Inhaled nitric oxide to improve oxygenation for safe critical care transport of adults with severe hypoxemia

Background: Inhaled nitric oxide (iNO) is a rescue treatment for severe hypoxemia in the intensive care unit setting. Objective: To evaluate the effectiveness and safety of iNO in adult patients with severe hypoxemia before and during transport to a tertiary care center. Methods: Prospective data were examined in a retrospective cohort study. Patients with severe hypoxemia and cardiopulmonary failure (n=139) at referring hospitals in whom conventional therapy was unsuccessful were treated with iNO in the intensive care units in anticipation of transfer to a tertiary center. Treatment wih iNO was initiated by the critical care transport team in 114 patients and continued in 25 patients. Arterial blood gas analysis was done before and after iNO treatment. Results: Patients treated with iNO had significant improvement in oxygenation: mean (SD) for PaO₂ increased from 60.7 (20.2) to 72.3 (40.6) mm Hg (P=008), and mean (SD) for ratio of PaO₂ to fraction of inspired oxygen (P:F) increased from 62.4 (26.1) to 73.1 (42.6) (P=03). Use of iNO was continued through transport in 102 patients, all of whom were transported without complication. The P:F continued to improve, with a mean (SD) of 109.7 (73.8) from 6 to 8 hours after arrival at the tertiary center (P<.001 relative to values both before and after treatment). Among patients treated with iNO, 60.2% survived to discharge. In 35 nonresponders, iNO was discontinued, and 15 patients could not be transferred owing to life-threatening hypoxemia; 2 were later transferred on extracorporeal membrane oxygenation. Of 18 patients transported without iNO, 9 (50%) survived. Conclusions: Use of iNO significantly improves oxygenation of patients with severe hypoxemia and allows safe transfer to a tertiary care center.