A femoral artery cannula that allows distal blood flow

Abstract

A femoral artery cannula is used for certain types of circulatory support but can cause ischemia, especially during prolonged perfusion. This study tests the function of a femoral cannula designed to allow proximal and distal blood flow. Five pigs were used in the study. In each animal a distal-flow cannula was implanted in the femoral artery of one leg, and the same-sized standard cannula was implanted in the other. Blood was drained from the left atrium and delivered to the femoral artery through the distal-flow cannula or standard cannula by using a centrifugal pump. An ultrasonic flow probe and microspheres were used to quantify flow and perfusion distal to the cannula. Distal femoral flow and tissue perfusion were present in all animals (5/5) with the distal-flow cannula but only in 1 of 5 animals with the standard cannula (P < .048). Distal flow did not change with pump flow. Mean distal flow at each level of pump flow was higher with the distal-flow cannula (P < .05). Tissue perfusion was also higher with the distal-flow cannula (0.052 +/- 0.028 vs 0.010 +/- 0.022 mL x min(-1) x g(-1), P < .03). In the swine model the distal-flow cannula allowed greater and more consistent distal flow than the standard cannula. The use of a distal-flow cannula for circulatory support might reduce the risk of distal limb ischemia.