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• To familiarise yourself with the various types of indwelling urinary catheter available
• To enhance your knowledge of potential complications of indwelling catheters, such as catheter-associated urinary tract infections (CAUTIs)
• To understand the measures that you could implement in your practice to prevent CAUTIs
Indwelling urinary catheters are considered an important healthcare intervention for many patients. However, these devices must be used with caution because they are associated with a risk of various potential complications such as catheter-associated urinary tract infections (CAUTIs), as well as a financial burden for healthcare organisations. This article outlines the various types of indwelling catheter that are available, explains the reasons for their use, and details the care required to prevent associated complications, particularly CAUTIs.
Nursing Standard. doi: 10.7748/ns.2021.e11594
Peer reviewThis article has been subject to external double-blind peer review and checked for plagiarism using automated software
Correspondenceann.b.wakefield@manchester.ac.uk
Conflict of interestNone declared
Wakefield A (2021) Use of indwelling catheters and preventing catheter-associated urinary tract infections. Nursing Standard. doi: 10.7748/ns.2021.e11594
*The patient safety functions of the National Patient Safety Agency are now undertaken jointly by NHS England and NHS Improvement
Published online: 31 March 2021
An indwelling urinary catheter is a hollow tube that is designed to drain urine from the bladder. It is usually inserted via the urethra, but can be inserted via the lower abdominal wall (suprapubically). It is secured in the bladder by a balloon inflated with fluid (Hill and Mitchell 2018, Tremayne 2020), with tubing that connects to a drainage bag to form a closed drainage system. Indwelling catheters typically remain in place for a few days or weeks, although in some cases they may be in situ for up to three months. The length of time a catheter is used for will be guided by clinical indications, the presence of any complications and the manufacturer’s recommendations (Tremayne 2020).
Indwelling catheters may be used for various reasons, including to (Minas et al 2014, The British Association of Urological Surgeons 2020):
• Manage intractable urinary incontinence.
• Prevent urinary retention when patients are unable to self-catheterise or where intermittent catheterisation is not possible.
• Rest the bladder to prevent leakage or rupture following cystoplasty (a surgical procedure to increase the size of the bladder).
• Protect the bladder from injury during lower abdominal surgery.
However, due to the risk of potential complications, most notably catheter-associated urinary tract infections (CAUTIs), indwelling catheters must only be used as a last resort.
One study of the prevalence of indwelling catheter use in England between 2012 and 2016 revealed that 1,194,902 patients were catheterised over that period, which represented almost 13% of the hospital population (Shackley et al 2017). In the UK, the average price of indwelling urinary catheters ranges from £0.42p to £4.29 per item (NHS Electronic Drug Tariff 2020). Additional costs include other essential equipment such as the insertion pack, cleaning solution, lubricant and anaesthetic gel, day and night bags, and leg straps, as well as the nurse’s time. This means that catheterisation is a major drain on financial resources.
Furthermore, expenditure escalates if a patient develops a CAUTI (Smith et al 2019). The harm caused by catheter use costs the NHS in the UK between £1 billion and £2.5 billion and accounts for around 2,100 deaths per year (Jeffery and Mundy 2020). Therefore, nurses need to be mindful that indwelling catheters should only be used when absolutely necessary and removed as soon as possible (Kranz et al 2020). It is also important that nurses understand the indications for catheter use and know how to care for these devices to reduce the risk of CAUTIs and other associated complications, such as bladder spasm, encrustation and blockages.
This article explores the use of indwelling catheters and reviews their effective management, particularly in relation to preventing CAUTIs.
• Indwelling urinary catheters typically remain in place for a few days or weeks, although in some cases they may be in situ for up to three months
• Due to the risk of potential complications, most notably catheter-associated urinary tract infections, indwelling catheters must only be used as a last resort
• When inserting an indwelling catheter, nurses must use an aseptic non-touch technique
• It is essential that nurses understand the rationale for the use of indwelling catheters and in what circumstances they should be inserted
The Foley catheter is the most common type of indwelling catheter used in clinical practice (Bardsley 2020). Its design dates back to the 1930s and has essentially remained unchanged since then. A Foley catheter is a sterile flexible tube that incorporates an inflatable balloon that is usually located just beneath the outlet eyelets. This balloon is typically filled with sterile water, which prevents the expulsion of the device from the bladder (Feneley et al 2015).
Two-way and three-way indwelling catheters are available. A two-way catheter has two lumens, or channels – one lumen to inflate the balloon inside the bladder and another lumen to drain the urine. Two-way catheters are supplied in two lengths – one for use in men and one for use in women. The female version is significantly shorter than the male version because a woman’s urethra is around 4cm in length, whereas in men it is around 20cm (Kohler et al 2008).
When inserting a catheter in male patients, it is crucial to ensure the appropriate length is used, since inserting the incorrect catheter can cause serious physiological damage, usually due to the catheter balloon of a shorter female catheter being inflated in the male urethra rather than in the bladder. Data from the National Patient Safety Agency* (2009) noted 114 reports of serious harm caused by female catheters being inserted in men between January 2006 and December 2009. Figure 1 shows an example of a two-way catheter.
Three-way catheters contain a third channel, which can be used to infuse a solution such as 0.9% sodium chloride solution. They are used post-operatively when there is a need to irrigate the bladder to prevent the retention of surgical debris. This may be following resection of a bladder tumour or the prostate gland and assists in ensuring there is no build-up of blood clots, which could block or restrict urine outflow following exposure of the prostatic tissue bed during surgery (Garden et al 2012).
The catheter tubing can be made of a variety of materials, such as latex, silicone and polyvinyl chloride (PVC) (Andersen and Flores-Mireles 2020). Polytetrafluoroethylene (PTFE) – commonly known by the brand name Teflon – is also used. Latex was the first substance to be used because of its flexibility and resistance to damage. However, during the 1980s, a series of urethral strictures were attributed to latex catheter use, due to its toxic properties, which meant that alternative materials needed to be developed to reduce the risk of iatrogenic damage to the urethra (Feneley et al 2015).
Silicone has become the material of choice for urinary catheters in many areas, either on its own, or as a coating for latex catheters to prevent toxicity and allergic reactions. Advantages of silicone include its non-allergenic properties, reduced susceptibility to ‘kinking’ and improved outflow of urine (Andersen and Flores-Mireles 2020).
Catheter design innovations have included impregnating the external coating of the catheter with antimicrobial agents. However, these are still in the testing phase and have been linked to antimicrobial resistance (Jeffery and Mundy 2020). Antifouling agents that assist in preventing bacteria from adhering to catheters are also in development. These include the development of hydrophilic materials, which are not yet in commercial production (Jeffery and Mundy 2020), or polymer-coated silicone catheters, which are undergoing pilot testing (Jeffery et al 2019). Additional innovations include the physical design of the catheter itself, for example coating the catheter with materials that cause microvibrations to prevent the build-up of biofilm (Markowitz et al 2018). The aim of this is to reduce the risk of complications such as urethral injury, infection and bladder spasm (Jeffery and Mundy 2020).
The size of urinary catheters is defined by the French gauge or scale (Fr) system, also known as the Charierre (Ch) system (Osborn and Baron 2006). Each Fr or Ch gauge equates to 0.33mm, so a 12Fr catheter indicates the circumference of the catheter measures 4mm. The higher the Fr gauge, the larger the circumference. When considering a catheter for insertion, nurses should select the smallest size possible, since this will cause the least damage to the urethra; in accordance with clinical guidelines, this will usually be size 12Fr-14Fr for men and women (Royal College of Nursing (RCN) 2019). Using larger sizes of catheters increases the risk of bladder spasm, which can force the urine around instead of down the catheter (Assanga et al 2016, Mota and Oliveira 2019, RCN 2019).
Table 1 outlines the circumstances and rationale for inserting an indwelling catheter. Healthcare practitioners can adopt the HOUDINI (haematuria, obstruction, urological surgery, decubitus ulcer, input and output monitoring, nursing at the end of life, and immobility) protocol to ensure an indwelling catheter is only inserted when absolutely necessary (RCN 2019).
When inserting an indwelling catheter, nurses must use an aseptic non-touch technique (ANTT) and follow local protocols. To prevent CAUTIs and urethral trauma, it is important to ensure that the catheter is correctly secured to prevent backflow of urine. The drainage bag must be positioned below the level of the bladder and should not be in contact with the floor (National Institute for Health and Care Excellence 2017), while pulling on the bladder neck also needs to be avoided (Assanga et al 2016, Mota and Oliveira 2019). The catheter tubing should not be kinked or too taut so as to become stretched and cause bladder neck and urethral trauma. Therefore, it should be attached to the leg bag and the outlet tubing of the bag secured as shown in Figure 2.
When attaching the leg bag, the straps should be placed through the slots and behind the inlet tube, because placing them over the inlet tube can result in blockages.
Some of the main issues associated with the use of indwelling catheters are encrustation, blockages, bladder spasms and CAUTIs. Catheterisation has also been linked to increased mortality (Andersen and Flores-Mireles 2020), particularly among patients who develop CAUTIs (Gyesi-Appiah et al 2020).
One potential issue associated with the use of indwelling catheters is encrustation. This occurs as a result of the presence of urease-producing bacteria, most commonly from Proteus mirabilis (Feneley et al 2015, Gibney 2016, Paterson et al 2019, Bardsley 2020), which causes the urine to become increasingly alkaline. The more alkaline a patient’s urine becomes, the greater the risk of calcified biofilm deposits forming, which in turn can cause crystalline encrustations that adhere to the lumen and/or the catheter tip. Alkalinity leads to the formation of apatite (a hydroxylated form of calcium phosphate) and struvite (magnesium ammonia phosphate) (Stickler 2014). Encrustation may result in catheter blockages, with a risk of ascending infection to the kidney, leading to complications such as CAUTI, pyelonephritis (kidney infection), sepsis, shock (Pelling et al 2019) and ultimately death.
To reduce the risks associated with catheter blockages, warning systems are being developed in which two sensors are placed between the catheter and the catheter bag. These sensors are designed to alert patients and healthcare practitioners by changing colour when the urine pH becomes increasingly alkaline, which may indicate an impending blockage (Long et al 2014). Although these innovations are not available in practice at present, they are undergoing trials and may improve catheters for the benefit and comfort of patients (Jeffery and Mundy 2020). Yates (2018) noted that long-term hydrogel and silicone catheters are less susceptible to encrustation than short-term PTFE-coated catheters, so these should be considered as part of the prevention of long-term complications.
Bladder spasms remain a severe complication of catheterisation where the detrusor muscle, bladder neck and bladder mucosa become irritated, in some cases resulting in infection. Bladder spasms can cause extreme pain and spontaneous expulsion of urine from the bladder, resulting in incontinence (Nazarko 2014), and potentially causing CAUTIs (Jeffery and Mundy 2020). To reduce this risk and leakage from the bladder, patients can be encouraged to perform pelvic floor exercises. Additionally, ensuring that only 10mL of water is used in the catheter balloon can reduce the weight of the catheter at the bladder neck, and subsequently reduce the incidence of bladder spasms (Caimei et al 2020).
If the patient continues to experience bladder spasms, anticholinergics (antispasmodics) can be administered to relax the detrusor muscles (Cravens and Zweig 2000). The reason for the use of an indwelling catheter should also be reviewed to determine if it could be removed. However, if anticholinergics are ineffective and the catheter remains necessary, patients may be prescribed transcutaneous electrical nerve stimulation to reduce any pain (Zhang et al 2017).
Once an indwelling catheter has been inserted into the bladder, CAUTIs can originate from several sources, such as (Pelling et al 2019):
• Where the catheter enters the urethra, microorganisms can enter the closed drainage system either due to the transmission of organisms from the perineal bed on insertion of the catheter, or due to movement of the catheter within the urethra after insertion.
• Where the catheter attaches to the catheter drainage bag or leg bag.
• When the day drainage bag is changed for a night drainage bag.
• When the drainage bag is emptied too frequently via the outlet tap, since opening this tap will compromise the closed drainage system and may lead to contamination.
• Where the night bag has an outlet tap and this is opened, thereby compromising the closed drainage system, particularly since this tap is frequently at floor level.
• Where urine samples are obtained via a urine sampling port, particularly if ANTT is not used.
When teaching patients, carers and other healthcare practitioners how to manage an indwelling urinary catheter, it is essential to provide information on how to care for the closed drainage system and reduce the risk of infection as much as possible. These practices are particularly important in women because their urethra is significantly shorter than that of men, so it is easier for bacteria to enter the bladder (Pelling et al 2019, Gyesi-Appiah et al 2020). Patients and/or carers may have to manage the catheter for several weeks or possibly a lifetime, so it is crucial they understand how to reduce the risk of CAUTIs developing by making sure the perineum is scrupulously clean, particularly following defaecation.
It is also vital that the catheter is changed in accordance with the manufacturer’s recommendations and depending on the patient’s needs, since changing the device too frequently increases the risk of bacteria being introduced each time a new catheter is inserted. Moreover, it is vital that the catheter is inserted using ANTT each time, to reduce the risk of infection.
Another important measure for reducing the risk of CAUTIs is to avoid inserting an indwelling catheter unless it is absolutely necessary (Selius and Subedi 2008, RCN 2019). Therefore, it is important that healthcare practitioners understand the rationale for indwelling catheter use in accordance with the HOUDINI protocol and the circumstances detailed in Table 1. Furthermore, indwelling catheter use needs to be regularly reviewed for each patient to establish whether the device is still necessary. If it is no longer required, the catheter should be removed to reduce the risk of complications such as CAUTIs, pain and bladder and/or urethral trauma. Box 1 summarises various CAUTI prevention measures.
• Only insert an indwelling catheter if it is absolutely necessary
• Insert the catheter using an aseptic non-touch technique
• Use the smallest size of catheter possible
• Use the most appropriate length of catheter, for example consider if a male or female two-way catheter needs to be used
• Obtain a sterile specimen of urine to check for the presence of bacteria when the patient is first catheterised, as a baseline assessment
• Label the drainage bag with the date and time when the catheter was inserted
• Document when an indwelling catheter is inserted and the reason for it. Clear documentation and forward planning can assist in reducing unnecessary long-term use
• Ensure the catheter is correctly positioned and secured
• Maintain a closed sterile drainage system
• Adhere to strict hand hygiene procedures before and after handling the catheter and closed drainage system
• Ensure the drainage bag is always positioned below the level of the bladder, to prevent back flow of urine
• Ensure the drainage bag does not touch the floor to prevent contamination of the outlet tap, reducing the risk of pathogens entering and ascending to the bladder
• Maintain an uninterrupted flow of urine to prevent urinary stagnation
• Empty the drainage bag when it is two thirds full, to prevent the closed drainage system being compromised and pathogens entering the system, back flow of urine to the bladder and the risk of urethral trauma
• Remove the catheter as soon as possible, ideally within 24 hours. If this is not possible, review the situation every 24 hours or when most appropriate and document this
• Provide education for patients and carers on how to care for the periurethral area, or where necessary undertake this care by washing the area with soap and water three times per day, and following defaecation
• Provide the patient with a ‘catheter passport’ and catheter card that informs them of the actions they need to take to prevent CAUTIs, the signs and symptoms of these and what to do if they suspect they might have a CAUTI
(Selius and Subedi 2008, World Health Organization 2009a, 2009b, Assanga et al 2016, Powers 2016, National Institute for Health and Care Excellence 2017, Taylor 2018, Mota and Oliveira 2019, Pelling et al 2019, Royal College of Nursing 2019, Gyesi-Appiah et al 2020, Kranz et al 2020)
While the use of indwelling urinary catheters remains an important intervention for some patients, these devices are associated with various complications, including CAUTIs. Therefore, it is essential that nurses understand the rationale for the use of indwelling catheters and in what circumstances they should be inserted. Nurses should also be aware of the potential sources of CAUTIs, recognise the need to avoid catheterisation where necessary and be able to develop clear plans to reduce long-term catheter use. Furthermore, indwelling catheters should be considered as a last resort and ANTT must be used during their insertion, to reduce the risk of infection and preserve patient safety.
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