Anti-henoptic drugs: its effects of nitroglycerin (NG) on the pulmonary circulation

ABSTRACT

1. Nitroglycerin, 10 to 5000 mcg./kg. intravenously, caused pulmonary hypotension in 10 dogs. In these 10 dogs, left and right atrial pressure measurements do not support the possibility that the pulmonary hypotension is secondary to decreased right ventricular output or increased left ventricular output2. Nitroglycerin, intra-arterially administered in 12 dogs prepared for constant inflow perfusion, caused a decrease in perfusion pressure in 11 and no change in one. Decrease in pulmonary perfusion pressure can be shown to occur with doses which cause no change in systemic blood pressure. Furthermore, when the intra-arterial doses of NG are large enough to bring about the known systemic hypotensive property of NG, the fall in pulmonary perfusion pressure always precedes the systemic hypotension. These phenomena speak speak strongly of a pulmonary vasodilatation caused by NG. No experiments were done to determine what role decreased transpleural pressure plays in the pulmonary vasodilatation3. Nitroglycerin, 10 mcg. to 12 mg. total doses, caused no change in the cardiac output of 8 dog heart-lung preparations4. The efficacy of NG, interavenously, as an anti-hemoptic was discussed.(Summary)