A catheter is a medical device consisting of a thin, flexible tube designed for insertion into the body. These tubes are made from various medical-grade materials, such as silicone, latex, or specialized plastics, chosen for their biocompatibility. The primary function of a catheter is to create a pathway for medical interventions, enabling healthcare professionals to access internal body structures without extensive surgery.
What is a Catheter and Its Purpose?
A catheter is a hollow tube that medical professionals insert into a body cavity, duct, or vessel. This insertion, known as catheterization, serves two main functions: draining fluids or delivering substances and devices. For example, catheters can remove accumulated fluids like urine from the bladder, preventing complications such as kidney damage.
Catheters also introduce various substances into the body, including medications, intravenous fluids, blood products, or gases directly into the bloodstream or specific organs. Beyond fluid management, catheters facilitate diagnostic procedures, such as imaging internal structures, and enable therapeutic interventions, like clearing blockages or placing medical implants. They are used for both short-term applications, such as during surgery, and long-term management of chronic conditions.
The Core Function: How Catheters Operate
A catheter creates a direct, controlled pathway into the body. Once inserted, its hollow lumen allows for the movement of fluids or the passage of instruments. For drainage, such as with urinary catheters, gravity often plays a role, with urine flowing down the tube into a collection bag positioned below the bladder. This passive flow is efficient for continuous drainage.
In other applications, pressure gradients facilitate movement. For instance, when delivering fluids or medications, an external pump or the fluid’s pressure pushes the substance through the catheter into the body’s circulatory system or a specific site. The catheter’s design, including its diameter and material stiffness, influences flow rate and ease of insertion. Some catheters incorporate specialized features like balloons, which can be inflated after insertion to hold the catheter securely in place or to dilate a vessel. This ensures the catheter remains correctly positioned for treatment or diagnostic procedures.
Common Types and Their Uses
Catheter operation principles apply across various specialized types. Urinary catheters, for example, drain urine from the bladder. Types include intermittent catheters, temporarily inserted to empty the bladder and then removed, and indwelling catheters, like the Foley catheter, which remain in place for longer periods, secured by an inflated balloon within the bladder. These devices aid individuals unable to urinate naturally due to conditions such as urinary retention, nerve damage, or during and after surgery.
Intravenous (IV) catheters provide access to a patient’s veins for delivering fluids, medications, or blood products directly into the bloodstream. Peripheral IVs are short tubes inserted into veins in the hand or arm for short-term treatments. For long-term or more intensive therapies, central venous catheters (CVCs) are used. These longer, flexible tubes are inserted into larger veins, such as those in the neck, chest, or arm, with the tip resting in a large vein near the heart. CVCs, including PICC lines (peripherally inserted central catheters), allow for administering medications that might damage smaller veins, frequent blood draws, or total parenteral nutrition.
Catheter Placement and Management
Catheter insertion is a medical procedure requiring a sterile environment to minimize infection risk. Healthcare professionals carefully insert the catheter into the designated body cavity, duct, or vessel, often using specific techniques depending on the catheter type and location. For instance, a urinary catheter might be inserted through the urethra, while a central venous catheter involves accessing a large vein, sometimes with imaging guidance. Proper placement ensures the catheter functions effectively and reduces patient discomfort.
Once a catheter is in place, consistent care and management prevent complications. This includes maintaining strict hygiene around the insertion site by cleaning it daily with soap and water. Regularly emptying drainage bags and ensuring the tubing is not kinked or obstructed helps prevent fluid buildup and backflow. Monitoring for signs of infection, such as fever, pain, or redness at the insertion site, is also important, as catheter-associated infections, particularly urinary tract infections, are a common risk. Catheters are removed when no longer medically necessary, or when they need replacement, with duration of use varying based on type and patient condition.