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  • Research That Empowers

    Below is a collection of studies dating back 40 years that document the traditional flaws of the Foley catheter.

Research & Education

Welcome the Poiesis Medical LLC clinical research page. Here you can find a library of research dating back 40 years that ties Foley catheter use to bladder trauma. This very research served as the impetus and compass for our design goals for the Duette™.

To begin, you may be interested in reading our White Paper. It reviews the basic premise of how bladder trauma is caused, and how we designed the Duette™ as a solution:

Download the White Paper

Below you will find several full length clinical studies, excerpts from others, and links to several addition studies, all of which substantiate the relationship between traditional catheter use and patient treatment complications.

Duette™ Studies

Two recent pilot studies were undertaken at Level 1 Trauma Centers, with patient counts for the two studies exceeding 300. The studies reported “The Duette™ infection rate not only lower than the Bard™ rate, but is also lower than the NHSN benchmark for NSICUs with traditional Foley catheters”(see clinical trial below). Below are summaries of those study results as presented at the Southeast Surgical Congress Annual Scientific Meeting and the 23rd National Evidence-Based Practice Conference:

2016 CAUTI Poster - St. Marys

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Clinical Research Overview

The urinary bladder has two main functions: to store urine and to void urine. (Please refer to the image below for a more detailed look at the anatomy of the bladder) To aid in the fulfillment of these functions, the bladder has several innate (non-specific) immune defense mechanisms to avoid bacterial colonization. The bladder’s immune system is comprised of two primary functions:

-the process of voiding (urination)
-the mucin (GAG) coating of the bladder wall, which acts as a barrier to bacterial attachment

The innate immune system functions as a first line of defense to inhibit or prevent the attachment of bacteria to the bladder wall. These defensive mechanisms are crucial in keeping the bladder healthy, as bacterial colonization on the bladder wall is the first step in symptomatic urinary tract infection and its virulence.

The following clinical documentation expresses the value of this system and how bacteria are able to dramatically increase attachment when it is damaged or removed. Please find areas highlighted yellow for a quick reference to key points in the study.

Relevant Studies

1. Antibacterial Mechanisms of the Urinary Bladder
Carl W. Norden, Gareth M. Green, Edward H. Kass
J Clin Invest. 1968 December; 47(12): 2689–2700.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC297440/

2. Bladder Surface Mucin Effects Against Bacterial Species
C. L. Parsons, S. G. Mulholland
Am J Pathol. 1978 November; 93(2): 423–432.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2018387/

3. Antibacterial Activity of Bladder Surface Mucin (When Mucin is Removed)
C. L. Parsons, S. G. Mulholland
H Anwarl. Infect. Immun. May 1979 vol. 24 no. 2 552-557
http://iai.asm.org/content/24/2/552.short

4. Mechanism of Bladder Wall Defense
Cox CE, Hinman F Jr.
J Urol. 1961 Dec;86:739-48.
http://www.ncbi.nlm.nih.gov/pubmed/13881887

5. The Role of the Urinary Epithelium as a Barrier
C. Lowell Parsons
Urology – April 2007 (Vol. 69, Issue 4, Supplement, Pages S9-S16)
http://www.goldjournal.net/article/S0090-4295%2806%2900497-3/abstract

The Role of the Foley Catheter in Damaging the Bladder’s Natural Defenses

 

The traditional Foley catheter has two fundamental flaws that work in concert to compromise the bladder’s natural defensive mechanisms. It features an exposed tip, which grinds against and sometimes embeds into the bladder wall during urinary drainage events. This friction strips away the mucosa lining of the bladder wall, allowing bacteria to attach and colonize this area of trauma. Second, the Foley design has drainage eyes that are unprotected. As the bladder drains, the bladder wall often becomes aspirated into the drainage eye itself, causing suction damage and blockage of urine flow.

Upon insertion of a catheter, drainage of urine from the bladder commences immediately. As the bladder drains, the dome and posterior walls collapse onto the catheter tip and around the drainage eyes. Multiple drainage events mean that the bladder wall will repeatedly collapse onto these damaging areas of the catheter, leading to a compromised protective mucin layer, swelling and hemorrhaging, and in severe cases, the embedding of the catheter tip in the bladder wall.

The following are clinical studies that document the trauma urinary catheters cause to the bladder’s natural innate immune system. However, it is interesting to note that many clinicians today believe most catheter damage results at the bladder neck. The following studies have shown that, contrary to this belief, the dome and posterior wall endure the brunt of the damage caused by the catheter tip, and, to a lesser degree, the suction aspiration of the drainage eyes.

Relevant Studies

7. Bacterial Attachment Diagram

8. Bladder Wall Study – Short Term
Catheter Damage Abstract

Peychl L, Zalud R.
Cas Lek Cesk. 2008;147(6):325-9.
http://www.ncbi.nlm.nih.gov/pubmed/18724530

9. Catheter Tip Areas of Damage
EKELUND, P. and JOHANSSON, S.
(1979) POLYPOID CYSTITIS. Acta Pathologica Microbiologica Scandinavica Section A Pathology, 87A: 179–184.
http://onlinelibrary.wiley.com/doi/10.1111/j.1699-0463.1979.tb00040.x/abstract

10. Catheter Damage by Suction Aspiration
Glahn BE, Braendstrup O, Olesen HP.
Scand J Urol Nephrol. 1988;22(2):93-9.
http://www.ncbi.nlm.nih.gov/pubmed/3206221

11. Histological Changes Due to Urinary Catheters
GOBLE, N. M., CLARKE, T. and HAMMONDS, J. C.
(1989), Histological Changes in the Urinary Bladder Secondary to Urethral Catheterisation. British Journal of Urology, 63: 354–357.
http://onlinelibrary.wiley.com/doi/10.1111/j.1464-410X.1989.tb05216.x/abstract

12. Posterior Wall and Dome Damage
Ekelund P, Anderström C, Johansson SL, Larsson P.
J Urol. 1983 Sep;130(3):456-9.
http://www.ncbi.nlm.nih.gov/pubmed/6887356

13. Catheter Damage as a Cause of Infection
Gray, Mikel PhD, FNP, PNP, CUNP, CCCN
July/September 2010 – Volume 21 – Issue 3 – p 247–257
http://journals.lww.com/aacnadvancedcriticalcare/Abstract/2010/07000/Reducing_Catheter_Associated_Urinary_Tract.4.aspx

14. Catheter Averse Events

The Importance of Materials: Why 100 Percent Silicone Matters

Studies have also shown that the material of the catheter selected is crucial to reducing trauma levels during catheterization. The Duette™ a 100% silicone catheter.

15. The Effects of Catheter Material and Bacteria on Cells
Jessica M.T. Barford,Yanmin Hu, Ken Anson, Anthony R.M. Coates
The Journal of Urology, Volume 180, Issue 4 , Pages 1522-1526, October 2008
http://www.jurology.com/article/S0022-5347%2808%2901543-7/abstract

16. Comparison of Latex and Silicone Catheters in Human Trials
NACEY, J. N., TULLOCH, A. G. S. and FERGUSON, A. F. (1985), Catheter-induced Urethritis: a Comparison Between Latex and Silicone Catheters in a Prospective Clinical Trial. British Journal of Urology, 57: 325–328.
http://onlinelibrary.wiley.com/doi/10.1111/j.1464-410X.1985.tb06354.x/abstract

Future Updates

Please check back soon to see newly added clinical studies that will continue to aid us in understanding and addressing the the shortcomings of current urinary drainage technology.


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