Objectives: Femoral artery cannulation is routinely used in circulatory support scenarios for cardiorespiratory support in patients with acute cardiac and/or pulmonary decompensation. During prolonged perfusion, this may cause acute ischemia of the leg and, in the worst case, even amputation. The aim of this experimental study was to test a newly designed arterial cannula allowing proximal and distal blood flow.
Methods: Veno-arterial cardiopulmonary bypass was established in three calves (67.6 ± 5.1 kg). The venous line was secured by cannulation of the external jugular vein. The arterial line of each animal was secured by cannulation of iliac arteries on both legs. On one side, we used a modified SmartCannula (SmartCannula 18Fr 130 mm) and, on the other side, a standard rectilinear BioMedicus cannula system was used, 19 Fr for retrograde and an 8 Fr BioMedicus shunt for anterograde flow toward the leg. An ultrasonic flow probe was used to quantify the perfusion of the distal leg.
Results: At 0.5, 1.0, 1.5, and 2.0 l/min, the anterograde leg blood flow increased steadily for each cannula, but remained higher in the self-expanding cannula. That is, the 8 F rectilinear cannula achieved a blood flow of 0.02 ± 0.01, 0.1 ± 0.04, 0.22 ± 0.09, and 0.21 ± 0.02 l/min, respectively, and the 18 F self-expanding cannula achieved 0.06 ± 0.02, 0.15 ± 0.03, 0.24 ± 0.07 and 0.36 ± 0.04 l/min.
Conclusion: The modified self-expanding cannula exhibited superior distal arterial flow compared to the routinely used rectilinear shunt system. This has a potential to reduce ischemic events of the inferior extremity in prolonged perfusion.