Methods of identifying and treating premature infants at risk for BPD

1. A method for reducing the likelihood of a premature infant of developing bronchopulmonary dysplasia comprising:

a) obtaining a plasma sample from the infant prior to initiation of inhaled nitric oxide therapy;

b) measuring a total concentration of nitrite and nitrate in the plasma sample;

c) determining whether the measured concentration of nitrite and nitrate is less than about 50 μM, wherein a concentration of less than about 50 μM indicates that the infant is likely to have a therapeutic response to inhaled nitric oxide; and

d) treating the infant with inhaled nitric oxide to reduce the likelihood of development of bronchopulmonary dysplasia when the measured concentration of nitrite and nitrate is less than about 50 μM,

wherein the premature infant is less than 30 weeks gestational age.

2. The method of claim 1 , wherein the measured concentration of nitrite and nitrate is about 0-45 μM, about 5-40 μM, about 10-30 μM, about 20 μM, or below the detection limit of an assay used to measure the concentration.

3. A method of reducing the likelihood of a premature infant of developing bronchopulmonary dysplasia comprising:

a) testing the infant for one or more of

(i) a plasma total concentration of nitrate and nitrite;

(ii) a concentration of nitric oxide in exhaled ambient or nitric oxide-free air; and

(iii) presence of a genetic mutation in a gene encoding nitric oxide synthase that results in decrease endogenous synthesis of nitric oxide;

b) determining whether the total concentration of nitrate and nitrite in the plasma is less than about 50 μM, whether the concentration of nitric oxide in the exhaled air is less than about 1.5 ppb and/or whether the genetic mutation is present or absent; and

c) treating the infant with inhaled nitric oxide to reduce the likelihood of development of bronchopulmonary dysplasia if the total concentration of nitrate and nitrite in the plasma is less than about 50 μM, the concentration of nitric oxide in the exhaled air is less than about 1.5 ppb, and/or that the genetic mutation is present,

wherein the premature infant is less than 30 weeks gestational age.

4. The method of claim 3 , wherein the infant is treated with decreasing dosages of inhaled nitric oxide.

5. The method of claim 4 , wherein an initial dose of 20 ppm is administered for 48-96 hours, and subsequent doses of 10, 5 and 2 ppm are administered at weekly intervals thereafter.

6. The method of claim 3 , wherein treatment is initiated at 5-14 days after birth.

7. The method of claim 3 , wherein the infant is treated for 20-30 days.