Catheter

In medicine, a catheter 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.

Catheters can be inserted into a body cavity, duct, or vessel. 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. The process of inserting a catheter is catheterization. In most uses, 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).

The ancient Syrians created catheters from reeds. "Katheter — καθετήρ" originally referred to any instrument that was inserted, such as a plug. It comes from the Greek verb "kathiemai — καθίεμαι" meaning "let down", because the catheter was 'let down' into the body.

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

The earliest American invention of the flexible catheter was during the 18th century. 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.

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

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.

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