Effects of preterm birth and bronchopulmonary dysplasia on infants’ pulmonary function: A cohort study of 117 infants

Abstract Background Despite improved preterm infant survival rates in recent years, the increasing prevalence of preterm birth requires ongoing attention to associated risks, especially pulmonary damage. This study explores pulmonary function impairment in preterm infants using plethysmography and examines its correlation with bronchopulmonary dysplasia. Methods One hundred and seventeen infants were divided into preterm and term groups, including 57 preterm infants and 60 term infants. Preterm infants were divided into bronchopulmonary dysplasia (BPD) and non-BPD groups. There were 22 cases in the BPD group and 35 cases in the non-BPD group. Preterm infants were further divided into a < 34 weeks group and a 34 ~ 36+ 6 weeks group according to gestational age. There were 26 cases in the < 34 weeks group and 31 cases in the 34 ~ 36+ 6 weeks group. The pulmonary function of each group was measured by plethysmography when the age of the infant was < 6 months. Results Compared with the term group, the preterm group had a significantly higher cesarean section rate and faster respiratory rate (RR) and lower values of the ratio of time to peak tidal expiratory flow to total expiratory time (TPEF/tE), the ratio of volume to peak tidal expiratory flow to total expiratory volume (VPEF/VE), compliance of the respiratory system (Crs), and plethysmographic functional residual capacity (FRCp). Comparisons among infants of different gestational ages revealed statistically significant differences in RR, TPEF/tE, respiratory resistance, VPEF/VE, and FRCp. Comparisons among the three groups of BPD group, non-BPD group, and term group revealed differences in RR, TPEF/tE, VPEF/VE, Crs, and FRCp that were statistically significant. Conclusions There is a certain degree of pulmonary function impairment in preterm infants, which is more severe in early preterm infants, and in preterm infants with BPD than in preterm infants without BPD. Plethysmography is helpful in the early assessment of pulmonary function in preterm infants.