Detection of a lower limb circulatory disorder caused by a venous cannula inserted into the femoral vein using regional oxygen saturation: a case report

Abstract

 　Lower limb circulatory disorders can occur during extracorporeal circulation using the femoral artery and vein. In most cases impaired arterial perfusion caused by the arterial cannula is the primary concern. Herein we report a case of femoral venous congestion caused by a venous cannula. A 67-year-old man underwent thoracic and abdominal aortic graft replacement. The regional oxygen saturation （rSO₂） of the lower limbs was monitored throughout the operation to detect complications. The left lower limb rSO₂ gradually decreased and was closely monitored after left femoral vein cannulation was performed. Extracorporeal circulation was initiated following left femoral artery cannulation but the left lower limb rSO₂ did not improve and remained persistently low. Femoral venous congestion was suspected due to swelling and discoloration of the left lower limb. A peripheral venous catheter was inserted under direct vision into the left femoral vein distal to the venous cannula insertion site with the catheter directed distally. Blood drainage was performed, which led to an improvement in the left lower limb rSO₂ along with amelioration of the swelling and discoloration. No further complications occurred thereafter. Monitoring the rSO₂ is effective for detecting lower limb circulatory disorders associated with extracorporeal circulation using femoral arterial and venous cannulation. A decrease in the lower limb rSO₂ during femoral arterial and venous cannulation may indicate impaired arterial perfusion caused by femoral artery cannulation and venous congestion caused by femoral vein cannulation.