High-frequency oscillatory ventilation and pediatric cardiac surgery: yes, we can

In the previous issue of Critical Care, Bojan and colleagues reported their experiences with high-frequency oscillatory ventilation (HFOV) after pediatric cardiac surgery. A total of 120 patients were treated with HFOV on the day of surgery, thus excluding rescue HFOV use. The main finding of the authors was that the duration of mechanical ventilation was significantly shorter in patients in whom HFOV was initiated on the day of surgery. Especially interesting about this work is that the authors used HFOV when there was evidence of pulmonary hypertension or right ventricular (RV) failure in their patients. This is an interesting approach as it is often assumed that high intra-thoracic pressures increase RV afterload and thus may enhance RV dysfunction. The findings of Bojan and colleagues may be explained by the fact that they were able to decrease the pulmonary vascular resistance by finding a proper balance between atelectasis and overdistension of the lung. It can be argued that it is possible to do so by applying positive end-expiratory pressure. But, at the same time, this may coincide with the delivery of high inspiratory pressures (>30 cm H2O). As HFOV is, in fact, a continuous positive airway pressure system, its advantage is that it is possible to maintain sufficient lung volume without large injurious pressure swings. Although the observations by Bojan and colleagues need to be confirmed in a prospective randomized trial, they have provided arguments not to rule out the early use of HFOV in pediatric cardiac surgery patients.