A urinary catheter is a tube that is inserted into the bladder through the urethra to drain urine. A tube made of natural rubber, silicone rubber, or polyvinyl chloride (PVC) can be inserted into the bladder through the urethra to drain urine out. After the catheter is inserted into the bladder, there is a balloon near the head of the catheter to fix the catheter. The tube stays in the bladder and is not easy to come out, and the drainage tube is connected to the urine bag to collect urine.

According to the circumference of the outer diameter, it is usually divided into 13 specifications and models from 6F to 30F. Commonly used urinary catheters for adults have four models: 12F, 14F, 16F, and 18F. (F is the abbreviation of French, which means the number of millimeters of the outer circumference. Conversion formula: F=2πr, rough conversion: F (mm) = 3 times the outer diameter (mm)).

1. Polyvinyl chloride (PVC): The product is harder, more irritating, has strong foreign body sensation, low price, and most of them are products without airbags.

2. Dry glue (raw rubber): The product is softer and more irritating. It is easy to cause inflammation of the urinary catheterization mucosa after long-term use. The price is low, and most of them are products without airbags.

3. Silicone rubber: The product is relatively soft, has good biological compatibility, and the patient has no foreign body sensation, but the surface of the molding process is not easy to keep smooth, and the cost is high. Most of the products are without airbags.

4. Natural rubber latex: The product is soft, has good biocompatibility, the patient feels comfortable, the surface is smooth, the irritation is low, the price is reasonable, most of the airbag products, and the indwelling operation is convenient.

According to the structure, it can be divided into the following types:

1. Single-lumen urinary catheter: Usually there is no airbag, only one channel, it is not easy to fix, and the indwelling time is short.

1) Single-lumen children's urinary catheter: commonly used models F6-F10, mainly used for children's urinary catheterization.

2) Single-lumen standard urinary catheter: commonly used models F12-F26, mainly used for temporary catheterization.

3) Single lumen plum-shaped urinary catheter: commonly used models F12-F28, mainly used for drainage of urine after bladder or kidney fistula.

4) Single-lumen elbow type urinary catheter: commonly used models F12-F26, the head is pointed, mainly used for male prostatic hypertrophy.

2. Double-lumen urinary catheter: There are two lumens, one is the water injection hole and the other is the liquid outlet. Can be fixed, mainly used for indwelling catheterization. 

1) Double-lumen single-capsule children's urinary catheter: commonly used models are F6-F10, and the airbag capacity is usually 5ml, which is mainly used for indwelling urinary catheterization in children.

2) Double-lumen single-balloon standard urinary catheter: commonly used models are F12-F28. The balloon capacity is usually 10ml and 30ml. It is mainly used for normal indwelling catheterization without other restrictions.

3) Double-cavity single-cyst female urinary catheter: commonly used models are F12-F24, the balloon capacity is usually 30ml, used for female indwelling catheterization.

4) Double-lumen single-balloon elbow catheter: commonly used models F12-F20, the balloon capacity is usually 30ml, used for female indwelling catheterization.

1. Patients with urinary retention or bladder outlet obstruction.

2. Urinary incontinence.

3. Accurately monitor urine output.

4. The patient is unable or unwilling to collect urine.

5. Patients who need to stay in bed for a long time or are forced to position.

6. Perioperative use during surgery.