Life-threatening status asthmaticus treated with inhaled nitric oxide

Stwty Objective: To determine response to inhaled nitric oxide (INO) for children with acute respiratory failure secondary to life-threatening status asthmaticus. Design: Prospective, clinical observational study. Setting: 13 bed Pédiatrie Intensive Care Unit at a 168 bed tertiary care Children's Hospital. Patients: Children who required mechanical ventilation for status asthmaticus with a pCO: of > 90 mm Hg and failed conventional medical treatment. Methods: Children with status asthmaticus requiring mechanical ventilation received inhalation therapy with [NO after failing to improve with conventional medical therapy including IV agonists and steroids, and continuous inhaled agonist therapy. FNO was sequentially titrated from 10 parts per million (ppm) to 20,40,60 and 80 ppm at 10 minute intervals. Protocol modification occurred during the study after our ARDS study reveikd worsening hypoxemia and no apparent benefit of INO concentrations > 40 ppm.' Under our modified protocol, INO was sequentially titrated at 10 minute intervals from baseline to concentrations of 20 ppm and 40 ppm. A20% reduction in pCOj, and a 2 20% increase in the PaOyTiO, ratio from pretreatment values was considered a therapeutic response. Following titration, children who responded received continuous INO at the lowest therapeutic dose. Rente: The index case and 4 additional children, received therapy with INO (median age = 156 months, range - 13 to 192 months). Two children and the index case showed a > 30 mm Hg decrease in PCO,. All children showed20% increase in their PaOFKX ratio. Maximum improvement in oxygénation occurred at 20 ppm of INO. Two children, in addition to the index case, received continuous INO therapy ranging from 5.5 to 14.5 hours. Systemic hypotension was not observed in any patient and the maximum metbemoglobin level was 1.9%. All children survived to hospital discharge. Conclnskm: INO has notable bronchodilating properties in some children with lifethreatening status asthmaticus requiring mechanical ventilation. This observation contrasts with previous reports of only mild broncbodilating effects of INO. It remains unclear why some children demonstrated marked bronchodilation from INO. It appears that children with higher pCO, levels respond better to INO. Maximum improvement in oxygénation occurs at 20 ppm of [NO. Systemic side effects did not occur in any child who received (NO therapy.