Hemodynamic, Ventilatory and Blood Gas Changes during Infusion of Sodium Nitroferricyanide (Nitroprusside)

Pulmonary Vasodilator Responses to Nitroprusside and Nitroglycerin in the Dog

“…The reduction in pulmo- Although vasodilator responses to nitroprusside and nitroglycerin were enhanced when pulmonary vasomotor tone was increased by an active process, responses to these agents were not enhanced when lobar vascular pressures were passively elevated by partially obstructing lobar venous outflow. These data suggest that reductions in pulmonary arterial pressure in response to nitroprusside in patients with congestive heart failure may, for the most part, be passive in nature and may be secondary to the improvement in left ventricular function which results in reductions in left ventricular end-diastolic and left atrial pressures (4,(9)(10)(11)(12). The passive nature of the pulmonary response to nitroprusside was observed in a recently published study in which this agent produced similar decreases in mean pulmonary arterial (11.7±1.5 mm Hg) and mean pulmonary arterial-wedge pressures (11.0±1.5 mm Hg) in patients with congestive heart failure (12).…”

“…Nitroglycerin is a vasodilator agent that is widely used in the treatment of anginal disease whereas nitroprusside is used in the management of hypertensive emergencies and for afterload reduction in patients with left heart failure and myocardial infarction (1)(2)(3)(4). Although the systemic vascular responses to nitroprusside and nitroglycerin have been intensively investigated (5)(6)(7)(8), the actions of these substances on the pulmonary circulation have received less attention and little, if anything, is known about the effects of these agents on the pulmonary veins (9)(10)(11)(12)(13). Nitroprusside and nitroglycerin have been reported to decrease pulmonary arterial pressure in patients with congestive heart failure (9)(10)(11)(12).…”

“…Although the systemic vascular responses to nitroprusside and nitroglycerin have been intensively investigated (5)(6)(7)(8), the actions of these substances on the pulmonary circulation have received less attention and little, if anything, is known about the effects of these agents on the pulmonary veins (9)(10)(11)(12)(13). Nitroprusside and nitroglycerin have been reported to decrease pulmonary arterial pressure in patients with congestive heart failure (9)(10)(11)(12). However, in those studies the vasodilator agents increased cardiac output and, when measured, decreased pulmonary arterial-wedge pressure so that the direct effects of these substances on the pulmonary vascular bed are uncertain (9)(10)(11)(12).…”

“…Nitroprusside and nitroglycerin have been reported to decrease pulmonary arterial pressure in patients with congestive heart failure (9)(10)(11)(12). However, in those studies the vasodilator agents increased cardiac output and, when measured, decreased pulmonary arterial-wedge pressure so that the direct effects of these substances on the pulmonary vascular bed are uncertain (9)(10)(11)(12). In a recently published study nitroprusside was reported to have no significant effect on pulmonary arterial pressure in the dog and the authors speculate that this vasodilator agent reduces pulmonary vascular distending pressure through its actions on the systemic circulation (13).…”

Mechanisms of gas exchange abnormality in patients with chronic obliterative pulmonary vascular disease.

“…These drugs alter not only pulmonary vascular resistance but also cardiac output and the distribution of ventilation aind perfusion in the lungs (6)(7)(8). Because these alterations may have detrimental effects on gas exchange, further development of this therapeutic approach depends upon a clear understanding of the underlying mechanisms of the gas exchange abnormality.…”