Effects of weight gain on preterm infant´s lung function

Abstract

Objective: to know the effect of weight gain on infant lung function in preterm infants with a gestational age Methods: Preterm infants were classified as having BPD when their oxygen dependency persisted at 36 weeks postmenstrual age. FVC and FEV0.5 were measured by means of the raised volume rapid thoraco-abdominal compression technique . A linear regression analysis was carried out considering z-score of lung function parameters (FVC, FEV0.5 and FEV0.5/FVC rate) and weight gain in grams per day. A logistic analysis was then performed including values of FEV0.5/FVC rate below lower limit of normality (LLN) and weight gain. These analysis were controlled by gender, gestational age, caffeine therapy, birth weight (z-score), corrected age and mother smoked during pregnancy (yes/no). Results: We found significant association between weight gain and increased z-score of FVC (β 0.028; 95%CI: 0.0035 to 0.052; p=0.025); and therefore significant association between weight gain and decreased z-score of FEV0.5/FVC rate (β -0.077; 95%CI: -0.132 to -0.022; p=0.006). We did not find this association in z-score of FEV0.5. The logistic analysis showed a significant increased proportion of z-scores of FEV0.5/FVC values below LLN in those preterm infants with higher weight gain (OR 1.16; 95%CI, 1.05-1.28; p=0.004). Conclusion: Increased weight gain in preterm infants below 31 weeks of gestational age and BPD diagnosis shows significant association with higher FVC values and lower FEV0.5/FVC rate. There is a risk effect of rapid weight gain in this group of preterm infants that could be causing dysanaptic lung growth.