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Halle Utter
Vein size to catheter size ratio REVISITED!!

I just read the comment posted by Pam Jasper, Clinical Specialist, Bard, regarding vein size/catheter size ratio that takes into account the AREA of the vein and the catheter, ie 2 dimensional, versus only looking at the 1 dimensional aspect of vessel and catheter diameter.  This makes a lot of sense to me and I HAVE NEVER HEARD OF IT BEFORE.  My question now becomes whether there are any studies that support looking at appropriate catheter size to vessel size from this angle, or are they all based on the 1 dimensional diameter only method?  I looked at the formula for calculating the area and also the chart that accompanied her post, and had also NEVER SEEN THESE BEFORE EITHER!  I know it makes a lot of sense to me, and supports what I've seen myself on the ultrasound, because when I have looked at a vessel WITH A CATHETER IN IT, it sure never looked like it took up 30% of the area!  Now I know why.  The conclusion that could be drawn from this information is that a smaller vein could accommodate a larger catheter than what I thought, but.....IS THAT CORRECT?  I would love to see more discussion on this from our local experts.  Obviously there are other factors to consider that can contribute to thrombogenicity, ie Virchow's Triad, but I would really like to know which interpretation of size ratio is supported by data!   Comments?  Lynn?  What do you say about this!

 

Addendum:  I always measure vessel size without any tourniquet.  This seems obvious to me.  A tourniquet can swell a vessel to almost double if not more of it's "un-tourniqueted" size.  It would not be appropriate to document size while the tourniquet is on - that means nothing as far as I'm concerned.    

   

Halle Utter RN, BSN

Intravenous Care, INC 

momdogz
Hi, Halle:  I just posted a

Hi, Halle:

 I just posted a reply in the other thread you commented on.

Best,

Mari

Mari Cordes, BS RN 

Nurse Educator IV Therapy
Fletcher Allen Health Care

Mari Cordes, BS RNIII VA-BC
Vascular Access Department
University of Vermont Medical Center

Pam Jaspers
Halle, I could not agree

Halle,

I could not agree more that we need to make sure we are comparing apples to apples!

Does anyone know either of the physicians who presented at AVA in 2007?  i believe their names are Dr. Marcowicz and Dr.Nifong. 

Perhaps we could discuss this issue with them and get their opinions and/or the standard to which they referred.

I am a firm believer in choosing the smallest catheter that is appropriate for the treatment needed and I also believe we will never get a black or white answer to this question. 

Nurses are well-trained professionals who need to make decisions that are based on standards, assessment and risk vs.benefit.

Have a great day!

Pam

 

lynncrni
For my entire career in

For my entire career in infusion nursing, we have always taught to use smaller gauge catheters in the largest vein possible, yet we have had no means to measure this. Ultrasound use has changed this and now we are able to measure vein diameter and compare it to catheter outer diameter. I am not aware of any published studies yet, but I do know that several groups are working on this. So I am not surprised that many people have never heard about the concept of 30 or 50% of the vein taken up by the vein. The age-old concept can now be supported because of advancing ultrasound technology that can measure vein diameter. So there will be much more coming about this but I am not aware of any actual peer-reviewed published studies yet. If someone else knows of them, please let us know. Thanks, Lynn

 

Lynn Hadaway, M.Ed., RN, BC, CRNI

www.hadawayassociates.com

Lynn Hadaway, M.Ed., NPD-BC, CRNI

Lynn Hadaway Associates, Inc.

PO Box 10

Milner, GA 30257

Website http://www.hadawayassociates.com

Office Phone 770-358-7861

Halle Utter
I may not have stated my

I may not have stated my question clearly.  I have been practicing the 30-50% standard, using the 1 dimensional vein DIAMETER measurement, as long as I have been using ultrasound.  I totally support the theory of using smallest catheter possible for the needed therapies.  But what I am wondering is in the cases where a larger multilumen catheter IS indicated, have I been misinformed, or not practicing based on good data? Using the vein & catheter area instead of the 1 dimensional diameter only, the 30-50% rule implies that vein COULD support a larger catheter than I have been willing to place. When the aforementioned physicians brought up the 30-50% rule, were they referring to diameter or area?  Makes a bit of a difference.  It sounds like the answer is "we don't know" because there have not been any good studies that clearly delineate which parameter they were/are using to determine the 30-50%, in fact no good research studies of either one.  Obviously a big need in our profession, and of course there are multiple other factors to consider when determining appropriate catheter size related to vein size.  

 

Halle Utter, RN, BSN

Intravenous Care, INC 

Hallene E Utter, RN, BSN Intravenous Care, INC

lynncrni
No you have not missed

No you have not missed anything. While this idea has been discussed - vein size to catheter size based on % of diameter - there are no published studies that have examined the issue. Great idea but definitely needs to be validated by published studies.   

Lynn Hadaway, M.Ed., RN, BC, CRNI

www.hadawayassociates.com

Lynn Hadaway, M.Ed., NPD-BC, CRNI

Lynn Hadaway Associates, Inc.

PO Box 10

Milner, GA 30257

Website http://www.hadawayassociates.com

Office Phone 770-358-7861

Robbin George
Cheryl "Fruitloop" Kelley
Cheryl "Fruitloop" Kelley has for several years now used this very subject in focus group discussions at AVA and has promised on this very Web site to author an article highlighting her considerable knowledge on this subject--Let us please all encourage her to go forth and publish  

Robbin George RN VA-BC

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