249 - Airway Colonization And Risk Factors For Development Of Bronchopulmonary Dysplasia In Intubated Very Low Birth Weight Infants

Poster Number: 249
Publication Number: 249.2790

Background: Bronchopulmonary dysplasia (BPD) is commonly seen in very low birth weight (VLBW) infants. Pathogenesis of BPD is multifactorial. Bacterial airway colonization and infection of lower respiratory tract have been suggested as important factors in the pathogenesis of BPD.

Objective: To characterize patterns of airway colonization of intubated VLBW infants from tracheal aspirate (TA) cultures and to identify risk factors, including the type of bacterial colonization associated with BPD.

Design/Methods: A retrospective study of VLBW infants admitted between July 2015 to July 2021 on invasive mechanical ventilation (IMV) for ≥ 1 week who had routine TA cultures. Neonatal and maternal demographics, clinical course, antibiotic use, radiology reports, laboratory results, and TA culture results were collected. BPD was defined as the need for positive respiratory support at 36 weeks postmenstrual age regardless of supplemental oxygen use and severity was defined as follow: Grade 1: Nasal Cannula Flow ≤2 L/min; Grade 2: Nasal Cannula Flow >2 L/min or non-invasive ventilation; Grade 3: IMV. Neonates were classified into 2 groups: no BPD/Grade 1 BPD and Grade 2/Grade 3 BPD.

Results: 62 intubated VLBW infants met inclusion criteria. Mean GA was 25.8 ± 1.8 weeks and mean BW was 748 ± 248 grams. There were 35/62 (56%) infants who had no BPD/Grade 1 BPD and 27/62 (44%) infants who had Grade 2/Grade 3 BPD. Infants with Grade 2/Grade 3 BPD were more likely to be male, had lower 5 minute Apgar score, received repeat doses of surfactant, had longer antibiotic exposure, higher rate of VAP, dexamethasone use, acetaminophen use for hemodynamically significant patent ductus arteriosus (hsPDA), ligation of hsPDA, longer duration of IMV, and longer length of stay (LOS). Majority of infants 39 (63%) were intubated at birth and mean duration of IMV was 33.5 ± 16 days. The first positive culture occurred with gram positive bacteria (GPB) at median day 9 post-intubation followed by gram negative bacteria (GNB) at median day 13 post-intubation. There was no significant difference in bacterial airway colonization between the two groups (Table).

Conclusion(s): Majority of intubated VLBW infants were initially colonized with GPB followed by GNB at two weeks post-intubation. Development of Grade 2/Grade 3 BPD was associated with longer exposure to antibiotic use likely related to treatment of underlying infection, longer duration of presence of hsPDA, prolonged duration of IMV, and longer LOS. There was no difference in airway colonization pattern observed in infants who developed more severe form of BPD versus absent or mild BPD.