A catheter is a device which is used to drain fluid from the body. A urinary catheter, therefore, is one which is inserted into the bladder to drain urine.
A foley catheter has a water-filled balloon which is inflated once the catheter is in situ and holds the catheter in the patient’s bladder for a period of time.
Foley catheters may be inserted into the bladder via the urethra (urethral catheter) or directly into the bladder via an incision in the wall of the abdomen (suprapubic catheter).
Foley catheters allow continual drainage while in situ. A foley catheter may be used for just a few hours or up to 3 months before being removed or replaced.
Foley catheterisation carries a high risk of urinary tract infection (UTI) because the catheter provides a pathway for bacteria to climb up the urethra into the bladder. Catheter-associated urinary tract infections (CAUTI) are the most common infections acquired in hospitals and long-term care facilities. Studies estimate the incidence of healthcare associated UTIs at around 2-3 patients per 100 admissions.
Foley catheters may be 2-way or 3-way. A 2-way catheter has two lumens – one to drain fluid (in this case urine) and one to inject fluid or medication (in this case water into the balloon). There are also 3-way urinary catheters which have a third lumen to flush water into the bladder. 3-way catheters are used to irrigate the bladder post-operatively and remove blood, clots, debris etc.
Most foley catheters are made of latex or silicone but many are also coated to make them more comfortable to insert and wear or (in the case of latex catheters) to reduce the risk of irritation or allergic reactions.
Intermittent Self-Catheters (ISC)
An ISC is inserted into the urethra to drain the bladder before being removed and either cleaned and reused or discarded. A patient may ISC up to 7 times per day.
ISC is used when a patient is able to hold urine in their bladder but cannot empty their bladder, possibly because of an obstruction such as an enlarged prostate, or because of a neurological disorder. ISC carries less risk of infection than foley catheterisation as the pathway into the bladder is kept closed, but patients must be capable of catheterising themselves. Most ISC are made of plastic or silicone and often have hydrophilic coatings to make them easier and more comfortable to insert.
A urinary sheath is worn by male patients over the penis. Urine drains through the sheath and is collected in a urine drainage bag.
As a sheath does not enter the bladder, it offers the best protection against UTIs of the three types of urinary catheter. However, many men do not find them comfortable to wear and they must be cleaned and cared for carefully to ensure no skin irritation or breakdown occurs. A 1-piece sheath is unrolled over the penis much like a condom. It has an adhesive to hold the sheath in place and can be removed using soap and water. A 2-piece sheath has a non-adhesive sheath which is placed over the penis and secured with a separate adhesive strip. Most urinary sheaths are made of silicone or latex.
All catheters need to be replaced every 3 months at least. You can discuss with your doctor or nurse when you should change your catheter. It's best if you plan in advance rather than await an emergency. Some surgeries and hospitals offer a catheter-changing service.