Resonance in the mechanical response of the respiratory system to high frequency jet ventilation

Eight normal domestic pigs (Large White breed) of body weights 17 kg to 62 kg were subjected to high frequency jet ventilation (HFJV) at frequencies of 1 to 10 Hz (60-600 breaths/min). Six animals survived the study. The gain response curves and phase shift response curves obtained for these animals indicate that respiratory system resonance can be excited at HFJV frequencies. Post-mortem examinations of the nonsurvivors' lungs suggested pulmonary barotrauma. These findings and their clinical implications are discussed.