OBJECTIVE: To study the effects of different models of mechanical ventilation on inflammatory cytokines, IL-6, IL-10 and TNF-α, in children after cardiopulmonary bypass (CPB). METHODS: Sixty patients who underwent CPB were randomly divided into group A and group B. After CPB, group A was ventilated with high tidal volume (VT, 10-12 mL/kg) /low positive end-expiratory pressure (PEEP, 3-5 cm H2O), while group B was ventilated with low VT (6-8 mL/kg) /high PEEP (6-9 cm H2O). Plasma levels of IL-6, IL-10and TNF-α were measured before operation, at the end of the operation, and 1 and 6 hrs after operation. RESULTS: Serum levels of IL-6, IL-10 and TNF-α in both groups increased significantly at the end of the operation and reached a peak by 1 hr after operation. Group B showed lower serum levels of IL-6, IL-10 and TNF-α than group A 1 and 6 hrs after operation. CONCLUSIONS: Mechanical ventilation with low VT /high PEEP may more effectively inhibit the release of inflammatory cytokines than that with high VT /low PEEP in children after CPB.