Neonatal platelet count trends during inhaled nitric oxide therapy

Recent debate has focused on the significance of platelets generated in lung tissue. Here, we retrospectively analyzed platelet count changes in neonates requiring inhaled nitric oxide (iNO) pulmonary vasodilation therapy for pulmonary hypertension. There were no clinically significant changes in platelet count upon iNO initiation or during iNO therapy. Unexpectedly, platelet counts increased after iNO cessation. These findings argue against a clinically meaningful untapped pulmonary repository of megakaryocytes and platelets in this context, although acute platelet count increases might be expected after discontinuing iNO in some patients. Further work is needed to clarify the underlying etiology for these observations, and to better delineate the mechanisms for platelet count increases after recovery from lung injury.