Catheter

In medicine a catheter is a tube that can be inserted 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 catheterisation. 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.

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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
• 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.

An external male condom catheter (Slang term: Texas Condom) is not a true catheter, as it is not inserted into a body cavity duct or vessel. Rather, this is a condom-like device with a plug where the condom's reservoir tip would be, and an adhesive at the base. This device allows for urinary catheterization without the insertion of a true catheter, and forms part of a Stadium buddy.

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 1940's. 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. Previous 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.

References

1. ^ http://www.jvir.org/cgi/content/full/11/8/955#SEC8 Practical approach to nephrostomy

See also

• cannula
• stent
• French catheter scale chart
• Seldinger technique