Which of the following inhaled gas is used to decrease pulmonary aery pressure in adults and infants?
C i.e. Nitric oxide Nitric oxide (NO) or endothelium derived relaxing factor (EDRF) is synthesized from L-arginine by nitric oxide synthase (NOS) enzyme in endothelium of blood vesselsQ. Physiologically it causes vasodilation & decreases vascular resistance throughout the bodyQ. It activates guanylyl cyclase producing C-GMP and binds rapidly to Hb & gets inactivatedQ. Whereas inhaled NO is a selective pulmonary-vasodilator decreases pulmonary aery pressure in infants & adults and improves V/P ratioQ. So it is used in treatment of pulmonary aery hypeensionQ. It has no systemic vasodilatory effectQ. Systemic effects of breathing NO includes platetlet & leukocyte inhibition and oxidation of extraerythrocytic hemoglobin. Inhaled NO decreases vascular smooth muscle cell hyperplasia & increases alveolarization in the injured developing limb. This pulmonary vascular & alveolar developmental effect of NO is used to prevent or ameliorate pulmonary hypeension in infants with congenital hea disease and chronic lung disease in premature infants.
Nitrous oxide
Nitrogen dioxide
Nitric oxide
Nitrogen