Ultrasonographic investigation of the effect of inguinal compression on the cross-sectional area of the femoral vein

Abstract

OBJECTIVES: The reverse Trendelenburg position increases the cross-sectional area (CSA) of the femoral vein, making it easier to cannulate, although this position is potentially harmful in hypovolemic patients. The authors hypothesized that compression above the femoral vein increases the CSA of the femoral vein during emergency cannulation. METHODS: Ultrasound was used to measure the CSA of the femoral vein of 20 healthy volunteers. The following five measurements were made inferior to the inguinal crease: 1) in the horizontal supine position (control), 2) with inguinal compression 2 cm above the inguinal crease (at the point of arterial pulsation and its medial side), 3) in the Trendelenburg position 15 degrees, 4) in the Trendelenburg position 15 degrees plus inguinal compression, and 5) in the reverse Trendelenburg position 15 degrees. RESULTS: Femoral vein CSA was increased by 35% by inguinal compression in the horizontal supine position (p < 0.001) and was decreased by the Trendelenburg position (p < 0.001). However, inguinal compression increased the CSA by 66% in the Trendelenburg position (p < 0.001). The reverse Trendelenburg position also increased the CSA of the femoral vein by 50% (p < 0.001). CONCLUSIONS: Inguinal compression presents an alternative method for increasing the CSA of the femoral vein for venous catheterization in normal patients.