LAUSR

I read with interest an article in your journal by Lotz et al.1 They demonstrated that nitric oxide (NO) inhalation decreases pulmonary shunting and improves arterial oxygenation, leading to a therapeutic effect on coronavirus disease 2019 (COVID-19)-induced acute respiratory distress syndrome (ARDS). Inhaled NO (iNO) acts as a selective pulmonary artery vasodilator, alleviating lung ventilation/perfusion ratio. However, Lotz and colleagues assume that improved oxygenation is not the sole reason for survival benefits in patients treated with iNO, suggesting other modes of iNO action could have beneficial effects on systemic circulation. This may indeed be the case, because iNO has a wide range of systemic effects that reduce vascular endothelial inflammation, in addition to local pulmonary effects.2,3.