The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [179]
Conformable catheter
Conformable catheter s are designed to conform to the shape of the female urethra, and allow partial filling of the bladder. The natural movement of the urethra on the catheter, which is collapsible, is intended to prevent obstructions (Brocklehurst et al. 1988). They are made of latex and have a silicone elastomer coating. Conformable catheters are approximately 3 cm longer than conventional catheters for women.
Other materials
Research into new types of catheter materials is ongoing, particularly examining materials that resist the formation of biofilms (bacterial colonies that develop and adhere to the catheter surface and drainage bag) and consequently reduce the instances of urinary tract infections (Pratt et al. 2007).
Catheters coated with a silver alloy have been shown to prevent urinary tract infections (Saint et al. 1998). However, the studies that demonstrated this benefit were all small scale and a number of questions about the long-term effects of using such catheters, such as silver toxicity, need to be addressed. Argyria is a condition caused by the deposition of silver locally or systemically in the body, and can give rise to nausea, constipation and loss of night vision (Bardsley 2009, Cymet 2001, Pratt et al. 2007). There is some suggestion in the research that the use of silver alloy-coated catheters does reduce the onset of bacteriuria and may be beneficial when catheterization is in high-risk situations, for example diabetic and intensive care patients (Saint et al. 2000). However, research trials analysed by the Cochrane Collaboration (Schumm and Lam 2008) indicate that this asymptomatic bacteraemia was only seen in the first 5–7 days; after this, the catheter type made little difference (Plowman et al. 2001, Pratt et al. 2007).
Catheters coated with antibiotics such as gentamicin, rifampicin, nitrofurazone and nitrouroxone have been investigated in the search to find a product that will reduce instances of catheter-associated urinary tract infections (CAUTI). They may have a role to play in the management of trauma patients; nitrofurazone-impregnated catheters were shown to reduce urinary infections when compared with standard catheters in a trial by Stensballe et al. 2007. Whether this effect would be present in non-trauma patients and in the management of patients with long-term catheters is unknown. However, issues such as antibiotic sensitivity or resistance have not been fully investigated or assessed (Schumm and Lam 2008).
The cost implications for routine use of these impregnated catheters would be huge for the NHS (Johnson et al. 2006). However, a recent review of impregnated catheters found that silver alloy (antiseptic)-coated or nitrofurazone-impregnated (antibiotic) urinary catheters do reduce infections in hospitalized adults, and siliconized catheters may reduce adverse effects in men, but the evidence is weak (Schumm and Lam 2008). Trials with a specific catheter may be appropriate on an individual patient basis when other types of catheter management of recurrent infections have failed (Brosnahan et al. 2006).
Drainage bags
A wide variety of drainage systems are available. Selecting a system involves consideration of the reasons for catheterization, the intended duration, the wishes of the patient, and infection control issues (Wilson and Coates 1996).
Urine drainage bags should only be changed according to clinical need, that is when that catheter is changed or if the bag is leaking, or at times dictated by the manufacturer’s instructions, for example every 5–7 days (Pratt et al. 2007, Wilson 1998). Urine drainage bags positioned above the level of the bladder and full bags cause urine to reflux, which is associated with infection. Therefore bags should always be positioned below the level of the bladder to maintain an unobstructed flow and emptied appropriately. Urine drainage bags should be hung on suitable stands to avoid contact with the