Hemodynamic effects and metabolic fate of inhaled nitric oxide in hypoxic piglets

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Journal of Applied Physiology (1985); (United States)

OSTI ID:6963551

Jacob, T D; Nakayama, D K; Seki, I; Exler, R; Lancaster, Jr, J R; Sweetland, M A; Yousem, S; Simmons, R L; Billiar, T R; Peitzman, A B ^[1]

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1. Univ. of Pittsburgh School of Medicine, PA (United States) Univ. of North Carolina, Chapel Hill, NC (United States); and others

The authors describe the hemodynamic effects and metabolic fate of inhaled NO gas in 12 anesthetized piglets. Pulmonary and systemic hemodynamic responses to incremental [NO] (5-80 ppm) were tested during ventilation with high- [0.30 inspired O[sub 2] fraction (FI[sub O2])] and low-O[sub 2] (0.10 FI[sub O2]) mixtures. In six animals, inhalation of 40 ppm NO was maintained over 6 h to test effects of prolonged exposure (0.30 FI[sub O2]). In the other six animals, pulmonary hypertension was induced by hypoxic ventilation (0.10 FI[sub O2]) and responses to NO were tested. Inhaled low [NO] partially reversed pulmonary hypertension induced by alveolar hypoxia; mean pulmonary arterial pressure decreased from 31.4 [+-] 2.3 mmHg during hypoxia to 18.2 [+-] 1.12 mmHg during 5 ppm NO. Mean pulmonary arterial pressure at 0.10 FI[sub O2] did not fall further at higher [NO] (10-40 ppm) and never reached control levels. Pulmonary vascular resistance increased with institution of hypoxic ventilation and fell with subsequent administration of NO, ultimately reaching control levels. Inhaled NO did not affect systemic vascular resistance. Plasma levels of NO[sub 2][sup [minus]] + NO[sub 3][sup [minus]] and methemoglobin (MetHb) levels increased with increasing [NO]. Over 6 h of NO administration during high-O[sub 2] ventilation, MetHb equilibrated at subtoxic levels while NO[sub 2][sup [minus]] + NO[sub 3][sup [minus]] increased. Nitrosylhemoglobin, analyzed by electron paramagnetic resonance spectrophotometry, was not detected in blood at any time. At the relatively low concentrations (5-80 ppm) that are effective in relieving experimental pulmonary hypertension induced by alveolar hypoxia, inhaled NO gas causes accumulation of NO[sub 2][sup [minus]] + NO[sub 3][sup [minus]] in plasma and a small increase in MetHb but no detectable nitrosylhemoglobin. 32 refs., 8 figs., 1 tab.

• OSTI ID: 6963551
• Journal Information: Journal of Applied Physiology (1985); (United States), Journal Name: Journal of Applied Physiology (1985); (United States) Vol. 76:4; ISSN JAPHEV; ISSN 8750-7587
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
BLOOD PRESSURE
CHALCOGENIDES
INHALATION
INTAKE
METABOLISM
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS