Therapeutic gases for neonatal and pediatric respiratory care

Though oxygen is the most frequently administered gas in respiratory care, the use of other specialty gases has become common practice in neonatal and pediatric intensive care and emergency departments across the United States. This report reviews the literature and evidence regarding 4 such specialty gases: heliox (helium-oxygen mixture), nitric oxide, hypoxic gas (ie, < 21% oxygen), and carbon dioxide. Because heliox is less dense than air or nitrogen, it offers less resistance and turbulence as an inhaled gas and therefore decreases the pressure and work of breathing necessary to ventilate the lung, which assists in the management of conditions that involve airway obstruction. Inhaled nitric oxide is a selective pulmonary vasodilator and during the last 2 decades research has focused on its potential value for treating disorders that involve pulmonary vasoconstriction. Hypoxic gas and carbon dioxide are used in the management of infants suffering hypoplastic left heart syndrome (a congenital heart defect), to equilibrate the pulmonary vascular resistance with the systemic vascular resistance, which is necessary to assure adequate oxygenation and tissue perfusion. Balancing the systemic and pulmonary vascular resistances requires increasing pulmonary vascular resistance and decreasing pulmonary blood flow; hypoxic gas does this by maintaining blood oxygen saturation at around 70%, whereas carbon dioxide does so by increasing P(aCO2) to the range of 45-50 mm Hg.