Pulmonary effect of inhaled furosemide in ventilated infants with severe bronchopulmonary dysplasia

Abstract

Background: When administered parenterally, furosemide, a loop diuretic, results in improved lung compliance and decreased airway resistance in infants with bronchopulmonary dysplasia (BPD). However, furosemide-induced diuresis results in hypokalemia, chloride deficiency, hypercalciuria, nephrocalcinosis, and rickets. In patients with asthma, inhaled furosemide has recently been demonstrated to inhibit the bronchoconstrictive effects of exercise, cold air hyperventilation, and antigen challenge. We hypothesized that inhaled furosemide will result in improved pulmonary mechanics in ventilated infants with BPD and will prevent the systemic complications of parenteral furosemide.

Objective: To determine the efficacy and safety of a single dose of inhaled furosemide on pulmonary mechanics in infants with severe BPD who are ventilator dependent at 21 days of age.

Design and methods: A randomized, double-blind, crossover study was performed on 9 infants with BPD, each serving as his own control. Each patient was randomized to receive an aerosol dose of furosemide (1 mg/kg in 2 mL of saline) or placebo (2 mL of saline) on the first day of the study and the other agent the following day of the study. Pulmonary mechanics were measured before and 1 and 2 hours after the inhalation using the Pulmonary Evaluation and Diagnostics 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 change 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): 0.46 +/- .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 conditions of our study, a single dose of 1 mg/kg inhaled furosemide does not improve the pulmonary mechanics in ventilator-dependent infants with severe BPD.