High-frequency oscillatory ventilation: Lessons learned from mechanical test lung models

Abstract

Mechanical test lung and artificial trachea simulations may provide useful information on the interaction of HFOV with altered lung mechanics and may contribute to the formulation of HFOV clinical strategies. Important limitations of these models include absence of gas exchange, histologic and biologic markers, or hemodynamic data.

Reflections on Pediatric High-Frequency Oscillatory Ventilation From a Physiologic Perspective

“…Yet, we (unpublished data) and others have observed in bench test studies that V T was smaller when combining high f (15 Hz) and high power (set to achieve a ⌬P of 90), compared with low f (5 Hz) and low power settings, as the distal pressure amplitude was much lower but still associated with a sufficient V CO 2 . 76 These findings were in agreement with the work from Hager and co-workers. They have measured V T in adult patients with ARDS managed on HFOV and found smaller V T with the combination high f and high power setting.…”

Oscillation transmission and volume delivery during face mask-delivered HFOV in infants: Bench and in vivo study

“…On the whole, multivariate analysis showed that OPRd is a main factor determining volume delivery and ventilation: these findings are consistent with the data already known for endotracheal oscillatory ventilation and with our previous study on nasal prongs delivered NHFOV. 3,28,29 These data need to be compared with those produced in different mechanical situations, especially in restrictive and mixed patterns that might require PICU care.…”

High-Frequency Oscillatory Ventilation in the Neonate

“…Several investigators have shown that alveolar ventilation is a function of the rate of oscillations and the squared tidal volume (V f CO Vt 2 2 = × ) ( Van de Kieft et al 2005;Courtney et al 2002). Tidal volume contributes more to CO 2 elimination than frequency, as tidal volume is squared in the formula.…”

“…After the endotracheal tube cuff has been deflated to produce a cuff leak, the proximal mean airway pressure will decrease. The expiratory valve or bias flow should be adjusted to maintain the same mean airway pressure in order for this manoeuvre to be effective (Van de Kieft et al 2005).…”