When a needle puncture is needed to obtain an ABG sample, the radial, brachial, or femoral arteries may be used. However, the angle of penetration varies.

For the radial artery (the artery most commonly used), the needle should enter bevel up at a 45-degree angle, as shown below. For the brachial artery, the angle should be 60 degrees; for the femoral artery, 90 degrees.

Whatever site you use, you should be adequately trained and follow your organization's protocol (Harris, 2022). Always apply pressure after performing a needle puncture of an artery until all signs of bleeding have resolved.