Characterization of Thoracic Pathophysiologic Conditions in Patients Receiving High-Frequency Oscillatory Ventilation: Pediatric Experience.

High-frequency oscillatory ventilation (HFOV) is a mode of mechanical ventilation used in severe pediatric respiratory failure. Thoracic ultrasound (US) is a powerful tool for diagnosing acute pathophysiologic conditions during spontaneous respiration and conventional noninvasive and invasive mechanical ventilation. High-frequency oscillatory ventilation differs from conventional modes of ventilation in that it does not primarily use bulk flow delivery for gas exchange but, rather, a number of alternative mechanisms as the result of pressure variations oscillating around a constant distending pressure. Thoracic US has not been well described in patients receiving HFOV, and it is unclear whether the US findings for assessing thoracic pathophysiologic conditions during conventional ventilation are applicable to patients receiving HFOV. We discuss the similarities and differences of thoracic US findings in patients who are spontaneously breathing or receiving conventional ventilation compared to those in patients receiving HFOV.