Snomed ct - empowering clinicians

SNOMED CT –EMPOWERING CLINICIANS

Dr SB Bhattacharyya

MBBS, MBA, FCGP

Member, National EHR Standardisation Committee, MoH&FW, GoI

Member, Health Informatics Sectional Committee, MHD 17, BIS

Hony. State Secretary (2015), IMA Haryana

President (2010 – 2011), IAMI

SNOMED CT

■ SNOMED CT is a semantically interoperable polyhierarchical subtype multi-lexical clinical terminology system that is able to deliver robust benefits to the health care services.

■ SNOMED CT is a reference terminology for clinical terms and consists of terms used in health and health care.

Dr SB Bhattacharyya© 2

Why SNOMED CT?

■ Natural language for end-users

– Doctors

– Dentists

– Nurses

– Paramedics

■ Since clinical documentation systems document the clinical thoughts of the observers, a concept-based system works best, not a term-based or classification-based one

■ For clinical analytics, evidence based medicine, clinical decision support, etc., the correct idea is vital, not a prefixed term


Advantages for Clinicians

■ Users get to choose the terms that they are most comfortable with in their own language/dialect

■ Users can express their clinical thoughts very precisely using expressions


SNOMED CT Components – Core

■ Concepts

– Concept Ids – meaningless machine-processable numbers

■ Descriptions (Terms)

– Human-processable terms

■ Relationships

– Between concepts: source to destination


SNOMED CT Terms

■ Fully Specified Name (FSN) – identified by having the term suffixed by its top-level hierarchy enclosed in parenthesis thus -“(disorder)”, “(body structure)”, “(procedure)”, etc.

■ Preferred Term (PT)

■ Acceptable (Terms) – synonyms


SNOMED CT Logical Model


SNOMED CT Relationships

Infective pneumonia (disorder)

Lung (body structure)

Infection (disorder)Respiratory disease (disorder)

Virus (organism)

Viral pneumonia (disorder)


SNOMED CT Relationships (schematic)


SNOMED CT – Attribute Value-Range

DOMAIN(hierarchy)

ATTRIBUTERANGE

(concept of hierarchy)

<< This concept or one of its

descendants| Clinical finding | | FINDING SITE |

<< 442083009| Anatomical or acquired body

structure |

| Body structure | | LATERALITY | < 182353008 |Side|

< Descendants only. Not the concept itself


The clinical thoughts are expressedusing SNOMED CT


SNOMED CT Expressions

■ Pre-coordinated

– Coordination already done : composed before-the-fact

– Through its ~ 1 million terms, most thoughts can be expressed using just this

■ Post-coordinated

– Coordination done on-the-fly by the users choosing various rules-based alternatives: composed after-the-fact

– Required intermittently, especially when the thought is a complex one and requires further refinement or qualification or combination with other terms


Expressions

■ The actual “code” of SNOMED CT and consists of either

– ConceptId only102556003or

– ConceptId | Description (Term) | 102556003 | pain in upper limb |

■ Needs to adhere to compositional grammar rules and expression constraint syntax

■ Never to be seen by any user, clinician or otherwise, ever


Clinicians need to work only with the terms that number more than one million…


Clinical Thought

■ Viral pneumonia


What the Clinicians gets to see…

■ Pain in upper limb


What the Machine works with…

■ 75570004


Clinical Thought

■ Family history of hypertension


Requires Post-coordinated Expression

This thought includes two separate concepts :

1. Family history

2. Hypertension

These need be combined, the following postcoordinated expression needs to be created as below and used to represent this family history –

281666001 | family history of disorder | : 246090004 | associated finding | = 38341003 | hypertension |

This can also be written as –281666001 : 246090004 = 38341003


What the Clinicians gets to choose from (list created by combining two separate SNOMED CT terms)…■ Family History of Disorder : BP - High

Blood Pressure

■ Family History of Disorder : BP+ -Hypertension

■ Family History of Disorder : HBP - High Blood Pressure

■ Family History of Disorder : High Blood Pressure

■ Family History of Disorder : High Blood Pressure Disorder

■ Family History of Disorder : HT -Hypertension

■ Family History of Disorder : HTN -Hypertension

■ Family History of Disorder : Hypertension

■ Family History of Disorder : Hypertensive Disorder

■ Family History of Disorder : Hypertensive Disorder, Systemic Arterial

■ Family History of Disorder : Hypertensive Vascular Degeneration

■ Family History of Disorder : Hypertensive Vascular Disease

■ Family History of Disorder : Systemic Arterial Hypertension


What the Machine Works with…

■ 281666001 : 246090004 = 38341003


Comments On SNOMED CT Expressions

■ NOT to be seen by any user ever

■ Akin to stuff that are handled by the machine far away from any user’s eyes, like HL7 messages that appear as but are never ever seen by any system user:MSH|^~\&|GHH LAB|ELAB-3|GHH OE|BLDG4|200202150930||ORU^R01|CNTRL-3456|P|2.4<cr>PID|||555-44-4444||EVERYWOMANÊVEÊ^^^^L|JONES|19620320|F|||153 FERNWOOD DR.^^STATESVILLEÔH^35292||(206)3345232|(206)752-121||||AC555444444||67-A4335ÔH^20030520<cr>OBR|1|845439^GHH OE|1045813^GHH LAB|15545^GLUCOSE|||200202150730|||||||||555-55-5555^PRIMARY^PATRICIA P^^^^MD^^|||||||||F||||||444-44-4444^HIPPOCRATES^HOWARD H^^^^MD<cr>OBX|1|SN|1554-5^GLUCOSE^POST 12H CFST:MCNC:PT:SER/PLAS:QN||^182|mg/dl|70_105|H|||F<cr>


Impact on Analytics

■ SNOMED CT has concept-based polyhierarchical structure based on a formal description logic and ability to support multiple languages

■ These permit broad aggregation of clinical observations, context-based interpretation of data, testing whether a particular observation is equivalent to or subsumed by some predefined set of clinical observations

■ Its multi-lingual nature permits queries to be made in any language without worrying about the language used in the record


Impact on Analytics

■ Ability to code all parts of a clinical record permits all data to be analysed to discover clinical knowledge in them

■ Point-of-care Analytics, Population Analytics, Observational Clinical Research, Semantic Search are all possible now


Observations On SNOMED CT

■ Not a piece of software, only a part of it

■ Akin to a gear-box of a car – on its own does nothing, when placed properly and used judiciously, it helps deliver quite a punch

■ A terminology coding system that greatly helps in automating various clinical processes including record-keeping, diagnostics, treatment planning, clinical decision support, clinical data analytics, services billing, health surveillance, etc.

■ Can code all parts of a clinical document covering terms ranging from abscess to zygote and aspects from reason for visit to outcome

■ Empower care providers to deliver best-of-possible care through the use of analytics and machine learning


Note that ICD / LOINC ≠ SNOMED CT

ICD / LOINC

■ A meaning-based classificationsystem where the literal meaning of the term used is taken into consideration

■ Useful for reporting purposes

■ Code system for medical records department

SNOMED CT

■ A concept-based terminologysystem where the meaning of the concept behind the term is taken into consideration

■ Useful for clinical decision support and analytics, besides reporting

■ Code system for care providers


References

■ Images are all courtesy IHTSDO, used with their kind permission

■ Matter generally based on “Introduction to SNOMED CT” by Dr SB Bhattacharyya


Introduction to SNOMED CT by Dr SB Bhattacharyya available at

■ http://www.amazon.com/Introduction-SNOMED-CT-S-B-Bhattacharyya/dp/9812878939/ref=sr_1_1?ie=UTF8&qid=1453269681&sr=8-1&keywords=introduction+to+snomed+ct – hardcopy only

■ http://www.amazon.in/Introduction-SNOMED-CT-2016-Bhattacharyya/dp/9812878939/ref=sr_1_1?ie=UTF8&qid=1453269722&sr=8-1&keywords=introduction+to+snomed+ct – hardcopy only

■ http://www.springer.com/gp/book/9789812878939 – ebook and hardcopy

■ http://link.springer.com/book/10.1007/978-981-287-895-3 – chapter-wise online access only


http://www.amazon.com/Introduction-SNOMED-CT-S-B-Bhattacharyya/dp/9812878939/ref=sr_1_1?ie=UTF8&qid=1453269681&sr=8-1&keywords=introduction+to+snomed+ct

http://www.amazon.in/Introduction-SNOMED-CT-2016-Bhattacharyya/dp/9812878939/ref=sr_1_1?ie=UTF8&qid=1453269722&sr=8-1&keywords=introduction+to+snomed+ct

http://www.springer.com/gp/book/9789812878939

http://link.springer.com/book/10.1007/978-981-287-895-3

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Snomed ct - empowering clinicians