In medicine, a catheter (/ˈkæθətər/)[1] is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. By modifying the material or adjusting the way catheters are manufactured, it is possible to tailor catheters for cardiovascular, urological, gastrointestinal, neurovascular, and ophthalmic applications. The process of inserting a catheter is "catheterization".

Catheter dissasembled.jpg
Catheter disassembled

In most uses, a catheter is a thin, flexible tube ("soft" catheter) though catheters are available in varying levels of stiffness depending on the application. A catheter left inside the body, either temporarily or permanently, may be referred to as an "indwelling catheter" (for example, a peripherally inserted central catheter). A permanently inserted catheter may be referred to as a "permcath" (originally a trademark).

Catheters can be inserted into a body cavity, duct, or vessel, brain, skin or adipose tissue. Functionally, they allow drainage, administration of fluids or gases, access by surgical instruments, and also perform a wide variety of other tasks depending on the type of catheter.[2] Special types of catheters, also called probes, are used in preclinical or clinical research for sampling of lipophilic and hydrophilic compounds,[3] protein-bound and unbound drugs,[4][5] neurotransmitters, peptides and proteins, antibodies,[6][7][8] nanoparticles and nanocarriers, enzymes and vesicles.


"Catheter" (from Greek καθετήρ kathetḗr) comes from the Greek verb καθίεμαι kathíemai, meaning "to thrust into" or "to send down" because the catheter allowed fluid to be "sent down" from the body. [9]


Single-use urinary catheter, 40 cm

Placement of a catheter into a particular part of the body may allow:


Ancient inventorsEdit

Catheters from the Roman Empire, 1st century A.D.

Ancient Chinese used onion stalks, the Romans, Hindus, and Greeks used tubes of wood or precious metals.[11]

The ancient Syrians created catheters from reeds.


The earliest invention of the flexible catheter was during the 18th century.[12] Extending his inventiveness to his family's medical problems, Benjamin Franklin invented the flexible catheter in 1752 when his brother John suffered from bladder stones. Franklin's catheter was made of metal with segments hinged together with a wire enclosed to provide rigidity during insertion.[13][14]

According to a footnote in his letter in Volume 4 of the Papers of Benjamin Franklin (1959), Franklin credits Francesco Roncelli-Pardino from 1720 as the inventor of a flexible catheter. In fact, Franklin claims the flexible catheter may have been designed even earlier.[15]

An early modern application of the catheter was employed by Claude Bernard for the purpose of cardiac catheterization in 1844. The procedure involved entering a horse's ventricles via the jugular vein and carotid artery. This appears to be an earlier and modern application of the catheter because this catheter approach technique is still performed by neurosurgeons, cardiologists, and cardiothoracic surgeons.[16]

David S. Sheridan invented the modern disposable catheter in the 1940s.[17] Prior to this, some reusable catheters consisted of braided cotton tubes, which were varnished, heat-treated and polished. As these were primarily produced in France, the advent of World War II threatened the supply chain.[18] Other reusable catheters consisted of red rubber tubes. Although sterilized prior to reuse, they still posed a high risk of infection and often led to the spread of disease.[19]: 142  Sheridan was dubbed the "Catheter King" by Forbes magazine in 1988. He also invented the modern "disposable" plastic endotracheal tube now used routinely in surgery.[17]


A range of polymers are used for the construction of catheters, including silicone rubber, nylon, polyurethane, polyethylene terephthalate (PET), latex, and thermoplastic elastomers. Silicone is one of the most common implantable choice because it is inert and unreactive to body fluids and a range of medical fluids with which it might come into contact. On the other hand, the polymer is weak mechanically, and a number of serious fractures have occurred in catheters.[20][21][22] For example, silicone is used in Foley catheters where fractures have been reported, often requiring surgery to remove the tip left in the bladder.

Polyimides are used to manufacture vascular catheters for insertion into small vessels in the neck, head and brain.

There are many different types of catheters for bladder problems. A typical modern intermittent catheter is made from polyurethane and comes in different lengths and sizes for men, women and children.

Some catheters have a thin hydrophilic surface coating. When immersed in water this coating swells to a smooth, slippery film making the catheter safer and more comfortable to insert. Since this wire is tooslippery to handle, torque devices are used to control the direction and spin the wire. It is useful in subintimal angioplasty. However, care should be taken as it can easily cause dissection of vascular wall.[23][24]

Some catheters are packed in a sterile saline solution.

Interventional proceduresEdit

Various settings of a 6 French pigtail catheter with locking string, obturator (also called stiffening cannula) and puncture needle.
A. Overview
B. Both puncture needle and obturator engaged, allowing for direct insertion.
C. Puncture needle retracted. Obturator engaged. Used for example in steady advancement of the catheter on a guidewire.
D. Both obturator and puncture needle retracted, when the catheter is in place.
E. Locking string is pulled (bottom center) and then wrapped and attached to the superficial end of the catheter.

Cardiac catheterization (cardiac cath or heart cath) is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.[25]

Hemodialysis uses a specialized "tunneled" catheter, placed under the skin. It features two pathways, one to draw blood from an artery, and into the dialysis device, and a second pathway, to return cleansed blood into the body, through a vein. [26]

Adverse effectsEdit

"Any foreign object in the body carries an infection risk, and a catheter can serve as a superhighway for bacteria to enter the bloodstream or body", according to Milisa Manojlovich, a professor at the University of Michigan School of Nursing. [27]

Catheters can be difficult to clean, and therefore harbor antibiotic resistant[28] or otherwise pathogenic bacteria.

See alsoEdit


  1. ^
  2. ^ Diggery, Robert (2012). Catheters: Types, applications and potential complications (medical devices and equipment. Nova Science. ISBN 978-1621006305.
  3. ^ Altendorfer-Kroath, Thomas; Schimek, Denise; Eberl, Anita; Rauter, Günther; Ratzer, Maria; Raml, Reingard; Sinner, Frank; Birngruber, Thomas (January 2019). "Comparison of cerebral Open Flow Microperfusion and Microdialysis when sampling small lipophilic and small hydrophilic substances". Journal of Neuroscience Methods. 311: 394–401. doi:10.1016/j.jneumeth.2018.09.024. ISSN 0165-0270. PMID 30266621. S2CID 52883354.
  4. ^ Schaupp, L.; Ellmerer, M.; Brunner, G. A.; Wutte, A.; Sendlhofer, G.; Trajanoski, Z.; Skrabal, F.; Pieber, T. R.; Wach, P. (February 1, 1999). "Direct access to interstitial fluid in adipose tissue in humans by use of open-flow microperfusion". American Journal of Physiology. Endocrinology and Metabolism. 276 (2): E401–E408. doi:10.1152/ajpendo.1999.276.2.e401. ISSN 0193-1849. PMID 9950802.
  5. ^ Ellmerer, Martin; Schaupp, Lukas; Brunner, Gernot A.; Sendlhofer, Gerald; Wutte, Andrea; Wach, Paul; Pieber, Thomas R. (February 1, 2000). "Measurement of interstitial albumin in human skeletal muscle and adipose tissue by open-flow microperfusion". American Journal of Physiology. Endocrinology and Metabolism. 278 (2): E352–E356. doi:10.1152/ajpendo.2000.278.2.e352. ISSN 0193-1849. PMID 10662720.
  6. ^ Dragatin, Christian; Polus, Florine; Bodenlenz, Manfred; Calonder, Claudio; Aigner, Birgit; Tiffner, Katrin Irene; Mader, Julia Katharina; Ratzer, Maria; Woessner, Ralph; Pieber, Thomas Rudolf; Cheng, Yi (November 23, 2015). "Secukinumab distributes into dermal interstitial fluid of psoriasis patients as demonstrated by open flow microperfusion". Experimental Dermatology. 25 (2): 157–159. doi:10.1111/exd.12863. ISSN 0906-6705. PMID 26439798. S2CID 34556907.
  7. ^ Kolbinger, Frank; Loesche, Christian; Valentin, Marie-Anne; Jiang, Xiaoyu; Cheng, Yi; Jarvis, Philip; Peters, Thomas; Calonder, Claudio; Bruin, Gerard; Polus, Florine; Aigner, Birgit (March 2017). "β-Defensin 2 is a responsive biomarker of IL-17A–driven skin pathology in patients with psoriasis". Journal of Allergy and Clinical Immunology. 139 (3): 923–932.e8. doi:10.1016/j.jaci.2016.06.038. ISSN 0091-6749. PMID 27502297. S2CID 30272491.
  8. ^ Kleinert, Maximilian; Kotzbeck, Petra; Altendorfer-Kroath, Thomas; Birngruber, Thomas; Tschöp, Matthias H.; Clemmensen, Christoffer (December 2019). "Corrigendum to "Time-resolved hypothalamic open flow micro-perfusion reveals normal leptin transport across the blood–brain barrier in leptin resistant mice" [Molecular Metabolism 13 (2018) 77–82]". Molecular Metabolism. 30: 265. doi:10.1016/j.molmet.2019.11.001. ISSN 2212-8778. PMC 6889745. PMID 31767178.
  9. ^ Feneley, Roger C. L.; Hopley, Ian B.; Wells, Peter N. T. (November 17, 2015). "Urinary catheters: history, current status, adverse events and research agenda". Journal of Medical Engineering & Technology. 39 (8): 459–470. doi:10.3109/03091902.2015.1085600. PMC 4673556. PMID 26383168.
  10. ^ "MedlinePlus: Urinary catheters". U.S. National Library of Medicine. November 6, 2019.
  11. ^ "MedTech Memoirs: Catheters". Advantage Business Media. June 16, 2015. Archived from the original on October 24, 2017.
  12. ^ "Didusch Site - Milestones - Relief in a Tube: Catheters Remain a Steadfast Treatment for Urinary Disorders". Archived from the original on January 17, 2015.
  13. ^ "Benjamin Franklin: In Search of a Better World". Minnesota Historical Society. Archived from the original on August 12, 2011.
  14. ^ Hirschmann, J.V. (December 2005). "Benjamin Franklin and Medicine". Annals of Internal Medicine. 143 (11): 830–4. doi:10.7326/0003-4819-143-11-200512060-00012. PMID 16330795. S2CID 32882591. Archived from the original (PDF) on December 17, 2019. Retrieved January 2, 2013.
  15. ^ Huth, E.J. (2007). "Benjamin Franklin's place in the history of medicine" (PDF). Journal of the Royal College of Physicians of Edinburgh. 37 (4): 373–8. PMID 18447203.
  16. ^ Baim, Donald (2005). Grossman's Cardiac Catheterization, Angiography, and Intervention. Lippincott Williams & Wilkins. ISBN 978-0781755672.
  17. ^ a b "David S. Sheridan". Washington Post. May 7, 2004.
  18. ^ "David Sheridan, 95; Dropout Invented Key Medical Device". Los Angeles Times. May 4, 2004.
  19. ^ Engineers, NPCS Board of Consultants & (January 1, 2014). Handbook on Medical and Surgical Disposable Products. Niir Project Consultancy Services. ISBN 9789381039281 – via Google Books.
  20. ^ McKenzie, J. M.; Flahiff, C. M.; Nelson, C. L. (October 1, 1993). "Retention and strength of silicone-rubber catheters. A report of five cases of retention and analysis of catheter strength". J Bone Joint Surg Am. 75 (10): 1505–1507. doi:10.2106/00004623-199310000-00011. ISSN 0021-9355. PMID 8408139. Archived from the original on September 23, 2016. Retrieved May 12, 2016.
  21. ^ Agarwal, Shaleen; Gandhi, Mamatha; Kashyap, Randeep; Liebman, Scott (March 1, 2011). "Spontaneous Rupture of a Silicone Peritoneal Dialysis Catheter Presenting Outflow Failure and Peritonitis". Peritoneal Dialysis International. 31 (2): 204–206. doi:10.3747/pdi.2010.00123 (inactive October 31, 2021). ISSN 0896-8608. PMID 21427251. Archived from the original on May 8, 2018.{{cite journal}}: CS1 maint: DOI inactive as of October 2021 (link)
  22. ^ Mirza, Bilal; Saleem, Muhammad; Sheikh, Afzal (August 14, 2010). "Broken Piece of Silicone Suction Catheter in Upper Alimentary Tract of a Neonate". APSP Journal of Case Reports. 1 (1): 8. ISSN 2218-8185. PMC 3417984. PMID 22953251.
  23. ^ Themes, U. F. O. (June 20, 2016). "Catheter-Based Technology and Devices". Thoracic Key. Retrieved August 15, 2021.
  24. ^ Fornell, Dave (October 12, 2016). "Understanding the Design and Function of Guidewire Technology". Diagnostic and Interventional Cardiology (DAIC). Retrieved August 15, 2021.{{cite web}}: CS1 maint: url-status (link)
  25. ^ Cardiac catheterization see this article for attribution
  26. ^ "Hemodialysis Catheters: How to Keep Yours Working Well". National Kidney Foundation. December 24, 2015.
  27. ^ Laura Bailey (July 1, 2019). "Catheters: Big source of infection, but often overlooked". University of Michigan. Retrieved February 16, 2020.
  28. ^ "Nobody wants to talk about catheters. Our silence could prove fatal | Mosaic". November 7, 2018. Retrieved November 13, 2019.

External linksEdit