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In medicine a catheter is a tube that can be insert into a body cavity, duct or vessel. Catheters thereby allow drainage or injection of fluids or access by surgical instruments. The process of inserting a catheter is catheterization. In most uses a catheter is a thin, flexible tube: a "soft" catheter; in some uses, it is a larger, solid tube: a "hard" catheter.
History and etymology
The ancient Egyptians created catheters from reeds. "Katheter" originally referred to an instrument that was inserted such as a plug. The word "katheter" in turn came from "kathiemai" meaning "to sound" with a probe. The ancient Greeks inserted a hollow metal tube through the urethra into the bladder to empty it and the tube came to be known as a "katheter".
Uses
Placement of a catheter into a particular part of the body may allow:
- draining urine from the urinary bladder as in urinary catheterization, e.g., the Foley catheter or even when the urethra is damaged as in suprapubic catheterisation.
- drainage of urine from the kidney pelvis by percutaneous nephrostomy[1]
- drainage of fluid collections, e.g. an abdominal abscess
- administration of intravenous fluids, medication or parenteral nutrition with a peripheral venous catheter
- angioplasty, angiography, balloon septostomy, balloon sinuplasty. Often Seldinger technique is used.
- direct measurement of blood pressure in an artery or vein
- direct measurement of intracranial pressure
- administration of anaesthetic medication into the epidural space, the subarachnoid space, or around a major nerve bundle such as the brachial plexus
- subcutaneous administration of insulin or other medications, with the use of an infusion set and insulin pump
A central venous catheter is a conduit for giving drugs or fluids into a large-bore catheter positioned either in a vein near the heart or just inside the atrium. A Swan-Ganz catheter is a special type of catheter placed into the pulmonary artery for measuring pressures in the heart.
A Touhy borst adapter is a medical device used for attaching catheters to various other devices.
A Quinton catheter is a double or triple lumen, external catheter used for hemodialysis.
Inventors
The modern application of the catheter was in use at least by 1868 when Dr. N.B.Sornborger patented the Syringe and Catheter (patent #73402) with features for fastening it to the body and controlling the depth of insertion.
David S Sheridan was the inventor of the modern disposable catheter in the 1940s. In his lifetime he started and sold four catheter companies and was dubbed the "Catheter King" by Forbes Magazine in 1988. He is also credited with the invention of the modern "disposable" plastic endotracheal tube now used routinely in surgery. Prior to his invention, red rubber tubes were used, sterilized, and then re-used which often led to the spread of disease and also held a high risk of infection. As a result Mr Sheridan is credited with saving thousands of lives.
In the early 1900s, a Dubliner named Walsh and a famous Scottish urinologist called Norman Gibbon teamed together to create the standard catheter used in hospitals today. Named after the two creators, it was called the Gibbon-Walsh catheter.
The Gibbon catheter and the Walsh catheter have been described and their advantages over other catheters shown. The Walsh catheter is particularly useful after prostatectomy for it drains the bladder without infection or clot retention. The Gibbon catheter has largely removed the necessity of emergency prostatectomy. It is also very useful in cases of urethral fistula. A simple procedure such as dilatation of the urethra and passage of a Gibbon catheter often causes the fistula to close. This catheter is also of use in the treatment of urethral stricture and, as a temporary measure, in the treatment of retention of urine caused by carcinoma of the prostate
Benjamin Franklin invented a flexible Catheter for his brother who had a bladder stone.
Materials
A range of polymers are used for the construction of catheters, including silicone rubber latex and thermoplastic elastomers. Silicone is one of the most common choices 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. It is widely used, for example, in breast implants where failures by rupturing of the silicone shell are well attested. It is also used in Foley catheters where fractures have been reported, often requiring surgery to remove the tip left in the bladder.
Interventional procedures
Different catheter tips can be used to guide the catheter into the target vessel. Refer to [1] for a picture of different catheter tips and their respective names.
References
- ^ http://www.jvir.org/cgi/content/full/11/8/955#SEC8 Practical approach to nephrostomy
See also
External links
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