monitored with prolonged use. In addition to undesired hypotension,
nitroprusside can also lead to pulmonary vasodilation and increased intra-
pulmonary shunting (i.e. reduced PaO 2 ), as well as cerebral vasodilation (i.e.
increased intracranial pressure). Rarely, it can also affect platelet function.
Inhaled nitric oxide (NO) is an endothelium-derived vasodilator that is
produced by the pulmonary capillary bed. Delivered through the airway, NO is
able to diffuse through the airways into the smooth muscle of the surrounding
pulmonary vasculature. NO is used primarily in the treatment of pulmonary
hypertension or with LCO associated with high pulmonary vascular pressures. It
selectively reduces pulmonary vascular resistance by dilating pulmonary arteries
near areas that are better ventilated and thus is able to improve ventilation-
perfusion matching within the lung. It has rare systemic effects since it is
metabolized rapidly and then bound to Hgb. The administration of NO needs to
include monitoring of methemoglobin levels, which can critically reduce oxygen
carrying capacity if levels exceed >20% of the total circulating Hgb. Normal dose
ranges for use are 1-40 parts per million (ppm).
Levosimindan is a newer agent that acts as a calcium sensitizer. It has
both inotropic and lusitropic effects. It is a pyridazole dinitrate derivative with a
short half-life but it has a longer acting metabolite (OR 1867; 70-80 hours) that
explains its persisting effects. There are few studies utilizing this medication in
pediatric patients. However, initial studies adult studies in heart failure suggest
that it is equivalent to milrinone and provides an ability to reduce myocardial
oxygen consumption as well as reducing concomitant catecholamine
marcin
(Marcin)
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