catheter
Meaning of catheter: One word covers devices as different as a bladder drain and a line threaded into a large vein near the heart.
Definition of catheter
A catheter is a thin flexible tube placed into the body to deliver fluid or medication, to drain fluid out, or to give access for a procedure. Catheters differ widely in length, width, material and design according to where they go and what they do, and one may stay in place for a few minutes or for many months.
Which kinds are used most?
| Type | Where it goes and why |
|---|---|
| Urinary | Into the bladder to drain urine, usually through the urethra and sometimes through the abdominal wall |
| Peripheral venous | A short tube in a vein of the hand or arm for fluids and medication given over days |
| Central venous | A long tube ending in a large vein near the heart, for chemotherapy, nutrition and drugs that damage small veins |
| Drainage | Into a cavity, an abscess or a kidney to let collected fluid escape |
Cardiac catheters form a further group, threaded from an artery or vein in the groin or wrist up to the heart to measure pressures, inject contrast or carry out treatment. Feeding tubes passed through the nose to the stomach are counted with them by some and separately by others. What unites the whole family is that the tube opens a route into a space the body normally keeps sealed, and every advantage and every drawback follows from that one fact.
Why does a catheter carry a risk of infection?
Skin and the lining of the urinary tract are barriers that keep organisms out. A tube passing through either one gives them a direct path in, and bacteria also settle on the plastic surface itself and grow there as a biofilm, a layer that antibodies and antibiotics struggle to penetrate. The chance of infection therefore accumulates with each day the tube remains, rather than being a fixed figure attached to the device. Bloodstream infection traced to a central line and urinary infection traced to a bladder catheter are both counted as measures of hospital safety, and rates fall in settings where catheters are removed once the reason for placing them has passed.
What else can go wrong?
Placement carries its own risks. A tube pushed toward a large vein in the chest can puncture the lung alongside it, and one reaching the heart can set off an irregular rhythm. Any catheter can block, kink, leak or work its way out of position, and one sitting in a vein encourages a clot to form around it. Urinary catheters can irritate or injure the urethra and the bladder wall. Designs that anchor themselves by inflating a small balloon at the tip add a failure of their own when the balloon will not deflate. A tube left in place after it stops being useful accumulates all of these risks while returning none of the benefit.
Used in a sentence
A central venous catheter was placed to allow ongoing administration of intravenous chemotherapy.
Good to know
A urinary catheter and a central venous catheter serve entirely different purposes despite sharing the same general name, one draining fluid from the bladder and the other providing prolonged access to the bloodstream.
Word origin
Where “catheter” comes from
Formed from Greek kathienai, meaning to send down or thrust into, from kata-, meaning down, and hienai, meaning to send.