Purpose: To evaluate the efficacy of inhaled nitric oxide (iNO) on oxygenation, shunt, and pulmonary vascular resistance index (PVRI) in severely hypoxemic, ventilated patients.
Methods: In a two-period double-blind crossover design, 14 critically ill, hypoxemic, ventilated patients were randomized to receive iNO 10 ppm in 100% oxygen or no iNO in 100% oxygen for 30 min followed by a 30-min washout period and then crossed over to the other intervention. Responders to iNO then received iNO, which was increased from 5 ppm to 25 ppm in 5 ppm increments. Severity of illness scores and cardiorespiratory variables were measured.
Results: Nitric oxide decreased shunt (P=0.002) and PVRI (P=0.033) and increased oxygenation (P=0.011) although the latter two were not statistically significant after adjustment for multiple comparisons. Treatment by period interactions were observed.
Conclusion: Our findings suggest that iNO improves oxygenation to a clinically significant extent in critically ill patients who are severely hypoxemic.