Sweep gas nitric oxide (sNO) is emerging as an adjunctive therapy, which may have positive impacts on thrombosis and inflammation during ECMO treatment. sNO is administered to the gas phase of the ECMO oxygenator with the aim of reducing contact activation of blood when flowing through and over artificial surfaces. NO delivery devices have gas flow requirements that are above the sweep gases requirements of smaller patients supported on ECMO. To facilitate sNO delivery in patients requiring a sweep flow rate below the required bias flow rate of NO delivery devices, varying sNO delivery setups have been described. Here, we describe three systems for safe and reliable sNO delivery.