High-frequency alternating lung ventilation

A new mode, high-frequency alternating lung ventilation (HFALV) is described and demonstrated in which the lungs are alternately pulsed. A fluidic oscillator may be used to deliver two pulsed gas streams, 180 degrees out of phase, to bronchial catheters placed via a double lumen endobronchial tube. Inspiratory phase of one lung thus coincides with expiratory phase in the other, and characteristic lateral rocking chest movement is observed. In six dogs, HFALV was compared to simultaneous pulsing of both lungs with comparable flow (18.5 l/min), frequency (144 min^-1), and pulse wave shape. Arterial P(CO₂) was significantly lower (P<0.001) with HFALV. Arterial P(CO₂) was also 'found to increase linearly (r=-0.862, P<0.001) with distance of the catheters' distal tips from the dogs' carinae. Theoretical mechanisms and possible applications of HFALV are discussed.