Intravenous (IV) therapy is a common medical procedure involving the insertion of a small catheter into a vein to administer fluids or medications. Valves, natural anatomical features within many veins, can complicate this process. These small, flap-like structures pose a challenge during IV insertion. Understanding how to navigate or avoid these valves is an important skill for successful IV access.
Understanding Valves in Veins
Venous valves are thin, one-way tissue flaps, typically consisting of two leaflets, located inside veins, particularly in the limbs. Their primary purpose is to prevent the backflow of blood, ensuring it flows efficiently towards the heart, especially against gravity. When an IV catheter encounters a valve, it can obstruct the catheter’s passage, making insertion difficult. Forcing the catheter past a valve risks damaging the vein, potentially leading to complications such as hematoma formation, patient discomfort, and increased risk of occlusion or infiltration.
Identifying Valve Locations Before Insertion
Locating potential valve sites before IV insertion can significantly improve success rates. Visually, valves may appear as small bulges or knotty regions along the vein. Vein bifurcations, where a vein splits into two, are also common locations for valves. Palpation, using fingertips to gently feel the vein, can reveal these valves as small, firm bumps or knots. Applying a tourniquet can help distend veins, making valves easier to identify through both visual inspection and palpation.
Strategic Insertion Techniques to Avoid Valves
Careful site selection is a primary strategy to avoid valves. Opt for a straight section of the vein, bypassing areas that appear to bulge or where the vein branches. Proper vein anchoring is also important; stabilize the vein by pulling the skin taut directly below the insertion site. This maneuver helps prevent the vein from rolling and can slightly flatten the valve leaflets, making them less obstructive.
Insert the IV needle with the bevel facing upward at a shallow angle. After observing blood flashback in the catheter hub, indicating vein entry, lower the angle even further. Advance the catheter slowly and steadily, allowing it to glide smoothly into the vein.
Managing Resistance from Valves During Insertion
If resistance is met after vein entry and flashback, it often indicates the catheter tip has encountered a valve. Do not force the catheter, as this can damage the vein. One technique to overcome this resistance is to gently withdraw the catheter slightly, then re-advance it while flushing with saline. This “floating” technique uses fluid pressure to help open the valve leaflets, allowing the catheter to pass through. If resistance persists, or if there is doubt about the catheter’s position, remove the catheter and select a new insertion site to prevent patient injury.