“…However, in patients with ES, an irreversibly increased pulmonary vascular resistance restricts blood flow to the lungs. Therefore, an increased plasma volume adds burden to the already compromised right ventricle [ 3 , 4 ]. Moreover, systemic vasodilation with pre-existing pulmonary hypertension increases the right-to-left shunt, which worsens the hypoxia [ 3 , 4 ].…”