Code Type. Code is valid for submission on a UB Field value is saying whether this code is valid for submission on a UB Additional note, saying whether this code is valid for submission on a UB MSH-7 Date and time the message was created. This includes the time zone. See the TS data type. Z is the time zone offset. Send values only as far as needed. When a system has only a partial date, e. The time zone is assumed to be that of the sender. Example: - May 26th, , , Pacific Time. MSH The message control ID is a string which may be a number uniquely identifying the message among all those ever sent by the sending system.
LAB will use "xxauniquevalue. NOTE: We have used 2. The PID segment is used by all applications as the primary means of communicating patient identification information. This segment contains permanent patient identifying and demographic information that, for the most part, is not likely to change frequently. PID-3 The unique medical record number of the patient's chart within the system. Patient's unique identifier s from the facility. Last name and first name are required.
LAB may ignore any time component in the birth date. S[S[S[S]]]]]]]][ ]. The user values the field only as far as needed. PID This field is required and must contain an account number. Definition: This field contains the patient account number assigned by accounting to which all charges, payments, etc.
The entire number including the check digit will be considered the patient account number. PV Patient Class does not have a consistent industry-wide definition and is subject to site-specific variations. Literal values: "E", "I" or "O". The Observation Request Segment carries general information about the sample, test, or result.
For laboratory-based reporting, the OBR defines the attributes of the original request for laboratory testing. Essentially, the OBR describes a battery or panel of tests that is being requested or reported. The OBR is similar to a generic lab slip that is filled out when a physician requests a lab test. The individual test names and results for the panel of tests performed are reported in OBX segments , which are described below.
Definition: It is assigned by the order filler receiving application. This string must uniquely identify the order as specified in the order detail segment from other orders in a particular filling application e. This uniqueness must persist over time. In the case of observations taken directly from a subject, it is the actual date and time the observation was obtained. OBR This is a complex element containing three components related to the ordering physician. OBR This field is used to indicate the date and time that the results are composed into a report and released to the individual OBX , or that a status, is entered or changed.
OBX segments have great flexibility to report information. When properly coded, OBX segments report a large amount of information in a small amount of space. OBX segments within the ORU message are widely used to report laboratory and other clinical information.
OBX-5 Result value. Singh H Sittig DF. The disclosure dilemma: large-scale adverse events. Aldershot, UK: Ashgate Publishing; Patient safety problems associated with heathcare information technology: an analysis of adverse events reported to the US Food and Drug Administration. Effects of two commercial electronic prescribing systems on prescribing error rates in hospital in-patients: a before and after study. PLoS Med. Computerized provider order entry implementation: no association with increased mortality rates in an intensive care unit.
The contribution of sociotechnical factors to health information technology-related sentinel events. Automation bias: empirical results assessing influencing factors. Nelson NC. Downtime procedures for a clinical information system: a critical issue. J Crit Care. Crisis management during anaesthesia: the development of an anaesthetic crisis management manual. Qual Saf Health Care. Measuring the effects of computer downtime on hospital pathology processes.
J Biomed Inform. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.
Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Editor's Choice. Problems with health information technology and their effects on care delivery and patient outcomes: a systematic review.
E-mail: mi. Oxford Academic. Enrico Coiera. Farah Magrabi. Select Format Select format. Permissions Icon Permissions. Health IT was broadly defined as computer hardware and software used by health professionals to support patient care. We focused on studies reporting problems with IT and its effects on care delivery and patient outcomes. These effects were examined using a new framework called the information value chain, which connects the use of a technology to final outcome Figure 1.
A subset of these interactions will yield new information, only some of which then lead to changed decisions. Next, only some decisions will see changes in the care process, and only some process changes will impact patient outcome. Using this framework, we sought to identify the effects of IT problems on each stage of this chain, from user interaction to clinical outcome. Open in new tab Download slide. Seventy-nine papers were selected for full review Figure 2.
Each study was assessed independently by 2 reviewers MK and FM against the inclusion criteria. All disagreements were resolved by consensus. After assessment, 34 studies remained. Authors year. Study period no. Method and design. Sample incidents. Health IT type. Key findings. Aarts et al. Software problems including poor user interfaces led to difficulties in entering orders and delayed care processes.
Ash et al. Specific consequences for care delivery included more work for clinicians and communication loss. Technical problems were related to inadequate software functionality such as poor user interfaces, fragmented displays, and inflexibility of system design.
System configuration issues were related to problems with decision support including reminders, alerts, and system messages. Contributing factors included poor integration with workflow, cognitive load due to interruptions. Workarounds were used to deal with many IT issues. The survey was based on 9 major categories of unintended consequences of CPOE implementation identified by Campbell et al. All hospitals reported 8 categories of unintended consequences ie, except category 4, problems related to paper persistence.
Campbell et al. Technical problems were related to software functionality, which confused users. Clinical care delivery became dependent upon CPOE technology. System failure and malfunctions delayed patient care and required use of hybrid records systems.
Cheung et al. Technical problems were related to poor design of user interfaces, which led to medication errors in community pharmacies. A total of incidents reached patients. Two deaths and 20 cases of serious but temporary harm were reported. Han et al. A poor user interface that was not adapted to local requirements led to delays in initiating treatment.
The CPOE did not allow entry of orders prior to arrival of critically ill patients, delaying life-saving treatment. New workflow also caused a breakdown in doctor-nurse communication. Hospitalwide implementation over a 6-day period did not allow staff enough time to adapt to new routines and responsibilities. In parallel with CPOE implementation, changes to policies and procedures for dispensing and administering medications exacerbated treatment delays.
For instance, all medications including ICU vasoactive drugs were relocated to a central pharmacy. Hanuscak et al. Technical problems were related to hardware and software issues, including malfunctioning systems, interfaces with other software components, and updates. Downtimes were also linked to use errors. Of the 39 medication errors linked to downtime, 14 reached patients. Horsky et al. Wrong, incomplete, and missing information in the hospital order entry system resulted in the patient receiving multiple doses of potassium.
In total, mEq potassium chloride was administered over 42 hours. Technical problems were related to software functionality, such as suboptimal screen display and lack of automated checking function.
Human factors issues were linked with inadequate training and poor familiarity with the system. Koppel et al. Technical problems involved software functionality and system configuration. Fragmented displays disrupted user interaction and led to errors in selecting medications. Poor displays delayed time to complete clinical tasks. Problems with process for reapproval of antibiotics led to gaps in therapy. CPOE downtime also contributed to delays in care process. Hybrid record systems were used to deliver care during downtimes.
Landman et al. Loss of this link resulted in decreased image viewer access rates for ED patients during the 10 days of the incident 2. In all, events impacted care delivery. In 21 events, patients were forced to seek care in other hospitals. One death was reportedly linked to downtime. Magrabi et al. Problems with IT disrupted clinical workflow, wasted time, caused frustration, and led to use of a hybrid records system.
Technical problems related to user interfaces, routine updates to software packages and drug databases, and migration of records from one package to another generated clinical errors. McDonald et al. Human factors issues involved rule violation and integration with workflow, such as missing verbal confirmation of patient identification and entering wrong information into a system. Meeks et al. Phase 1: unsafe technology or technology failures, Phase 2: unsafe or inappropriate use of technology, Phase 3: lack of monitoring of safety concerns, 1.
Introduction to Embedded System Design. In this section, we will introduce the product development process in general. The basic approach is introduced here, and the details of these concepts will be presented throughout the remaining chapters of the book.
As illustrated in Figure 7. For complex systems with long life-spans, we transverse multiple times around the life cycle. For simple systems, a one-time pass may suffice. Product Life Cycle and Requirements. During the analysis phase , we discover the requirements and constraints for our proposed system. We can hire consultants and interview potential customers in order to gather this critical information.
A requirement is a specific parameter that the system must satisfy. We begin by rewriting the system requirements, which are usually written in general form, into a list of detailed specifications. In general, specifications are detailed parameters describing how the system should work.
For example, a requirement may state that the system should fit into a pocket, whereas a specification would give the exact size and weight of the device. For example, suppose we wish to build a motor controller. During the analysis phase, we would determine obvious specifications such as range, stability, accuracy, and response time. There may be less obvious requirements to satisfy, such as weight, size, battery life, product life, ease of operation, display readability, and reliability.
Often, improving the performance on one parameter can be achieved only by decreasing the performance of another. This art of compromise defines the tradeoffs an engineer must make when designing a product. A constraint is a limitation, within which the system must operate. The system may be constrained to such factors as cost, safety, compatibility with other products, use of specific electronic and mechanical parts as other devices, interfaces with other instruments and test equipment, and development schedule.
The following measures are often considered during the analysis phase of a project:. Safety : The risk to humans or the environment. Accuracy : The difference between the expected truth and the actual parameter. Precision : The number of distinguishable measurements. Resolution : The smallest change that can be reliably detected. Response time : The time between a triggering event and the resulting action.
Bandwidth : The amount of information processed per time. Maintainability : The flexibility with which the device can be modified.
Testability : The ease with which proper operation of the device can be verified. Compatibility : The conformance of the device to existing standards. Mean time between failure : The reliability of the device , the life of a product. Size and weight : The physical space required by the system. Power : The amount of energy it takes to operate the system.
Nonrecurring engineering cost NRE cost : The one-time cost to design and test. Unit cost : The cost required to manufacture one additional product. Time-to-prototype : The time required to design, build, and test an example system.
Time-to-market : The time required to deliver the product to the customer. Checkpoint 7. The following is one possible outline of a Requirements Document. A requirements document states what the system will do. It does not state how the system will do it. The main purpose of a requirements document is to serve as an agreement between you and your clients describing what the system will do. This agreement can become a legally binding contract.
Write the document so that it is easy to read and understand by others. It should be unambiguous, complete, verifiable, and modifiable. Objectives: Why are we doing this project? What is the purpose? Process: How will the project be developed? Roles and Responsibilities: Who will do what? Who are the clients? Interactions with Existing Systems: How will it fit in? Terminology: Define terms used in the document. Security: How will intellectual property be managed?
Functionality: What will the system do precisely? Scope: List the phases and what will be delivered in each phase. Prototypes: How will intermediate progress be demonstrated? Performance: Define the measures and describe how they will be determined. Usability: Describe the interfaces. Be quantitative if possible. Safety: Explain any safety requirements and how they will be measured.
Reports: How will the system be described? Audits: How will the clients evaluate progress? Outcomes: What are the deliverables? How do we know when it is done? Observation: To build a system without a requirements document means you are never wrong, but never done.
It is in this model that we exploit as much abstraction as appropriate. The project is broken into modules or subcomponents. During this phase, we estimate the cost, schedule, and expected performance of the system. At this point we can decide if the project has a high enough potential for profit. A data flow graph is a block diagram of the system, showing the flow of information. Arrows point from source to destination.
The rectangles represent hardware components, and the ovals are software modules. We use data flow graphs in the high-level design, because they describe the overall operation of the system while hiding the details of how it works. Issues such as safety e. A data flow graph for a simple position measurement system is shown in Figure 7. The sensor converts position in an electrical resistance.
The ADC converts analog voltage into a digital sample. The software converts voltage to position. Voltage and position data are represented as fixed-point numbers within the computer.
Figure 7. A data flow graph showing how the position signal passes through the system. Next, we finish the top-down hierarchical structure and build mock-ups of the mechanical parts connectors, chassis, cables etc. Sophisticated 3-D CAD systems can create realistic images of our system. Detailed hardware designs must include mechanical drawings. Data structures , which will be presented throughout the class, include both the organization of information and mechanisms to access the data.
Again safety and testing should be addressed during this low-level design. A call graph for a simple position measurement system is shown in Figure 7. Again, rectangles represent hardware components, and ovals show software modules. An arrow points from the calling routine to the module it calls. A high-level call graph, like the one shown in Figure 7.
In this system, the timer hardware will cause the ADC software to collect a sample. The double-headed arrow between the ISR and the hardware means the hardware triggers the interrupt and the software accesses the hardware. Observation : If module A calls module B, and B returns data, then a data flow graph will show an arrow from B to A, but a call graph will show an arrow from A to B.
The next phase involves developing an implementation. An advantage of a top-down design is that implementation of subcomponents can occur simultaneously. One major advantage of simulation is that it is usually quicker to implement an initial product on a simulator versus constructing a physical device out of actual components. Rapid prototyping is important in the early stages of product development.
This allows for more loops around the analysis-design-implementation-testing-deployment cycle, which in turn leads to a more sophisticated product. Recent software and hardware technological developments have made significant impacts on the software development for embedded microcomputers.
The simplest approach is to use a cross-assembler or cross-compiler to convert source code into the machine code for the target system. The machine code can then be loaded into the target machine. Debugging embedded systems with this simple approach is very difficult for two reasons. First, the embedded system lacks the usual keyboard and display that assist us when we debug regular software.
Second, the nature of embedded systems involves the complex and real-time interaction between the hardware and software. These real-time interactions make it impossible to test software with the usual single-stepping and print statements. The next technological advancement that has greatly affected the manner in which embedded systems are developed is simulation. During the testing phase, we evaluate the performance of our system. First, we debug the system and validate basic functions.
Next, we use careful measurements to optimize performance such as static efficiency memory requirements , dynamic efficiency execution speed , accuracy difference between expected truth and measured , and stability consistent operation.
Debugging techniques will be presented at the end of most chapters. Maintenance is the process of correcting mistakes, adding new features, optimizing for execution speed or program size, porting to new computers or operating systems, and reconfiguring the system to solve a similar problem. No system is static. Customers may change or add requirements or constraints.
To be profitable, we probably will wish to tailor each system to the individual needs of each customer. Maintenance is not really a separate phase, but rather involves additional loops around the life cycle.
With a bottom-up design we begin with solutions and build up to a problem statement. The low-level designs can be developed in parallel. Bottom-up design may be inefficient because some subsystems may be designed, built, and tested, but never used. As the design progresses the components are fit together to make the system more and more complex.
Only after the system is completely built and tested does one define the overall system specifications. The bottom-up design process allows creative ideas to drive the products a company develops. It also allows one to quickly test the feasibility of an idea. If one fully understands a problem area and the scope of potential solutions, then a top-down design will arrive at an effective solution most quickly. Throughout the book in general, we discuss how to solve problems on the computer.
In this section, we discuss the process of converting a problem statement into an algorithm. Later in the book, we will show how to map algorithms into assembly language. We begin with a set of general specifications, and then create a list of requirements and constraints. The general specifications describe the problem statement in an overview fashion, requirements define the specific things the system must do, and constraints are the specific things the system must not do. These requirements and constraints will guide us as we develop and test our system.
Observation: Sometimes the specifications are ambiguous, conflicting, or incomplete. There are two approaches to the situation of ambiguous, conflicting, or incomplete specifications. The best approach is to resolve the issue with your supervisor or customer. The second approach is to make a decision and document the decision. Performance Tip: If you feel a system specification is wrong, discuss it with your supervisor.
We can save a lot of time and money by solving the correct problem in the first place. Successive refinement , stepwise refinement , and systematic decomposition are three equivalent terms for a technique to convert a problem statement into a software algorithm. We start with a task and decompose the task into a set of simpler subtasks. Then, the subtasks are decomposed into even simpler sub-subtasks. We make progress as long as each subtask is simpler than the task itself.
During the task decomposition we must make design decisions as the details of exactly how the task will be performed are put into place.
Eventually, a subtask is so simple that it can be converted to software code. We can decompose a task in four ways, as shown in Figure 2. The sequence , conditional , and iteration are the three building blocks of structured programming.
Because embedded systems often have real-time requirements, they employ a fourth building block called interrupts. We will implement time-critical tasks using interrupts, which are hardware-triggered software functions. Interrupts will be discussed in more detail in Chapters 9, 10, and When we solve problems on the computer, we need to answer these questions:.
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