The effect of nitric oxide in acute right heart syndrome

Purpose: Inhaled nitric oxide (NO), a selective pulmonary vasodilator, has been found to be beneficial in patients with adult respiratory distress syndrome (ARDS). Acute increases in pulmonary vascular resistance may also contribute to the hemodynamic compromise and hypoxia in patients with acute right heart syndrome. Inhaled NO may benefit these patients by reducing pulmonary vascular resistance and improving peripheral tissue oxygen delivery. We evaluated the effect of inhaled NO on twelve intubated patients with acute right heart syndrome documented by echocardiogram. Methods: Baseline systemic and pulmonary hemodynamic measurements including left ventricular stroke volume index (LV SVI), pulmonary vascular resistance (FVR), the ratio of arterial oxygen pressure to the fraction of inspired oxygen (PaO2/FIO2), and mixed venous oxygenation saturation (MVO2) were determined. Inhaled nitric oxide was then incrementally increased every twenty minutes from 5 ppm to 80 ppm and patients were titrated to the optimal dose of NO. All patients were monitored for potential toxicity of NO, NO2 and methemoglobin. Results: Table I demonstrates an improvement in hemodynamic status in five of eleven patients receiving NO. on NO SW DL CN OS WZ Δ PVR -128 -73 9 32 -177 (dynes)(s)(cm-5) Δ LVSVI 9.3 7.2 4.9 1.5 10 (ml/m2) Δ MVO2 (%) 5.0 28 5.0 11 12 Δ PaO2/FIO2 106 41 180 23 -22 (mmHg). Conclusions: Our findings suggest that inhaled NO may increase LVSVI and oxygen delivery in certain patients with acute right heart syndrome. The exact patient population to be benefited and the potential effect on survival needs to be further evaluated. Clinical Implication: Inhaled NO may benefit certain patients with acute right heart syndrome.