Objectives: To determine whether peripheral veins can be detected by ultrasound (US) and to determine vein characteristics, as measured by US, that are associated with successful peripheral venous (PV) catheterization in young children.
Methods: The authors conducted an observational study in the pediatric emergency department (ED), with a convenience sample of children younger than 7 years. They evaluated attempts at PV catheterization in two groups on the basis of the visibility and palpability of the patients' veins: 1) clinically apparent (visible or palpable) and 2) not clinically apparent (nonvisible and nonpalpable). The authors obtained sonographic measurements in a transverse view (vertical diameter, circumference, and area) and in a longitudinal view (maximal uninterrupted length). Practitioners blinded to the US images then attempted to catheterize veins in the usual manner. The proportion of clinically apparent veins and the proportion of veins that were successfully catheterized that were identified by US were assessed, and the association between ultrasonographic vein measurements and success at catheterization, controlling for possible confounders, was determined.
Results: The authors assessed 120 attempts (90 clinically apparent and 30 not clinically apparent) at PV catheterization in 83 patients. US detected all 90 clinically apparent veins, and cannulation success rate was 62/90 (69%). In the not clinically apparent vein group, the rate of success was only 3/30 (10%), and US detected all successfully catheterized veins. In no instance was cannulation successful when the vein was not detected by US. Maximal vein length in longitudinal view was an independent predictor of cannulation success in multivariate analysis.
Conclusions: Ultrasound appears to be capable of detecting peripheral veins in children younger than 7 years of age, with lack of US vein visualization likely leading to unsuccessful PV placement. Greater vein length visualization may be a useful predictor of successful PV catheterization.