In medicine, a catheter (/ˈkæθətər/) 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. Catheters are manufactured for specific applications, such as cardiovascular, urological, gastrointestinal, neurovascular and ophthalmic procedures. The process of inserting a catheter is catheterization. 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. Special types of catheters, also called probes, are used in preclinical or clinical research for sampling of lipophilic and hydrophilic compounds, protein-bound and unbound drugs, neurotransmitters, peptides and proteins, antibodies, nanoparticles and nanocarriers, enzymes and vesicles. Etymology
"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.
Sidewinder catheter is a selective catheter is used to navigate the aorta. Headhunter, Newton, Simmons, Bentson, and Berenstein catheters are used to navigate the into one of the three branches of the arch of aorta. Yashiro Catheter is a selective, hydrophilic catheter designed for optimal entry into celiac trunk. Whereas endothelial cell sampling through endovascular sampling with coils, stents, stent retrievers, or guidewires suffer from poor selectivity and a low or highly variable cell yield, a micro-3D-printed device adapted for endovascular techniques can harvest endothelial cells for transcriptomic analysis. Balloon catheters
There are also balloon catheters used in angioplasty procedures such as plain balloon catheters that is useful in passing tight vessel stenosis, drug coated balloons that contains paclitaxel on the surface to prevent smooth muscle cells proliferation of the vessel walls, thus reducing the likehood of vessel blockage in the future, high pressure balloons that can open stubborn vessel stenoses in veins and arteriovenous fistula, and cutting balloon angioplasty that contains 3 to 4 small blades on its surface (endotomes) that helps to control the distribution of balloon dilatation more uniformly and cut through resistant stenosis due to fibrous scar tissue. Dialysis catheters
There is no difference in achieving adequacy of blood flow, period of catheter usage, infection, and thromboembolism risk whether the dialysis catheter has step-tip, split-tip, or symmetrical tip. Palidrome catheter is superior to Permcath catheter in terms of maximum blood flow, dialysis adequecy, and annual patency rate. Similar to Permcath, Palidrome catheter has high infection and thromboembolism rate.