Foley catheterIn medicine a catheter is a tube that can be inserted into a body cavity, duct or vessel. Catheters thereby allow drainage, injection of fluids or access by surgical instruments. The process of inserting a catheter is catheterization. In most uses a catheter is a thin, flexible tube , although...
s are flexible (usually
latexLatex refers generically to a stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic. Latex as found in nature is a milky sap-like fluid within many plants that coagulates on exposure to air. It is a complex emulsion in which proteins, alkaloids,...
) tubes that are passed through the
urethraIn anatomy, the urethra is a tube which connects the urinary bladder to the outside of the body. The urethra has an excretory function in both sexes to pass urine to the outside, and also a reproductive function in the male, as a passage for semen.The external urethral sphincter is a striated...
during
urinary catheterizationIn urinary catheterization, or "cathing" for short, a plastic tube known as a urinary catheter is inserted into a patient's bladder via their urethra. Catheterization allows the patient's urine to drain freely from the bladder for collection, or to inject liquids used for treatment or diagnosis of...
and into the
bladderIn anatomy, the urinary bladder is the organ that collects urine excreted by the kidneys prior to disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
to drain
urineUrine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream...
. They are retained by means of a balloon at the tip which is inflated with sterile water. The balloons typically come in two different sizes: 5 cc and 30 cc. They are commonly made in
silicone rubberSilicone rubber is a polymer that has a "backbone" of silicon-oxygen linkages, the same bond that is found in quartz, glass and sand. Normally, heat is required to vulcanize the silicone rubber; this is normally carried out in a two stage process at the point of manufacture into the desired shape,...
or natural rubber.
The relative size of a Foley catheter is described using
French unitsThe French catheter scale is commonly used to measure the outer diameter of cylindrical medical instruments including catheters...
(F). The most common sizes are 10 F to 28 F. 1 F is equivalent to 0.33 mm = .013" = 1/77" of diameter. Thus the size in French units is roughly equal to the circumference of the catheter in millimetres.
Foley catheters come in several sub-types. Coudé (French for elbowed) catheters have a 45° bend at the tip to allow easier passage through an enlarged
prostateThe prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system. Females do not have prostate glands...
. Council tip catheters have a small hole at the tip which allows them to be passed over a wire. 3-way catheters are used primarily after bladder,
prostate cancerProstate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. The cancer cells may metastasize from the prostate to other parts of the body, particularly the bones and lymph nodes. Prostate cancer may cause pain, difficulty in urinating, problems...
or prostate surgery. They have a third arm or bell that allows an irrigant to pass to the tip of the catheter through a small separate channel into the bladder. This serves to wash away blood and small clots through the primary arm that drains into a collection device. This prevents larger clots, which might plug the catheter, from forming. The second, or inflation, arm has a small plastic valve that allows for the introduction or removal of
sterile water through a very small channel to inflate or deflate the retaining balloon.
Foley catheters can also be used to "ripen" the
cervixThe cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. Approximately half its length is visible with appropriate medical equipment; the remainder lies above...
, to allow the
inductionInduction is a method of artificially or prematurely stimulating labour in a woman.Common causes for induction include:* The baby is believed to be getting too big.* Postdate pregnancy, i.e. if the pregnancy has gone past the 42 week mark....
of
labourChildbirth is the culmination of a human pregnancy or gestation period with birth of one or more newborn infants from a woman's uterus...
. The catheter is inserted behind the cervical wall and inflated. The remaining length of the catheter is gently pulled and taped to the inside of the woman's leg. The inflated balloon applies pressure to the cervix, like the baby's head would prior to labour, causing it to dilate. Over time the catheter is adjusted and re-taped to maintain pressure on the cervix. When the cervix has dilated sufficiently, the catheter simply drops out.
They were designed by
Frederic FoleyDr. Frederic Eugene Basil Foley, MD was an American urologist who is remembered for designing the Foley catheter.-Biography:Frederic Foley was born in St. Cloud, Minnesota in 1891...
, a surgeon working in Boston, Massachusetts, in the 1930s, when he was a medical student.
His original design was adopted by C. R. Bard of
Murray Hill, New JerseyMurray Hill is an unincorporated area within portions of both Berkeley Heights and New Providence, located in Union County in north-central New Jersey....
, who manufactured the first prototypes and named them in honour of the surgeon.
A major problem with Foley catheters is that they have a tendency to contribute to
urinary tract infectionA urinary tract infection is a bacterial infection that affects any part of the urinary tract.The main causitive agent is:Escherichia coli. Although urine contains a variety of fluids, salts, and waste products, it usually does not have bacteria in it. When bacteria get into the bladder or kidney...
s (UTI). This occurs because bacteria can travel up the catheters to the bladder where the urine can become infected. To combat this, the industry is moving to antibiotic coated catheters. This has been helpful, but it has not completely solved this major problem. An additional problem is that Foley catheters tend to become coated with time with a biofilm that can keep them from properly draining the bladder. This increases the degree of static urine left in the bladder, which further contributes to the problem of
urinary tract infectionA urinary tract infection is a bacterial infection that affects any part of the urinary tract.The main causitive agent is:Escherichia coli. Although urine contains a variety of fluids, salts, and waste products, it usually does not have bacteria in it. When bacteria get into the bladder or kidney...
s. When a Foley catheter becomes clogged, it must be flushed or replaced. Thus keeping Foley Catheters from clogging may help reduce UTIs as well.
When Foley catheters are used
Foley catheters are used during the following situations:
- On patients who are anesthesized
Anesthesia, or anaesthesia , has traditionally meant the condition of having sensation blocked or temporarily taken away. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience...
or sedatedSedation is a medical procedure involving the administration of sedative drugs, generally to facilitate a medical procedure with local anaesthesia.- Uses :...
for surgery or other medical care
- On coma
In medicine, a coma is a profound state of unconsciousness. A comatose person cannot be awakened, fails to respond normally to pain or light, does not have sleep-wake cycles, and does not take voluntary actions....
tose patients
- On some incontinent
Urinary incontinence is any involuntary leakage of urine. It is a common and distressing problem, which may have a profound impact on quality of life. Urinary incontinence almost always results from an underlying treatable medical condition...
patients
- On patients whose prostate is enlarged to the point that urine flow from the bladder is cut off. The catheter is kept in until the problem is resolved.
- On patients with acute urinary retention.
- On patients who are unable due to paralysis or physical injury to use either standard toilet facilities or urinals.
- Following urethral surgeries
- Sometimes before Furosemide
Furosemide or frusemide is a loop diuretic used in the treatment of congestive heart failure and edema. It is most commonly marketed by Sanofi-Aventis under the brand name Lasix...
administration
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