A Study of Inflammatory Response and Lung Injury Induced by Variable Tidal Volumes in Mechanically Ventilated Children

Background We aimed to compare the effects of high tidal volume (Vt) versus low Vt mechanical ventilation (MV) on systemic interleukin-۸ (IL-۸), and tumor necrosis factor alpha (TNF- α) cytokines production and induction of lung injury in mechanically ventilated children. Materials and Methods: Thisprospectiveobservational study was performed on ۶۰ critically ill mechanically ventilated children from ۲۰۱۸ to ۲۰۱۹, at PICU of South Valley University and Minia University hospitals, Qena and Minia cities, Egypt. After application of the inclusion and exclusion criteria, we compared MV with high Vt of ۹-۱۱ ml (group I) versus low Vt of ۵-۷ml (group II) per kilogram of predicted body weight in critically ill children. Plasma levels of IL۸ and TNF- α cytokines were estimated at the onset of MV and after ۲۴ hours in both groups. Lung injury development was evidenced by change in oxygenation parameters.  Results: Sixty patients on MV (۳۰ with high Vt versus ۳۰ with lower Vt) were enrolled in the study. Plasma levels of interleukin-۸ and TNF- α were increased in both groups ۲۴ hours after initiation of MV, but this rise was significantly higher in high Vt group (p <۰.۰۵). There were significant positive correlations between tidal volume and oxygenation index (p-value <۰.۰۵, r=۰.۳۲), and with plasma IL-۸ (r=۰.۳۴, p= ۰.۰۱), while negative correlation between tidal volume and change in PaO۲/fiO۲ ratio after ۲۴ hours MV (r= -۰.۳۴, p <۰.۰۵). Conclusion Mechanical ventilation with high Vt was associated with increased IL-۸, and TNF- α cytokines production, and will induce lung injury as evidenced by acute hypoxemia and deterioration in oxygenation parameters (PaO۲/FiO۲ ratio less than ۳۰۰ mmHg).