Influence of the Method of Secondary Noninvasive Respiratory Support on Systemic Markers of Inflammation in Preterm Very-Low-Birth-Weight Infants

Introduction: Development of inflammatory reactions (biotrauma) is the primary mechanism of lung injury during mechanical ventilation (MV). Cytokines play a key role in this process. This open randomized study looked at the influence of different methods of respiratory support on interleukin (IL)-6 and IL-8 serum levels in very preterm infants.

Materials and Methods: The study included very preterm infants (gestation age ≤ 32 weeks) with respiratory distress syndrome who were treated with MV. Within the first 3 days of life, before extubation infants were randomized into two groups: nonsynchronized noninvasive ventilation (NV) (n = 19) and continuous positive airway pressure (СРАР) (n = 18). The third group included 10 infants ventilated longer than 3 days (comparison group). The levels of ILs in blood serum were measured by ELISA on the 3rd and 14th days of life.

Results: Forty-seven infants were studied (19 in the NV and 18 in the СРАР group, respectively). There were no statistically significant differences between the levels of IL-6 and IL-8 in the groups on the 3rd and 14th days of life. However, statistically significant reduction of IL-6 concentrations was observed in the NV group on the 14th day of life compared with the initial ones (р  <  0.05). Longer duration of MV (rS = 0.3; p  <  0.05), death (rS = 0.3; p  <  0.05), incidence of bronchopulmonary dysplasia (BPD) or death (rS = 0.34; p  <  0.05) were associated with higher IL-6 levels on the 3rd day of life. Longer duration of noninvasive respiratory support (rS = 0.5; p  <  0.05), longer neonatal intensive care unit stay (rS = 0.44; p  <  0.05), BPD or death (rS = 0.33; p  <  0.05), and moderate BPD (rS = 0.35; p  <  0.05) were associated with higher IL-6 levels on the 14th day of life. Levels of IL-8 assessed on the 3rd and 14th days of life did not correlate with total duration of respiratory support, incidence of BPD, or mortality.

Conclusion: In this study, NV was associated with a statistically significant reduction of serum IL-6 levels in preterm infants within the first 14 days of life as opposed to CPAP and could be protective against BPD.

Keywords: noninvasive ventilation, CPAP, serum interleukins, BPD, very preterm infants