Single Lumen Midline Catheter vs Long Peripheral Intravenous Cather for Difficult Intravenous Access in the ED

Many patients in the emergency department have veins that are difficult to get an intrevenous (IV) catheter into (called "difficult IV access"). These patients may require other methods to obtain access to a vein for administration of the necessary medications. The 2-inch long IV is most commonly used in emergency departments for people with difficulty IV access. Typically, a healthcare worker will use an ultrasound to help to see the veins underneath the skin while inserting the IV into the vein. That is, the ultrasound helps the healthcare worker visualize veins that are deeper in the arm and may not be felt through the skin. Another device that can be used is a 4-inch midline catheter. This device is less commonly used as many emergency departments do not have participants available, but it serves the same purpose as the 2-inch long IVs (that is, to give medicine into the vein and sometimes to take blood). A 4-inch midline catheter is similar to a 2-inch long IV, but has a few differences. First, the 4-inch midline catheter is even longer than the 2-inch long IV. The 4-inch midline catheter is 10-cm (about 4-inches or the size of 4 quarters side-by-side), while the 2-inch long IV is 4.78-cm (nearly 2-inches or two quarters side-by-side). Second, the 4-inch midline catheter is inserted into using a guidewire to help move the catheter in the vein (similar in concept to a train moving along a track), while the 2-inch long IV does not have this guidewire. The guidewire does not hurt and most do not know it is being used. It is just an additional step to help guide the catheter in the vein. The investigators are conducting this research study to determine which catheter is better for patients with difficult IV access: the 4-inch midline catheter or the 2-inch long IV.