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momdogz
Revisiting vein diameter/PICC diameter ratio
Found this early release publication of a pedi DVT & catheters study, done by Josée Dubois MD MSc, Françoise Rypens MD, Laurent Garel MD, Michèle David MD,

Jacques Lacroix MD, France Gauvin MD MSc:         http://www.cmaj.ca/cgi/rapidpdf/cmaj.070316v1.pdf


Following the practice standard of smallest size catheter possible.....we still attempt to use the 33% rule (no more than 33% of catheter filling vein) and find that we can still place most PICCs that we assess that the patient needs.  We can measure vein diameter very accurately with our U/S machines.


Anyone else use the 33% or 50% rule, or some other (in addition to the INS Practice Standard)?  Is anyone aware of more data to prove or disprove this as best practice?  I searched this site and didn't find any recent or new info.


Thanks,


Mari


irene chris
hi all I am relatively new

hi all

I am relatively new at all this, and am learning so much from this site.  Without sounding stupid can someone let me know what the 33% rule is.  I think I get it, but would sure like to know I am practicing as best I can.

Thank You in advance

Irene

lynncrni
It is really not a published
It is really not a published rule or a standard or a guideline. Several PICC experts have suggested that you choose the catheter size based on the vein diameter. This is based on the standard of practice that the smallest diameter of catheter be placed in the largest vein diameter. Now with the use of US we can actually measure vein diameter. So the suggestion is that the catheter size fill no more than 1/3, some say 1/2 of the vein diameter. Lynn

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

irene chris
Thank You
Thank You
afruitloop
When looking at how much
When looking at how much blood flow is reduced in a vessel, remember to consider that in veins, the blood flow is not consistent.  Flow in the center of the vein is faster than along the walls.

Cheryl Kelley RN BSN, VA-BC

kokotis
Kathy Kokotis Bard Access

Kathy Kokotis

Bard Access Systems

You know I find this entire conversation over the vein size at placement interesting.  Has anyone ever looked at a dye study because the veins are not a funnel.  The size you see as a point of entry is not the same size as above that point.  The diameter of the vein increases and decreases along the length of the vein.  We are not talking plumbing tubes here but anatomy that scars and scleroses over time with disease and catheterization (repeated).  I personally believe that 70% of all patients get a thrombosis of their vessels regardless of line type and that they are asymptomatic.  Crazy you may think I am but there is some basis of proof in the literature on asymptomatic thrombosis.  Vessel size is not the only factor and catheter size although you may all want to believe that myth.  It is great to look at size at insertion of 33% rule or 50% rule but a few inches up are you checking the size there and up and up the entire length of the vessel getting the PICC.  Vessels thrombose even those put in with fluoro.  Most asymptomatic.  I have not figured out a solution except to not catheterize and even than a patient gets a DVT non-symptomatic.  My mom had an upper leg DVT no symptoms, no surgery, no hospitalization.  Just a fluke that it was found.  You could be walking around right now with an arm or leg clot and not know it.  How do you prevent it?  Who knows. Don't get old, sick, non-active, eat or smoke or live beyond birth.

 

Kathy Kokotis

Bard Access Systems

momdogz
Hi, Kathy:  I agree with

Hi, Kathy: 

I agree with you that veins have differing size/elasticity along their length - I'm well aware of it.  I also agree that many or most of our patients probably have an asymptomatic thrombus.

Which is why, with incomplete data or lack of good data about this topic, we do what we consider is best practice with the information that we have - including a thorough evaluation prior to placing a PICC line (disease states, hypercoagulability issues, etc. etc.)  None of this is in a vacuum, and I don't think any of us are assuming that one technique (like trying to choose the smallest possible catheter for the vein/case) will solve all of the problems.

Should we proceed then in ignorance, saying it won't matter anyway? 

I don't think so - I think it's worth the further investigation.

 

 

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

Gwen Irwin
Interesting discussion. I

Interesting discussion.

I have a question about the 33% or 50% rule.  Maybe everyone else knows, but is that when evaluating the vein with or without the tourniquet in place?

Gwen Irwin

Austin, Texas

afruitloop
Without..... it does not
Without..... it does not matter  what size his vessel is with a tourniquet on.  What is iimportant is the vessel size in a "relaxed" state, no distention.  This give the true size because this is the condition of the vessel with the catheter in it, as long as it dwells.  A distended vein, is  not the natural state of it for the dwell time.

Cheryl Kelley RN BSN, VA-BC

kathybrn
Kathy Brown RN,

Kathy Brown RN, BSN,CRNI

I've started to use the ultrasound to measure diameter and area on all my PICC insertions, and I understand the 33 to 50% rule--but my question involves documentation. Is best practice to not only document diameter and area, but also document which percentage of the vein the catheter? Should an image of the vein with measurements also be printed as documentation?

Kathy Brown RN,CRNI

Kathy Brown RN, BSN,CRNI

momdogz
We only use the % guide as a

We only use the % guide as a tool, but don't document the percentage.  We do document the diameter of the vessel and the size of the catheter we place.

It's also a good idea to document that you assessed the size and condition (compressibility, valves, stenosis, bifurcations etc) of the vein along the length of the upper arm.  Knowing and documenting the 2 dimensional diameter of the area of the vein that you punctured to place the PICC is a small part of the story.  If the vein is significantly smaller superior to your insertion site, then what does your measurement mean?  It may or may not impact your catheter size decision, but you've demonstrated that it was part of your full assessment.

If you are able to bill for real time u/s guidance, then you'll need an image. If you can't, then you don't necessarily need an image, but it might come in handy in - heaven forbid - a court case.  You'd have documentation, for e.g., that you knew what vein you were using. 

Mari Cordes, BS RN 

Nurse Educator IV Therapy
Fletcher Allen Health Care, Burlington VT
Educator, Bard Access Systems 

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

Karen Day
Karen Day's picture
would anyone like to post

would anyone like to post the catheter diameters and the appropriate vessel sizes based on this recommendation.  I have my own measurements, just want to see if I am on track with everyone else. 

We try to follow this suggestion when placing lines as well.  We know that vessel to catheter ratio alone is not going to eliminate a DVT, but when you take away a risk don't you possibly reduce the chances of one receiving a DVT?  Just a thought

Karen

 

KATHLEENT.MOHN
kathy mohn-las vegas-I went

kathy mohn-las vegas-I went back through these articles and Mr Cavanaugh referred toa study presented at the last AVA conference-could you please list this study?  Our network publishes a newsletter and this information would probably be helpful to our readers-Thanks

kathy mohn-las vegas

Mike Brazunas
 I think that carefully

 I think that carefully assessing PICC size in relation to vein size is an important step in reducing the incidence of thrombus. 

 Of course we will never be able to eliminate the  risk of thrombus.  But isn’t so much of  nursing  and medicine about reducing health risks?

In this case the logic may be a little ahead of the studies, but it makes perfectly good sense to me. 

Virchow’s triad shows us that 3 things effect thrombus formation

1.    Alterations in normal blood flow (stasis)

2.    Injuries to the vascular endothelium

3.    Alterations in the constitution of blood (hypercoagulability)

 A large PICC certainly alters the blood flow.  A smaller one will too- but to a lesser extent.

Also, if we put the largest PICCs in the sickest patients with the highest chance of hypercoagulability, surely we’re increasing the risk in patients already at high risk.  

To all of you who are using or tracking vein size and PICC size, I urge you to collect data and publish or present.   

Mike Brazunas RN

Clinical Specialist

Angiodynamics

momdogz
See also: "Prevalence of

See also:

"Prevalence of Thrombophilia and Catheter-Related Thrombosis in Cystic Fibrosis", Michael Barker, MD et. al

"Incidence of upper limb venous thrombosis associated with peripherally inserted central catheters (PICC)", Abdullah, FRCR et.al.

In another post I was looking for help with a case study and now have a couple of iv-therapy folks who will be helping me off line, but at some point in the near future I'd like to post the details about the case.  Just for the sake of adding something of interest to this post, however: the patient we'll be doing a case study on had anti-phospholipid syndrome, lupus, and was addicted to opiates, among other problems/risk factors.

Mari Cordes, BS RN 

Nurse Educator IV Therapy
Fletcher Allen Health Care, Burlington VT
Educator, Bard Access Systems 

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

gretchen
This is for Kathy Kokotis of

This is for Kathy Kokotis of Bard:

Are the french sizes and mm on my Bard SITE-RITE 6 based on one of these rules (the 33% or 50%)?  Or what do those numbers mean?

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