INHALED NITRIC-OXIDE IN CHILDREN WITH SEVERE LUNG-DISEASE - RESULTS OF ACUTE AND PROLONGED THERAPY WITH 2 CONCENTRATIONS

Objectives: To evaluate the acute effects of 11 and 60 parts per milli on (ppm) inhaled nitric oxide on the pulmonary vascular resistance and systemic oxygenation of children with severe lung disease, and to com pare the outcome of prolonged therapy with similar to 10 and 40 ppm in haled nitric oxide. Design: Prospective, randomized study. Setting: A 26-bed pediatric intensive card unit in a tertiary children's hospital . Patients: Nineteen patients (median age 11 yrs, range 7 months to 16 yrs) with acute bilateral lung disease requiring a positive end expir atory pressure (PEEP) of >6 cm H2O and an F10(2) of >0.5 for >12 hrs w ere treated with inhaled nitric oxide. One patient was treated twice d uring the same hospitalization. Interventions: Acute hemodynamic and b lood gas effects of 11 and 60 ppm inhaled nitric oxide were studied, w hile delivering these concentrations in random order for intervals of 20 to 30 mins, Each interval was preceded by an interval of 20 to 30 m ins without nitric oxide, Patients were then randomized and treated fo r a prolonged period with similar to 10 or 40 ppm inhaled nitric oxide independent of their initial acute responses to 11 and 60 ppm. Nitric oxide was discontinued when ventilatory support was decreased to a PE EP of less than or equal to 6 cm H2O and an F10(2) of less than or equ al to 0.5. Measurements and Main Results: inhaled nitric oxide selecti vely decreased pulmonary vascular resistance and improved systemic oxy genation. Acute hemodynamic and blood gas effects of 11 and 60 ppm nit ric oxide were similar. Systemic oxygenation improved to a greater ext ent in patients with radiographic evidence of residual aerated lung re gions than in patients with diffuse bilateral lung disease. Maximum me themoglobin concentrations were greater in patients treated for a prol onged period with 40 ppm nitric oxide. The mortality and duration of t herapy were similar for patients treated with 10 and 40 ppm inhaled ni tric oxide. Conclusions: Pulmonary vascular resistance and systemic ox ygenation are acutely improved to a similar extent by 11 and 60 ppm in haled nitric oxide, and concentrations in excess of 10 ppm are probabl y not needed for prolonged therapy of children with severe lung diseas e.