Positive Pressure Ventilation with the Open Lung Concept Optimizes Gas Exchange and Reduces Ventilator-Induced Lung Injury in Newborn Piglets

Previous studies demonstrated that high-frequency oscillatory ventilation using the open lung concept (OLC) resulted in superior gas exchange and a reduction in ventilator-induced lung injury (VILI). We hypothesized that these beneficial effects could also be achieved by applying the OLC during positive pressure ventilation. After repeated whole-lung-lavage, newborn piglets were assigned to either OLC positive pressure ventilation (PPV OLC ), OLC high-frequency oscillatory ventilation (HFOV OLC ), or conventional positive pressure ventilation (PPV CON ) and ventilated for 5 h. In both OLC groups, collapsed alveoli were actively recruited and thereafter stabilized using the lowest possible airway pressures. In the PPV CON group, ventilator settings were adjusted to prevent critical hypoxia. Airway pressure, blood gas analysis, pressure-volume curve, and alveolar protein infiltration was recorded. A lung injury score was used for histologic comparison. Mean airway pressures were comparable in the three ventilation groups over time (1.2-1.5 kPa). Arterial oxygenation increased to mean values above 60 kPa in both OLC groups compared with 10 kPa in the PPV CON group ( p < 0.001). Maximal lung compliance was superior in both OLC groups (PPV OLC : 91 ± 23; HFOV OLC : 90 ± 31 mL/kPa/kg, p < 0.01) compared with the PPV CON group (39 ± 14 mL/kPa/kg). Alveolar protein infiltration was significantly reduced in the PPV OLC group (0.33 ± 0.10 mg/mL, p < 0.01) and the HFOV OLC group (0.40 ± 0.13 mg/mL, p < 0.01) compared with the PPV CON group (0.70 ± 0.15 mg/mL). Lung injury scores were significantly higher in the PPV CON group (33.5 ± 9.5, p < 0.01) compared with both OLC groups (PPV OLC : 10.5 ± 2.6; HFOV OLC : 11 ± 2.2). There were no differences between the two OLC groups. We conclude that, in surfactant-depleted newborn piglets, application of the OLC during PPV is feasible and results in superior gas exchange and a reduction in VILI compared with conventional PPV. These beneficial effects are comparable to HFOV.