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Objective: Pulsatile‐flow veno‐arterial extracorporeal membrane oxygenation (V‐A ECMO) has shown encouraging results for microcirculation resuscitation and left ventricle unloading in patients with refractory cardiogenic shock. We aimed to comprehensively assess different V‐A ECMO parameters and their contribution to hemodynamic energy production and transfer through the device circuit. Methods: We used the i‐cor® ECMO circuit, which composed of Deltastream DP3 diagonal pump and i‐cor® console (Xenios AG), the Hilite 7000 membrane oxygenator (Xenios AG), venous and arterial tubing and a 1 L soft venous pseudo‐patient reservoir. Four different arterial cannulae (Biomedicus 15 and 17 Fr, Maquet 15 and 17 Fr) were used. For each cannula, 192 different pulsatile modes were investigated by adjusting flow rate, systole/diastole ratio, pulsatile amplitudes and frequency, yielding 784 unique conditions. A dSpace data acquisition system was used to collect flow and pressure data. Results: Increasing flow rates and pulsatile amplitudes were associated with significantly higher hemodynamic energy production (both p < 0.001), while no significant associations were seen while adjusting systole‐to‐diastole ratio (p = 0.73) or pulsing frequency (p = 0.99). Arterial cannula represents the highest resistance to hemodynamic energy transfer with 32%–59% of total hemodynamic energy generated being lost within, depending on pulsatile flow settings used. Conclusions: Herein, we presented the first study to compare hemodynamic energy production with all pulsatile ECLS pump settings and their combinations and widely used yet previously unexamined four different arterial ECMO cannula. Only increased flow rate and amplitude increase hemodynamic energy production as single factors, whilst other factors are relevant when combined. [ABSTRACT FROM AUTHOR]

Background: Evaluation of donor lung function relies on the arterial oxygen partial pressure to inspired oxygen fraction ratio (PaO2/FiO2) measurement. Hemodynamic, metabolic derangements, and therapeutic intervention occurring during brain dead observation may influence the evaluation of gas exchange. Methods: We performed a mathematical analysis to explore the influence of the extrapulmonary determinants on the interpretation of PaO2/FiO2 in the brain‐dead donor and during Ex‐Vivo Lung Perfusion (EVLP). Results: High FiO2 and increased mixed venous oxygen saturation, caused by increased delivery and reduced consumption of oxygen, raise the PaO2/FiO2 despite substantial intrapulmonary shunt. Anemia does not modify the PaO2/FiO2—intrapulmonary shunt relationship. During EVLP, the reduced artero‐venous difference in oxygen content increases the PaO2/FiO2 without this corresponding to an optimal graft function, while the reduced perfusate oxygen‐carrying capacity linearizes the PaO2/FiO2—intrapulmonary shunt relationship. Conclusions: Adopting PaO2/FiO2 to evaluate graft suitability for transplantation should account for extrapulmonary factors affecting its interpretation. [ABSTRACT FROM AUTHOR]