Inhaled nitric oxide. A selective pulmonary vasodilator reversing hypoxic pulmonary vasoconstriction.
C Frostell, MD Fratacci, JC Wain, R Jones, WM Zapol - Circulation, 1991 - Am Heart Assoc
C Frostell, MD Fratacci, JC Wain, R Jones, WM Zapol
Circulation, 1991•Am Heart AssocBackground. The gas nitric oxide (NO) is an important endothelium-derived relaxing factor,
inactivated by rapid combination with heme in hemoglobin. Methods and Results. Awake
spontaneously breathing lambs inhaled 5-80 ppm NO with an acutely constricted pulmonary
circulation due to either infusion of the stable thromboxane endoperoxide analogue U46619
or breathing a hypoxic gas mixture. Within 3 minutes after adding 40 ppm NO or more to
inspired gas, pulmonary hypertension was reversed. Systemic vasodilation did not occur …
inactivated by rapid combination with heme in hemoglobin. Methods and Results. Awake
spontaneously breathing lambs inhaled 5-80 ppm NO with an acutely constricted pulmonary
circulation due to either infusion of the stable thromboxane endoperoxide analogue U46619
or breathing a hypoxic gas mixture. Within 3 minutes after adding 40 ppm NO or more to
inspired gas, pulmonary hypertension was reversed. Systemic vasodilation did not occur …
Background
The gas nitric oxide (NO) is an important endothelium-derived relaxing factor, inactivated by rapid combination with heme in hemoglobin. Methods and Results
Awake spontaneously breathing lambs inhaled 5-80 ppm NO with an acutely constricted pulmonary circulation due to either infusion of the stable thromboxane endoperoxide analogue U46619 or breathing a hypoxic gas mixture. Within 3 minutes after adding 40 ppm NO or more to inspired gas, pulmonary hypertension was reversed. Systemic vasodilation did not occur. Pulmonary hypertension resumed within 3-6 minutes of ceasing NO inhalation. During U46619 infusion pulmonary vasodilation was maintained up to 1 hour without tolerance. In the normal lamb, NO inhalation produced no hemodynamic changes. Breathing 80 ppm NO for 3 hours did not increase either methemoglobin or extravascular lung water levels nor modify lung histology compared with control lambs. Conclusions
Low dose inhaled NO (5-80 ppm) is a selective pulmonary vasodilator reversing both hypoxia- and thromboxane-induced pulmonary hypertension in the awake lamb [corrected].Am Heart Assoc