often used to describe the organization of information management, i.e. how it is organized in order to support the goals of the hospital. The elements of those models are usually units or roles which stand in a certain organizational relationship to each other. Typical questions to be answered with models derived from organizational metamodels are: • Which organizational units exist in a hospital? • Which institutions are responsible for information management? • Who is responsible for information management of a given area or unit? Clinical documentation system (Clindoc) (≈3700 user) Electronic patient record (EPA) (≈2900 user) Communication server (KomServ) Radiologic information system (RadIS) (≈250 user) Laboratory information system (LIS) (≈400 user) Anaesthesia documentation system (AnIS) (≈10 user) Pathological information system (PATH) (≈50 user) others ... Tumo r documentation system (Tumorix) (≈15 user) Dental information system (Dental) (≈150 user) Rostering information system (Timy) (≈300 user) Mail system (Exchange) (≈2000 user) Medical Knowledge Server (≈2500 user) Web Server Business Management Systems (Personal management, Controling Financing management, material management ...) (≈450 user) Office Products (≈4000 user) Patient management system (PMS) (≈500 user) Figure 40: An extract of a technical HIS model with some application components and their communication links of the hospital information system of the Plötzberg Medical Center and Medical School. 48 Strategic Information Management in Hospitals Organizational models are typically represented as a list of organizational units (e.g., list of the departments and sections in a hospital), or as a graph (e.g., graphical description of the organizational relationships). An example is presented in Figure 41. Data modeling Data metamodels are used to create models which describe the data processed and stored in a hospital information system. The elements they offer are typically data objects and their relationships. Typical questions to be answered with models derived from data metamodels are: • What data are processed and stored in the information system? • Which relationship do the data elements have? E.g., the class diagrams in UML20 offer a typical metamodel for data modeling. An example is presented in Figure 42. 20 Object Management Group (OMG): Unified Modeling Language – UML. http:www.uml.org. Figure 41: Extract from the organizational model of Plötzberg Medical Center and Medical School. Hospitals Executive Commitee Dept. of Surgery Dept. of Internal Medicine Dept. of Pathology Hospitals administration General surgery Paediatr ic s surgery inpatient units outpatient units Human resources Financal accountancy Engineering Acquisition ... ... Dept. of Information Management ..... ... 3. What do Hospital Information Systems Look Like? 49 Business process modeling Business process metamodels are used to create models which focus on a dynamic view of information processing. The elements used are activities and their chronological and logical order. Often, other elements are added, such as the role or unit which performs an activity, or the information processing tools which are used. The following perspectives can usually be distinguished: • Functional perspective: What activities are being performed, and which data flows are needed to link these activities? • Behavioral perspective: When are activities being performed, and how are they performed, using mechanisms such as loops and triggers? • Organizational perspective: Where and by whom are activities being performed? • Informational perspective: Which entities (documents, data, products) are being produced or manipulated? Typical questions to be answered with models derived from business process metamodels are: • Which activities are executed with regard to a given hospital function? • Who is responsible, and which tools are used, in a given process? • Which activity is the pre or postcondition for a given activity? • What are the weak points of the given process and how can it be improved? identification number name birthday address Patient identification number insurance Case type date provider Procedure 1 1 admission date discharge date ward identification Inpatient treatment date clinic identification Outpatient Figure 42: A simplified data model (UML class diagram), describing the relationships between the objects patient, case, and procedure, as extract from the data model of the HIS of the Plötzberg Medical Center and Medical School. 50 Strategic Information Management in Hospitals Due to the amount of different perspectives, various business process metamodels exist. Example are simple process chains, eventdriven process chains, activity diagrams, and petri nets. Simple process chainsdescribe the (linear) sequence of process steps. They simply describe the specific activities which form a process, in addition to the responsible role (e.g., a physician). Eventdriven process chainsadd dynamic properties of process steps: events and logical operators (and, or, xor) are added to the functions, allowing the more complex modeling of branching and alternatives. In addition, some instances of eventdriven process chains allow the addition of data objects (e.g., a chart). 21 Activity diagrams(as part of the modeling technique of the Unified Modeling Language, UML) also describe the sequence of process steps, using activities, branching, conditions, and data objects (see Figure 43). In addition, the method allows the splitting and synchronization of parallel subprocesses. 22 Finally, petri netsalso describe the dynamic properties of processes, but in a more formal way than the other methods which are mentioned.23 21 Scheer AW. ARIS Business Process Frameworks. Berlin: Springer; 1999. 22 Object Management Group (OMG): Unified Modeling Language – UML. http:www.uml.org. 23 Mortensen KH, Christensen S, editors. Petri Nets World. http:www.daimi.au.dkPetriNets. 3. What do Hospital Information Systems Look Like? 51 Enterprise modeling Enterprise modeling intends to describe the architecture of the enterprise, and especially the enterprises information system. Enterprise models do not only contain several enterprise views, such as functional models, technical models, organizational models, data models, or process models, but also the interactions between them, and, therefore, offer a more holistic view. Metamodels for enterprise modeling are often presented as matrices where the rows reflect distinctive layers and the columns reflect several views on these layers. A model has to be created for each cell of the matrix (which, of course, is normally based on a more specific metamodel). Typical questions to be answered with models derived from enterprise metamodels are: • Which hospital functions are supported by which information processing tools? Figure 43: Example of a business process model, based on a UML activity diagram, describing a part of the admission process in the Department of Child and Juvenile Psychiatry at Plötzberg Medical Center and Medical School. patients relative is calling holding first conversation get patient record start new record necessary not necessary necessity unclear forward call to physician arrange date note made check admission check if its patients first admission make a note of date secretary not necessary necessary physician administrative staff check admission no finish call finish call record got record started yes 52 Strategic Information Management in Hospitals • Are the information processing tools sufficient to support the enterprise functions? • Is the communication between the application components sufficient to fulfil the information needs? One of the most well known metamodels for enterprise modeling is the Zachman24 framework for information systems architectures (see Figure 44). Data (What) Function (How) Network (Where) People (Who) Time (When) Motivation (Why) Scope (Contextual) Enterprise Model (Conceptual) System Model (Logical) Technology Model (Physical) Detailed Representations Individual modeling aspects as mentioned above can be found within this framework. Data models are placed in the dataenterprise model cell, if the more conceptual aspect is stressed, or in the datasystem model cell if the database aspect is stressed. Technological models may be found at the system model or the technology model level especially in the function and network rows. Organizational models are placed in the people row, and functional models in the function row. The difficulty in using such a comprehensive framework will lay in the task to present the dependencies between the separated cells. Reference models for hospital information systems Until now we talked about HIS metamodels, i.e. about models to describe hospital information systems from various views. To support HIS modeling, it may also be helpful to use reference models. Reference models present a kind of 24 Zachman JA. A framework for information systems architecture. IBM systems journal 1999; 38(23): 45470 (Reprint). Figure 44: The Zachman Enterprise Architecture Framework. 3. What do Hospital Information Systems Look Like? 53 model pattern for a certain class of aspects. On the one hand, these model patterns can help to derive more specific models through modifications, limitations or addons (generic reference models). On the other hand, these model patterns can be used to directly compare models, e.g. concerning their completeness (nongeneric reference models). As well as specific models, reference models are instances of metamodels. A specific model may be considered as a variant of a reference model developed through specialization. This variant is an instance of that metamodel which also underlies the corresponding reference model. A reference model is always directed towards a certain aspect. For example, we can define reference models for hospital information systems, for communication systems, or for the gastrointestinal system. A (general) model can be defined as a reference model for a certain class of aspects. A reference model should be followed by a description of its usage, e.g. how specific models can be derived from the reference model, or how it can be used for the purpose of comparison. Specific models can be compared with a reference model, and consequently models can also be compared with each other, judging their similarity or discrepancy when describing certain aspects. Reference models can be normative in the sense that they are broadly accepted and have practical relevance. Reference models are more likely to be accepted if they are either recommended by a recognized institution, or if they are reliable and welltested. Different types of reference models can be described. For example, business reference modelsdescribe models of processes, data and organization of a certain class of organizations (e.g., of a certain industrial branch). A subtype of these reference models are information system reference models. They focus on information processing of a class of organizations. These reference models will be based on the metamodels we have presented in the previous chapter. For example, data reference models can describe typical data structures for a hospital information system. Organizational reference models can describe typical organizational structures for information management. Enterprise reference models can describe typical functions and architectures of hospital information systems. A second type of reference models are software reference models. They serve to derive models for different variants of a software product. Such a derived model can, e.g., describe in which form a software product can be parameterized for a specific usage. These models normally integrate different views on the software product, such as a data, functional or process view. A third class of reference models are procedure reference models. They focus on how to do certain things, e.g. how to introduce an information system component. Examples of procedure reference models from other areas include clinical guidelines. Using such a reference model together with additional 54 Strategic Information Management in Hospitals information, a project plan can be derived for a specific project to introduce a component. Various reference models for hospital information systems exist. Already in the 1980s, the Dutch National Hospital Institute developed a catalogue of hospital functions, which comprised the description of hospital functions and information needs. 25 The Common Basic Specification of the British National Health Service (NHS) from the early 1990s is also a functional reference model 26 . It describes the functions of different institutions which have to be supported by a computerbased information system. All functions are described as activities, combining the tasks enable, plan, do and execute. This also represents a part of a process reference model. In addition, a data reference model is described which contains objects types which are usually processed in hospitals. The NHS reference models are partly compulsory for the NHS institutions. In the framework of the European RICHE (Réseau dInformation et de Communication Hospitalier Européen) project, a process reference model for the description of activities in hospitals was established. This is the socalled orderandactmodel. 27 Activities are seen as part of a process, where a client (for example, a physician) orders an activity (order). This order is communicated to the executing person (for example, a nurse), which carries out the order (act) and reports the results to the client. A more recent example of a reference model for hospital functions is the Heidelberg reference model from 2000, developed with the support of the German Research Association.28 It is presented in Figure 45. This reference model focuses on the process of patient care. It distinguishes between functions central to the patient care process and functions supporting the patient care process. The main hospital functions supporting the process of patient care are presented as a sequence on the left side. The hospital functions which support patient care are presented on the right side. 25 van Bemmel JH, editor. Handbook of Medical Informatics. Heidelberg: Springer; 1997. p. 322 ff. 26 Herbert I. The Common Basic Specification (version 4.4), Information Management Group (IMG), United Kingdom National Health Service (NHS), 1993. 27 Frandji B. Open architecture for health care systems: the European RICHE experience. In: Dudeck J, Blobel B, Lordieck W, Bürkle T, editors. New technologies in hospital information systems Amsterdam: IOS Press; 1997. p. 1123. 28 Haux R, Ammenwerth E, Buchauer A et al. Requirements Index for Information Processing in Hospitals. Heidelberg: Dept. of Medical Informatics, Report No. 12001. Available at: http:www.umit.atreqhis. 3. What do Hospital Information Systems Look Like? 55 Figure 45: The Heidelberg reference model for hospital functions. Until now, there are only few available reference models for typical functions, processes or data of hospital information systems. Nevertheless, consultants create specific reference models for their clients. For example, a health care provider wants to standardize the business process of some hospitals. In this case, a system analysis will usually be performed in each hospital, and a general model of the planned state will be derived as the basis for detailed change planning. This is a (providerspecific) reference model and can be used to derive specific models to compare the current state with the planned state. Examples Example 3.3.1 A reference model for hospital functions The following Table 3 of hospital functions was established in 1997 by the German Research Association.29 The following list presents that part of the reference model relevant for patient care. 29 Haux R, Michaelis J. Investitionsschema zur Informationsverarbeitung in Krankenhäusern (investment scheme for information processing in hospitals). Das Krankenhaus 1997; 7: 42526. 1.1 patient admission 1.2 planning and organization of patient treatment 2.5 archiving of patient records 2.6 administration of patient records 1.3 order entry and taking samples 1.4 order entry and scheduling 1.5 execution of diagnostic or therapeutic procedures 1.8 clinical documentation 1.6 administrative documentation 1.7 billing 3.5 office communication support 3.4 general organization of work 4.3 costperformance accounting 3.1 scheduling and resource allocation 3.3 management and maintenance of equipment 4.5 human resources management 4.4 financial accounting 4.2 controlling and budgeting 1 Central Process:Treatment of patients 2 Handling of Patient Records 3 Work Organization and Resource Planning 4 Hospital Management 4.1 quality management 2.3 coding of diagnoses and procedures 3.6 basic information processing support 1.9 discharge and referral to other institutions 3.2 materials and pharmaceuticals management 2.1 creation and dispatch of documents 2.2 management of special documentation and clinical registers legend: x.x name hospital function logical operators process sequence including data exchange 2.4 analysis of patient records 4.6 general statistical analysis 56 Strategic Information Management in Hospitals Part I: patient care 1. General patient care functions 1.1 Patient administration 1.2 Management of the patient record 1.3 Electronic archiving of patient records (for example digitaloptical) 1.4 Basic clinical documentation 1.x Other functions 2 Ward functions 2.1 Ward management for physicians (including clinical documentation, writing documents, order entry, accounting) 2.2 Ward management for nurses (including nursing documentation, order entry, accounting) 2.3 Intensive care unit documentation 2.x Other functions 3 Outpatient unit functions 3.1 Management of outpatient units (including scheduling, process management, clinical documentation, document writing, order entry, accounting) 3.x Other functions 4 Diagnostic unit functions 4.1 Clinical laboratory 4.2 Radiology (organization) 4.3 Radiology (PACs – picture archiving and communication) 4.4 Immunology, microbiology, virology 4.5 Pathology 4.x Other functions 5 Therapeutic unit functions 5.1 Anesthesia documentation 5.2 Management of operating rooms (incl. documentation, reports, planning) 5.3 Radiotherapy 5.x Other functions 6 Functions for other units 6.1 Pharmacy 6.2 Blood bank 6.x Other functions 7 Other patient care functions 7.1 Roster planning 7.2 Documentation, organization and billing for dentistry departments 7.3 Telemedicine (especially telediagnostics) 7.x Other functions Part II: Support of patient care 1 Administrative functions 1.1 Accounting (in and outpatients) 1.2 Financial accounting 1.3 Maintenance of buildings 1.4 Calculation of costs and services, controlling 1.5 Stock management 1.6 Staff management 1.x Other functions 2 Communication functions 2.1 Office communication 2.2 Communication management (communication server) 2.3 Network management 2.x Other functions 3 Other functions for the support of research, education, patient care 3.1 Access to medical knowledge (for example Medline, diagnostic or therapeutic guidelines) 3.x Other functions Table 3: An example of a reference model for hospital functions. 3. What do Hospital Information Systems Look Like? 57 Exercises Exercise 3.3.1 Typical realization of hospital functions Please look at the hospital functions presented in Figure 45 and describe how they are realized in a hospital which you know. Try to classify each function according to how it is typically realized: • primarily conventional, • mostly conventional, • mixed, • mostly computersupported, • primarily computersupported. For example, patient admission is typically primarily realized with computersupported information processing tools, whereas nursing documentation is mostly realized conventionally. Exercise 3.3.2 Comparison of reference models for hospital functions Different reference models exist for hospital functions. Please compare the reference model presented in Table 3 with the Heidelberg reference model of hospital functions (Figure 45). • Which functions can be matched, and which cannot? • What could the reason be for the differences? Exercise 3.3.3 Modeling business processes with activity diagrams Goal of this exercise: To become familiar with a typical business process modeling method and its fields of application. a) Modeling a given process Design a graphical process model of nursing documentation. Use activity diagrams with the typical symbols for activities, transitions, branching, conditions and synchronization, responsible roles, and data objects to model the following process: Every time a patient is admitted to the ward, a new nursing plan is created: the nursing anamnesis is written down, together with the problems of the patients, the corresponding goals of the nursing treatment and the tasks to be executed. The anamnesis is written on conventional forms and then inserted in the conventional patient record. The other parts are created with the aid of a computerbased application component known as NDS and then printed out and inserted in the conventional patient record. At the beginning of each shift, the nurse reads the printed nursing plan to see which measures are to be executed. She copies the tasks to be executed during her shift onto a little paper which she carries with her. On this paper, she marks the tasks which have been taken care of. At the end of each shift, the nurse 58 Strategic Information Management in Hospitals documents which tasks have been executed in the printed nursing plan (by signing each task). She writes a short report on a special form about special occurrences during her shift. Finally, she validates the nursing plan and adopts it to the new state of the patients problems and the nursing goals. During the patient’s stay in the hospital, the nursing plan can be changed several times. The new plan is then again printed out and inserted into the conventional record. b) Weak point analysis of a given process Analyze the process modeled in a) and try to find weaknesses in the process. Weak points can, for example, be double documentation, changes in tools used, or possible transcription errors. If you find weak points, discuss possible solutions and redesign the process based on your improvements. Summary HIS models represent HIS. They are used to support description, management and operation of HIS. A good model adequately supports information managers in these tasks. According to their different purposes, different metamodels (models of models) exist for HIS. We can, for example, find functional metamodels, technical metamodels, organizational metamodels, data metamodels, business process metamodels, and enterprise metamodels. Functional models describe the functionality of a HIS. Technical models focus on the information processing tools used to reach this functionality. Organizational models describe the organization of areas or units. Data models describe the data processed and stored in an information system. Process models stress the dynamic aspects of HIS. Enterprise models provide a survey of an enterprise. Reference models are specific models which serve as model patterns. They can be used to derive concrete models, or to compare models. A typical reference model for hospital functions is the presented requirement catalog schema which distinguishes functions central to the patient care process from functions supporting the patient care process. 3.4 A metamodel for modeling HIS: 3LGM Let us now introduce a metamodel used to statically describe information processing functionality and tools, the so called three layer graphbased metamodel (3LGM) for modeling hospital information systems. It aims to support the systematic management of HIS, especially of heterogeneous ones, as well as the quality assessment of information processing. 3LGM combines a functional metamodel with technical metamodels. It is 3. What do Hospital Information Systems Look Like? 59 represented in UML notation. 30 The 3LGM distinguishes three layers of information management: The domain layer(see Figure 46) describes a hospital independent of its implementation. In the static view, a hospital is an accumulation of its functions. For example, PATIENT ADMISSION, NURSING, or TREATMENT may be functions. To fulfill these functions, information about objects (e. g. patients, findings, etc.) is used, generated, or deleted. Objects, which share the same attributes are classified as object types. For example, PATIENT, CASE, or LABORATORY RESULT may be object types. A function accesses an object type to get the information needed for its execution. This access may just use information (type: reading) or change information (type: writing) of an object. Which object types and which functions are modeled depends on the hospital being modeled. Reference models may offer recommendations about important object types and functions for certain kinds of hospitals. 1.. access 1.. object type 0..1 0.. function is part of 0.. 0..1 is part of access type: reading, writing Figure 46: 3LGM domain layer. Figure 47 shows an example of a domain layer. Rectangles represent object types and ovals represent functions. An arrow from an object type to a function marks read access, from a function to an object type, write access. Note that in the static view there are no direct relations between functions. This would be part of a dynamic view, i.e. of business process modeling. The domain layer is restricted to information about objects, and to functions to be performed. 30 Object Management Group (OMG): Unified Modeling Language – UML. http:www.uml.org. 60 Strategic Information Management in Hospitals patient admission insurance ordering diagnosing patient case order result diagnosis patient discharge laboratory services treatment Figure 47: 3LGM domain layer example. To perform functions, application components, which may be installed and adapted software products or conventional working plans, are used. These belong to the logical tool layer(see Figure 48). On this layer we describe how information about objects is logically stored, and how tools have to communicate to ensure the access to information as described in the domain layer. Application components may have a local database system to store data. They are controlled by application programs, which are adapted software products (this is what we can buy). A software product may be installed multiple times on one or more physical data processing components. As a result, we get several different application components. Communication interfaces ensure the communication among application components based on message types (like HL7 31 messages), but also between a component and a user (user interfaces). Application components may be refined. 31 HL7 is a communication standard in health care. See Health Level Seven. http:www.hl7.org. 3. What do Hospital Information Systems Look Like? 61 application component database system database management system application program communication interface is_controlled_by 1 disposes_of 0..1 is_controlled_by 0..1 owns 0.. software product is_based_on working plan {xor} user interface application component interface {disjoint} communication standard is_based_on 1 0..1 sending interface receiving interface 0.. 1 0.. 1 communicates_with is_part_of 0.. 1 message type 1.. object type function object type application component configuration function 1.. 0.. contains can_be_supported_by 1.. 1.. 1.. 1.. stores_objects_of_object_type 1 1 1 1.. 1.. 1.. can_support 1.. 1.. 1.. 1 1.. 1.. transports_information_about contains 1.. 1.. 1 is_mastered_by communicates type: {receives, sends} Figure 48: 3LGM logical tool layer. Dotted lines denote interlayer relationships (see page 570 ff.) Figure 49 shows an example of a logical tool layer. In this example we just look at the application components depicted as large rounded rectangles and the relationships between them via communication interfaces (small rectangles), depicted as arrows. Here, communication is based on HL7 or proprietary interfaces. The direction of the arrow represents the direction of the communication. For clarity, this example does not include database system aspects. 62 Strategic Information Management in Hospitals prop. HL7 PMS (patient ADT) ARCHIVES (archives administration) prop. LABSYS (laboratory system) HL7 HL7 MEDDB (medical database system) HL7 COMSERV (communication server) HL7 WARD (clinical documentation system) HL7 HL7 HL7 prop. prop. prop. prop. prop. HL7 HL7 Figure 49: 3LGM logical tool layer example. This example refers to the computer supported part of a hospital information system. It is simplified and fictive, but reflects a typical situation: indeed there is a HL7 based communication server, but obviously not all application components are able to use this communication service. As a consequence, a lot of proprietary interfaces are needed. Additionally, some application components communicate directly via HL7 interfaces. The physical tool layer(see Figure 50) is a set of physical data processing components (like personal computers, servers, switches, routers, etc), which are physically connected via socalled data transmission connections (e.g. data wires). The constellation of these connections leads to physical networks, which are based on network? protocols. Arbitrary subnets can be defined as projections of the entire network. Note that physical as well as logical networks can be represented on the physical tool layer. 3. What do Hospital Information Systems Look Like? 63 subnet net type net protocol physical data processing component 1.. 1.. belongs_to 0.. location component type 0.. is_part_of data transmission connection 1 is_based_on 1 data processing component configuration application component contains can_be_used_via 1.. 1.. 1.. 1.. 1.. 1.. 1.. 1.. is_based_on 1 1.. 0.. 0.. belongs_to Figure 50: 3LGM physical tool layer. Dotted lines denote interlayer relationships (see page 570 ff.) Figure 51 shows an example of a physical tool layer. In this example we distinguish between two component types: the rectangles represent servers and personal computers (PC) and the black dots represent connection points. Data transmission connections are depicted as lines. In this example, all physical data processing components belong to one network, i.e. there are no subnets. Information about network type, or network protocol is not represented. file server communication server laboratory server database server application server PC1 PC2 PC3 PC4 PC5 PC6 PC7 firewall server Figure 51: 3LGM physical tool layer example. A variety of dependencies, called interlayerrelationshipsexist among components of different layers. Relations exist between classes of the domain layer and the logical tool layer and 64 Strategic Information Management in Hospitals between classes of the logical tool layer and the physical tool layer. Considering the domain layer and the logical tool layer, the most important relationship is between functions and application components which is represented by a socalled application component configuration. It states, that a hospital function may be supported either by several application components together, by a single application component, or by combinations of the two. Two questions lead to the application component configurations for a specific function: Which application components are jointly necessary to support a function completely? An application component configuration contains all application components which are together directly necessary to support a function. If we remove an application component from this configuration, the function can no longer be supported by this configuration. Which possible alternatives are there to support a function? A function may be supported by more than one application component configuration. If we remove such a configuration the function is still supported by one of the remaining configurations, but may suffer from loss of quality. Application component configurations can not only, e.g. give hints about redundancies within hospital information systems, but also about weaknesses in the domain layer model. Figure 52 shows an example of an application component configuration. function: patient admission application component: PMS application component: MED DB application component: WARD necessarily necessarily alternatively application component configuration 1 application component configuration 2 Figure 52: Example of an application component configuration. Other relations between classes of the domain layer and the logical tool layer are: The first relation between object type and database system (stores_objects_of_object_types) describes in which databases the information about objects of a certain object type are stored. It can give hints about redundant data storage. The second relation between object type and database system (has_as_master) describes which database is responsible for the storage of objects of a certain 3. What do Hospital Information Systems Look Like? 65 object type, and, therefore, in case of redundant data storage, contains the current data. The relation between object type and message type expresses that information about objects of a certain object type is transported by a message of a certain message type. The relation between function and software product
Trang 1Reinhold Haux Alfred Winter
Elske Ammenwerth Birgit Brigl
Strategic Information Management in Hospitals
An Introduction to Hospital Information Systems
Trang 23 What do Hospital Information Systems look like?
3.1 Introduction
A hospital information system (HIS) was previously defined as the subsystem
of a hospital, which comprises all information processing as well as theassociated human or technical actors in their respective information processingroles
We will now take a closer look at what hospital information systems looklike We will then present typical functions and processes of hospitals We willdiscuss how to describe hospital information systems using appropriate modelingmethods We will in detail describe the three layer graph-based metamodel todescribe HIS Finally, we will discuss typical architectures of hospitalinformation systems
After this chapter, you should be able to answer the following questions:
• Which typical hospital functions exist?
• Which metamodels exist for modeling which aspects of HIS?
• What is the three layer graph-based metamodel (3LGM)?
• Which typical information processing tools exist in hospitals?
• Which architectural styles of HIS exist?
and administration In addition, each patient
must be correctly identified, and a unique
patient and case identification must be
assigned Sub-functions are:
• Appointment scheduling: The hospital
must be able to schedule an appointment
for a patient's visit In addition, unplanned
admissions must be possible (e.g., in case
of emergencies)
Figure 26: A patient beingadmitted in a patient admissiondepartment
Trang 3Figure 27: Typicalorganizational media.
• Patient identification: A unique patient identification number (PIN) must beassigned to each patient This PIN should be valid and unchangeablelifelong (i.e the PIN should not be based on changeable patient’s attributessuch as name) The PIN is the main precondition for a patient-orientedcombination of all information arising during a patient's stay Before a PINcan be assigned, the patient must be correctly identified, usually based onavailable administrative patient data If the patient has already been in thehospital, she or he must be identified as recurrent, and previouslydocumented information must be made available (such as previousdiagnoses and therapies) If the patient is in the hospital for the first time, anew PIN must be assigned In addition, the
hospital must be able to distinguish between
different cases or hospital stays of a patient
Therefore, in addition to the PIN, a case
identification is usually assigned
• Administrative admission: Administrative
admission starts following patient identification
For example, insurance data, type of admission,
details about special services, patient's relatives,
admitting physician, and referral diagnoses must
be recorded The patient is assigned to a ward
and a bed Some of the administrative data must
be made available to other hospital functions
through the help of certain organization media
(such as labels and magnetic cards, see Figure
27) Administrative data form the backbone of
information processing In case of changes,
patient data must be maintained and communicated If the admittingphysician has communicated relevant information (e.g previous laboratoryfindings), this information must be communicated to the responsiblephysician in the hospital Administrative admission is usually either done in
a central patient admission, or
directly on the ward (for example,
during emergencies or on the
weekend)
• Clinical admission: The responsible
physician and nurse will proceed
with the medical and nursing
admission This typically comprises
the anamnesis (both by physician
and nurse), and the introduction of
the patient to the ward These
basic data have to be available for
Figure 28: Information of patient’srelatives at a ward
Trang 4each of the following hospital functions.
• Information: The hospital management must always have an overview of therecent bed occupation, i.e about the patients staying at the hospital This is,for example, important for the porters which must be able to inform relativesand visitors correctly (see Figure 28), and also for some general hospitalmanagement statistics
Planning and organization of patient treatment
All clinical procedures of health care
professionals must be discussed, agreed upon,
initiated, and efficiently planned In contrast
to patient admission, the management of
patient treatment is a continuous task which is
initiated each time new information is
available Sub-functions are:
• Presentation of information and
knowledge: Staff members must be able
to access all relevant patient data specific
to a situation, in addition to general
clinical knowledge (e.g., guidelines and
standards) supporting patient care (see
Figure 29)
• Decision making and patient information: Responsible team members mustdecide upon the next steps such as certain diagnostic or therapeuticprocedures (see Figure 30) Depending on the complexity of a diagnostic ortherapeutic decision, they should be able to consult internal or externalexperts (e.g., in specialized hospitals) to
get a second opinion (e.g., about the
question if a patient can be transported by
exchanging CT images) In this context,
(tele)-conferences may be useful
Decisions about clinical procedures must
be documented The patient should be
included in the decision making process,
and his informed consent must be
documented as well
• Care planning: The next steps now have
to be planned in detail For each
procedure (such as an operation or a
chemotherapeutic treatment), the type,
extent, duration and responsible person have to be fixed In nursing,treatment planning is documented in nursing care plans, containing nursingproblems, nursing goals, and planned nursing procedures If necessary, otherhealth care professionals are ordered to execute the planned clinical
Figure 29: Infrastructure toaccess medical knowledge
Figure 30: Regular meeting ofhealth care professionals todiscuss care plans for patients
Trang 5procedures (e.g., medical bandaging orders which have to be executed by anurse).
Order entry and communication of findings
Diagnostic and therapeutic procedures must often be ordered at specializedservice units (e.g., laboratory, radiology, or pathology) These units execute theordered procedures and communicate the findings or results back to the orderingdepartment Subfunctions are:
• Preparation of an order: Depending on the available service spectrumoffered by a service unit, which may be presented in the form of catalogs,the physician or nurse selects the adequate service on an order entry form(see Figure 31) Patient and case identification, together with relevantinformation such as recent diagnoses, the concrete questions, the serviceordered (e.g laboratory, radiology), and other comments (e.g on specialrisks) are documented An order should only be initiated by authorizedpersons
• Taking samples or scheduling
appointments and procedures:
Depending on the type of order,
specimens which must be
unambiguously assigned to a patient are
submitted (e.g., blood samples), or
patient’s appointments must be fixed
(e.g., in radiological units) During
scheduling, the demands of all parties
must be fairly balanced (e.g ordering
physician, service unit, patient,
transport unit)
• Transmission of the order: The order
must quickly and correctly be transmitted to the service unit If a specimen istransferred, it must be guaranteed that the order and specimen can be linked
to each other at the service unit If necessary, modification to alreadytransferred orders by the ordering physician or nurse should be possible
• Reporting of findings: Findings and
reports must be transmitted (as quickly
as necessary) back to the ordering unit
on time and presented to the responsible
health care professional They must be
unambiguously assigned to the correct
patient The responsible physician
should be informed about new results,
and critical findings should be
Trang 6Execution of diagnostic or therapeutic procedures
The planned diagnostic, therapeutic or nursing procedures (such asoperations, radiotherapy, radiological examinations, medication) must beexecuted (see Figure 32) The hospital must offer adequate tools and resources(e.g staff, room, equipment) for necessary procedures
It is important that changes in care planning which may be due to newfindings are directly communicated to all involved units and persons, enablingthem to execute them as quickly as possible
Clinical documentation
The goal of clinical documentation is to record all clinically relevant patientdata (such as vital signs, orders, results, decisions, dates) as completely,correctly and quickly as possible This supports the coordination of patienttreatment between all involved persons, and also the legal justification of theactions taken Data should be recorded in as structured a form as possible It isimportant that data can be linked by patient and case identification, even whendata originate in different areas (such as ward, service unit, outpatient unit)
Usually, the hospital has to fulfill a lot of different legal reporting (such asepidemiological registers) and documentation requirements Often, data must beadequately coded (for example, using the
International Classification of Diseases,
ICD-1018, for diagnoses codes)
The content of clinical documentation
depends on the documenting unit and the
documenting health care professional group
(such as documentation by nurses or
physicians, documentation in outpatient
units or in operation rooms) Clinical
information should be available for other
purposes such as accounting, controlling,
quality management, or research and
education
Sub-functions are:
• Nursing documentation (see Figure 33) comprises the documentation or thenursing care process (nursing anamnesis, care planning, proceduredocumentation, evaluation and reports writing), together with documentation
of vital signs, medication, and other details of patient care
18 World health organization (WHO): Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) http://www.who.int/whosis/icd10/
Figure 33: Nursing documentation on award
Trang 7• Physician documentation comprises the documentation of medicalanamnesis, diagnoses, therapies and findings, and also documentation forspecial areas (such as documentation in intensive care units) or specialpurposes (such as clinical trials) It also comprises order entry for serviceunits and for other health care professional groups (such as nurses).
Administrative documentation and billing
The hospital must be able to document all services carried out in a correct,complete, quick and patient-oriented way Those data are then the basis for thehospital's billing The administrative service can also be used for controlling,cost center accounting and internal budgeting, cost responsibility accounting (i.e.the presentation of costs with regard to the source, for example a patient), andfor other economic analysis In addition, some of the data must be documentedand communicated due to legal requirements
During administrative documentation, diagnoses and procedures are recorded
in a standardized way, and then processed Administrative documentation should
be at least partly derivable from clinical documentation To supportadministrative documentation, adequate catalogs must be offered andmaintained, containing lists of typical diagnoses and procedures relevant for aunit or a hospital
Patient discharge and referral to other institutions
When patient treatment is terminated, the patient is discharged and referred
to other institutions (e.g., a general practitioner, or a rehabilitation center).Administrative patient’s discharge contains the initiation of final billing and thefulfillment of legal reporting requirements (e.g statistics on diagnoses andprocedures) Clinical and nursing patient’s discharge comprises the completing
of documentation and writing of a discharge report The hospital must be able totransmit this and other information (e.g., radiological images) to the otherinstitutions as quickly as possible To speed up this process, a short report (i.e.,physician's discharge letter) is often immediately communicated to the nextinstitution, containing for example the diagnoses and therapeutical propositions,which is then later followed by a more detailed report
Handling of patient records
Relevant data and documents must be created, gathered, presented and storedsuch that they are efficiently retrievable during the whole process of patienttreatment This storage is primarily done in patient records Usually, a certainamount of legal requirements must be considered Sub-functions are:
• Creation and dispatch of documents: Medical documents, such as physicianletters and surgical reports, should be easy to create, be available on timeand be patient-oriented Already documented information should be reusable
as much as possible (e.g laboratory results and coded diagnoses should be
Trang 8reusable for the discharge report) All
documents should be signed with author and
date of generation
• Management of documentation for special
areas or special purposes and clinical registers:
They should by easy to create and maintain, for
example, to support quality management,
research, or individual departments Already
documented data (e.g from clinical
documentation) should be reusable as much as
possible Queries for a given subset of patients
should be possible
• Coding of diagnoses and procedures: Basic
medical data such as diagnoses and procedures
should be easy to document in a structured
way Basic dataset documentation serves for the internal hospital reportingstructure as well as for the fulfillment of legal requirements
• Analysis of patient records (see Figure 34): All data from patient records(whether computer-based or not) should be available on time and in an easy,comprehensive and structured way Therefore, a uniform structure for thepatient record is useful Health-related data are very sensitive, the hospitalmust, thus, guarantee data protection and data security
• Archiving of patient records: After discharge of the patient, patient recordsmust be archived for a long time (e.g for 10 or 30 years, depending on thelegal regulations) The archive must offer
enough space to allow the long-term storage of
the created patient records Their authenticity
and correctness can be proven more easily, e.g
in case of civil actions, when they are archived
in accordance to legal regulations
• Administration of patient records: The hospital
archive must be able to manage patient records
and make them available upon request within a
defined timeframe The exact location of each
record should be available (e.g in which
archive, on which shelf) Lending and return of
records (e.g for recurring patients) has to be
organized (see Figure 35), while respecting
different access rights which depend on the
role of the health care professionals in the process of patient care
Figure 34: Analysis ofthe patient record
Figure 35: Documentingthe lending of patientrecords which have beenordered by clinicaldepartments
Trang 9Work organization and resource planning
The hospital must offer sufficient and well-organized resources for patientcare This is true for wards (ward management), outpatient units (outpatientmanagement), and service units (department management) Sub-functions are:
• Scheduling and resource allocation: Resources needed for patient care are,for example, staff, beds, rooms and devices
Resource management, therefore, comprises
staff planning, bed planning, room planning
and device planning All resource planning
activities must be harmonized with each other
When procedures are scheduled, the interests
to decide on the appointment of both the
service unit and the ordering unit must be
harmonized Request, reservation,
confirmation, notification, postponement and
cancellation must be supported All involved
staff members and the patients should be
informed about the next relevant appointments
Postponement and cancellations should be
communicated in time to all involved persons
• Materials and pharmaceuticals management
(see Figure 36 and 37): Supply and disposal of
materials, food, drugs and so on must
be guaranteed All departments of the
hospitals should be able to order them,
based on up-to-date catalogs The
corresponding service units (stock,
pharmacy, kitchen) must be able to
deliver correctly and on time
• Management and maintenance of
equipment: Various medical devices are
used in hospitals They must be
documented and maintained according
to legal legislation
• General organization of work: An
efficient process organization is
extremely important for hospitals, for example in outpatient units or serviceunits This can be supported, for example, by offering working lists, byreminding of next appointments, or by visualizing optimal processes
• Office communication support (see Figure 38): The hospital must be able tosupport communication between all persons involved in patient care Thiscomprises synchronous (e.g., telephone) and asynchronous (blackboards,brochures, e-mail) communication Staff members must be contactablewithin a definite time
Figure 36: The stock ofdrugs on a normal ward
Figure 37: In the central pharmacy
of a hospital
Figure 36: The stock ofdrugs on a normal ward
Trang 10• Basic information processing support: The hospital
must support basic information processing tasks such
as writing letters or calculating statistics
Hospital management
Hospital management supports the organization of
patient care and controls the financial issues of the
hospital One of the main tasks is recording and billing of
all accountable services Sub-functions are:
• Quality management: Quality management
supports a definitive quality of structure,
process and outcome of the hospital This
covers, for example, internal reporting
containing quality indices Quality
management requires information about patients and treatments as well asknowledge about diagnostic and therapeutic standards
• Controlling and budgeting: The hospital must be able to gather andaggregate data about the hospital's operation in order to control and optimize
it This covers, for example, staff controlling, process controlling, materialcontrolling, and financial controlling
• Cost-performance accounting: For controlling purposes, it is necessary tokeep track of services, their costs and who has received them This coversfor example, accounting of cost centers, cost units and process cost
• Financial accounting: All hospital's operations which deal with companiesvalues (for example, money, values, fortune, debt) have to be systematicallyrecorded according to legal requirements Financial accounting comprises,for example, debtor accounting, credit accounting, and facility accounting
• Human resources management: This contains all tasks for the developmentand improvement of the productivity of staff It comprises, for example, staffand position planning, staff recording, staff scheduling and staff billing
• General statistical analysis: The hospital must support general statisticalanalysis, for example calculation and analysis of economic data
Examples
{Example for an index of hospital functions?}
Figure 38: A physiciancommunicating by phonewith a generalpractitioner
Trang 11Exercises
Exercise 3.2.1 Differences in hospital functions
Please have a look at the hospital functions presented in this chapter Nowimagine a small hospital (for example, 350 beds) and a big university medicalcenter (for example, with 1,500 beds) What are the differences between bothhospitals with regard to their functions? Please explain your answer
Exercise 3.2.2 Different health care professional groups and hospital functions
Please have a look at the hospital functions listed in this chapter Analyze therelationships between the hospital functions and the different health careprofessional groups (physicians, nurses, administrative staff, others) working in ahospital Which hospital functions are performed by which health careprofessional group?
Please create a table with health care professional groups as columns,hospital functions as rows, and the following symbols as content in the boxes:
’++’ = hospital function is primarily performed by this profession;
’+’ = function is also performed by this profession;
’-‘ = function is not performed by this profession;
‘.’ = neither ‘++’, ‘+’ nor ‘-‘
Summary
Typical main hospital functions are
• patient admission with appointment scheduling, patient identification,administrative admission, clinical admission, and information processing;
• planning and organization of patient treatment with presentation ofinformation and knowledge, decision making and patient information, andcare planning;
• order entry and communication of findings with preparation of an order,preparation of specimen or scheduling of appointments and procedures,transmission of the order, and reporting of findings;
• execution of diagnostic or therapeutic procedures;
• clinical documentation with documentation performed by physician’s andnurses;
• administrative documentation and billing;
• patient discharge and referral to other institutions
These hospital functions are typically supported by functions such as
• handling of patient records with creation and dispatch of documents,management of documentation for special areas or special purposes and
Trang 12clinical registers, coding of diagnoses and procedures, and analysis,archiving and management of patient records;
• work organization and resource planning with scheduling and resourceallocation, materials and pharmaceuticals management, management andmaintenance of equipment, support in the general organization of work,office communication support, and basic information processing support;
• hospital management with quality management, controlling and budgeting,cost-performance accounting, financial accounting, human resourcesmanagement, and general statistical analysis
3.3 Modeling hospital information systems
Modeling HIS is an important precondition for their management: What wecannot describe, we usually cannot manage adequately We will present sometypes of information system metamodels, describing different aspects of HIS,and present some smaller examples of HIS models
HIS models and metamodels
A model was defined in chapter 2.3 as a description of what the modelerthinks to be relevant of a system The significance of models is based on theirability to present a subset of the (usually complex) reality and to aggregate thegiven information in order to answer certain questions or to support certain tasks.That means that models should present a simplified, but appropriate view of aHIS in order to support its management, and operation
Models should be appropriate for respective questions or tasks Examples ofquestions or tasks which are important with regard to hospital informationsystems could be:
• Which hospital functions are supported by a HIS?
• Which information processing tools are used?
• What are the steps of the business process of patient admission?
• What will happen if a specific server breaks down?
• How can the quality of information processing be judged?
A model is only 'good' when it is able to answer given questions or cansupport a given task (such as detection of weaknesses, or planning the futurestate of HIS) The better you can 'see' a HIS, and the better a model assists you inmanaging it (e.g in identifying good or also critical parts of HIS), the better themodel is Thus, the model you select depends on the problems or questions youhave
When looking at the amount of possible (and important) questions and tasks,
it is clear that a large number of different classes of models exists The class of amodel is described by its metamodel We can distinguish some typical
metamodels which each describe a class of similar models Metamodels describe
the modeling framework which consists of:
Trang 13• modeling syntax and semantics (the available modeling objects togetherwith their meaning),
• the representation of the objects (how the objects are represented in aconcrete model, e.g often in a graphical way),
• the modeling rules (e.g the relationships between objects),
• and (sometimes) the modeling steps
Just as different architectural views on HIS exist, there also exist variousmetamodels Typical types of metamodels for HIS are:
• functional metamodels, focusing on hospital functions which are supported
by the information system, i.e on the functionality of a HIS;
• technical metamodels that are used to built models describing theinformation processing tools used;
• organizational metamodels that are used to create models of theorganizational structure of HIS;
• data metamodels, used for building models of the structure of dataprocessed and stored inside a HIS;
• business process metamodels, focusing on the description of what is done inwhich chronological and logical order;
• enterprise metamodels, that combine different sub-models to an integrated,enterprise-wide information system model
Business process metamodels are also referred to as dynamic metamodels incontrast to the other more static metamodels
The art of HIS modeling is based on the right selection of a metamodel.Thus, for HIS modeling, you should consider the following steps:
1 Define the questions or tasks to be supported by the HIS model
2 Select an adequate metamodel
3 Gather the information needed for modeling
4 Model the information in a model (e.g., in a graphical way)
5 Analyze and interpret the model (answer your questions)
6 Evaluate if the right metamodel was chosen, i.e if the model wasadequate to answer the questions If not: proceed with step 2
In the next paragraphs, we will focus on some typical metamodels We willanswer the following questions for each metamodel:
• What elements does the metamodel offer?
• Which relationships between the elements can be modeled?
• Which questions can be answered by using this metamodel?
• What could a typical model look like, when derived from thismetamodel?
Functional modeling
Functional metamodels are used to build models which represent thefunctionality of a hospital (what is to be done) The elements they offer are thehospital functions which are supported by the hospital information system Therelationships of the hospital functions can, for example, represent the
Trang 14information exchange between them In addition, functions are often described in
a hierarchical way, comprising more global functions (such as patientmanagement) and more specific (refined) functions (such as patient billing)
Typical questions to be answered with models derived from functionalmetamodels are:
• Which hospital functions are supported by which HIS components?
• Which specific hospital functions are part of which global hospital function?
• Which hospital functions share the same data?
• Does the functional model correspond to a reference model?
Typical representations of functional models are (hierarchical) lists of functions,
as well as graphical presentations of the hospital functions Table 2 presents anextract from a three-level-hierarchy of hospital functions for informationprocessing in nursing:
Documentation of patient's resourcesDocumentation of nursing goalsPlanning and documentation of nursing tasksWriting of nursing reports
Nursingdocumentation
Documentation of ordersDocumentation of findings
Management of
the patient
record
Physician’sdocumentationrelevant for nursing
Admission of a patientDischarge of a patientPatient management
19 This example is an extract from: Ammenwerth E, Haux R A compendium of information processing functions in nursing - development and pilot study Computers in Nursing 2000; 18(4): 189-96.
Trang 15relationships, they describe the data transmission between physical dataprocessing components (e.g., network diagrams), or the communication betweenapplication components.
Typical questions which can be answered with models derived from technicalmetamodels are:
• Which information processing tools are used?
• Which application components communicate with each other?
• What are the data transmission connections between the physical dataprocessing components?
• What does the network technology look like?
• What technical solutions are used to guarantee security and reliability ofinformation processing components?
• Technical models are typically presented as lists (e.g., lists of informationprocessing tools used) or as graphs (e.g., graph of the network architecture
of computer systems) Examples for graphical models are presented inFigures 39 and 40
Storage Area Network
Switch inf001S
inf004S 2x50 GB backup
Figure 39: An extract of a technical HIS model with some
physical data processing components and their data
transmission links of the hospital information system of the
Plötzberg Medical Center and Medical School
Trang 16Organizational modeling
Organizational metamodels are used to build models which describe theorganization of a unit or area For example, they may be used to describe theorganizational structure of a hospital (e.g., consisting of departments with in- andoutpatient units) In the context of HIS, they are often used to describe theorganization of information management, i.e how it is organized in order tosupport the goals of the hospital
The elements of those models are usually units or roles which stand in acertain organizational relationship to each other Typical questions to beanswered with models derived from organizational metamodels are:
• Which organizational units exist in a hospital?
• Which institutions are responsible for information management?
• Who is responsible for information management of a given area or unit?
Clinical documentation system (Clindoc) (≈≈≈≈ 3700 user)
Electronic patient record (EPA) (≈≈≈≈ 2900 user)
Communication server (KomServ)
Radiologic information system (RadIS) (≈≈≈≈ 250 user)
Laboratory information system (LIS) (≈≈≈≈ 400 user)
Anaesthesia documentation system (AnIS) (≈≈≈≈ 10 user) Pathological information system (PATH) (≈≈≈≈ 50 user)
Rostering information system (Timy) (≈≈≈≈ 300 user)
Figure 40: An extract of a technical HIS model with some application components andtheir communication links of the hospital information system of the Plötzberg MedicalCenter and Medical School
Trang 17Organizational models are typically represented as a list of organizational
units (e.g., list of the departments and sections in a hospital), or as a graph (e.g.,
graphical description of the organizational relationships) An example is
presented in Figure 41
Data modeling
Data metamodels are used to create models which describe the data
processed and stored in a hospital information system The elements they offer
are typically data objects and their relationships Typical questions to be
answered with models derived from data metamodels are:
• What data are processed and stored in the information system?
• Which relationship do the data elements have?
E.g., the class diagrams in UML20 offer a typical metamodel for data
modeling An example is presented in Figure 42
20 Object Management Group (OMG): Unified Modeling Language – UML.
http://www.uml.org.
Figure 41: Extract from the organizational model of Plötzberg Medical
Center and Medical School
Hospitals Executive Commitee
Dept of Surgery Dept of Internal Medicine Dept of Pathology Hospital's administration
General surgery
Paediatrics
surgery
inpatient units
outpatient units
Human resources
Financal accountancy
Trang 18Business process modeling
Business process metamodels are used to create models which focus on adynamic view of information processing The elements used are activities andtheir chronological and logical order Often, other elements are added, such asthe role or unit which performs an activity, or the information processing toolswhich are used The following perspectives can usually be distinguished:
• Functional perspective: What activities are being performed, and which dataflows are needed to link these activities?
• Behavioral perspective: When are activities being performed, and how arethey performed, using mechanisms such as loops and triggers?
• Organizational perspective: Where and by whom are activities beingperformed?
• Informational perspective: Which entities (documents, data, products) arebeing produced or manipulated?
Typical questions to be answered with models derived from business processmetamodels are:
• Which activities are executed with regard to a given hospital function?
• Who is responsible, and which tools are used, in a given process?
• Which activity is the pre- or post-condition for a given activity?
• What are the weak points of the given process and how can it be improved?
Case
-type -date -provider
Procedure
-admission date -discharge date -ward identification
Inpatient
-treatment date -clinic identification
Outpatient
Figure 42: A simplified data model (UML class diagram), describing therelationships between the objects patient, case, and procedure, as extract from thedata model of the HIS of the Plötzberg Medical Center and Medical School
Trang 19Due to the amount of different perspectives, various business processmetamodels exist Example are simple process chains, event-driven processchains, activity diagrams, and petri nets.
Simple process chains describe the (linear) sequence of process steps They
simply describe the specific activities which form a process, in addition to theresponsible role (e.g., a physician)
Event-driven process chains add dynamic properties of process steps: events
and logical operators (and, or, xor) are added to the functions, allowing the morecomplex modeling of branching and alternatives In addition, some instances ofevent-driven process chains allow the addition of data objects (e.g., a chart).21
Activity diagrams (as part of the modeling technique of the Unified Modeling
Language, UML) also describe the sequence of process steps, using activities,branching, conditions, and data objects (see Figure 43) In addition, the methodallows the splitting and synchronization of parallel sub-processes.22
Finally, petri nets also describe the dynamic properties of processes, but in a
more formal way than the other methods which are mentioned.23
21 Scheer AW ARIS - Business Process Frameworks Berlin: Springer; 1999.
22 Object Management Group (OMG): Unified Modeling Language – UML http://www.uml.org.
23 Mortensen KH, Christensen S, editors Petri Nets World http://www.daimi.au.dk/PetriNets.
Trang 20Enterprise modeling
Enterprise modeling intends to describe the architecture of the enterprise, andespecially the enterprise's information system Enterprise models do not onlycontain several enterprise views, such as functional models, technical models,organizational models, data models, or process models, but also the interactionsbetween them, and, therefore, offer a more holistic view
Metamodels for enterprise modeling are often presented as matrices wherethe rows reflect distinctive layers and the columns reflect several views on theselayers A model has to be created for each cell of the matrix (which, of course, isnormally based on a more specific metamodel)
Typical questions to be answered with models derived from enterprisemetamodels are:
• Which hospital functions are supported by which information processingtools?
Figure 43: Example of a business process model, based on a UML activity diagram,describing a part of the admission process in the Department of Child and JuvenilePsychiatry at Plötzberg Medical Center and Medical School
[patient's relative is calling]
holding first
conversation
get patient record
start new record
[necessary]
[not necessary]
[necessity unclear] forward call
[no]
finish call finish call
[record got] [record started]
[yes]
Trang 21• Are the information processing tools sufficient to support the enterprisefunctions?
• Is the communication between the application components sufficient to fulfilthe information needs?
One of the most well known metamodels for enterprise modeling is theZachman24 framework for information systems architectures (see Figure 44)
Data
(What)
Function (How)
Network (Where)
People (Who)
Time (When)
Motivation (Why)
Reference models for hospital information systems
Until now we talked about HIS metamodels, i.e about models to describehospital information systems from various views To support HIS modeling, itmay also be helpful to use reference models Reference models present a kind of
24 Zachman JA A framework for information systems architecture IBM systems journal 1999; 38(2&3): 454-70 (Reprint).
Figure 44: The Zachman Enterprise Architecture
Framework
Trang 22model pattern for a certain class of aspects On the one hand, these modelpatterns can help to derive more specific models through modifications,limitations or add-ons (generic reference models) On the other hand, thesemodel patterns can be used to directly compare models, e.g concerning theircompleteness (non-generic reference models) As well as specific models,reference models are instances of metamodels A specific model may beconsidered as a variant of a reference model developed through specialization.This variant is an instance of that metamodel which also underlies thecorresponding reference model.
A reference model is always directed towards a certain aspect For example,
we can define reference models for hospital information systems, forcommunication systems, or for the gastrointestinal system A (general) modelcan be defined as a reference model for a certain class of aspects
A reference model should be followed by a description of its usage, e.g howspecific models can be derived from the reference model, or how it can be usedfor the purpose of comparison
Specific models can be compared with a reference model, and consequentlymodels can also be compared with each other, judging their similarity ordiscrepancy when describing certain aspects
Reference models can be normative in the sense that they are broadlyaccepted and have practical relevance Reference models are more likely to beaccepted if they are either recommended by a recognized institution, or if theyare reliable and well-tested
Different types of reference models can be described For example, business
reference models describe models of processes, data and organization of a
certain class of organizations (e.g., of a certain industrial branch) A subtype ofthese reference models are information system reference models They focus oninformation processing of a class of organizations These reference models will
be based on the metamodels we have presented in the previous chapter Forexample, data reference models can describe typical data structures for a hospitalinformation system Organizational reference models can describe typicalorganizational structures for information management Enterprise referencemodels can describe typical functions and architectures of hospital informationsystems
A second type of reference models are software reference models They
serve to derive models for different variants of a software product Such aderived model can, e.g., describe in which form a software product can beparameterized for a specific usage These models normally integrate differentviews on the software product, such as a data, functional or process view
A third class of reference models are procedure reference models They
focus on how to do certain things, e.g how to introduce an information systemcomponent Examples of procedure reference models from other areas includeclinical guidelines Using such a reference model together with additional
Trang 23information, a project plan can be derived for a specific project to introduce acomponent
Various reference models for hospital information systems exist
Already in the 1980s, the Dutch National Hospital Institute developed acatalogue of hospital functions, which comprised the description of hospitalfunctions and information needs.25
The 'Common Basic Specification' of the British National Health Service(NHS) from the early 1990s is also a functional reference model26 It describesthe functions of different institutions which have to be supported by a computer-based information system All functions are described as activities, combiningthe tasks enable, plan, do and execute This also represents a part of a processreference model In addition, a data reference model is described which containsobjects types which are usually processed in hospitals The NHS referencemodels are partly compulsory for the NHS institutions
In the framework of the European RICHE (Réseau d'Information et deCommunication Hospitalier Européen) project, a process reference model for thedescription of activities in hospitals was established This is the so-called order-and-act-model.27 Activities are seen as part of a process, where a client (forexample, a physician) orders an activity (order) This order is communicated tothe executing person (for example, a nurse), which carries out the order (act) andreports the results to the client
A more recent example of a reference model for hospital functions is theHeidelberg reference model from 2000, developed with the support of theGerman Research Association.28 It is presented in Figure 45 This referencemodel focuses on the process of patient care It distinguishes between functionscentral to the patient care process and functions supporting the patient careprocess The main hospital functions supporting the process of patient care arepresented as a sequence on the left side The hospital functions which supportpatient care are presented on the right side
28 Haux R, Ammenwerth E, Buchauer A et al Requirements Index for Information Processing in Hospitals Heidelberg: Dept of Medical Informatics, Report No 1/2001 Available at: http://www.umit.at/reqhis.
Trang 243 What do Hospital Information Systems Look Like? 55
Figure 45: The Heidelberg reference model for hospital functions
Until now, there are only few available reference models for typicalfunctions, processes or data of hospital information systems Nevertheless,
consultants create specific reference models for their clients For example, a
health care provider wants to standardize the business process of some hospitals
In this case, a system analysis will usually be performed in each hospital, and a
general model of the planned state will be derived as the basis for detailed
change planning This is a (provider-specific) reference model and can be used
to derive specific models to compare the current state with the planned state
Examples
Example 3.3.1 A reference model for hospital functions
The following Table 3 of hospital functions was established in 1997 by theGerman Research Association.29 The following list presents that part of the
reference model relevant for patient care
29 Haux R, Michaelis J Investitionsschema zur Informationsverarbeitung in
Krankenhäusern (investment scheme for information processing in hospitals) Das Krankenhaus 1997; 7: 425-26.
1.1 patient admission
1.2 planning and organization of patient treatment
2.5 archiving of patient records
2.6 administration of patient records
1.3 order entry and
1.8 clinical documentation 1.6 administrative
documentation
1.7 billing
3.5 office communication support
3.4 general organization of work
4.3 cost-performance accounting
resource allocation
3.3 management and maintenance of equipment
4.5 human resources management
4.4 financial accounting
4.2 controlling and budgeting management
2.3 coding of diagnoses and procedures
3.6 basic information processing support
referral to other institutions
3.2 materials and pharmaceuticals management
dispatch of documents
2.2 management of special documentation and clinical registers
legend: x.x name hospital
function
logical operators process sequence including data exchange
2.4 analysis of patient records
4.6 general statistical analysis
Trang 25Part I: patient care
1 General patient care functions
1.1 Patient administration
1.2 Management of the patient record
1.3 Electronic archiving of patient records (for
example digital-optical)
1.4 Basic clinical documentation
1.x Other functions
2 Ward functions
2.1 Ward management for physicians
(including clinical documentation, writing
documents, order entry, accounting)
2.2 Ward management for nurses
(including nursing documentation, order
entry, accounting)
2.3 Intensive care unit documentation
2.x Other functions
3 Outpatient unit functions
3.1 Management of outpatient units
(including scheduling, process
management, clinical documentation,
document writing, order entry,
accounting)
3.x Other functions
4 Diagnostic unit functions
4.1 Clinical laboratory4.2 Radiology (organization)4.3 Radiology (PACs – picturearchiving and communication)4.4 Immunology, microbiology,virology
4.5 Pathology4.x Other functions
5 Therapeutic unit functions
5.1 Anesthesia documentation5.2 Management of operating rooms(incl documentation, reports,planning)
5.3 Radiotherapy5.x Other functions
6 Functions for other units
6.1 Pharmacy6.2 Blood bank6.x Other functions
7 Other patient care functions
7.1 Roster planning7.2 Documentation, organization andbilling for dentistry departments7.3 Tele-medicine (especially tele-diagnostics)
3 Other functions for the support of research, education, patient care
3.1 Access to medical knowledge (forexample Medline, diagnostic ortherapeutic guidelines)3.x Other functionsTable 3: An example of a reference model for hospital functions
Trang 26Exercises
Exercise 3.3.1 Typical realization of hospital functions
Please look at the hospital functions presented in Figure 45 and describe howthey are realized in a hospital which you know Try to classify each functionaccording to how it is typically realized:
Exercise 3.3.2 Comparison of reference models for hospital functions
Different reference models exist for hospital functions Please compare thereference model presented in Table 3 with the Heidelberg reference model ofhospital functions (Figure 45)
• Which functions can be matched, and which cannot?
• What could the reason be for the differences?
Exercise 3.3.3 Modeling business processes with activity diagrams
Goal of this exercise: To become familiar with a typical business processmodeling method and its fields of application
a) Modeling a given process
Design a graphical process model of nursing documentation Use activitydiagrams with the typical symbols for activities, transitions, branching,conditions and synchronization, responsible roles, and data objects to model thefollowing process:
"Every time a patient is admitted to the ward, a new nursing plan is created:the nursing anamnesis is written down, together with the problems of thepatients, the corresponding goals of the nursing treatment and the tasks to beexecuted The anamnesis is written on conventional forms and then inserted inthe conventional patient record The other parts are created with the aid of acomputer-based application component known as 'NDS' and then printed out andinserted in the conventional patient record
At the beginning of each shift, the nurse reads the printed nursing plan to seewhich measures are to be executed She copies the tasks to be executed duringher shift onto a little paper which she carries with her On this paper, she marksthe tasks which have been taken care of At the end of each shift, the nurse
Trang 27documents which tasks have been executed in the printed nursing plan (bysigning each task) She writes a short report on a special form about specialoccurrences during her shift Finally, she validates the nursing plan and adopts it
to the new state of the patients problems and the nursing goals During thepatient’s stay in the hospital, the nursing plan can be changed several times Thenew plan is then again printed out and inserted into the conventional record."
b) Weak point analysis of a given process
Analyze the process modeled in a) and try to find weaknesses in the process.Weak points can, for example, be double documentation, changes in tools used,
or possible transcription errors If you find weak points, discuss possiblesolutions and redesign the process based on your improvements
Summary
HIS models represent HIS They are used to support description,management and operation of HIS A good model adequately supportsinformation managers in these tasks
According to their different purposes, different metamodels (models ofmodels) exist for HIS We can, for example, find functional metamodels,technical metamodels, organizational metamodels, data metamodels, businessprocess metamodels, and enterprise metamodels
Functional models describe the functionality of a HIS Technical modelsfocus on the information processing tools used to reach this functionality.Organizational models describe the organization of areas or units Data modelsdescribe the data processed and stored in an information system Process modelsstress the dynamic aspects of HIS Enterprise models provide a survey of anenterprise
Reference models are specific models which serve as model patterns Theycan be used to derive concrete models, or to compare models A typicalreference model for hospital functions is the presented requirement catalogschema which distinguishes functions central to the patient care process fromfunctions supporting the patient care process
3.4 A metamodel for modeling HIS: 3LGM
Let us now introduce a metamodel used to statically describe informationprocessing functionality and tools, the so called three layer graph-basedmetamodel (3LGM) for modeling hospital information systems It aims tosupport the systematic management of HIS, especially of heterogeneous ones, aswell as the quality assessment of information processing
3LGM combines a functional metamodel with technical metamodels It is
Trang 28represented in UML notation The 3LGM distinguishes three layers ofinformation management:
The domain layer (see Figure 46) describes a hospital independent of its
implementation In the static view, a hospital is an accumulation of its functions.For example, PATIENT ADMISSION, NURSING, or TREATMENT may befunctions To fulfill these functions, information about objects (e g patients,findings, etc.) is used, generated, or deleted Objects, which share the sameattributes are classified as object types For example, PATIENT, CASE, orLABORATORY RESULT may be object types A function accesses an objecttype to get the information needed for its execution This access may just useinformation (type: reading) or change information (type: writing) of an object
Which object types and which functions are modeled depends on the hospitalbeing modeled Reference models may offer recommendations about importantobject types and functions for certain kinds of hospitals
type: reading, writing
Figure 46: 3LGM domain layer
Figure 47 shows an example of a domain layer Rectangles represent objecttypes and ovals represent functions An arrow from an object type to a functionmarks read access, from a function to an object type, write access Note that inthe static view there are no direct relations between functions This would bepart of a dynamic view, i.e of business process modeling The domain layer isrestricted to information about objects, and to functions to be performed
30 Object Management Group (OMG): Unified Modeling Language – UML http://www.uml.org.
Trang 29Figure 47: 3LGM domain layer - example
To perform functions, application components, which may be installed andadapted software products or conventional working plans, are used These
belong to the logical tool layer (see Figure 48) On this layer we describe how
information about objects is logically stored, and how tools have to communicate
to ensure the access to information as described in the domain layer Applicationcomponents may have a local database system to store data They are controlled
by application programs, which are adapted software products (this is what wecan buy) A software product may be installed multiple times on one or morephysical data processing components As a result, we get several differentapplication components Communication interfaces ensure the communicationamong application components based on message types (like HL731 messages),but also between a component and a user (user interfaces) Applicationcomponents may be refined
31 HL7 is a communication standard in health care See Health Level Seven http://www.hl7.org.
Trang 30application component
database system database
disposes_of 0 1
{disjoint}
communication standard
is_based_on 1
Figure 48: 3LGM logical tool layer Dotted lines denote interlayer relationships (see page
570 ff.)
Figure 49 shows an example of a logical tool layer In this example we just look
at the application components depicted as large rounded rectangles and therelationships between them via communication interfaces (small rectangles),depicted as arrows Here, communication is based on HL7 or proprietaryinterfaces The direction of the arrow represents the direction of thecommunication For clarity, this example does not include database systemaspects
Trang 31HL7
COMSERV
(communication server)
WARD
( clinical tation system )
Figure 49: 3LGM logical tool layer - example
This example refers to the computer supported part of a hospital informationsystem It is simplified and fictive, but reflects a typical situation: indeed there is
a HL7 based communication server, but obviously not all applicationcomponents are able to use this communication service As a consequence, a lot
of proprietary interfaces are needed Additionally, some application componentscommunicate directly via HL7 interfaces
The physical tool layer (see Figure 50) is a set of physical data processing
components (like personal computers, servers, switches, routers, etc), which arephysically connected via so-called data transmission connections (e.g datawires) The constellation of these connections leads to physical networks, whichare based on network? protocols Arbitrary subnets can be defined as projections
of the entire network Note that physical as well as logical networks can berepresented on the physical tool layer
Trang 32subnet net protocol
physical data processing component
1 *
1 *
belongs_to 0 *
file server
communi-cation server
laboratory server
database server
application server
PC1 PC2 PC3 PC4 PC5 PC6 PC7 firewall
server
Figure 51: 3LGM physical tool layer - example
A variety of dependencies, called inter-layer-relationships exist among
components of different layers
Relations exist between classes of the domain layer and the logical tool layer and
Trang 33between classes of the logical tool layer and the physical tool layer Consideringthe domain layer and the logical tool layer, the most important relationship isbetween functions and application components which is represented by a so-
called application component configuration It states, that a hospital function
may be supported either by several application components together, by a singleapplication component, or by combinations of the two Two questions lead to theapplication component configurations for a specific function:
Which application components are jointly necessary to support a function completely?
An application component configuration contains all application componentswhich are together directly necessary to support a function If we remove anapplication component from this configuration, the function can no longer besupported by this configuration
Which possible alternatives are there to support a function?
A function may be supported by more than one application componentconfiguration If we remove such a configuration the function is still supported
by one of the remaining configurations, but may suffer from loss of quality.Application component configurations can not only, e.g give hints aboutredundancies within hospital information systems, but also about weaknesses inthe domain layer model Figure 52 shows an example of an applicationcomponent configuration
function: patient admission
application component: PMS application component: MED DB application component: WARD
alternatively application component
configuration 1
application component configuration 2
Figure 52: Example of an application component configuration
Other relations between classes of the domain layer and the logical tool layerare:
The first relation between object type and database system('stores_objects_of_object_types') describes in which databases the informationabout objects of a certain object type are stored It can give hints aboutredundant data storage
The second relation between object type and database system ('has_as_master')describes which database is responsible for the storage of objects of a certain
Trang 34object type, and, therefore, in case of redundant data storage, contains thecurrent data.
The relation between object type and message type expresses that informationabout objects of a certain object type is transported by a message of a certainmessage type
The relation between function and software product describes which functionscan be supported by a software product
Between the logical tool layer and the physical tool layer, there exists a relationbetween application components and physical data processing components
which is represented by a so-called data processing component configuration It
states, that an application component may be installed either on several dataprocessing components together (e.g typical client-sever-installations), on asingle data processing component (typical stand-alone-application components),
or through combinations of these two Two questions lead to the data processingcomponent configurations for a specific application component:
Which physical data processing components are jointly necessary to install a application component completely?
A data processing component configuration contains all physical data processingcomponents which are together directly necessary to install an applicationcomponent completely If we remove a physical data processing component fromthis configuration, the application component will no longer work
Which possible alternatives are there to install an application component?
An application component may be utilized by more than one data processingcomponent configuration If we remove such a configuration, the applicationcomponent still works through one of the remaining configurations, but maysuffer from loss of quality
Application component configurations can, e.g give hints about physicalredundancies within the hospital information systems An example of a dataprocessing component configuration is given in Figure 53
Trang 35Figure 53: Example of a data processing component configuration.
Exercise 3.4.2 Modeling with 3LGM
The following description of a sub-information system of a hospital is given:
"The patient admission is supported by an application component calledPATADMIN, which is installed at the hospital's central server Theadministration personnel works with two personal computers The patient dataare stored in the Oracle-based medical database (MEDDB) After the patientadmission is completed, patient data are transmitted to the computer-basedapplication components at the laboratory department (LABSYS) and at theradiology department (RADSYS), using an HL7-based message broker Forcommunication with conventional application components i.e for ordering orclinical documentation, labels containing the identifying patient data as text and
as barcodes are printed."
a) HIS components
Identify the 3LGM-relevant components of the described HIS and assignthem to one of the three layers Which necessary information to get a competemodel of this sub-information system is missing?
application component: WARD
data processing component:
application server
data processing component:
database server
data processing component: PC2
alternatively data processing component
configuration 1
data processing component configuration 2