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Updated: May 29, 2026

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects
Published on: May 4, 2021
Inhaled nitric oxide therapy increases blood nitrite, nitrate, and s-nitrosohemoglobin concentrations in infants with
Yomna I Ibrahim1, Janet R Ninnis, Andrew O Hopper
1Department of Pediatrics, Division of Neonatology, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
Objective:
To measure the circulating concentrations of nitric oxide (NO) adducts with NO bioactivity after inhaled NO (iNO) therapy in infants with pulmonary hypertension.
Study Design:
In this single center study, 5 sequential blood samples were collected from infants with pulmonary hypertension before, during, and after therapy with iNO (n = 17). Samples were collected from a control group of hospitalized infants without pulmonary hypertension (n = 16) and from healthy adults for comparison (n = 12).
Results:
After beginning iNO (20 ppm) whole blood nitrite levels increased approximately two-fold within 2 hours (P<.01). Whole blood nitrate levels increased to 4-fold higher than baseline during treatment with 20 ppm iNO (P<.01). S-nitrosohemoglobin increased measurably after beginning iNO (P<.01), whereas iron nitrosyl hemoglobin and total hemoglobin-bound NO-species compounds did not change.
Conclusion:
Treatment of pulmonary hypertensive infants with iNO results in increases in levels of nitrite, nitrate, and S-nitrosohemoglobin in circulating blood. We speculate that these compounds may be carriers of NO bioactivity throughout the body and account for peripheral effects of iNO in the brain, heart, and other organs.
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