In order to minimise the risk of complications such as UTIs, urethra trauma, bleeding and displacement, it is clear that the insertion and maintenance of these devices require significant and thorough care from healthcare professionals (NHS 2020).
What is a Urinary Catheter?
A urinary catheter (also known as an indwelling catheter or long-term catheter) is a hollow, flexible tube inserted through the urethra into the bladder that drains urine into an external collection bag (Healthy WA 2014; Cafasso 2017).
Once the catheter has been inserted, a small balloon on the internal end is inflated with sterile water to keep it in-situ. The balloon is deflated when the catheter needs to be removed (Healthy WA 2014; Cafasso 2017).
Generally, urinary catheters are required by patients who are unable to urinate on their own or are immobile, and are essential in avoiding a build-up of urine, which has the potential to cause pressure in the kidneys and lead to kidney failure (Cafasso 2017).
The process of insertion, known as urethral catheterisation, is invasive and poses significant risks of infection and trauma. Therefore, catheterisations must only be performed by registered nurses or physicians who have undertaken the required qualifications and training (RCHM 2017).
Recording and maintaining accurate fluid balance documentation is important to ensure the patient maintains adequate renal perfusion, minimising the risk of acute kidney injury (NHS 2020).
Other Types of Urinary Catheters
There are two other types of urinary catheter in addition to indwelling catheters.
External catheters are non-invasive condom-like devices that attach to a drainage bag. They are often used by men with urinary incontinence, an overactive bladder, dementia or mobility issues. They are more comfortable and less prone to causing infections.
Intermittent (‘in and out’) catheters are used to empty the bladder and are then removed. The next time drainage is required, a new catheter is used and then taken out. In some cases, the patient can learn to self-catheterise themselves. As these catheters do not stay in-situ between drainages, there is less risk of infection or other complications.
(Moyer 2019; Healthy WA 2014)
Given significant differences in urethra length depending on age and gender, catheters vary in length. Male and female urethras are approximately 20cm and 4cm long, respectively (Cadogan 2019).
Paediatrics generally use 30cm catheters.
Males generally use 41-46cm catheters.
Females generally use 20-25cm catheters.
Catheters also come in a variety of sizes, measured according to their external diameter. The unit used for catheter sizes is French gauge (abbreviated as Fr or Fg), where one Fr is equal to a third of a millimetre (Gilbert, Naidoo & Redwig 2018).
Paediatrics generally use 6-10 Fr catheters.
Males generally use 14-18 Fr catheters.
Females generally use 12-14 Fr catheters.
(Gilbert, Naidoo & Redwig 2018)
Patients should use the smallest size catheter appropriate for adequate drainage. However, if the patient is passing clots or other debris in their urine, a larger size may be used to avoid occlusion (Cadogan 2019).
Indications for Catheterisation
A patient may need to be catheterised for the following reasons:
Surgical procedures that require pre or postoperative bladder draining;
The need for bladder irrigation;
Monitoring during surgery;
Bladder nerve injury;
Spinal cord injury;
Dementia or other conditions that impair mental functioning (Note: Catheters must be used with caution on these patients as they are at high risk of pulling them out, causing injury to the urethra);
Medications that impair the bladder’s ability to squeeze; and
Improving comfort for end-of-life care;
(Cafasso 2017; ANZUNS 2013)
Caring for and Assessing Urinary Catheters
When caring for a patient with a urinary catheter:
There are no kinks or loops in the drainage bag tubing and the urine is being continuously drained.
Both the catheter and draining device are connected securely.
The drainage bag is being supported by a stand or hook so that the outlet and tubing are kept off the floor and there are no loops in the tubing.
The drainage bag is below bladder-level at all times, including during transportation and ambulating.
The catheter is attached to the patient with a securing device.
The drainage device is closed unless it is being emptied.
The drainage bag should be emptied when it is ¾ full, and before any patient transport.
Before opening the catheter valve, check whether drainage is needed.
When draining urine, ensure a clean receptacle is used for each patient. Avoid contact between the outlet and the receptacle.
The insertion site should be washed on a daily basis using soap and water and you should check for discharge, inflammation or erosion. Antiseptic solutions or ointments should generally be avoided. Dressings are only needed if discharge is present. You should ensure the catheter is secure after washing.
Males: Wash the meatus, glans penis, catheter and perineum (retracting the foreskin if the patient is not circumcised).
Females: Wash the urethral meatus, labia minora, catheter and perineum.
Drainage devices should be changed according to the manufacturer’s recommendations.
Catheters should only be changed when:
The closed system has been breached;
The drainage is obstructed; or
The patient has a UTI.
The patient’s need for a catheter should be reviewed daily.
Incorrect insertion in females (due to difficulty locating the urethral meatus).
(ANZUNS 2013; RCHM 2017; Cafasso 2017)
Urinary catheters require thorough assessment and maintenance in order to minimise the risk of infection or injury for patients. It is essential to perform regular daily care, maintain accurate fluid balance documentation and be able to detect and address UTIs, kidney injury or other complications appropriately.
Note: This article is intended as a refresher and should not replace best-practice care. Always refer to your facility's policy on caring for urinary catheters.
Centers for Disease Control and Prevention 2015, Catheter-associated Urinary Tract Infections (CAUTI), Centers for Disease Control and Prevention, viewed 14 May 2020, https://www.cdc.gov/hai/ca_uti/uti.html