Medical catheters are tubes used in healthcare to deliver medications, fluids or gases to patients or to drain bodily fluids such as urine. Examples include vascular access devices or intravenous catheters, urinary catheters and chest drainage tubes.
Catheters are generally inserted into a body cavity, duct, or blood vessel. They may be thin, flexible tubes called soft catheters or thicker and more inflexible catheters called hard catheters. A catheter that may be left in the body, whether temporarily or permanently, is referred to as an indwelling catheter.
History of catheter use
Catheters have been used by mankind since ancient times. Ancient Syrians made catheters out of reeds. Ancient Greeks used hollow metal tubes that they inserted through the urethra into the urinary bladder to empty it. In modern medicine, catheter use was first described by Dr. N. B. Sornborger who patented the syringe and catheter in 1868.
Making a catheter
Unlike in ancient times, when inflexible metal was used to make catheters, modern technology employs a range of polymers such as silicone rubber, latex, and thermoplastic elastomers to make the tubes. Of these, silicone is the most commonly chosen material due to its inertness as it does not react with body fluids.
Mechanically, however, it is a weak polymer that is prone to breakages which can lead to complications such as a part of the catheter remaining within the body after catheter removal.
It was in the early 1900's that a man from Dublin called Walsh and a famous Scottish urologist called Norman Gibbon created the standard catheter that is used in hospitals today - the Gibbon-Walsh catheter.
The modern disposable catheter was first built by David S. Sheridan who invented it in the 1940's. He also developed the modern disposable plastic endotracheal tube that is used for keeping airways open during surgery and emergencies.