Which statement about IV needle size is correct for a thin, emaciated patient?

• A. An 18-gauge needle is appropriate for a thin, emaciated patient.
• B. A 20-gauge needle is never used for IV therapy.
• C. An 18-gauge needle is NOT appropriate; it would cause unnecessary trauma and high risk of phlebitis.
• D. A 16-gauge needle is standard for all IV therapy.

Answer: (C)

When choosing IV needle size, match the bore to the vein condition and the therapy needs. Thin, emaciated patients often have small, fragile veins, so using a large-bore needle increases the risk of vein injury and phlebitis. An 18-gauge needle is too large for these veins and would cause unnecessary trauma; that’s why it’s not appropriate in this scenario. In contrast, a smaller bore needle (higher gauge number), such as 22 or 24, minimizes damage while still allowing routine IV therapy. The other options aren’t correct for typical IV goals: 20-gauge is commonly used, 16-gauge is larger and used for rapid transfusions rather than standard IV therapy.