Download c00140_catheter_cannula_or_line_final_2009

SNOMED Clinical Terms®
Issue Notification / Change Proposal / Referral form
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1. Do not alter the original document
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Issue Notification
Reference Number:
Submission Date:
Title:
Category / WG:
Source:
Status:
WG Recommendation /
Discussion: (rewritten
April 2009)
Change Proposal
Referral
: From_________ To_______
C00140
Revision Number: 3
02/09/07
July 2006
SCT Edition:
Catheter, Cannula or Line
Anesthesia Working Group
New issue
Any term related to catheter, cannula or line should be considered for
appropriate synonym terms for each of these concepts. Which is the
preferred term is often immaterial (and would vary from country to
country). Word equivalence tables are considered an alternate approach.
This approach is principally endorsed for intravascular devices and similar
naming conventions may not be appropriate for devices inserted into other
body cavities/sites (e.g. urinary tract, abdomen)
There are a number of separate device (physical object) concepts that are in
fact synonymous. A preferred term should be chosen, appropriate
synonyms created from the synonymous concepts and the redundant
concepts required
SIEB Discussion /
Decision:
Change Status:
Description of Issue or Rationale for Change
After extensive discussion, it is felt that these terms are essentially synonymous and cannot be
differentiated in any consistent way. SNOMED CT already implicitly recognizes this, (see examples
below) but it is not implemented in a consistent and systematic way.
Medical device classifications and standards are not able to consistently define any differentiating
criteria between these concepts.
At the base class level of device definition, it would appear that there are distinguishing characteristics
between a catheter and a cannula.
For example, GMDN defines a catheter as: “A flexible tube designed for insertion into a blood vessel,
organ, or body cavity for purposes that include introducing/
withdrawing fluids, occluding/dilating openings, or taking physical measurements. Some of these
devices are implantable,”
A cannula is defined as “A semi-rigid or rigid plastic or metal tube that is inserted into the lumen of a
blood vessel, duct, or body cavity for the instillation or aspiration of fluid to/from a targeted area of the
body”
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The fundamental differentiation that GMDN tries to impose is the rigidity characteristic of the device.
When applied to site specific devices
An arterial catheter is “A flexible tube designed for passage into arteries, usually for arterial
infusion/aspiration.
An arterial cannula is” A semi-rigid tube that is inserted into an artery to serve as a channel for the
transport of fluid. Insertion is achieved with the use of a removable trocar. This device is single use.
Not clear whether the “rigid” property has been omitted due to the fact that such a device would be
inappropriate or whether an incidental omission
In practice, this differentiation is of little practical value as all peripheral indwelling devices have
properties of both semi rigidity (to maintain patency at pressure) and flexibility (to allow passage in
vessels)
Similar principles are applied to venous devices.
Venous Cannula A semi-rigid or rigid tube that is inserted into a vein to serve as a channel for the
transport of fluid. Insertion is achieved with the use of a trocar. This device is single use.
Catheter, intravenous, peripheral A flexible tube designed for insertion into percutaneously accessible
blood vessels of the extremities (i.e. the peripheral vasculature) and that is short in length to keep its
distal tip near the insertion site.
There is no term defined for central venous cannula.
Catheter, central venous A flexible tube usually introduced into a neck or thoracic vein and inserted
into the superior vena cava for the purposes of infusion of substances and aspiration of blood. The
proximal end of the tube is fixed to the patient for long-term use.
It is a characteristic of modern central venous devices, especially multi lumen devices that there is a
degree of both rigidity of the device, which facilitates sampling from the device as well as adequate
flexibility to allow insertion and adaptation to venous anatomy.
Another supposed differentiation between a cannula and a catheter is the presence on an insertion trocar
in the former. This is less and less true with modern devices and Seldinger techniques of insertion.
There are a number of exceptions to this rule, for example oxygen nasal cannula 336623009 which has
no insertion trochar
Illustrations
catheterization of vein 392230005. includes synonym terms that include the term “line” but not
cannula, whereas an immediate descendant, “central venous cannula insertion” 233527006 includes
“cannula” and “line” although its parent term is a “catheterization”
Terms exist for arterial line
261241001, arterial cannula 75192006 and arterial catheter
303727009 . In practice, unless constrained by the application, there would inevitably be inconsistency
of usage and recording, and the potential for significant reporting and aggregation issues.
Suggested Action(s) or Change(s)
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The anesthesia SIG considers that vascular access terms including, catheter, cannula, line,
catheterization, cannulation should be populated with synonyms for each of the three terms.
This principally affects two main areas of the SNOMED hierarchies – device and procedure terms.
There is a large number of terms affected in the catheterization (procedure) 45211000 hierarchy where
consistency could be significantly improved.
For other types and anatomical sites, a case by case analysis of common usage and accepted
nomenclature in the IHTSDO charter member states and other SNOMED users is required.
Impact of Action or Change(s)
Technical impact
Two principle issues – harmonization of synonymy amongst existing terms. The more significant issue
would be approaching the existing concept duplication in SNOMED and defining a policy for retirement
and preferred term usage
User impact
Would generally be beneficial to achieve simplification and term equivalence, although will no doubt
create dissent amongst those who continue to believe a clear distinction in concepts exists,
Business impact
Resource impact
Impact of no Action
Incomplete search results depending on user convention of which concept forms the key search term.
Progress Notes
Additional Notes / Discussion
Notes from Anesthesia SIG meeting April 2008
Judith Warren and Cyndie Lundberg gave feedback on the nursing group’s reaction to IOTA’s proposal that these terms
are synonymous. They are unwilling to support this proposal at the present time as they feel that it would conflict with
nursing practice standards. However, the various standards will be examined to see if the distinctions made are real
distinctions. Judith Warren will feed back to IOTA on the outcome of this. There were also concerns over collating the
terms as vendors distinguish between the three.
Cyndie Lundberg pointed out that this issue had been discussed in the late 1990s by the SNOMED Editorial Board.
Although it was decided to keep the three terms separately, no real distinction had been found between them. It will be
worth finding documentation of this.
Notes from the Anesthesia SIG / Nursing SIG meetings April 2009
It had been established at the October working group meetings that there did not seem to be any significant conflict with
nursing practice standards. Indeed it was notable that at this meeting there is a very clear clinical difference in terminology
for the same concept. Peripheral Intravenous cannula in the UK is identical with peripheral intravenous catheter in the
USA.
No resolution of the proposal had been reached at the previous meeting. The action decided upon was that Andrew
Norton would present existing and remodeled examples to the Nursing SIG.
This was done at this meeting. The main issues are that:
1) For procedure hierarchy terms, there are often existing synonyms for catheter and line, where the term cannula
may appear in a higher level of the same hierarchy
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SNOMED CT® Issue, Change, Referral Form
2) This could be addressed by the creation of the relevant additional synonym terms or possibly by the use of a word
equivalence table.
3) The number of concepts in this domain needs to be scoped so as to quantify potential workload for CAP-STS
4) In device (physical object terms) there are a number of examples where the concept catheter, cannula and line
have been treated as separate and distinguishable concepts: e.g. arterial cannula, arterial line, arterial catheter.
5) It is proposed that these should be aggregated into a preferred concept with synonyms and the redundant terms
retired.
Notes added October 2009
The paper has been expanded with references to GMDN and other definitions. Recommendation for change formulated
that should be applied to vascular device related terms and others examined on a case by case basis with due reference
to language and common usage variants amongst SNOMED CT user nations.
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