An intravenous catheter, often simply called an IV, is a common device used in modern healthcare to access the body’s circulatory system. This small, flexible tube provides a direct gateway into the bloodstream, allowing medical professionals to rapidly deliver necessary treatments. These treatments include fluids for hydration, essential medications like antibiotics, or blood products for transfusion. Using an IV catheter prevents the need for repeated needle sticks, which is beneficial when a patient requires ongoing treatment over several days.
Anatomy and Primary Function
The standard peripheral IV catheter consists of core components designed for safe placement and function. It includes a sharp, hollow needle, known as a stylet, which is necessary for puncturing the skin and the vein wall. The stylet is encased by a thin, flexible plastic tube called the cannula or catheter, which remains inside the vein.
The assembly includes a hub for connecting to IV tubing or a syringe, and a flash chamber. The flash chamber is a clear section that instantly fills with blood upon successful entry into the vein, confirming correct placement. Once the cannula is securely threaded, the stylet is fully withdrawn and safely discarded, leaving the flexible catheter in place to facilitate therapy administration.
Differentiating Catheter Types
Catheters for venous access are categorized based on where the tip rests, which determines their suitability for different treatments and durations. The most common type is the Peripheral Intravenous Catheter (PIV), inserted into smaller veins in the hand, arm, or foot. PIVs are used for short-term treatments, usually lasting a few days, and for administering solutions mild to the vein lining.
For patients requiring longer-term therapy (several weeks or months) or delivery of irritating medications, a Central Venous Catheter (CVC) is necessary. A CVC is a longer tube whose tip is positioned in a large central vein, typically the superior vena cava near the heart. The Peripherally Inserted Central Catheter (PICC line) is a common CVC example, threaded into a central vein from an insertion point in the arm. The choice between a PIV and a CVC depends on the projected treatment length and the medication properties.
The Insertion Process
The placement of a peripheral IV line ensures sterility and minimizes patient discomfort. A healthcare professional first selects a suitable vein, often in the hand or forearm, and cleanses the insertion site with an antiseptic solution. A tourniquet is placed above the site to restrict blood flow, making the vein more prominent and easier to access.
The catheter assembly is inserted through the skin and into the vein at a shallow angle, usually between 10 and 30 degrees. Blood appearing in the flash chamber confirms the needle tip has entered the vein. Following confirmation, the angle is lowered, and the flexible cannula is advanced while the stylet is retracted. Once the cannula is fully seated, the tourniquet is released. The catheter is then secured to the skin with a sterile, transparent dressing to stabilize the device and protect the site from contamination.
Maintaining the Site and Recognizing Issues
Maintenance is required to prevent complications and ensure the catheter remains functional. The transparent dressing must be kept clean and dry to protect the entry site from bacteria. Patients should avoid pulling on the tubing and limit excessive movement of the limb, which can dislodge the catheter or irritate the vein wall.
Two common non-infectious problems are infiltration and phlebitis. Infiltration occurs when the catheter shifts, causing infused fluid to leak into the surrounding subcutaneous tissue. Signs include swelling, a cool feeling around the site, and slowed fluid flow. Phlebitis is inflammation of the vein’s inner lining, manifesting as localized pain, redness, and warmth along the vein’s path. Less frequent but more serious complications involve localized infection, indicated by increasing pain, pus discharge, or fever. If any of these signs develop, a patient should immediately alert a healthcare provider for site assessment and potential catheter removal.