Prospective Cohort Study On Risk Factor For Bronchopulmonary Dysplasia In The Premature Infant

Objective To investigate the incidence,clinical features and the risk factors for bronchopulmonary dysplasia (BPD) in premature infants with a prospective cohort study and provide a basis for the integrated intervention of the premature infants with BPD.Methods Single-center prospective cohort study. Between January 1,2009 and June 01,2010, we paid regular visits to the maternity wards,and neonatal intensive care unit (NICU) for an in-depth study and investigation of all the live births of premature infants. The investigation was conducted in three stages: (1) For those pregnant women whose pregnancy was less than 37 weeks and who showed premature signs, surveys were launched right after their admission to the Obstetrics Wards concerning their history of pregnancy as well as social factors; (2) Surveys were conducted in the maternity wards on the premature infants; ( 3) Investigations were done on the infants between their birth and their corrected gestational age of 40 weeks, including the collection of following information: the morbidity incidence of such major diseases as respiratory problems, infection, brain injury, ROP,and deformity; the premature infants'use of oxygen, antibiotics; the cultured results of their airway secretion; the respiratory parameters of mechanical ventilation; the duration of mechanical ventilation; the number of times of mechanical ventilation; the dynamic observation of chest radiograph; the data of hemoglobin, platelet, serum albumin; the infants'feeding conditions; the application of acid drugs and so on. With the final clinical diagnosis of BPD, we also recorded the prognosis of the disease, the growth and development status and the nutritional status of the BPD group and the non-BPD group between birth and the corrected gestational age of full-term pregnancy. Questionnaire forms have been used to collect the above data. BPD risk factors are screened through Univariate Pearson Chi-square tests or Fisher exact test and multivariate Logistic regression analysis. Results Among 425 cases of premature infants, 266(62.6%) cases male, and 159(37.4%) cases female, with average gestational age -- 33.9±2.4w, and birth weight -- 2800g ~ 750g, with an average of 1820±462g, of which 97 cases were of very low birth weight infants. Among these infants there were 45 BPD cases with the incidence of 10.59%, 7 of them being death cases (including the deaths after automatic discharge from hospital and weaning mechanical ventilation) with the crude mortality of 15.56%. The potential risk factors of BPD in univariate pearson Chi-Square test were mother not local people (OR 2.634, 95%CI 1.409~4.921; P=0.002) , abnormal generation history (OR 2.824 , 95%CI 1.456～5.480; P=0.002),test-tube baby (OR17.239, 95%CI 6.275～47.361; P=0.000) , birthcanal infection(OR3.642, 95%CI 1.682～7.888; P=0.001), prematurerupture of menbranes (0R4.056,95%CI 1.675～9.817;P=0.001), gestational age<32w (OR3.887, 95%CI 1.217～12.416; P=0.025) , < 2000g (OR6.518 , 95%CI 2.198～19.328; P=0.02501), male(OR2.258,95%CI 1.085～4.696; P=0.026),severe neonatal asphyxia (OR2.783, 95%CI 1.211～6.398; P=0.026), baby's PH<7.20(0R4.302,95%CI 2.189～8.454; P=0.000), NRDS(OR13.905,95%CI 7.002～27.615;P=0.000) , infectious pneumonia (OR7.347 , 95%CI 3.742～14.425;P=0.000),premature apnea(OR 5.151, 95%CI 2.713～9.780;P=0.000),PDA(OR42.452,95%CI 13.176～136.778; P=0.000),feed intolerance(OR6.377,95%CI3.32～12.240; P=0.000),sepsis(OR4.302,95%CI 2.189～8.454; P=0.000), mechanical ventilation(OR53.958,95%CI 23.055～126.283;P=0.000),administration of histamine(H-2)antagonists(OR17.281,95%CI 8.144～36.672; P=0.000) , parenteral Nutrition≥20 days(OR8.894,95%CI4.339～18.230; P=0.000) , albumin<25g/L(OR3.728,95%CI 1.795～7.744;P=0.000), frequencies of blood transfusion exceed three(OR10.459 , 95%CI 5.311～20.596;P=0.000) , administration of advanced broad-spectrum antibiotics (OR15.122,95%CI 6.793～33.663;P=0.000). Multivariate Logistic regression analysis with backward (Likehood ratio) method found that abnormal generation history(0R1.57,95%CI0.90～3.32; P=0.066) , gestational age<30w(OR3.1,95%CI 1.58～5.47; P=0.001) , < 1500g(OR2.29 , 95%CI 1.32～4.55; P=0.010), infectious pneumonia(OR2.74,95%CI 1.45～4.71;P=0.001) , PDA(OR2.12 , 95%CI 1.12～4.41;P=0.010) , mechanical ventilation(OR9.57,95%CI 4.78～22.26; P=0.000), antacids (OR1.36,95%CI 1.00～3.57; P=0.047),advanced broad-spectrum antibiotics (OR2.59,95%CI 1.23～4.12; P=0.030) were independent risk factors of BPD in premature infants.Conclusion Among premature infants there is a high BPD incidence and mortality rate. The independent risk factors for the BPD in premature infants are as follows: the abnormal pregnancy and birth history of pregnant women, the infants'gestational age less than 30 weeks, the birth weight less than 1500g, infectious pneumonia (including ventilator-related pneumonia), patent ductus arteriosus, mechanical ventilation, and the use of advanced broad-spectrum antibiotics and antacids.