Possible Alternative to Inhaled Nitric Oxide
Conclusion
All studies demonstrate that the clinical response to inhaled PGI2 in terms of selectively decreasing PAP without effecting SAP, and/or improved oxygenation is as good, if not better, than INO. Where continuous inhalation has been used, the rate of PGI2 administration is comparable to the IV infusion dose, i.e. 1.5 to 50 ng/kg/min. Mikhail et al12 were unable to detect a dose response between 15 to 50 ng/kg/min suggesting that lower doses should be evaluated. In a dog model of hypoxic pulmonary vasoconstriction, Zwissler et al found a dose of inhaled PGI2 as low as 0.9 ng/kg/min caused a significant reduction in PAP27. The actual dose reaching the pulmonary vasculature is unknown as only approximately 10% of the initial dose of a nebulized agent reaches the alveolus28. Distal deposition of a nebulized drug is related to particle size; to achieve distal deposition a particle must be less than 5μm.
