title: Effects of low doses of inhaled nitric oxide combined with oxygen for the evaluation of pulmonary vascular reactivity in patients with pulmonary hypertension.
abstract: The purpose of this study was to evaluate the hemodynamic effects of inhaled nitric oxide in oxygen (NO + O2) in patients with pulmonary hypertension. Eighteen patients (median age 31.5 months) with pulmonary hypertension inhaled through a mask 100% O2 and 20 parts per million NO + inspired O2 fraction (FiO2) at 0.4. Hemodynamic measurements were made at baseline and after O2 and NO + O2 administration. The pulmonary vascular resistance index decreased after inhalation of O2 and NO + O2 (p = 0.0018 and p = 0.0003, respectively), the decrease being significantly greater after NO + O2 (p = 0.0311). Concerning the transpulmonary pressure gradient, a reduction occurred in values after O2 and NO + O2 inhalation when compared with baseline values (p = 0.0014 and p = 0.0008). In patients with congenital heart disease, an increase occurred in pulmonary blood flow after O2 (p = 0.0089) and NO + O2 (p = 0.0019) compared with baseline values, and an increase also occurred in the pulmonary/systemic blood flow ratio after NO + O2 (p = 0.0017). The main side effect related to NO + O2 was pulmonary congestion in 3 patients. Low doses of NO combined with O2 demonstrated a selective pulmonary vasodilator response in patients with pulmonary hypertension. Despite its use for testing pulmonary reactivity, inhalation of NO + O2 should be carefully administered because of the potential risk of pulmonary congestion.
authors.affiliation: Heart Institute (InCor), University of São Paulo Medical School, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Azeka
authors.forename: J O
authors.initials: JO
authors.lastname: Costa Auler
authors.forename: L
authors.initials: L
authors.lastname: Kajita
authors.forename: A C
authors.initials: AC
authors.lastname: Alliman
authors.forename: J A A
authors.initials: JA
authors.lastname: Franchini Ramires
authors.forename: M
authors.initials: M
authors.lastname: Ebaid
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006330:Heart Defects, Congenital / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000503:physiopathology; D007223:Infant; D008297:Male; D009569:Nitric Oxide / Q000008:administration & dosage / Q000627:therapeutic use*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D014665:Vasodilator Agents; D009569:Nitric Oxide