Catheters

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.

Types and sizes of catheters

Diameters:

• 5Fr, 6fr, 8fr 10fr, 12fr, 14fr, 16fr, 18fr, 20fr, 22fr, 24fr, 26fr.
• The higher the number the larger the diameter of the catheter.
• 3Fr. = 1mm (i.e. a 24fr. catheter is 8mm in diameter)

Types:

• Straight-single use catheters
  • Have a single lumen with a small 1¼ cm opening

• 2-way Foley catheters (retention catheters)
  • Have an inflatable balloon that encircles the tip near the lumen or opening of the catheter.

• Curved or Coude
  • Catheters have a rounded curved tip (elbowed) used in older male patients with enlarged prostates which partially obstruct the urethra.

• 3-way Foley catheter
  • Often called retention catheter, they have 2 or 3 lumens that encircle the body of the catheter. One lumen drains the urine through the catheter into a collection bag. The second lumen holds the sterile water when the catheter is inflated and is also used to deflate the balloon. The third lumen may be used to instill medications into the bladder or provide a route for continuous bladder irrigation.