LINKS:

JIRA: https://projects.jira.snomed.org/browse/IHTSDO-320

Document review: 

Amendment History

Review Timetable

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Table of Contents
1 Glossary
1.1 Domain Terms
2 Introduction
2.1 Purpose
2.2 Audience and stakeholder domain
2.2.1 Input from stakeholders
2.2.2 Degree of consensus on the statement of problem
3 Statement of the problem or need
3.1 Summary of problem or need, as reported
3.2 Summary of requested solution
3.3 Statement of problem as understood
3.4 Detailed analysis of reported problem, including background
3.4.1 Editorial Guidance - Background
3.4.2 Subjectivity of Procedure Prioritization
3.4.3
3.4.4 Regional and Institutional Variation in Procedure Prioritization
3.4.5 SNOMED CT International Request Submission (SIRS) Requests Related to Prioritization of Procedures
3.5 Subsidiary and interrelated problems
4 Risks / Benefits
4.1.1 Risks of not addressing the problem
4.1.2 Risks of addressing the problem
5 Requirements: criteria for success and completion
5.1 Criteria for success/completion
5.1.1 Consistent meaning, modeling and editorial policy
5.2 Strategic and/or specific operational use cases
5.2.1 Clear editorial policy development for
6 Solution Development
6.1 Initial Design
6.1.1 Outline of initial design
6.1.2 Significant design or implementation decisions / compromises
6.1.3 Evaluation of Design
6.2 Iteration One
6.2.1 Outline of revised design
6.2.2 Significant design or implementation changes
6.2.3 Evaluation of Revised Design
7 Recommendation
7.1.1 Detailed design final specification
7.1.2 Iteration plan
8 Quality program criteria
8.1 Quality metrics
8.1.1 Quality metric 1
8.1.2 Quality metric 2
8.1.3 Quality metric 3
9 Project Resource Estimates
9.1 Estimate of project size:
9.1.1 Editing
9.1.2 Providing guidance for Procedures by Priority for the Editorial guide
9.2 Scope of construction phase
9.3 Projection of remaining overall project resource requirements
9.3.1 Expected project resource requirement category
9.3.2 Expected project impact and benefit
9.3.3 Indicative resource estimates for construction, transition and maintenance:

Glossary

Domain Terms

Introduction

Purpose

The purpose of this project is:

1. To evaluate whether the attribute 260870009 |Priority (attribute)|, used to define the priority of a procedure, meets URU criteria and whether it adds value to pre-coordinated and/or post-coordinated SNOMED CT content

2. To propose a model or course of action for if/how the attribute should be used

Audience and stakeholder domain

The audience for this document includes all standards terminology leaders, implementers and users but is especially targeted at those stakeholders:

• Developing pre-coordinated SNOMED CT |Procedure by priority| content in the IHTSDO International Release

• Developing post-coordinated SNOMED CT |Procedure by priority| content)

• Implementing SNOMED CT in the Electronic Health Record, particularly in the surgical domain

• Involved in quality assurance of content in the |Procedure by priority| and |Procedure with explicit context| hierarchies

• Concerned with SNOMED CT interoperability

Input from stakeholders

Internal Stakeholders: The inability of |Priority (attribute)| to meet URU criteria has been an ongoing issue for internal SNOMED CT content modelers and was originally submitted to the IHTSDO in 2008 by the internal editing team.
External Stakeholders: In recent years, there have also been some requests in the SNOMED CT International Request Submission (SIRS) System which indicate users' needs for pre-coordinated |Procedure by priority| content and also highlight some problems related to |Priority (attribute)|.

Content Developers

For insight into some of the needs of content developers and implementers related to |Procedure by priority| content, please refer to Section 3.4.5 on SIRS Requests related to |Procedure by priority| content.

Implementers

Data on implementation of procedure prioritization in the EHR is sparse. An old and small code usage dataset obtained from a U.K vendor (using a CTV3 system that had implemented the templates file and exposed the attributes to GP end users) showed that only a few attributes (e.g., Laterality, Severity, Episodicity, and Site) were used with any regularity. In this U.K. dataset, |Priority (attribute)| was used infrequently with the most frequently assigned value for |Priority (attribute)| being |Scheduled - priority (qualifier value)|.
U.K. Vendor usage data for |Priority (attribute)|:

Degree of consensus on the statement of problem

As will be demonstrated in Section 3, there is generally agreement among internal SNOMED CT content modelers that |Priority (attribute)| does not meet URU (understandable, reproducible, useful) criteria. For this reason, the addition of new |Procedure by priority| content had been on hold in recent years pending the outcome of the "artf6250: PRIORITY" project. During this period, the following guidance was approved by the IHTSDO as a standard reply to submitters requesting new |Procedure by priority| content:
Pre-coordination of new <priority> <procedure> content is on hold and will be addressed as part of an IHTSDO project.
Achieving stakeholder consensus with respect to a proposed solution for an attribute that is part of the SNOMED CT Concept Model may be more challenging than achieving consensus that there is a problem with the attribute. Lack of data with respect to implementation of |Priority (attribute)| may also lead to uncertainty about the impact of changes and may ultimately influence the proposed solution, notwithstanding the current unsatisfactory status of the attribute.

Statement of the problem or need

Summary of problem or need, as reported

IHTSDO Content Tracker description for artf6250 - PRIORITY:
The PRIORITY attribute requires future review for reproducibility and consistency. There is some subjectivity to assigning this attribute. It is generally assigned when the Fully Specified Name (FSN) explicitly states the priority [e.g. Emergency operation (procedure)]. However, it is easily omitted when the FSN does not explicitly state the priority.

Summary of requested solution

While a specific solution was not proposed with the initial artifact, review of an attribute for reproducibility and consistency normally requires Quality Assurance processes which include:

1. Review of Editorial Guidance on use of the attribute.

2. Review of content where the attribute is applied to evaluate whether:

   1. It is used correctly in the concept definition

   2. The classification results are correct

3. Review for errors of omission - concepts where the attribute should be applied but was not

4. Review of the attribute's value set (|272125009 |Priorities (qualifier value)|) for completeness and for incorrect values

Initial proposals for a solution are provided the Solution Development Section (Sections 6).

Statement of problem as understood

The 260870009 |Priority (attribute)| attribute is intended to subclass a |Procedure (procedure)| concept according to its priority. However, the attribute has been used sparsely and inconsistently in concept definitions. As of the January 2015 International Release, |Priority (attribute)| had been used in 162 stated procedure definitions and in 191 inferred procedure definitions.
Issues related to the use of |Priority (attribute)| include:

1. Subjectivity related to interpretation of the "priority" of procedures for FSNs where priority is explicitly stated and, even more so, for FSNs where priority is not explicitly stated

2. Ambiguity in the meaning of the allowed values for |Priority (attribute)| (the range is 272125009 |Priorities (qualifier value)|)

   1. Some allowed values are ambiguous in their own right

   2. Some have a meaning that is relative to the procedure that is being qualified

Examples:

• Emergent surgical priority may have a different meaning (with respect to urgency and timeline) than emergent administrative priority

• Even within a specialty realm such as Surgery, surgical priorities can have different definitions in different settings and specialties

1. Overlap between values for |Priority (attribute)| (the range for which is 272125009 |Priorities (qualifier value)|) and for |Procedure context (attribute)| (the range for which is 288532009 |Context values for actions (qualifier value)|)

For the reasons stated, |Priority (attribute)| does not reliably differentiate or retrieve |Procedure by priority (procedure)| concepts. This is particularly problematic because |Procedure by priority (procedure)| is sufficiently defined which misleads users to assume that the concept will classify its appropriate subtypes. Although |Procedure by priority (procedure)| classifies some appropriate subtypes, many appropriate subtypes are omitted and some subtypes are inappropriate.
Nevertheless, |Priority (attribute)| may be useful for differentiating some emergent or non-emergent procedures for scheduling, billing or other purposes. Therefore, even if it is retired as a defining attribute in the International Release, the question of whether it may still have a purpose for post-coordination or in pre-coordinated content in local extensions should be considered. However, the risk/benefit ratio for the use of |Priority (attribute)| should still be taken into account for these use cases.

Detailed analysis of reported problem, including background

Editorial Guidance - Background

The SNOMED CT® Editorial Guide January 2015 (Section 6.2.2.7 PRIORITY) offers the following guidance for the |Priority| attribute:
This attribute refers to the priority assigned to a procedure.
Domain: |Procedure| hierarchy
Range: 272125009 |Priorities (qualifier value)|
Example:

• |PRIORITY| |Emergency (qualifier value)|
It is worth noting that some procedures with priority (e.g., an Emergency caesarean section) may be performed differently in an emergency than when done under more routine conditions. However, this is not necessarily the case for many of the |Procedure by priority| concepts where the technique for performing the procedure is basically the same regardless of the urgency/prioritization for the procedure. Additionally, based on the Editorial Guidance, the purpose of this attribute is not to identify procedures where the technique may vary based on priority, the purpose is to identify the priority of the procedure.

Subjectivity of Procedure Prioritization

There is a significant degree of subjectivity in assigning priority to procedures. Without clear-cut definitions and criteria for how to prioritize procedures, it is often not clear which procedures should be assigned |Priority (attribute)| and when a procedure might be deemed to be essential but not necessarily emergent.
Examples:

• Intracoronary artery thrombolytic infusion (procedure)

• Repair of rupture of coronary artery (procedure)

• Emergency excision of normal appendix (procedure)

• Control of hemorrhage (procedure)

• Thoracoscopy with control of traumatic hemorrhage (procedure)

• Repair of chest wall herniation of lung (procedure)

• Excision of ruptured appendix by open approach (procedure)

• Stabilization of spinal dislocation (procedure)

• Acute pain control (procedure)

As of the January 2015 Release, of the concepts above, only Emergency excision of normal appendix (procedure) had |Priority (attribute)| in its concept definition. This was most likely triggered by the word "Emergency" (which is in the value set for |Priority (attribute)|) in the FSN.

Definitions for Surgical Priority

The definitions below are illustrative of the challenge in determining the priority of a surgical procedure (for this example whether it might be might be emergent, essential or elective).
Definitions for Emergent, Essential and Elective Surgery (The Encyclopedia of Surgery, n.d.)

• Emergency surgery

Non-elective surgery performed when the patient's life or well-being is in direct jeopardy.

• Essential surgery

An operative procedure that is considered to be vitally necessary for treating a disease or injury. Postponing or deciding against an essential procedure may result in a patient's death or permanent impairment. May be performed on either an elective or emergency basis.

• Elective surgery 

Surgery that can be scheduled in advance and is not considered an emergency. It may be either medically required (e.g., cataract surgery), or optional (e.g., breast augmentation or implant) surgery. However, some elective surgeries can be considered essential.
It is easy to see how confusion might arise because some essential surgeries can be performed on either an elective or emergency basis and some elective surgeries can be essential.

Concept Definitions

The difficulty in determining whether a procedure should be assigned a priority is illustrated in the examples below.
Example 1: 233370007 |Aortic aneurysm repair (procedure)|
This may be an essential surgery that can, at times, be scheduled as an emergency procedure or as an elective procedure. This concept definition does not include |Priority (attribute)|.

Example 2: 386308007 |First aid (procedure)|
Based on some of the definitions available for first aid, it may be difficult to determine whether a term as basic as "First aid" warrants |Priority (attribute)| and, if so, which value.

Depending on which definitions above is chosen, |First aid (procedure)| could be assigned:

3. No priority at all (per the nursing definition of "initial care of a minor injury")

In SNOMED CT, |First aid (procedure)| is modeled as a child of |Emergency treatment (procedure)| from which it inherits |Priority (attribute)| = |Emergency (qualifier value)|.

Example 3: 703985001 |Chest thrust (procedure)|