- Paper Report
- Open Access
Choosing optimal PAW during high-frequency oscillation
- Adrian Mellor1
© Biomed Central Ltd 2001
- Received: 2 July 2001
- Published: 4 December 2001
- Adult respiratory distress syndrome
- high-frequency ventilation
High-frequency oscillation (HFO) is increasingly used as rescue therapy in adults with severe ARDS. Ventilating with the lower pressure above the lower corner pressure (PCL), and upper pressure below the upper corner pressure of the pressure-volume (P-V) curve, should result in more recruitment and less ventilator induced injury. Currently, the ventilator settings are based on the settings of the conventional ventilator prior to HFO and on trial and error. In this paper the authors questioned whether the mean airway pressure (PAW) resulting in optimal oxygenation could be predicted from the inflation limb of the P-V curve of the injured lung.
A PAWequal to PCL + 6 cm H2O optimised oxygentaion without adversely affecting haemodynamics. Lower pressures had a suboptimal effect on oxygenation, whilst higher pressures yielded no additional advantage to oxygenation, but adversely affected haemodynamics.
Sheep model using saline lavage to produce severe lung injury; inspiratory and expiratory P-V curves constructed using a 2-l syringe; invasive monitoring of haemodynamic variables; animals subjected to four cycles of HFO at different PAW.