Show Catheters are semi-rigid but flexible tubes. They drain the bladder but block the urethra. The challenge is to produce a catheter that matches as closely as possible to the normal physiological and mechanical characteristics of the voiding system. This requires construction of a thin-walled, continuously lubricated, collapsible (conformable) catheter to protect the integrity of the urethra; a system to hold the catheter in place without a balloon; and a design to imitate the intermittent washing of the bladder with urine. Catheter products have changed significantly in their composition, texture, and durability since the 1990s. The catheter should have a smooth surface with two drainage eyes at the tip that allow for urine drainage. Drainage eyes are placed either laterally or opposed. Opposing drainage eyes generally facilitate better drainage. Catheter Tips The most commonly used catheter is a straight-tipped catheter. A Coudé-tipped catheter, or Tiemann catheter, is angled upward at the tip to assist in negotiating the upward bend in the male urethra. This feature facilitates passage through the bladder neck in the presence of obstruction from a slightly enlarged prostate gland (e.g., in benign prostatic hyperplasia) or through a narrowed stricture in the urethra. The Carson catheter is a slightly larger bulb to assist in negation of restrictions. The Council catheter features a reinforced hole at the tip of the catheter. A whistle-tipped catheter is open at the end and allows drainage of large amounts of debris (e.g., blood clots). Catheter Size and Length Each catheter is sized by the outer circumference and according to a metric scale known as the French (Fr) gauge (range is 6 to 18 Fr), in which each French unit equals 0.33 mm in diameter. The golden rule is to use the smallest catheter size (termed bore), generally 14 to 16 Fr, that allows for adequate drainage. The use of large-size catheters (e.g., 18 Fr or larger) is not recommended because catheters with larger diameters can cause more erosion of the bladder neck and urethral mucosa, can cause stricture formation, and do not allow adequate drainage of periurethral gland secretions, causing a buildup of secretions that may lead to irritation and infection. Also, large size catheters can cause pain and discomfort. Balloon Size A retention balloon prevents the catheter from being expelled. The preferred balloon size may be labeled either 5 mL or 10 mL, and both are instilled with 10 mL of sterile A fully inflated balloon allows the catheter tip to be located symmetrically. If a 5 mL balloon is inflated with more than 10 mL of water, irritation may occur unilaterally on the bladder wall from increased pressure of the balloon. The specified amount of inflation ensures a symmetrical shape and allows for the catheter to maintain position in the bladder while minimizing patient discomfort Underfilling or overfilling may interfere with the correct positioning of the catheter tip, which may lead to irritation and trauma of the bladder wall. A balloon with a fill size greater than 10 mL, such as a 30 mL balloon, is not recommended because the 10 mL size keeps residual urine minimal, thus reducing the risk of The catheterized bladder is in a collapsed state as a result of constant urine drainage. However, a 30 mL balloon will allow persistence of a small pool of undrained urine, so the bladder emptying is not complete and the undrained urine can leak around the catheter (referred to as “catheter bypassing”).. The use of a larger balloon size is mistakenly believed by many nurses to be a solution to catheter leakage or urine bypassing around the catheter. However, a large balloon increases the chance of contact between the balloon or catheter tip and the bladder wall, leading to bladder spasms that may cause urine to be forced out around the catheter. A 30 mL balloon is used primarily to facilitate traction on the prostate gland to stop bleeding in men after prostate surgery or to stop bleeding in women after pelvic Routine use of larger capacity balloons (30 mL) should be avoided for long-term use as they can lead to bladder neck and urethral erosion. Several catheter materials have been found to lose water from the inflated balloon over time in the bladder with 100% silicone catheters losing as much as 50% of their volume within 3 weeks. In men, the catheter should be passed initially to the bifurcation (the “Y” junction where the balloon arm and catheter meet) to ensure that the balloon will not be inflated in the urethra. Catheter Materials A wide range of catheter materials are available, and the material selected should be chosen by:
Note: Prior to insertion, all indwelling catheters should be visually inspected for any imperfections or surface deterioration. 1. Latex Catheter: The possibility of a latex allergy is an important consideration as many urinary catheters are constructed from latex or a related material. There are reported increases in allergies and reactions in patients with long-term use of all urinary latex and rubber catheters. Patients who have asthma and other allergies are at increased risk for these allergies. Latex allergy can result in symptoms such as skin irritation, rashes, and blisters. Urethritis and urethral strictures can also result from latex allergies. Coatings such as silicone and polytetrafluoroethylene (PTFE) are used to coat latex catheters. 2. Hydrogel coating, which remains intact when used, has demonstrated the ability to reduce the high level of cytotoxicity associated with latex catheters. However, coated latex catheters do not protect against an allergic reaction to the underlying latex because the coating wears off. Bonded hydrogel-coated latex catheters may be longer lasting than silicone catheters because their hydrogel coating prevents bacterial adherence and reduces mucosal friction. Hydrogels or polymers coat the catheter, absorbing water to produce a slippery outside surface. This results in the formation of a thin film of water on the contacting surface, thus improving its smoothness and lubricity. These properties might act as potential barriers to bacterial infection and reduce the adhesion of both gram-positive and gram-negative bacteria to catheters. 3. Silicone- and hydrogel-coated catheters usually last longer than PTFE-coated catheters. If the person is latex sensitive, silicone catheters should be used. Avoiding 4. Antimicrobial-coating: A major problem with Foley catheters is that they have a tendency to contribute to urinary tract infections (UTI). This occurs because bacteria can travel up the catheters to the bladder where the urine can become infected. In an attempt to prevent bacterial colonization, catheters have been coated with silver alloy or nitrofurazone, a nitrofurantoin-like drug. This has been helpful, but it has not completely solved this major problem. An additional problem is that Foley catheters tend to become coated over time with a biofilm that can obstruct the drainage. This increases the amount of stagnant urine left in the bladder, which further contributes to the problem of urinary tract infections. When a Foley catheter becomes clogged, it must be flushed or replaced. Both nitrofurazone-coated and silver alloy-coated catheters seem to reduce the development of asymptomatic bacteriuria during short-term
(< 30 days) use.
Drainage bags and an anchor for the drainage tube are parts of the design of an indwelling urinary catheter system. These may include a: leg drainage bag, overnight The current design of urinary drainage bags prevents the introduction of bacteria into the closed indwelling urinary catheter system. There are anti-reflux bags, single use bags, closed urinary drainage systems, and bags with urine sampling ports. A leg bag cannot be characterized as closed because of the need to regularly open the leg bag for drainage and connect to an overnight drainage bag in most cases. To minimize opening of a catheter system, a leg bag can be attached to a larger bag for overnight drainage.
References: What is the minimum length of an intermittent catheter that should be inserted through the urethral meatus in a female?What is the minimum length of an intermittent catheter that should be inserted through the urethral meatus in a female patient? Record your answer using a whole number. Rationale: The minimum insertion length of an intermittent catheter is 5 cm (2 inches).
What is the length of catheter insertion for male patient?Insert the catheter for about 15–25cm or until you see urine flow. Insert it almost to its bifurcation before inflating the balloon to ensure it has cleared the prostatic bed and is in the bladder (Fig 6, attached). Inflation of the balloon in the urethra is painful (Dougherty and Lister, 2015).
How far is the catheter inserted into the meatus?Encourage your patient to breathe deeply as you gently insert the catheter tip into the meatus. Advance it 7 to 9 inches (17.5 to 22.5 cm) or until urine starts draining, then advance it another inch (2.5 cm). If you meet any resistance, rotate or withdraw the catheter slightly.
What length of catheter is suitable for male catheterisation?Recommended Sizes of Catheter
For urethral use: Female length - 12-14ch. Standard (male) length - 12-16ch. Standard length catheters must always be used for males (National Agency for Patient Safety 2009)
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