A urinary catheter is a flexible, hollow tube designed to drain urine from the bladder. This device is inserted when the body cannot empty the bladder naturally or when healthcare providers need to precisely monitor output. Understanding the procedure and the anatomy involved can help reduce anxiety about this common medical intervention.
The Urethra: Precise Anatomical Placement
The catheter is inserted into the female urethra, which is the body’s natural exit for urine. This small, tubular structure is short, typically measuring about 3.5 to 4 centimeters in length in an adult woman. The external opening of the urethra, known as the meatus, is located in the vulva.
The meatus is situated anteriorly, positioned just below the clitoris and above the vaginal opening. Healthcare providers gently part the labia to visualize this opening and distinguish it from the vaginal opening, which is positioned posteriorly. The catheter is guided directly into the meatus, through the urethra, and into the bladder.
Medical Necessity for Catheter Use
Catheterization is reserved for specific medical situations, serving both temporary and long-term needs. A common temporary reason is to relieve acute urinary retention, a painful condition where the bladder cannot empty. Catheters are also used during and after surgical procedures, particularly pelvic or abdominal surgeries, to ensure the bladder remains empty and facilitate healing.
For diagnostic purposes, a catheter may be inserted briefly to collect an uncontaminated urine sample or to accurately measure hourly urine output in critically ill patients.
Types of Catheters
Catheters used only for immediate drainage and then removed are called intermittent or straight catheters. When a catheter must remain in place for continuous drainage, it is called an indwelling catheter, typically a Foley catheter. An indwelling catheter uses a small, inflated balloon to hold its position inside the bladder. Long-term use may be necessary to manage severe urinary incontinence, especially in patients with non-healing skin wounds that require a dry environment.
The Insertion Procedure
The insertion process begins with positioning the patient comfortably, usually lying on their back with knees bent and hips flexed to allow clear access. A strict sterile technique is used throughout the process to prevent introducing bacteria into the urinary tract. The area around the urethral meatus is thoroughly cleaned with an antiseptic solution before insertion.
A water-soluble lubricant, often containing a topical anesthetic, is applied to the catheter tip to reduce friction and discomfort. The healthcare provider gently inserts the lubricated catheter into the meatus and advances it slowly. The patient may feel pressure or a brief, mild sting as the catheter passes through the urethra.
Once urine begins to flow, the catheter is advanced a few more centimeters to ensure the tip and retention balloon are fully inside the bladder. For an indwelling catheter, sterile water is injected to inflate the balloon, securing the device in place before it is connected to a drainage bag.
Maintenance and Safe Removal
Proper care is necessary once an indwelling catheter is in place to prevent complications, most notably a catheter-associated urinary tract infection (CAUTI). The catheter should be secured to the inner thigh with a securement device, ensuring enough slack in the tubing to prevent tension when the patient moves. The drainage bag must always be kept positioned below the level of the bladder to prevent the backflow of urine.
Daily hygiene involves cleaning the meatus and the portion of the catheter exiting the body with mild soap and water to minimize bacterial buildup. The drainage bag should be emptied when it is about two-thirds full to prevent it from becoming too heavy and pulling on the catheter.
When the catheter is no longer needed, the removal process is straightforward. Sterile water is withdrawn from the retention balloon using a syringe, causing the balloon to deflate. The catheter is then pulled out gently in one smooth motion, which may feel like a brief, slightly unusual sensation of gliding.