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when does a study become too old

I have always wondered if there is a firm rule published anywhere on when a study becomes too old?

For example:

The Maki study saying that PICC lines have high infection rates was published in chest 2005.  The data was collected in 1998 and the catheters used were not placed with ultrasound or MST and the tips were not central.  The PICC lines did not get chlorhexidiene or biopatchs or full barrier placement.  Is this study obselete?

The grove study that everyone brings out was published in 2000 or 2001 and the PICC lines placed were silicone.  The RN placements were not placed with ultrasound or MST and were not even x-rayed as some were midclavicular.  The data was collected in the late 1990's. 

At AVA a study was presented by Monreal from 1994 from Spain on a 15.3% PE rate for upper arm catheters.  The catheters were made from poly vinyl chloride which was discontinued in the US in the 80's however there were also silicone lines as well.  The midlines were made of PVC.  PVC was very stiff and caused a higher rate of infection in the old literature and was discontinued in the US. 

Back to the point at what point does a study become too old to use.  At what point is a study no longer valid.   Technology changes but we are pulling out studies with old technology to validate rationales and assumptions. 

Is there a rule?  I just bought a book by Dotter on IV Therapy from 1924 so I thought I would pull some rationale to use today from that book.  I am sure all of the info is still valid.

Kathy Kokotis

Bard Access Systems



Cindy Schrum
Cindy Schrum RN

Cindy Schrum RN CRNI

Virchow's Triad was formulated well over 100 years ago.  Is it still valid? 

Kathy, I believe you are speaking facetiously, but the intent of your message comes across clearly.

There is much anecdotal evidence that the reverse taper does cause increased thrombus.  A larger catheter not only causes reduced flow but has more surface area for fibrin to adhere to.  There are some things in science that aren't going to change.  Analyzing and manipulating the data doesn't alter the one important thing.  Patient outcomes.Most Vascular Access Nurses would never put a 16 gauge short peripheral in all patients.  We can easily see the results of a too large catheter in a superficial vessel.  Is the anatomy of a deeper vessel different or are we just unable to see the vessel damage?  Not every 16 gauge IV creates a problem, and neither does every tapered PICC.  But it's so important that we are aware of the potential damage that can be incurred when placing any catheter. 

There is more awareness of the size of a taper.  And this isn't because the manufacturers have been straightforward about it.  A 5 fr is 7 fr at the hub and a 6 fr is 8 fr at the hub.  This is not labeled on the products nor is addressed in the IFUs.  Knowledge of catheter and taper size is a critical component of the assessment process.  No matter which catheter is used, thorough and complete knowledge of that product will lead to safer insertions and better outcomes. 

The Forum is a place where nurses can share information about their own practice.  The unpublished experience of our vascular access peers is indispensable.  Clinician to clinician communication can't be sold short. 

Manufacturing representatives should use the information shared as a catalyst for change when change is the right thing to do for the patient.

As a disclaimer I want to add that I work as a Clinical Specialist for Arrow International.   



Cindy Schrum RN CRNI

Both points are valid.  The

Both points are valid.  The highest level of evidence is a review of multiple RC peer reviewed trials.  The lowest level is individual professional or professional organization.  They're both necessary and very important, and not mutually exclusive.

And, I agree that we need to be smart about how we support our own arguments, let alone how we support our own clinical practice.  Be sure you are using the most recent data at the highest level of evidence possible whenever possible.  

I don't know the answer to the age of literature question, but I have 3-5 years in my head.  Seems like it would depend on what you were looking to support; if it's something relatively new (last 10-20 years) and relatively untested in an area that is evolving rapidly (sounds like vascular access!) - you'd want pretty fresh data.

I'm going to check this out a bit more..... 


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

Lynn Davis-Deutsch Seton

Lynn Davis-Deutsch

Seton Family of Hospitals

Vascular Access

I am working on my BSN from California State University Dominques Hills and the reseach for my papers has to be within 5 years.

Lynn Davis-Deutsch

Seton Family of Hospitals

Vascular Access

Scott Lawson
I am just curious what made

I am just curious what made you think of this? I believe that there are older dated studies that still have some applicable information to our field. Yes, technology, techniques and materials change, but common sense stays the same.

Medical professionals use these studies to help them make educated decisions about the products they use on their patients! Nurses are still the patient advocate. Discounting a study because it is too old is crazy. I do agree, however (from a previous message), that nurses need to start conducting their own studies.

Scott Lawson, RN

Clinical Sales Specialist


I apologize if I am out of

I apologize if I am out of line responding to a "non-PacerView"/ ECG guidance/ tip location question, but my background before becoming a clinician was research and this is a very important issue.

The answer, I believe, is data never becomes obsolete. However, the conclusions one draws from that data must be made cautiously and not extend beyond it. If a study looks at a specific drug or device in a certain population in a certain setting, then the conclusions are restricted to that product in that population in that setting. That holds true regardless of whether the study was done years ago or yesterday. Like a picture taken with too few pixels, the more you "blow it up" and expand it to situations not addressed, the more fuzzy and unreliable the picture becomes. Too often we find men are different from women, children from adults, one catheter coating different than another, etc.. If a specific antibiotic works for a particular condition, would you extend that conclusion to all antibiotics or to more than that specific condition? The same goes for a catheter from one company to another, one anatomic position to another, perhaps whether the patient has a fever, what other medications he/she's on, etc. The potential list of confounding variables is vast and we often try to simplify, summarize and extend studies beyond what the data supports.

Two things I've learned from research and clinical medicine:

"The Devil is in the details" and

"Absence of evidence is not evidence of absence".

Kathy Kokotis Bard Access

Kathy Kokotis

Bard Access Systems

Actually I was not thinking specifically of the reverse taper:

I was thinking of the Maki article in Chest 2005 first and foremost which points out that acute care coated CVC's have the same rate of infection as PICC lines.  The data on the PICC lines was pulled from old studies that had midclavicular placements in the antecubital area and had no full barrier placement, no chlorhexidiene, no biopatch, no ultrasound and each patient had over 3 PICC lines in the study group.  I am not sure this study is conclusive of the conclusion stated.  That is why I asked this question.

Monreal was also put out there recently from 1994 which is a study composed of poly vinyl chloride catheters.  The results showed a 15.3% PE ratio for upper arm catheters that are midline, midclavicular and SVC.  PVC was eliminated almost 20 years ago so how is this data relevant to a PICC line in the SVC today made of polyurethane.  When do you stop using data

It is unfortunate when studies are mis-appropriated to prove ones ideal personal thought process.  I heard Dr Dennis Maki get up at AVA in 2005 (which is the last time he was ever invited to speak) tell a group of PICC nurses based on his study to stop placing PICC lines and go  back to tunneled lines and coated acute care CVC's without discussing the limitations of his study group and data collection.  One can draw from a study and support conclusions that they want and misappropriate information to support their cause.

Buyer beware of the information presented.  Read the studies yourself and don't take a speaker, nurse clinician, or sales reps word for it.  I don't. 


Kathy Kokotis

Bard Access Systems

I would agree with PRMMD

I would agree with PRMMD that data is never obsolete but we must not try to apply any set of data to situations beyond the original setting, population, etc. So all data can be used but how we apply that data is tempered with common sense. 

 For publications processes, authors are frequently told to not use a reference older than 5 years unless it is considered to be a classic article or study. So there is flexibility there when some studies are considered  to be a classic. One earlier message drew a parellel to Virchow's Triad which is well over 150 years old, but still very much in use today. 

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

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

Lynn Hadaway Associates, Inc.

PO Box 10

Milner, GA 30257


Office Phone 770-358-7861

Scott Lawson
I am with you now.
I am with you now. Absolutely, there is still an element of critical thinking that goes along with reading and accepting studies. You are 100% correct that individuals need to thoroughly exam the studies presented and use those skills to determine if it is applicable. Mis-representation occurs too often for the benefit of others!

Scott Lawson, RN

Clinical Sales Specialist


Cindy Schrum
Cindy Schrum RN CRNI Pull

Cindy Schrum RN CRNI

Pull the Maki's Chest article out and read it one more time.  He

 refer's to 'conventional' CVCs vs Piccs.  There is no reference to the use of a coated catheter.

Quoted as follows is the Conclusion from the abstract of this article:

"This prospective study shows that PICCs used in high-risk hospitalized patients are associated with a rate of catheter-related BSI similar to conventional CVCs placed in the internal jugular or subclavian veins (2 to 5 per 1,000 catheter-days), much higher than with PICCs used exclusively in the outpatient setting (approximately 0.4 per 1,000 catheter-days), and higher than with cuffed and tunneled Hickman-like CVCs (approximately 1 per 1,000 catheter-days).

A randomized trial of PICCs and conventional CVCs in hospitalized patients requiring central access is needed. Our data raise the question of whether the growing trend in many hospital hematology and oncology services to switch from use of cuffed and tunneled CVCs to PICCs is justified, particularly since PICCs are more vulnerable tothrombosis and dislodgment, and are less useful for drawing blood specimens. Moreover, PICCs are not advisable in patients with renal failure and impending need for dialysis, in whom preservation of upper-extremity veins is needed for fistula or graft implantation." (CHEST 2005; 128:489–495)

Since nurses don't insert CVCs they are often unaware of the benefits of an antimicrobial catheter.  Chg-silver sulfadiazene impregnation of the antimicrobial catheter protects against staph epi, staph aureus and fungal infections (mortality rate 30%).  Since it is antimicrobial there are no issues of resistance.  If infection rates are similar for a conventional CVC vs Picc, then use of an antimicrobial catheter can increase patient safety.  Impregnation intraluminally, extraluminally and on the catheter pigtails delivers the most protection that a single device can offer.

Considering this article, the choice between an unprotected triple lumen Picc and an antimicrobial CVC on the critical care patient should be made with that consideration.

Cindy Schrum RN CRNI

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