High Frequency Oscillatory Ventilation Combined With Intermittent Sigh Breaths: Effects on Lung Volume Monitored by Electric Tomography Impedance.

"It is planned only to investigate infants already ventilated on the HFOV-modus on high frequency oscillators, where the HFOV modus can be superimposed on conventional modes of ventilation. This gives the opportunity to combine HFOV with intermittent sigh breaths with a pre-set frequency and pre-set peak inspiratory pressure (PIP) and thus comparing HFOV combined with sigh breaths (HFOV-sigh) with conventional HFOV (HFOV-only).~All included participants will be exposed to the two different ventilator strategies tested in this trial, albeit in alternating and different order.~Each patient will serve, as it's own control. The trial will involve four alternating 1-hours periods allowing a sufficient wash-out period, as it has been shown that alveolar recruitment and derecruitment may take up to 25 min after changes to ventilator pressures At study start the patients will randomly be assigned to either starting with HFOV-only or HFOV-sigh"