What is the main purpose of using a tourniquet before starting an IV?

The main purpose of using a tourniquet before starting an IV is to visualize veins by engorging them with blood. When the tourniquet is applied above the site where the IV will be inserted, it temporarily restricts venous outflow while allowing arterial blood to flow into the veins. This causes the veins to become distended and more prominent, making them easier to locate and access with a needle. Proper visualization of the veins is crucial for successful IV insertion, as it reduces the likelihood of multiple attempts and can lead to a smoother procedure for both the patient and the healthcare provider.

The other options, while related to IV therapy, do not accurately capture the primary role of the tourniquet in this context. Decreasing patient discomfort may be a secondary benefit of a successful and efficient IV placement, but it is not the main purpose of the tourniquet. Preventing excessive blood loss is important in managing IV therapy but is not the function of the tourniquet at the point of insertion. Similarly, ensuring medication delivery relates to the effectiveness of the IV therapy itself, rather than the preparatory step of applying a tourniquet.