Response of Very Premature Infants with Bronchopulmonary Dysplasia to Inhaled Salbutamol

Bronchopulmonary Dysplasia (BPD) is the most common chronic respiratory disease found in premature infants following prolonged supplemental oxygen and mechanical ventilation. Although salbutamol, a selective s2 agonist, is known to relax the hypertrophied smooth muscles around the small airways in adults, earlier literature has suggested that neonates did not have enough peribronchial smooth muscle for constriction and thus lacked a bronchodilatory response to s2 agonists. The present study was designed to determine whether infants of less than 32 weeks gestational age with elevated lung resistance were responsive to salbutamol. Nineteen premature infants (mean gestational age 26.0 +/- 2.1 weeks and mean birth weight 851.3 +/- 244.4 g) were recruited for the study. Immediately before and 30 minutes after the commencement of nebulized salbutamol administration, a minimum of 15 breaths were measured and analyzed for each patient. From this breath-by-breath analysis, the lung mechanics and Work of Breathing (WOB) were calculated. Results were then compared by paired t-tests. The use of salbutamol resulted in a significant improvement in airway resistance (p = 0.008) and tendency for impedance reduction. These results indicate that very premature infants (< 32 weeks) with BPD respond favorably to bronchodilators. Although the mechanism of action remains to be elucidated, salbutamol most probably achieves its effects through the relaxation of the hypertrophied peribronchial smooth muscle. Early intervention to relieve airway obstruction may promote early weaning from mechanical ventilation and diminish both duration and severity of BPD.