Caring For a Urinary Catheter


Published: 21 May 2023

Did you know that urinary catheters are responsible for 80% of hospital-acquired urinary tract infections (ACSQHC 2018)?

Despite being commonly used, urinary catheters are often inserted unnecessarily and managed poorly, contributing to morbidity and prolonged hospital stays (Gilbert et al. 2018).

Therefore, in order to minimise the risk of complications such as UTIs, the insertion and maintenance of these devices require significant and thorough care from healthcare professionals.

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 (Cafasso 2022).

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 (Cafasso 2022).

Generally, urinary catheters are used by patients who are unable to urinate on their own or have impaired mobility. They 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 2022).

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 2020).

Note: Patients with an enlarged prostate or urethral strictures etc. are at increased risk of complications. Therefore, these cases should be escalated to a urologist (Schaeffer 2023).

urinary catheter diagram
A urinary catheter is a hollow, flexible tube inserted through the urethra into the bladder that drains urine into an external collection bag.

Other Types of Urinary Catheters

There are 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. Each 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.
  • Suprapubic catheters are inserted through the abdominal wall directly into the bladder rather than through the urethra. These catheters are more invasive and require surgical insertion but are usually more comfortable for the patient.

(Healthline 2019; Better Health Channel 2021; Jewell 2019; Schaeffer 2023)

Catheter Sizes

Given significant differences in urethra length depending on age and gender, catheters vary in length. Male and female urethras are approximately 20 cm and 4 cm long, respectively (Cadogan 2020).

On average:

  • Paediatrics generally use 30 cm catheters.
  • Males generally use 41-46 cm catheters.
  • Females generally use 20-25 cm catheters.

(Schaeffer 2023; Gilbert et al. 2018)

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 et al. 2018).

  • Paediatrics generally use 6-10 Fr catheters.
  • Males generally use 14-18 Fr catheters.
  • Females generally use 12-14 Fr catheters.

(Gilbert et al. 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 2020).

urinary catheter insertion diagram
Given significant differences in urethra length depending on age and gender, catheters vary in length.

Indications for Catheterisation

A patient may have a urinary catheter inserted for the following reasons:

  • Urinary retention or obstruction
  • Blood clot retention associated with gross haematuria
  • Monitoring (sepsis, trauma, renal function, electrolyte or fluid balance)
  • Injury or surgery that affects the patient’s urinary function or mobility (e.g. spinal cord injury)
  • Investigation, diagnosis or treatment (e.g. bladder irrigation or instillation)
  • Urinary incontinence management for wound care, end-of-life care or chemotherapy (only if other available options are too uncomfortable for the patient)
  • Urogenital or bladder management (e.g fistula, haematuria).

(CEC 2021)

Caring for and Assessing Urinary Catheters

When caring for a patient with a urinary catheter:

  1. Ensure that:
    • 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.

  2. 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 and clean the outlet with a alcohol wipe afterwards.

  3. The insertion site should be washed on a daily basis using soap and warm water. Check for discharge, inflammation or ulceration. 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.

  4. Drainage devices should be changed according to the manufacturer’s recommendations.

  5. Catheters should only be changed when:
    • The closed system has been breached
    • The drainage is obstructed
    • The patient has a UTI, or
    • The catheter has reached its maximum timeframe, as specific by the manufacturer’s instructions.

  6. The patient’s need for a catheter should be reviewed daily. Ensure the catheter isn't used for longer than necessary to avoid the risk of complications such as infection.

  7. All catheter care and maintenance, as well as fluid balance charts, should be documented.

(CEC 2021)

The amount of time a catheter can stay in-situ may vary. Always refer to the manufacturer’s instructions.

urinary catheter drainage bag
The drainage bag should be emptied when it is ¾ full, and before any patient transport.

Complications of Urinary Catheters

Catheter insertion is a risky procedure with the potential for a variety of complications. These include:

(Gilbert et al. 2018; RCHM 2020)


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 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.


Test Your Knowledge

Question 1 of 3

True or false: The French gauge (Fr) measurement is used to describe the length of a catheter.


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