US PIV: Pre-scanning

Key points:

  • Forearm >> AC or Upper arm
  • Avoid > 1.2 cm depth
  • Pre-scan vessel (at least 1/2 the arm)

Recall the typical anatomy (and be aware of frequent variation):

Typical venous anatomy of the arm

Choose the right depth [1]

151 US guided PIVs, all 20 gauge and 4.8 cm long

Survival probability @ 48 hr varied on depth of vessel (P < 0.0001)

  • 100% survived @ 48 hr in shallow (<0.4 cm) vessels
  • 62% in intermediate depth vessels (0.40-1.19 cm)
  • 29% for deep (≥1.2 cm) vessels

PIVs in the antecubital fossa or forearm are more likely to survive @ 48 hr (85%) vs. Upper arm (50%).


  • Track vessel course and depth
  • Avoid proximal impediments
    (vessel damage, thrombus, significant narrowing)
This image has an empty alt attribute; its file name is PrescanGif-3.gif
Hannah Kopinksi and Dr. Lindsay Davis
NYU Emergency Medicine

Back to US PIV flowchart

  • Identify and avoid nerves and arteries (see image)
  1. Fields JM, et al. The effect of vessel depth, diameter, and location on ultrasound-guided peripheral intravenous catheter longevity. Am J Emerg Med. 2012 Sep;30(7):1134-40.