| Objective: By examining lung function of preterm infants who did and did not develop BPD throughout the neonatal period,to explore the differences and dynamic characteristics of pulmonary function in the neonatal period between preterm infants with and without BPD,to assess the influence of BPD on lung function in premature infants,to explore the value of baby body plethysmography on early lung function monitoring,and to further provide evidence for early detection of BPD and improvement of its lung function.Methods: Altogether 72 cases of premature babies who were admitted to the department of neonatology,affiliated hospital of southwest medical university from December 2017 to April 2019 were enrolled as study objects,All premature infants were excluded from complex congenital heart disease,neuromuscular diseases affecting breathing and chromosomal diseases,etc.Pulmonary function parameters including tidal breathing parameters,functional residual capacity and airway resistance parameters were assessed by baby body plethysmography on days 7,14 and 28 after birth during quiet natural sleep,the preterm infants were divided into non-BPD group with 44 infants,mild BPD group with 15 infants and moderate BPD group with 13 infants according to the diagnostic criteria of BPD adopted in 2000.Results: The preterm infants in the three groups had gradual increases in tidal volume(TV),tidal volume per kilogram(TV/kg),functional residual capacity(FRC),ratio of time to peak tidal expiratory flow to total expiratory time(%T-PF),ratio of volume to peak tidal expiratory flow to total expiratory volume(%V-PF),peak expiratory flow(PTEF),expiratory flow at 25% tidal volume(FEF25),expiratory flow at 50% tidal volume(FEF50)and expiratory flow at 75% tidal volume(FEF75)on days 7,14 and 28 after birth(P<0.05),while there were gradual reductions in effective airway resistance(Reff),effective airway resistance per kilogram(Reff/kg)and respiratory rate(RR)(P<0.05).Regardless of the 7th,14 th,or 28 th days after birth,the moderate BPD group had significantly higher Reff,Reff/kg and RR,while lower TV,TV/kg,FRC,%T-PF and %V-PF compared with the non-BPD group(P<0.05),the mild BPD group had significantly higher Reff,Reff/kg and RR,while lower TV,TV/kg,FRC,%T-PF,%V-PF,PTEF,FEF25,FEF50 compared with the non-BPD group(P<0.05),there were no significant differences in %T-PF and %V-PF between the mild and moderate BPD group no matter on days 7,14 or 28 after birth(P>0.05).Compared with the mild BPD group on day 7 after birth,the moderate BPD group had significant higher Reff,Reff/kg and FRC/kg(P<0.05).On day 7 after birth,the mild BPD group had significantly higher specific effective airway resistance(sReff)than the non-BPD group(P<0.05).The ratio of PTEF and FEF25(PF/V25)and sReff were higher in the moderate BPD group than the mild BPD group on day 28 after birth(P<0.05).Compared with non-BPD group,moderate BPD group had higher sReff,lower PTEF and lower FEF50 on day 28(P<0.05).Infants who developed mild BPD had significantly lower FEF75 than who did not develop BPD(P<0.05).TV,FRC,FRC/kg,Reff/kg,sReff and FEF50 had interaction effects between group and time(P<0.05).Conclusions: Overall,Whether or not premature infants develop BPD,the pulmonary function of preterm infants gradually becomes mature with the increase of age throughout the neonatal period.Premature babies who develop BPD have already suffered varying degrees of impaired lung function during the neonatal period,mainly manifested as small airway obstruction and reduced lung volume,while there is a certain degree of pulmonary catch up,the pulmonary function of premature who have developed BPD on day 28 after birth is still lower than that of who have not developed BPD.Baby body plethysmography pulmonary function tests can detect a certain extent damage of BPD on pulmonary function in early time,which can be extended to clinical work. |
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