Indications for VA-ECMO and Management of ECMO Support
VA-ECMO indications were: acute refractory cardiovascular failure, defined as evidence of tissue hypoxia concomitant with adequate intravascular volume status; severely diminished RV function or LVEF; low cardiac index (≤2.1 L/min/m2); sustained hypotension despite high-dose catecholamine infusion (epinephrine ≥1 γ/kg/min or dobutamine ≥20 γ/kg/min + norepinephrine ≥1 γ/kg/min).
All patients, regardless of age or comorbid conditions, were considered candidates for this intervention, unless their predicted survival independent of the PE, was less than 1 year. ECMO consist of a centrifugal pump, a hollow fiber oxygenator (Livanova, Sorin Group, Italy) and cannulas (Xenios AG-Medos, Heilbronn Germany). Cannulation was performed under ultrasound guidance, with a 23F to 25F venous drainage cannula placed in a femoral vein and a 17F to 19F arterial return cannula placed in a common femoral artery in the contralateral groin whether in the ICU or in the operation room. A 6F distal perfusion cannula was placed in the superficial femoral artery as a first step previously, unless the patient was actively requiring cardiopulmonary resuscitation (CPR), to allow for better ultrasound visualization of the superficial femoral artery.
ECMO Flows were maintained in the range of 2 to 4 L/minute, requiring pump speeds of approximately 3,000 to 4,000 rpm, and were adjusted with the goals of reversing acidosis while maintaining arterial saturation and cardiac output. Support flow was also titrated up until the right ventricle was decompressed by TTE and maintain a systemic blood pressure of 90 mmHg. However, some pulmonary blood pulmonary flow was maintained to allow for APT. Systemic anticoagulation was maintained with activated clotting time of 180-200 seconds by unfractionated heparine infusion. Figure 1. shows one survivor patient who have high-risk PE and cardiac arrest, stabilized hemodynamically with VA-ECMO; just before catheter-based intervention with EKOS APT.