Arden syntax

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Arden syntax is a markup language used for representing and sharing medical knowledge. [1] This clinical and scientific knowledge language is used in an executable format by clinical decision support systems [2] to generate alerts, interpretations, and to screen and manage messages to clinicians. This syntax is used to share medical knowledge within and across many health service institutions. [2] Rule sets, called Medical Logic Modules (MLMs), comprise enough logic to make a single medical decision. [1] Medical logic modules are written in Arden syntax, and are called by a program – an event monitor – when the condition they are written to help with occurs.

Contents

Arden syntax was formerly a standard under ASTM, published in 1992, and is now part of Health Level Seven International. [2] Arden syntax version 2.0 was published by HL7 in 1999. Arden syntax version 2.10 is the current version.

History

Arden Syntax and its first applications were conceived and developed as the primary deliverables of a multimillion-dollar joint research and development program between Columbia Presbyterian Medical Center and IBM Health Industry Marketing in Atlanta, Georgia, between 1989 and 1993. IBM provided program funding, S/370 mainframe hardware, software, peripheral equipment, and other materials for the work, and program management oversight of the collaborative effort.

The name "Arden" comes from the location of the IBM/CPMC conferences and working sessions, Arden House, in Orange County, New York, in recognition of important milestones achieved there in the development and refinement of the syntax and its implementation. (Originally purchased by Edward Henry Harriman in 1885, the estate was given to Columbia University by his son W. Averell Harriman in 1950 following its use by the U.S. Navy in World War II. The house and grounds became a National Historic Landmark in 1966, and it is now a conference center.) [3]

At Columbia-Presbyterian Medical center, 40 Arden syntax MLMs have been implemented in which 18 of those are clinical MLMs, including 4 interpretations and 14 alerts. For example, a user is alerted by three MLMs to the presence of hypokalemia and digoxin use that might lead to cardiac dysrhythmia. One MLM is activated by storage of a pharmacy order by digoxin,a second MLM is activated by the storage of a blood potassium result and the third activated by the storage of blood digoxin level. Twelve are research MLM examples, which include the ability to identify patients with abnormal cervical pathology, etc. that notify the researcher of the details of the patient's medical record and their inpatient location to enroll the patient in a study, and the remaining ten are administrative MLMs.

IBM's artificial intelligence product, KnowledgeTool, provided the original basis for MLM syntax representation and processing, as enhanced and applied by CPMC researchers Drs. James J. Cimino, George Hripcsak, Steve Johnson, Carol Friedman, and others at CPMC, under the leadership of Paul D. Clayton. In a related effort under the same program, another prototype implementation of the syntax was developed by Peter Ludemann using Quintus Prolog. IBM program management and AI technology services were provided by Terry Rankin, Pete Smith, and Eddie Sanders.

Uses

Arden syntax is used when:

Its advantages include:

Real-world examples

Arden syntax is used in computerized care plans for the management of patients following coronary artery bypass surgery [5]

The Regenstrief Institute, an international non-profit medical research organization "recognized for its role in improving quality of care, increasing efficiency of healthcare delivery, preventing medical errors and enhancing patient safety", [6] uses Arden Syntax MLMs in its CARE system to deliver reminders or hints to clinicians regarding patient treatment recommendations (e.g., the next clinic appointment, based on rules applied to the digitized notes and pertinent patient data stored in the system). Additionally, LDS hospital in Salt Lake City has contributed much to this standard as well as body of knowledge. Indiana University's section of Children's Health Services Research within the School of Medicine extensively uses Arden Syntax MLMs to control clinical decision support within the CHICA (Child Health Improvement through Computer Automation) pediatric clinical decision support system, an ambulatory CDS that has been running within Indianapolis-area health systems for 11 years. [7] Arden syntax is implemented at LDS hospital, Salt Lake City, Utah, using the HELP system. [8]

A medical decision support system at Linkoping University comprises a clinical database, medical database dictionary, and a knowledge base component. Syntax for the knowledge base is Arden syntax. [9] Samwald et al. group developed many clinical decision support system using Arden syntax standard ranging from a few to several dozens of MLMs. These systems are Hepaxpert, [10] Thyrexpert, [11] Toxopert [12] and RHEUMexpert. [13] The Hepaxpert system helps in interpretation of hepatitis serology test results, whereas the Thyrexpert system helps in interpretation of thyroid hormone test results. The Toxopert system helps in interpretation of time sequences of toxoplasmosis serology test results. Differential diagnosis decision support in rheumatology is offered by RHEUMexpert. [2]

Features

Rationale

The syntax offers potential users help deciding if the standard is appropriate for their purposes. It offers users and implementors knowledge of how parts of the standard were designed to be used. It also provides authors of other standards an insight that might be helpful in their own attempts in future designing of new languages. [14]

Fuzzy Arden syntax

The main aim of fuzzy Arden syntax is to provide easy method in processing of uncertain data which routinely appears in medicine. New concepts are incorporated into Arden syntax by fuzzy Arden syntax in order to assist in processing information that may not be completely defined. [15] For example, a fuzzy logic has been used in knowledge base in Moni–ICU system at clinical institute of hospital hygiene of the Vienna general hospital. It is a system that detects and constantly checks hospital-acquired infections. [2] Use of fuzzy logic in knowledge base provide physicians with more precise information on the degree of the presence of nosocomial infections, that aids to recognize borderline cases and allows former detection of an infection onset and its decline. [2]

Limitations

Technical implementation

Several developers have used Yacc-based compilers or similar tools to translate the MLMs to an intermediate form which is executed later. Other developers use Prolog for both parsing and interpretation and optimising MLMs by converting them to single-assignment declarative form. [14] The open source compiler Arden2ByteCode translates MLMs to Java Bytecode that is executable on the Java Virtual Machine. [18] The accompanying plugin for Eclipse called Arden4Eclipse supports MLM developers with an integrated development environment (IDE).

Testing

Arden syntax is tested for reliability and imprecision using tools lex and Yacc that, when used together, create a compiler or interpreter. Source file is split into tokens by lex and the hierarchical structure of the programme is found by Yacc. These tools reduce ambiguities in the syntax. [8]

Example

maintenance:title:Tocheckthediastolicbloodpressureofthepatient;;mlmname:Hypotension;;arden:version2.7;;version:1.00;;institution:LaTrobeUniversityBundoora;;author:LakshmiDevineni;;specialist:;;date:2013-06-02;;validation:testing;;library:purpose:checkifthediastolicbloodpressureofthepatientiswithinlimits;;explanation:ThisMLMisanexampleforreadingdataandwritingamessage;;keywords:hypotension;categorization;;citations:;;links:http://en.wikipedia.org/wiki/Hypotension;;knowledge:type:data_driven;;data:/* read the diastolic blood pressure */diastolic_blood_pressure:=readlast{diastolicbloodpressure};/* the value in braces is specific to your  runtime environment *//* If the height is lower than height_threshold, output a message */diastolic_pressure_threshold:=60;stdout_dest:=destination{stdout};;;evoke:null_event;;logic:if(diastolic_blood_pressureisnotnumber)thenconcludefalse;endif;if(diastolic_blood_pressure>=diastolic_pressure_threshold)thenconcludetrue;elseconcludefalse;endif;;;action:write"Your Diastolic Blood Pressure is too low (hypotension)"atstdout_dest;;;resources:default:de;;language:en'msg':"The normal range from 60 to 90";;;language:de'msg':"Der Normalbereich von 60 bis 90";;;end:

Structure

The unit of representation in the Arden syntax is the Medical Logic Module (MLM). [19] A Medical logic Module is composed of four categories, namely maintenance, library, knowledge and resources, with appropriate slots. [2] Arden Syntax is an instance of a Knowledge Resource-Centric Knowledge Integration Architecture, where the knowledge resources command the delivery mechanisms of clinical decision support system. [20]

Maintenance

This category contains metadata about the MLM. The maintenance category consists of slots that indicate maintenance information unrelated to the medical knowledge in the module. [21] The first slot is the title which gives a brief description of the module followed by a file name, a distinct identifier used to specify the MLM. The third slot is the version which specifies the version used. It also maintains a track of updates to the MLMs. A version slot is followed by institution and author slots that specify where the MLM is written and the person who wrote it. [1] The sixth slot is the specialist slot that names the person in the institution liable for validating and installing the MLM in the institution. This slot is always meant to be blank when transferring information from one institution to another. [8] This slot is followed by date and validation slots which show the date at which MLM was last updated. The validation level is set by the specialist, it indicates that the MLM is only used for testing. [1] These slots are used for knowledge base maintenance and change control. [17]

Library

This category contains five slots called purpose, explanation, keywords, citations and links. The purpose slot explains what a particular MLM is used for, whereas the explanation slot illustrates how an MLM works. Terms that can be used to search through a knowledge base of MLM is supplied by a keyword slot. The citation and link slots are optional. References to literature that support MLM's medical behaviour are included in the citation slot. Institution specific links to other sources of information such as electronic textbooks and educational modules are contained in the links slot. [1]

Knowledge

This category contains the actual medical knowledge of the MLM. It consists of type, data, priority, evoke, logic and action slots. The way in which MLM is used is known by type slot. Terms used in the rest of the MLM are defined by the data slot. Its goal is to separate those parts of the MLM that are specific to an institution from the more generic parts of the MLM. The order in which the MLM must be invoked are indicated by the priority, which can be a number from 1 (last) to 99 (first). It is a rarely used optional slot. An MLM can be activated by an event, or by a direct call from an MLM or an application programme which is specified by the evoke slot. [1] A real medical condition or rule to test for is contained in the logic slot which may include compound calculations. [8] The action slot creates a message that is sent to the health care provider, such as sending an alert to the destination, evoking other MLMs and returning values. The urgency slot is optional; it can be a number from 1 to 99 which indicates the importance of an MLMs action or message. [1]

See also

Related Research Articles

Fuzzy logic is a form of many-valued logic in which the truth value of variables may be any real number between 0 and 1. It is employed to handle the concept of partial truth, where the truth value may range between completely true and completely false. By contrast, in Boolean logic, the truth values of variables may only be the integer values 0 or 1.

<span class="mw-page-title-main">Blood pressure</span> Pressure exerted by circulating blood upon the walls of arteries

Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" refers to the pressure in a brachial artery, where it is most commonly measured. Blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure in the cardiac cycle. It is measured in millimeters of mercury (mmHg) above the surrounding atmospheric pressure, or in kilopascals (kPa). The difference between the systolic and diastolic pressures is known as pulse pressure, while the average pressure during a cardiac cycle is known as mean arterial pressure.

Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when standing up or sitting down. Primary orthostatic hypotension is also often referred to as neurogenic orthostatic hypotension. The drop in blood pressure may be sudden, within 3 minutes or gradual. It is defined as a fall in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg after 3 minutes of standing. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain adequate blood pressure when changing the position to standing. As a result, blood pools in the blood vessels of the legs for a longer period, and less is returned to the heart, thereby leading to a reduced cardiac output and inadequate blood flow to the brain.

Health Level Seven, abbreviated to HL7, is a range of global standards for the transfer of clinical and administrative health data between applications with the aim to improve patient outcomes and health system performance. The HL7 standards focus on the application layer, which is "layer 7" in the Open Systems Interconnection model. The standards are produced by Health Level Seven International, an international standards organization, and are adopted by other standards issuing bodies such as American National Standards Institute and International Organization for Standardization. There are a range of primary standards that are commonly used across the industry, as well as secondary standards which are less frequently adopted.

<span class="mw-page-title-main">Sphygmomanometer</span> Instrument for measuring blood pressure

A sphygmomanometer, also known as a blood pressure monitor, or blood pressure gauge, is a device used to measure blood pressure, composed of an inflatable cuff to collapse and then release the artery under the cuff in a controlled manner, and a mercury or aneroid manometer to measure the pressure. Manual sphygmomanometers are used with a stethoscope when using the auscultatory technique.

<span class="mw-page-title-main">Pulse pressure</span> Difference between systolic and diastolic blood pressure

Pulse pressure is the difference between systolic and diastolic blood pressure. It is measured in millimeters of mercury (mmHg). It represents the force that the heart generates each time it contracts. Healthy pulse pressure is around 40 mmHg. A pulse pressure that is consistently 60 mmHg or greater is likely to be associated with disease, and a pulse pressure of 50 mmHg or more increases the risk of cardiovascular disease. Pulse pressure is considered low if it is less than 25% of the systolic. A very low pulse pressure can be a symptom of disorders such as congestive heart failure.

Atenolol is a beta blocker medication primarily used to treat high blood pressure and heart-associated chest pain. Although used to treat high blood pressure, it does not seem to improve mortality in those with the condition. Other uses include the prevention of migraines and treatment of certain irregular heart beats. It is taken orally or by intravenous injection. It can also be used with other blood pressure medications.

<span class="mw-page-title-main">Mean arterial pressure</span> Average blood pressure in an individual during a single cardiac cycle

In medicine, the mean arterial pressure (MAP) is an average calculated blood pressure in an individual during a single cardiac cycle. Although methods of estimating MAP vary, a common calculation is to take one-third of the pulse pressure, and add that amount to the diastolic pressure. A normal MAP is about 90 mmHg.

<span class="mw-page-title-main">Medical algorithm</span>

A medical algorithm is any computation, formula, statistical survey, nomogram, or look-up table, useful in healthcare. Medical algorithms include decision tree approaches to healthcare treatment and also less clear-cut tools aimed at reducing or defining uncertainty. A medical prescription is also a type of medical algorithm.

A clinical decision support system (CDSS) is a health information technology that provides clinicians, staff, patients, and other individuals with knowledge and person-specific information to help health and health care. CDSS encompasses a variety of tools to enhance decision-making in the clinical workflow. These tools include computerized alerts and reminders to care providers and patients, clinical guidelines, condition-specific order sets, focused patient data reports and summaries, documentation templates, diagnostic support, and contextually relevant reference information, among other tools. CDSSs constitute a major topic in artificial intelligence in medicine.

A guideline execution engine is a computer program which can interpret a clinical guideline represented in a computerized format and perform actions towards the user of an electronic medical record.

A medical logic module (MLM) is an independent unit in a healthcare knowledge base that represents the knowledge published on a requirement for treating a patient according to a single medical decision.

In medicine, systolic hypertension is defined as an elevated systolic blood pressure (SBP). If the systolic blood pressure is elevated (>140) with a normal (<90) diastolic blood pressure (DBP), it is called isolated systolic hypertension. Eighty percent of people with systolic hypertension are over the age of 65 years old. Isolated systolic hypertension is a specific type of widened pulse pressure.

<span class="mw-page-title-main">Cerebrospinal fluid leak</span> Medical condition

A cerebrospinal fluid leak is a medical condition where the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord leaks out of one or more holes or tears in the dura mater. A CSF leak is classed as either spontaneous (primary), having no known cause, or nonspontaneous (secondary) where it is attributed to an underlying condition. Causes of a primary CSF leak are those of trauma including from an accident or intentional injury, or arising from a medical intervention known as iatrogenic. A basilar skull fracture as a cause can give the sign of CSF leakage from the ear, nose or mouth. A lumbar puncture can give the symptom of a post-dural-puncture headache.

<span class="mw-page-title-main">Complications of hypertension</span>

Complications of hypertension are clinical outcomes that result from persistent elevation of blood pressure. Hypertension is a risk factor for all clinical manifestations of atherosclerosis since it is a risk factor for atherosclerosis itself. It is an independent predisposing factor for heart failure, coronary artery disease, stroke, kidney disease, and peripheral arterial disease. It is the most important risk factor for cardiovascular morbidity and mortality, in industrialized countries.

Orthostatic syncope refers to syncope resulting from a postural decrease in blood pressure, termed orthostatic hypotension.

<span class="mw-page-title-main">Orthostatic hypertension</span> Medical condition

Orthostatic hypertension is a medical condition consisting of a sudden and abrupt increase in blood pressure (BP) when a person stands up. Orthostatic hypertension is diagnosed by a rise in systolic BP of 20 mmHg or more when standing. Orthostatic diastolic hypertension is a condition in which the diastolic BP raises to 98 mmHg or over in response to standing, but this definition currently lacks clear medical consensus, so is subject to change. Orthostatic hypertension involving the systolic BP is known as systolic orthostatic hypertension.

<span class="mw-page-title-main">Heart failure with preserved ejection fraction</span> Medical condition

Heart failure with preserved ejection fraction (HFpEF) is a form of heart failure in which the ejection fraction – the percentage of the volume of blood ejected from the left ventricle with each heartbeat divided by the volume of blood when the left ventricle is maximally filled – is normal, defined as greater than 50%; this may be measured by echocardiography or cardiac catheterization. Approximately half of people with heart failure have preserved ejection fraction, while the other half have a reduction in ejection fraction, called heart failure with reduced ejection fraction (HFrEF).

<span class="mw-page-title-main">Blood pressure measurement</span> Techniques for determining blood pressure

Arterial blood pressure is most commonly measured via a sphygmomanometer, which historically used the height of a column of mercury to reflect the circulating pressure. Blood pressure values are generally reported in millimetres of mercury (mmHg), though modern aneroid and electronic devices do not contain mercury.

Arden2ByteCode is a free Arden Syntax compiler. The compiler translates HL7 International Arden Syntax for Medical Logic Modules (MLMs) to Java Bytecode. The Arden Syntax is a standardized language that can be used to express medical knowledge. Arden2ByteCode runs on the Java Virtual Machine and can be used on a wide variety of platforms.

References

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