High Frequency Oscillatory Ventilation in the Neonate: An Experimental study

Convective flow mechanisms during High Frequency Oscillatory Ventilation (HFOV) are investigated experimentally by measuring the time-resolved, three-dimensional (3D) flow fields in a physiologically-relevant, asymmetric, true-scale, multi-generational upper airway model of a premature newborn infant. HFOV is an atypical form of mechanical ventilation credited with reducing ventilator induced lung injury (VILI) in premature infants. The strategy involves ventilating much smaller volumes of air at high frequencies (10-15 Hz), and while common in clinical practice, the optimal settings or a methodology for adapting to specific patients remains ill-defined. The present study employs Tomographic Particle Image Velocimetry to explore for the first time the characteristic convective features of gas dispersion as a function of Reynolds and Womersely numbers, via tidal volume and oscillation frequency.