PULMONARY EFFECT OF INHALED FUROSEMIDE IN VENTILATED INFANTS WITH SEVERE BRONCHOPULMONARY DYSPLASIA

Background. When administered parenterally, furosemide, a loop diureti c, results in improved lung compliance and decreased airway resistance in infants with bronchopulmonary dysplasia (BFD). However, furosemide -induced diuresis results in hypokalemia, chloride deficiency, hyperca lciuria, nephrocalcinosis, and rickets. In patients with asthma, inhal ed furosemide has recently been demonstrated to inhibit the bronchocon strictive effects of exercise, cold air hyperventilation, and antigen challenge. We hypothesized that inhaled furosemide will result in impr oved pulmonary mechanics in ventilated infants with BPD and will preve nt the systemic complications of parenteral furosemide. Objective. To determine the efficacy and safety of a single dose of inhaled furosemi de on pulmonary mechanics in infants with severe BPD who are ventilato r dependent at 21 days of age. Design and Methods. A randomized, doubl e-blind, crossover study was performed on 9 infants with BPD, each ser ving as his own control. Each patient was randomized to receive an aer osol dose of furosemide (1 mg/kg in 2 mL of saline) or placebo (2 mL o f saline) on the first day of the study and the other agent the follow ing day of the study. Pulmonary mechanics were measured before and I a nd 2 hours after the inhalation using the Pulmonary Evaluation and Dia gnostics System. Results. Gestational age (mean +/- SEM) was 29 +/- 1 weeks; birth weight was 1.1 +/- 0.1 kg; age at study was 47 +/- 6 days ; and weight at study was 1.8 +/- 0.2 kg. There was no significant cha nge in the pulmonary function measurements before treatment and 1 or 2 hours after treatment with either placebo or furosemide. Baseline and 2-hour values were: dynamic compliance (mL/ cm H2O per kilogram): 0.4 6 +/- .03 to 0.50 +/- .03 (placebo) and 0.50 +/- 0.02 to 0.51 +/- 0.02 (furosemide); dynamic resistance (cm H2O/L per second): 118 +/- 9 to 106 +/- 7 (placebo) and 111 +/- 8 to 105 +/- 7 (furosemide); and tidal volume (mL/kg): 8.6 +/- 0.5 to 8.9 +/- 0.5 (placebo) and 8.9 +/- 0.2 to 9.4 +/- 0.3 (furosemide). Conclusion. We conclude that, under the c onditions of our study, a single dose of 1 mg/kg inhaled furosemide do es not improve the pulmonary mechanics in ventilator-dependent infants with severe BPD.