Improved oxygenation with superimposed high frequency jet ventilation at resonant frequency.

Superimposed high-frequency jet-ventilation (SHFJV) is a new form of a combined high frequency (HF) jet ventilation technique in treatment of ARDS. Since the HF jet-stream improves oxygenation partially due to enhancement of the intra-pulmonary gas mixture [1] the question arises which frequency would be the most effective. Animal models and in vitro experiments demonstrate that the best results may be achieved with frequencies close to the resonant frequency (RF) of the lungs [1,2]. In this study we tried to find RF using SHFJV.