ANATOMY OF FEMORAL VESSELS IN INFANTS AND GUIDELINES FOR VENOUS CATHETERIZATION

Abstract

An ultrasound study was performed to formulate and validate guidelines for femoral venous catheterization. 36 infants (2 wk to 20 mo) were evaluated in a supine, straight leg position. The sector scan transducer was oriented vertically and perpendicular to the axis of the femoral vessels, 1 cm below the groin skin crease. No difference was detected in distance between central points of veins and arteries bilaterally and distance between vessels was not related to age, height, or weight (p>.05). Because symmetry was demonstrated, further evaluation was performed on the right side only. Guidelines were formulated from observations in half the patients, and independently validated by inspection of scans of the others, with random selection of groups. For 18 patients, the central point of femoral veins lay 5.3mm medial to the central point of the artery. Hypothetical success in catheterization of the other 18 patients was evaluated by assuming that successful catheterization requires entering the central half of the vein's horizontal diameter. It was also assumed that the central point of the artery corresponds to the palpable pulse. Successive needle insertion attempts first at 5.3mm, then 6.3mm, and finally at 4. 3mm medial to the pulse would result in cumulative successful IV catheterization in 11/18 (61%), 12/18 (67%), and 11/18 (7859, respectively. No arterial punctures would result from the first 2 attempts, but 2/18 (11%) would occur from the attempt closest to the artery. Among both extremities in all 36 patients, the vein was located inaccessibly behind the artery in 2/72 in 2 different infants.