Preventing Urethral Trauma During Catheterisation

Authors:

^*Niall F. Davis,^1,2
Rory O’C. Mooney,²
Conor V. Cunnane,²
Eoghan M. Cunnane,²
John A. Thornhill,¹
Michael T. Walsh²

1. Department of Urology, Tallaght Hospital, Dublin, Ireland
2. Centre for Applied Biomedical Engineering Research, Materials and Surface Science Institute, University of Limerick, Castletroy, Ireland
*Correspondence to: [email protected]

Citation:

EMJ Urol. 2017;5[1]:60-61. Abstract Review No. AR19.

Keywords:

Urethral trauma,
urethral catheterisation,
urethral rupture,
urethral injury,
urethral catheter,
safety device,
safety syringe

Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.

Urethral catheterisation is a routine task that is frequently performed within a healthcare setting. Almost 25% of hospitalised patients are catheterised during their inpatient stay.¹ Urethral injury typically occurs in men when the catheter’s anchoring balloon is inadvertently inflated inside the urethra.² Short-term complications include pain, bleeding, and acute urinary retention.² Urethral rupture can lead to the long-term complication of urethral stricture disease and may require urethral reconstruction in severe cases.²

There are currently no studies that demonstrate urethral strain thresholds for rupture during traumatic urethral catheterisation. Our aim was to investigate internal urethral diametric strain and threshold maximum inflation pressure as parameters for urethral rupture during inadvertent inflation of a catheter anchoring balloon in the urethra. In addition, we also designed and evaluated a novel safety device with the inability to cause urethral trauma, despite inadvertent balloon inflation in the urethra based on these parameters.

Inflation of a urethral catheter anchoring balloon was performed in the bulbar urethra of 21 ex vivo porcine models using 16 Fr catheters. Urethral trauma was characterised and graded with retrograde urethrography. Urethral rupture was correlated with internal urethral diametric strain (%) and maximal urethral pressure threshold values in kilopascals (kPa). Internal urethral diametric strain was calculated by averaging urethra luminal diameter proximal and distal to the traumatised site, and maximum luminal diameter at the traumatised site. Urethral catheters were then inflated in the bulbar urethras of seven fresh male cadavers using a standard syringe and a prototype safety-syringe prototype safety-syringe (Figure 1). The plunger of the standard syringe was depressed until opposing resistance pressure generated by the urethra prevented further inflation of the anchoring balloon. The plunger of the prototype safety-syringe was depressed until sterile water in the syringe decanted through an activated safety threshold pressure valve (Figure 1).

Figure 1: The prototype syringe used to determine urethral resistance pressure. The safety valve (arrow) is activated at threshold resistance pressure, allowing fluid to vent out of the activated valve.

Retrograde urethrography demonstrated that porcine urethral rupture consistently occurred at an internal urethral diametric strain >40% and a maximum inflation pressure >150 kPa (Figure 2). The mean±standard deviation maximum human urethral threshold inflation pressure required to activate the safety prototype syringe pressure valve was 153±3 kPa. In comparison, the mean maximum inflation pressure was significantly greater using the standard syringe than the activated prototype syringe (452±188 kPa, [p<0.001]).

Figure 2: Maximum catheter balloon/urethral pressure and internal diametric strain recorded for each of the 21 urethral samples tested.
This figure clearly demonstrates a safety cut-off of >40% internal urethral diametric strain and/or maximum balloon pressure cut-off of 150 kPa before urethral rupture (red dashed lines). Open circles indicate ruptured urethral samples. Filled circles indicate unruptured samples.

Internal urethral diametric strain and threshold maximum inflation pressures are important parameters for designing a safer urethral catheter system with lower intrinsic threshold inflation pressures. We have validated our porcine and cadaver findings in human male-to-female transgender urethral models and have recently implemented our safety device into clinical practice in Tallaght Hospital, Dublin, Ireland for patients requiring urethral catheterisation. This transition of a safety device from bench to bedside was commended during my presentation during March 2017, held at the European Association of Urology (EAU) congress, hosted in London, UK.

References

Chenoweth C, Saint S. Preventing catheter-associated urinary tract infections in the intensive care unit. Crit Care Clin. 2013;29(1):19-32.
Davis NF et al. Incidence, Cost, Complications and Clinical Outcomes of Iatrogenic Urethral Catheterization Injuries: A Prospective Multi-Institutional Study. J Urol. 2016;196(5):1473-7.

Designs – Indwelling Urinary Catheters

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 water for inflation per manufacturer’s instructions. Larger balloons (30 cc – 60 cc) are generally used to facilitate drainage or provide hemostasis when necessary, especially in the postoperative period. The balloon of the catheter usually sits at the base of the bladder, obstructing the internal urethral orifice. 

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 infections and irritation.

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 surgery.

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: 

1. how long the catheter will remain in place,
2. comfort,
3. the presence of latex sensitivity,
4. ease of insertion and removal, and
5. ability to reduce the likelihood of complications such as urethral and bladder tissue damage, colonization of the catheter system by microorganisms, and encrustation

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 latex catheters may also decrease the incidence of encrustation. All-silicone (100%) catheters are biocompatible and are believed to have encrustation-resistant properties.  Silicone catheters are thin-walled, rigid catheters with a larger diameter drainage lumen. 

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.
Despite their unit cost, there is a suggestion that these devices might be a cost-effective option if overall numbers of infections are significantly reduced through their use.

• Antibiotic-coated catheters were found in a meta-analysis to prevent or delay bacteriuria in short-term catheterized, hospitalized patients.   However, in 2012, nitrofurazone impregnated catheters were taken off the market.  
• Silver is an antiseptic that inhibits growth of gram-positive and gram-negative bacteria. Silver alloy-coated catheters are thought to cause less inflammation and have a bacteriostatic effect because they reduce microbacterial adherence and migration of bacteria to the bladder.
  Because they prevent bacterial adherence, these catheters also minimize biofilm formation through their release of silver ions that prevent bacteria from settling on the surface.  
  There appear to be few adverse effects, and microbial resistance to the active agent is unlikely. 

Catheter Drainage BagsDrainage 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 drainage bag, and a spare leg strap or a device to secure the catheter tubing to the leg.  Drainage bags that cannot be worn and concealed are commonly referred to as “nighttime or overnight bags,” or “large capacity bags,” or “bedside bags”. Drainage bags that can be worn and concealed are commonly referred to as “leg bags” or abdominal bags, commonly referred to as “belly bags.”  Leg bags generally hold 300- 900 cc whereas an overnight bag can hold up to 2000cc.  It is recommended that reusable drainage bag be replaced every 30 days.   

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: 
1. Brosnahan J, A. Jull, et al. Types of urethral catheters for management of short-term voiding problems in hospitalized patients. Cochrane Database of Systematic Reviews, 2004, (1): CD004013.
2. Gray M. Does the construction material affect outcomes in long-term catheterization? JWOCN, 2006, 33: 116-121.
3. Lawrence EL. and IG. Turner. Materials for urinary catheters: A review of their history and development in the UK. Med Engineering Phys, 2005, 27: 443-453.
4. Leuck AM, Johnson JR, Hunt MA, Dhody K, Kazempour K, Ferrieri P, et al. Safety and efficacy of a novel silver-impregnated urinary catheter system for preventing catheter-associated bacteriuria: a pilot randomized clinical trial. Am J Infect Control. 2015;43:260-5. DOI: 10.1016/j.ajic.2014.11.021.
5. Newman D. The indwelling urinary catheter: Principles for best practice. JWOCN, 2007, 24: 655-661.
6. Pickard R, Lam T, MacLennan G, Starr K, Kilonzo M, McPherson G, et al. Antimicrobial catheters for reduction of symptomatic urinary tract infection in adults requiring short-term catheterisation in hospital: a multicentre randomised controlled trial. Lancet. 2012;380:1927-35. DOI: 10.1016/S0140-6736(12)61380-4.  
7. Politano AD, Campbell KT, Rosenberger LH, Sawyer RG. Use of silver in the prevention and treatment of infections: silver review. Surg Infect (Larchmt). 2013;14:8-20. DOI: 10.1089/sur.2011.097.
8. Weissbart SJ, Kaschak CB, Newman DK. Urinary drainage bags. In: Newman DK, Rovner ES, Wein AJ, editors. Clinical Application of Urologic Catheters and Products.  Switzerland: Springer International Publishing; 2018, 133-147.
9. Zugail AS, Pinar U, Irani J. Evaluation of pain and catheter-related bladder discomfort relative to balloon volumes of indwelling urinary catheters: A prospective study.  Investig Clin Urol. 2019 Jan;60(1):35-39. doi: 10.4111/icu.2019.60.1.35. Epub 2018 Dec 6.

Placement, replacement and care of the Foley catheter.

Structure of the bladder

Placement of a Foley catheter.

Hygiene procedures must be carried out before insertion of the catheter.

The clinician should wash the patient’s hands and perineum with soap and water, disinfect with an antiseptic, and wear sterile gloves. Prepare the catheter (take with sterile tweezers, treat with a lubricant if necessary).

Female catheter insertion procedure:

Lying on your back, bend and spread your legs.

After parting the labia and finding the opening of the urethra, carefully insert the catheter. As soon as urine has gone through the catheter, you should stop.

After that, through one of the passages at the outer end of the catheter, inject sterile water with a syringe in a volume sufficient to inflate the balloon. Then attach the urine collection bag to the outer end. It is necessary to ensure that the bag is always below the level of the belt in order to avoid backflow of urine through the catheter.

Catheter insertion procedure for men:

Catheter insertion is more difficult for men. Since the urinary canal is longer and has physiological constrictions. The patient needs to lie on his back and slightly bend his knees, relax, the catheter is inserted into the urethra slowly and smoothly, with rotational movements, clamping the catheter with 5 and 4 fingers of the right hand, and first the genital organ must be held vertically, and then tilted down. Carefully advance the catheter. The presence of urine indicates that the catheter is placed correctly.

For children:

When placing a catheter, it is necessary to ensure the psychological comfort of the child.

Disinfect the genital area twice and wrap it with a sterile drape. Lubricate the end of the catheter, such as Vaseline.

Do not force the catheter if an obstruction is felt – this can damage the urethra.

The procedure for inserting the catheter is similar to that for adults, but the insertion depth is less because the urethra is shorter.

Urinary catheter care:

Wash the area around the catheter with soap and water several times a day to avoid irritating the infection. Do this after every bowel movement. Women are washed from front to back.

Drain the bag in time, keeping it below the level of the bladder to avoid urine flowing back into the catheter.

Change of catheter:

In case of normal urine outflow, the catheter is changed according to the recommendation of the doctor and instructions for use of the catheter.

Silicone has a shelf life of up to 30 days, latex up to 7 days, silicone with silver up to 90 days.

Never pull on the catheter. Disconnect the catheter only for rinsing or replacing it, as well as emptying the urinal.

Cases when you need to see a doctor:

– There are pains in the abdomen, flakes and blood in the urine.

— Urine is leaking from under the catheter.

– Urine outflow stopped.

Reasons for leaking urine:

catheter too thin, balloon not inflated enough, catheter or urinal tube kinked, catheter blocked.

Reasons for not passing urine:

a kink in the catheter or tube of the urinal,

insufficient fluid intake in the body (increase the amount of fluid consumed),

urinal is fixed too high (lower it below the level of the bladder),

blockade of the catheter,

impaired renal function (anuria) when the patient’s condition worsens.

Urinary catheters are flushed as directed by a physician:

Warm saline is used for flushing. If sediment or flakes appear in the urine, the catheter is washed with a solution of furacilin, as well as miramistin or chlorhexidine solution. For washing, Jeanne’s syringe is used.

Foley catheter

FAQ

When and why is intermittent catheterization recommended?

Intermittent catheterization is an effective and safe urinary diversion method that offers patients independence and significantly improves quality of life. In recent years, intermittent catheterization has become the preferred method for managing patients with neurogenic bladder dysfunction, paraplegia, diseases such as spina bifida or multiple sclerosis.

The choice of method of intermittent catheterization is carried out only after this method is recommended by the doctor in each case. Catheterization is carried out by emptying the bladder at regular intervals with disposable catheters.

How is intermittent catheterization performed in children?

Children with neurogenic bladder dysfunction may be catheterized by a parent or healthcare professional, always using asepsis. Parents should ask their doctor or medical professional who will explain and demonstrate the correct catheterization procedure. Only by carefully preparing you can be sure that you are performing the catheterization procedure correctly.

For infants and small children, the following sizes are generally used: 2.0-2.7 mm (Ch06-Ch08).

How many times a day should the bladder be catheterized?

Normal bladder emptying frequency is approximately 56 times a day. The frequency of catheterizations depends on the individual and factors such as how much you drink, medication, etc. Your healthcare provider can recommend how often you need to catheterize your bladder. You can determine for yourself when and how it will be best for you to carry out catheterization.

How much liquid should I drink every day?

This may vary depending on how active you are. You should aim to drink about 1.5-2 liters of fluid per day. Try to avoid drinks that contain caffeine, such as tea or coffee.

What should I do if I have difficulty inserting a catheter?

Sit in a comfortable position, try to relax and wait a while before performing the catheterization procedure. If you are unable to insert the catheter on your own, contact your healthcare provider.

What if I have difficulty removing the catheter?

Try not to worry and wait a while before trying again. Coughing can sometimes help insert or remove a catheter.

Are there any signs or symptoms I should be aware of?

Don’t wait until your bladder is full. The following symptoms may indicate that your bladder is too full:

• tense and swollen lower abdomen,
• headache,
• feeling of heat and sweating.