An intravenous (IV) line is a soft, flexible tube placed inside a vein, typically in the hand or arm. Healthcare providers use IV lines to administer fluids or medications directly into a person’s bloodstream. This method allows for rapid absorption and precise control over the dosage of the substance delivered. IVs are specifically designed to be inserted into veins, not arteries.
Key Differences Between Veins and Arteries
The human circulatory system relies on both veins and arteries, but they possess distinct characteristics that make veins suitable for IV placement and arteries unsuitable. Arteries carry blood away from the heart, which means the blood within them is under high pressure due to the heart’s pumping action. In contrast, veins carry blood back to the heart, operating under significantly lower pressure. This pressure difference is a primary reason for choosing veins, as the lower pressure reduces the risk of significant bleeding and makes it easier to infuse fluids without resistance.
Another distinction lies in their wall thickness and elasticity. Arteries have thick, muscular, and elastic walls built to withstand high pressure. Veins, however, have thinner, more pliable walls, which makes them easier to puncture safely with a catheter. The goal of IV medication is to reach the systemic circulation, and the venous system offers a safer entry point.
Veins are also more superficial and visible beneath the skin, making them readily accessible for medical procedures. Arteries, conversely, are located deeper within the body, often protected by muscle and bone. This deeper location and their pulsatile nature make arterial access more challenging and riskier for IV insertion.
The Purpose and Process of IV Insertion
Intravenous lines serve several medical purposes, primarily delivering substances directly into the bloodstream for rapid systemic distribution. Common uses for IVs include administering fluids to address dehydration, delivering medications, providing blood transfusions, and supplementing nutrients when a patient cannot eat or drink. The direct route into the bloodstream bypasses the digestive system, allowing for rapid therapeutic effects.
The process of IV insertion begins with a healthcare professional selecting a suitable vein and applying a tourniquet to make the vein more prominent. The chosen site is then cleaned with an antiseptic solution. A needle, which contains a flexible plastic catheter, is inserted into the vein at a shallow angle. Once blood is observed in the catheter, the needle is withdrawn, leaving only the soft, flexible catheter inside the vein. This catheter is then secured to the skin with tape and a dressing, and connected to the IV line for fluid or medication delivery.
Potential Complications of IV Placement
While IV placement in veins is a common and safe procedure, complications can occur. Accidental puncture of an artery instead of a vein is a concern. If an artery is inadvertently punctured, the immediate sign is bright red, pulsating blood flow from the insertion site due to the higher arterial pressure. Medical professionals are trained to identify this and will promptly remove the catheter and apply firm pressure to the site to prevent a hematoma, which is a collection of blood outside the vessel. Accidental arterial injection of certain medications can also lead to severe pain, tissue damage, or other serious outcomes.
More common, less severe complications include bruising, bleeding, or discomfort at the insertion site. Infiltration, where IV fluid leaks into the surrounding tissue, can cause swelling and coolness around the site. Phlebitis, an inflammation of the vein lining, may present as redness, pain, or warmth along the vein. These minor issues are temporary and managed by removing the IV and applying compresses to the affected area. Other potential complications include hematoma formation, which is bruising caused by blood leaking from the vessel, and dislodgement of the catheter.