The effect of inguinal compression, Valsalva maneuver, and reverse Trendelenburg position on the cross-sectional area of the femoral vein in children.

Background: For facilitation of femoral venous cannulation, the larger cross-sectional area (CSA) of the vein is helpful and can be achieved by inguinal compression, Valsalva maneuver, or the reverse Trendelenburg position. In this study, we evaluated these methods using ultrasonography in children.

Methods: Ultrasound was used to measure the CSA of the common femoral vein of 50 anesthetized pediatric patients (Group L: 25 patients more than 2 yr, Group S: 25 patients younger than 2 yr). The following six measurements of the CSA of the femoral vein were made: 1) in the supine position (control), 2) with digital compression above the inguinal ligament, 3) in the Trendelenburg position 15 degrees , 4) in the Trendelenburg position 15 degrees plus inguinal compression, 5) with Valsalva maneuver, and 6) in the reverse Trendelenburg position 15 degrees . We defined 20% change of the CSA as clinically significant.

Results: Inguinal compression increased the CSA of the femoral vein by 40% in Group L and by 57% in Group S (each P < 0.001). Inguinal compression during the Trendelenburg position also increased the CSA by 43% in Group L and by 73% in Group S (each P < 0.001). Valsalva maneuver for increasing the CSA of the femoral vein was more effective in Group S (increased by 35%) than in Group L (by 19%). The changes in the CSA were not clinically significant during the Trendelenburg position or the reverse Trendelenburg position.

Conclusions: Inguinal compression effectively increases the CSA of the femoral vein and its effect is also prominent in the Trendelenburg position. Valsalva maneuver is more effective in small children. Gravitational position changes have little effect on the size of the femoral vein in children.