Ultrasound measurements of the saphenous vein in the pediatric emergency department population with comparison to i.v. catheter size.

BACKGROUND Saphenous vein cutdown is a rare venous access procedure. Ultrasound (US) can assist with many vascular access procedures. OBJECTIVES Our objective was to identify the saphenous veins (SVs) using US in pediatric emergency department (ED) patients, and to determine if the SV size allows for potential cannulation by different standard-size intravenous (i.v.) catheters. METHODS This study was a prospective, observational convenience sample of 60 pediatric patients at an urban, regional referral pediatric ED. Inclusion criteria were children ages 1 through 12 years categorized into four age groups: 1-<2, 2-4, 5-7, and 8-12 years, with informed consent and assent. Investigators performed US examination using a 10-MHz multi-frequency transducer to identify the SV on both legs and measure the SV in short-axis view. The US measurements were then used to calculate the SV areas. Diameters of typical pediatric gauge (G) catheters (24G, 22G, 20G, 18G) were used to calculate catheter areas. RESULTS Sixty patients were enrolled, with five SVs unable to be measured in 4 patients (1 patient with both SVs). For the remaining 115 (96%) SVs available for further analysis, the median age was 4 years (interquartile range [IQR] 2) and median weight was 22.7 kg (IQR 14.5). Mean area (mm(2)) of the right SV was 2.85 ± 1.9 and for the left SV, 2.88 ± 1.8. For our study group, the compatibility rates of different size i.v. catheters to fit the measured SV areas were as follows: 24G = 100%, 22G = 100%, 20G = 97.3%, and 18G =86.1%. CONCLUSIONS US can localize the SV in pediatric ED patients. US size of the SV in various pediatric age ranges suggests that the SV may be a potential US venous access site with multiple-size i.v. catheters up to 18G.