Figure 2

SO₂ in the ARF sheep model with different cannulations of VA ECMO. (A) The cannulation of IVC-FA in normal sheep did not affect the SO₂ of the SVC, PA, aorta and IVC. After establishing ARF in these sheep, the SO₂ of the SVC, PA and aorta decreased; the SO₂ of the IVC remained high. (B) The SO₂ in the ARF sheep model with SVC-FA, IVC-CA, and FA-IJV. ‘before’ indicates the SO₂ value of IVC-FA. ‘after’ indicates the SO₂ value after cannulation shifting. ^*Indicates P <0.01 between IVC-FA and mechanical ventilation or between IVC-FA and cannula-shifted sheep. ARF: acute respiratory failure; FA-IJV: an additional return cannula was added into the internal jugular vein on the basis of femoral veno-arterial extracorporeal membrane oxygenation; IVC-CA: a drainage cannula was inserted into the inferior vena cava and a return cannula was inserted into the carotid artery; IVC-FA: a drainage cannula was placed into the inferior vena cava through the femoral vein and a return cannula was inserted into the femoral artery; PA: pulmonary artery; SO₂: oxygen saturation; SVC-FA: a drainage cannula was placed into the superior vena cava through the femoral vein and a return cannula was placed into the femoral artery; VA ECMO: veno-arterial extracorporeal membrane oxygenation.