Inhaled nitric oxide reverses hypoxic pulmonary vasoconstriction without impairing gas exchange

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of Applied Physiology (1985); (United States)

OSTI ID:6521072

Pison, U; Lopez, F A; Heidelmeyer, C F; Rossaint, R; Falke, K J ^[1]

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1. Freie Universitaet Berlin (Germany)

Nitric oxide (NO) is an endogenous endothelium-derived relaxing factor that participates in the regulation of vascular tone. The authors studied the effects of inhaled NO gas on transient hypoxic pulmonary vasoconstriction and normal lungs in mechanically ventilated sheep. They measured hemodynamics and pulmonary gas exchange. For gas exchange measurements they used conventional blood gas analysis and the multiple inert gas elimination technique to estimate ventilation-perfusion heterogeneity. The hypotheses were (1) inhaled NO reverses hypoxic pulmonary vasoconstriction, (2) the hemodynamic effects of inhaled NO are limited to the pulmonary circulation, and (3) inhaled NO does not impair pulmonary gas exchange and may redistribute blood flow to better ventilated areas of the lungs. Hypoxic pulmonary vasoconstriction was induced by using a hypoxic inspiratory gas mixture. The addition of 20 ppm NO to the hypoxic inspiratory gases returned pulmonary arterial pressure to baseline values. Systemic hemodynamics and gas exchange indexes derived from conventional blood gas analysis remained constant. Gas exchange indexes for ventilation-perfusion ratios and gas dispersions improved. The addition of 20 ppm NO to medical air (21% O[sub 2]) had no such significant effects on hemodynamics or pulmonary gas exchange. The findings show that inhaled NO reverses transient hypoxic pulmonary vasoconstriction. The hemodynamic effects of NO are limited to the pulmonary circulation; it does not impair pulmonary gas exchange. Moreover, it redistributes blood flow to better ventilated alveoli. As such, NO has potential in the treatment of lung diseases associated with pulmonary hypertension. 35 refs., 4 figs., 3 tabs.

• OSTI ID: 6521072
• Journal Information: Journal of Applied Physiology (1985); (United States), Journal Name: Journal of Applied Physiology (1985); (United States) Vol. 74:3; ISSN JAPHEV; ISSN 8750-7587
• Country of Publication: United States
• Language: English

Related Subjects

551000 -- Physiological Systems
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
BLOOD FLOW
BODY
CARDIOVASCULAR DISEASES
CHALCOGENIDES
DISEASES
GAS ANALYSIS
HYPERTENSION
LUNGS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANS
OXIDES
OXYGEN COMPOUNDS
RESPIRATORY SYSTEM
SYMPTOMS
THERAPY
VASCULAR DISEASES
VASOCONSTRICTION
VENTILATION