Caliber of the deep veins of the arm in infants and neonates: The VEEIN study (Vascular Echography Evaluation in Infants and Neonates).

The age and the weight of the child have a small role in predicting the caliber of the veins of the arm. Veins should be measured case by case through a proper and systematic ultrasound evaluation; however, the clinician can expect that insertion of a 3 Fr PICC may be feasible in one third of children weighing between 4 and 7 kg, and in most children weighing more than 7 kg, especially if adopting the tunneling technique.