Uses and types of single-lumen urinary catheters

Single-lumen catheter, also known as a balloonless catheter or a balloonless catheter, is characterized by a single channel, no fixing device, and short-term use.

Single-lumen catheters, lacking a balloon, cannot be fixed in the bladder after insertion. Therefore, they are primarily used in situations requiring short-term procedures and not long-term indwelling catheterization. Specifically, they include:

• Temporary catheterization: Used to relieve urinary retention temporarily; removed immediately after bladder emptying.
• Urine sample collection: Obtains uncontaminated "midstream urine" samples for diagnostic tests (such as urine culture).
• Bladder instillation therapy: Direct injection of contrast agents, chemotherapy drugs, etc., into the bladder.
• Special scenarios: Used in certain drainage methods, such as balloon-free mushroom-head catheters for suprapubic cystostomy drainage.

Single-lumen urinary catheters can be categorized based on shape, size, target population, and material.

1. Classification by Tip Shape

• Standard type (straight tip): The most common type, with a straight tip, suitable for routine catheterization procedures.
• Curved tip: Pointed and curved tip, primarily used for men with benign prostatic hyperplasia causing urethral stricture, facilitating passage through the obstructed urethra.
• Plum blossom tip/mushroom tip: Triangular or mushroom-shaped tip, its shape allows it to be fixed within the bladder (independent of a balloon), suitable for suprapubic stoma catheterization or drainage of renal pelvis.

2. Classification by Common Sizes (French, Fr)

The unit for catheter size is French (Fr). The larger the number, the larger the diameter. One unit of Fr is approximately 0.333 mm.

• Type: Pediatric type, Common sizes (Fr): F6 - F10, Main features and applicable population: Small diameter, specifically designed for pediatric catheterization.
• Type: Standard type, Common sizes (Fr): F12 - F26, Main features and applicable population: The most common size, mainly used for temporary adult catheterization. Adults commonly use F12-F24 tubing.

3. Classification by Material

• Silicone Catheters: Soft, biocompatible, and cause minimal irritation to the urethra, especially suitable for patients with latex allergies. However, they are relatively expensive, and the tube walls may not be smooth enough.
• Latex Catheters: Soft and comfortable, moderately priced, but some patients may be allergic to latex, and the surface is more prone to smegma buildup.
• Polyvinyl Chloride Catheters: Harder, more irritating, and cause noticeable foreign body sensation. Inexpensive, but rarely used clinically now.

Single-lumen catheters are the first choice for short-term, disposable catheterization procedures in clinical practice due to their simple structure and lack of fixing devices.