A comparison of continuous positive pressure ventilation, combined high frequency ventilation and airway pressure release ventilation on experimental lung injury.

In pigs with oleic induced lung injury, the effectiveness of combined high frequency ventilation (CHFV, with VDR-Phasitron) and airway pressure release ventilation (APRV) were compared to continuous positive pressure ventilation (CPPV) in a randomized study. The respiratory rate was 15/min, CPAP 8 mmHg and FiO2 0.25. PaCO2 was maintained at 5 kPa. PaO2 was significantly lower with APRV (12.5 +/- 3.9 kPa, CPPV: 15.8 +/- 3.9 kPa, and CHFV: 15.5 +/- 3.2 kPa). This was in accordance with the lowest peak airway pressure during APRV (20.9 +/- 4.8 mmHg, CPPV: 26.3 +/- 4.4 mmHg and CHFV: 28.2 +/- 3.7 mmHg). There was no difference in the pericardiac pressure between the 3 ventilation modes. The pressure related depressive effects on the cardiovascular function during CHFV and APRV were similar to those during CPPV. Adequate oxygenation and ventilation could be achieved with both CHFV and APRV, but these methods were not superior to CPPV.