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1.3.1. History of Urinary Catheterisation

The word catheter in Greek means to let or to send down [11]. Catheterisation of the urinary tract has been performed from time immemorial and a variety of materials have been used to form the tubes. Amongst the materials used to form the shaft of the catheter have been metals such as tin and bronze, silver and gold by the Greeks in the 3rd century, lead and papyrus by the Egyptians and dried reeds and palm leaves by the Chinese [11, 12]. Advancements in catheter design came in the 11th century when more malleable materials were developed and it was realised that by boring holes into the sides of the catheter shaft this helped to facilitate urinary drainage. Latex catheters became popular in the 18th century but initially were weak and friable at body temperature. The process of vulcanization, however, saw the firmness, flexibility and durability of the rubber improve. By the mid 1800‟s the first self retaining urinary catheter consisting of a retention balloon made of rubber or woven fabric was formed [12].

1.3.2. Urinary Catheters Today

Urinary catheters nowadays come in a variety of designs, sizes and materials. The most common type of self retaining catheter in use today is the Foley catheter, developed by the American urologist, Frederick E.B. Foley [12]. It has been commercially available since the mid-1930‟s and remains relatively unchanged in design today. A typical Foley catheter is 220 - 380 mm in length and consists of a balloon at the proximal tip near to the drainage eyelet and a two - or three - way

8 outlet at the other end (Figure 1.2). The outlets are for urine drainage, as a means of inflating the balloon with saline to secure the catheter in place within the bladder, and for bladder irrigation if necessary. Catheter size is measured in French units, where 1 French unit = 0.33 mm diameter. Adult catheters vary in diameter from 12 Fr to 30 Fr (4 to 10 mm) with the standard being 14 Fr (4.6 mm) and in balloon size that have a capacity of 5 mL to 30 mL. In the first few decades of use, an „open catheter system‟ existed whereby the Foley catheters were attached to tubes which drained the urine into buckets [13]. Nowadays, a drainage bag is attached to the urine outlet forming a „closed system‟ and is either hung beside the patient‟s bed or strapped to the patient‟s leg. Urine can either drain freely by gravity into the drainage bag or a catheter valve can be fitted into the end of the catheter which may be switched on or off to allow for the urine to drain.

The most widely used materials for Foley catheters are latex or silicone with the first being manufactured from latex. Latex is inexpensive, has good elastic properties but tends to be more prone to bacterial adherence and have more allergic potential than some other materials [14]. Silicone is soft, non - irritating and clinically stable making it ideal for long - term use in the urinary tract [15]. Silicone catheters are more expensive than latex catheters but are inert putting patients at less risk of allergic reaction. Their surface properties make for easy insertion and lower rates of bacterial adherence and encrustation as reported by some studies possibly relating to their smoother surfaces exhibiting less niches for microbial aggregation than latex catheters [14, 16].

9 Figure 1.2: A polytetrafluoroethylene (PTFE) coated latex Foley catheter with the balloon inflated [12].

1.3.3. Forms of Urinary Catheterisation

There are two main forms of urinary catheterisation: intermittent and indwelling.

1.3.3.1. Intermittent Catheterisation

Intermittent catheterisation is a form of self - catheterisation that is used in individuals who are unable to empty their bladder properly. It is often a method of choice for patients requiring long - term care but is not always suitable if a patient is mentally or physically unable to carry out catheterisation e.g. spinal cord injuries and dementia patients, although catheterisation can also be carried out by a carer. Intermittent catheters differ from Foley catheters described in section 1.3.2 as they do not have retention balloons to hold the catheter in the bladder. Instead, once the flow of urine has stopped the catheter is immediately removed and disposed of or many can be re - used as required.

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1.3.3.2. Indwelling Catheterisation

The most common form of catheterisation is indwelling where the catheter is held in the bladder. This category can further be divided into short and long - term use, although this is somewhat arbitrary. Short - term catheterisation (STC) is classed as a catheter being in place for <14 days [5] and long - term catheterisation (LTC) as a catheter remaining in situ for 30 days or more [1]. Indwelling catheters can be inserted in two ways: - either directly into the bladder through a small incision in the wall of the abdomen known as suprapubic catheterisation, or most commonly through the urethra into the bladder, which is what this study concentrates on.

1.3.4. Reasons for Long - Term Urinary Catheterisation

It has been reported that up to 25% of patients admitted to a hospital in the UK will require a urinary catheter at some point [13]. Prolonged catheterisation is common not only in patients in hospital but also amongst residents in nursing home settings as well as people within the community. LTC is utilised in the management of a wide range of conditions both in acute and chronic care settings [1]. Frequently older adults with urinary retention or incontinence problems are catheterised. Other indications for LTC are listed in Table 1.2. Many of these patients can be catheterised for months or years.

11 Table 1.2: Some indications for long - term urinary catheterisation [1].

Bladder outlet obstruction not correctable medically or surgically Intractable skin breakdown caused or exacerbated by incontinence Patients with neurogenic bladder and retention

Patients who have not responded to specific incontinence treatments

Palliative care for terminally ill or severely impaired incontinent patients for whom bed and clothing changes are uncomfortable

1.4. Problems Associated with Long - Term Urinary