Utility of Infant Pulmonary Function Test in Bronchopulmonary Dysplasia

Kim, Kyung Won; Choi, Bong Seok; Lee, Yong Ju; Eun, Ho Seon; Sohn, Myung Hyun; Park, Kook In; Namgung, Ran; Lee, Chul; Kim, Kyu Earn

Abstract

PURPOSE
Pulmonary function is decreased in varying degrees in healthy premature infants as well as those with bronchopulmonary dysplasia. The evaluation of pulmonary function in infants is finally standardized after strenuous efforts, but it has not yet been in Korea. In this study, we aimed at the evaluation of the utility of pulmonary function tests in premature infants with chronic lung disease by objectively measuring pulmonary function and by analyzing the risk factors that may decrease lung function.
METHODS
Fifty-four premature infants born in Severance Hospital were selected. Among the 54 infants, 31 were male and 23 were female, and their mean age was 5.6+/-3.7 years. Exhalyser was used to measure tidal volume and functional residual capacity, and then their change after the inhalation of bronchodilators was evaluated. There was no test related complication in all subjects.
RESULTS
Among the 54 subjects, 22 were at the gestational age of <28 weeks, 25 were at the gestational age between 28 and 33 weeks, and 7 were at the gestational age between 33 and 37 weeks. As for birth weight, 23 had extreme low birth weight, 23 had very low birth weight, and 8 had low birth weight. The delta functional residual capacities (FRCs) before and after the inhalation of bronchodilator were significantly increased in infants with younger gestational age (P<0.05) and lower birth weight (P<0.05). There was a significant negative correlation between gestational age and birth weight, and a significant positive correlation with the duration of ventilator care and that of oxygen therapy. The delta FRC before the inhalation of bronchodilator was significantly lower in infants with lower birth weight, and the tidal volume before the inhalation of bronchodilator correlated negatively with the duration of ventilator care.
CONCLUSION
The reversibility of FRC is increased in premature infants with lower birth weight, younger gestational age, and longer duration of ventilator care and oxygen therapy. The reversibility of FRC may be a useful parameter of pulmonary function that can be safely measured in premature infants with chronic lung disease.