Catheters play a crucial role as flexible tubes designed for fluid removal or delivery within the body. This blog serves as a comprehensive guide, covering the diverse applications of catheters across medical settings. It delves into the various types available, including urinary catheters for bladder drainage, central venous catheters for medication administration, and peripheral intravenous catheters for vein access during treatments. Additionally, the blog explores the importance of understanding French sizes and lengths in catheter selection, outlines key differences between these types, and offers practical tips on insertion techniques and maintenance to ensure optimal performance and patient comfort.

Why are Catheters used?

Catheters are essential medical devices used to access, drain, or deliver fluids in various clinical scenarios. They are primarily employed for managing urinary retention, facilitating medication administration, and monitoring critical physiological parameters. Urinary catheters, for instance, help patients unable to urinate normally due to surgery, illness, or injury, ensuring bladder drainage and preventing complications. In hospitals, central venous catheters allow for the administration of medications, fluids, and nutrition directly into large veins, while arterial catheters enable continuous monitoring of blood pressure and blood gases. Beyond these applications, catheters play a vital role in diagnostic procedures like angiography, aiding in the visualization and treatment of vascular conditions. Despite their benefits, proper insertion and maintenance are crucial to minimize risks such as infection and tissue damage, underscoring the importance of trained healthcare professionals in their management.

What are the Types of Catheters?

Urinary Catheters: 

There are two kinds of urinary catheter.

• Indwelling Foley Catheters: These are commonly used for patients who require continuous bladder drainage over a period. They have a balloon at the tip that is inflated once inside the bladder to keep the catheter in place.
• Intermittent Catheters: Used periodically to drain urine from the bladder. They are inserted when needed and removed once the bladder is emptied, reducing the risk of urinary tract infections compared to indwelling catheters.

Central Venous Catheters (CVC):

There are two main type of CVC catheter.

• Peripherally Inserted Central Catheters (PICC): Inserted into a vein in the arm, PICCs are threaded through to a central vein near the heart. They are used for long-term administration of medications, nutrition, or chemotherapy, and their placement is less invasive than traditional CVCs.

• Central Venous Catheters (CVC): These are placed directly into a large vein in the neck (internal jugular vein), chest (subclavian vein), or groin (femoral vein). They are used for delivering medications, fluids, and total parenteral nutrition (TPN) over an extended period, and for monitoring central venous pressure (CVP).

Peripheral Intravenous Catheters (PIVC): Inserted into veins in the arms, hands, or legs for short-term administration of medications, fluids, or blood products. PIVCs are commonly used in hospitals and clinics for treatments that do not require long-term access.

Arterial Catheters: Inserted into an artery, usually in the radial or femoral artery, for continuous monitoring of blood pressure and blood gases. They are also used for drawing blood samples without repeated needle sticks.

Dialysis Catheters: Specifically designed for hemodialysis, these catheters are placed into a large vein, usually in the neck or groin, to allow access to the bloodstream for filtering and cleansing blood during dialysis treatments.

Each type of catheter serves a distinct medical purpose, ranging from urinary drainage and medication administration to continuous monitoring and dialysis. Proper selection and management of catheters are crucial to minimize complications and ensure effective patient care.

Classification based on Intermittent catheter:

Straight catheters, often considered the standard in catheter technology, have seen continual advancements to improve comfort and convenience. Innovations like polished drainage eyelets make insertion and withdrawal smoother for the user. These uncoated intermittent catheters require lubrication before use, which can be achieved with sterile single-use lubrication packets or lubricating jelly.

The catheter features an insertion tip on one end, designed to go into the urethra or stoma for bladder drainage. Depending on the manufacturer, a catheter may have one to four drainage eyelets, although most have one or two. The opposite end typically has a funnel, which serves as a grip for directing urine flow into a toilet or urinal. Alternatively, the funnel can be connected to a drain bag. Some users may prefer a luer end catheter, which comes without a funnel.

Hydrophilic catheters are similar to straight intermittent catheters but feature a unique hydrophilic coating that acts as lubrication when activated by water. This bonded coating becomes slippery when wet, making catheterization more comfortable and reducing urethral friction.

Most hydrophilic catheters come with a sterile water packet within the package, which can be easily burst with applied pressure to soak the catheter and activate its lubrication. This feature ensures optimal comfort and ease of use, whether you're catheterizing at home, work, school, or on the go.

Closed system catheters are unique because they include a pre-lubricated or hydrophilic catheter inside a sterile collection bag. This self-contained system allows for private and convenient self-catheterization. Key benefits include a touch-free design to reduce infection risk, an introducer tip to bypass high bacteria areas, and additional supplies like gloves and disinfecting wipes. This makes them ideal for wheelchair users, frequent travellers, and those who prioritize hygiene and convenience.

Catheter French Sizes and Lengths:

Determining the appropriate catheter size involves selecting the correct French size, which indicates the diameter of the catheter tube. Your doctor will prescribe the ideal French size, but you should inform them if the size feels uncomfortable. Catheters generally range from 10 to 20 French, with specialty sizes available. Pediatric catheters are also available for children who need catheterization.

Here are the standard catheter lengths:

1. Male Catheters: Typically, 16 inches long.
2. Female Catheters: Usually between 6 to 8 inches long.
3. Pediatric Catheters: Generally, 10 inches long.

Colour Coding for Catheter Sizes

Catheter sizes are often colour-coded to make it easier to identify the French size at a glance. Here is a general guide to the colour coding:

Difference between types of catheters:

Catheter Type	Common Sizes (French)	Material	Common Uses	Importance
Straight Catheter	10-20 Fr	PVC, Silicone, Latex	Intermittent catheterization	Uncoated, requires lubrication
Hydrophilic Catheter	10-20 Fr	PVC, Silicone	Intermittent catheterization	Coated, activated by water for lubrication
Closed System Catheter	10-20 Fr	PVC, Silicone	Intermittent catheterization, reducing UTI risk	Self-contained, touch-free
Foley Catheter	12-24 Fr	Latex, Silicone	Indwelling catheterization	Balloon tip for long-term use
Coude Catheter	10-20 Fr	PVC, Silicone, Latex	Intermittent or indwelling catheterization	Bent tip for navigating obstructions
Pediatric Catheter	6-10 Fr	PVC, Silicone	Intermittent catheterization in children	Smaller sizes for pediatric use
Suprapubic Catheter	12-24 Fr	Latex, Silicone	Indwelling catheterization through abdominal wall	Used for long-term catheterization
Arterial Catheter	18-22 Ga (1.2-0.7 mm)	Polyurethane, Teflon	Monitoring blood pressure, drawing blood samples	Inserted into an artery
Peripherally Inserted Central Catheter (PICC)	2-5 Fr	Silicone, Polyurethane	Long-term IV antibiotics, nutrition, medications	Inserted into a peripheral vein and advanced to central veins
Central Venous Catheter (CVC)	7-10 Fr	Silicone, Polyurethane	Administering medications, fluids, parenteral nutrition	Inserted into a large vein (subclavian, jugular, or femoral)

Different Types of Catheter Insertion Tips:

The two primary types of catheter insertion tips are:

• Straight Tip: This is the standard type used by most catheter users. It has a straight insertion tip.
• Coudé Tip: This type features a curved insertion tip, which can be beneficial for individuals who find it challenging to pass a straight catheter. Coudé catheters are often recommended for males with conditions like an enlarged prostate or urethral blockage. They are available in male length or pediatric length variants.

How to maintain Catheter?

Maintaining a catheter involves key steps for cleanliness and comfort:

• Wash hands before and after handling.
• Regularly empty drainage bag.
• Gently clean around catheter exit daily.
• Ensure catheter is taped securely.
• Drink fluids unless advised otherwise.
• Watch for signs of infection.
• Follow schedule for catheter changes.
• Attend appointments for catheter care and health monitoring.

What Type of Catheter is right to use?

Choosing the right type and size of intermittent catheter should always involve a discussion with your prescribing physician, who can assess your medical condition and specific requirements.