Background
We aimed to compare the effects of high tidal volume (Vt) versus low Vt mechanical ventilation (MV) on systemic interleukin-8 (IL-8), 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 60 critically ill mechanically ventilated children from 2018 to 2019, 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 9-11 ml (group I) versus low Vt of 5-7ml (group II) per kilogram of predicted body weight in critically ill children. Plasma levels of IL8 and TNF- α cytokines were estimated at the onset of MV and after 24 hours in both groups. Lung injury development was evidenced by change in oxygenation parameters. 
Results: Sixty patients on MV (30 with high Vt versus 30 with lower Vt) were enrolled in the study. Plasma levels of interleukin-8 and TNF- α were increased in both groups 24 hours after initiation of MV, but this rise was significantly higher in high Vt group (p <0.05). There were significant positive correlations between tidal volume and oxygenation index (p-value <0.05, r=0.32), and with plasma IL-8 (r=0.34, p= 0.01), while negative correlation between tidal volume and change in PaO2/fiO2 ratio after 24 hours MV (r= -0.34, p <0.05).
Conclusion
Mechanical ventilation with high Vt was associated with increased IL-8, and TNF- α cytokines production, and will induce lung injury as evidenced by acute hypoxemia and deterioration in oxygenation parameters (PaO2/FiO2 ratio less than 300 mmHg).