The main doubts regarding the use of HFOV concern the possible hemodynamic impact that this mode ventilation may have on children with congenital heart disease. Although, there is no evidence in the literature to imagine that this ventilation mode can be used in the same conditions that can occur in patients not affected by congenital pathologies [
26,
35,
36]. Numerous clinical studies have demonstrated that the perception of the hemodynamic impact of HFOV is often overrated, both in normal and congenital heart disease populations. The actual impact on hemodynamics is frequently less significant than initially perceived. [
37,
38,
39,
40,
41,
42]. Two clinical studies conducted on a pediatric population showed how cardiac output was reduced when switching from conventional ventilation to HFOV in patients with ARDS, but they were very small single-center studies, composed of small preterm populations and in one of them the blood pressure was measured noninvasively [
43,
44]. Fort et al., in a study on an adult population, found an increase in pulmonary wedge pressure without significant alterations on other hemodynamic parameters such as cardiac output [
45]. Clinical studies in adult populations have demonstrated that when switching from conventional ventilation to oscillatory ventilation in patients with ARDS, there is a significant increase in pulmonary wedge pressure and central venous pressure, without changes in heart rate, blood pressure and cardiac output [
26,
35]. Similar results have been found in studies on pediatric populations [
41,
42]. It was seen by Gutiérrez et al. in a single patient that a possible reduction in cardiac output and cardiac index may occur in the recruitment phase indicating possible alveolar overdistention, instead Goodman et al. observed an improvement in hemodynamic parameters such as cardiac index, cardiac output and oxygen transport accompanied only by a slight reduction in heart rate. This possible effect was explained by two contemporary mechanisms: the reduction of paCO2 and the reduction of transthoracic impedance. Correction of hypercapnia-induced acidosis and reduction of cardiac afterload improved patients' cardiovascular performance on both fronts [
41,
42]. While clinical studies on the hemodynamic effects of oscillatory ventilation in the pediatric population are rare, those on the pediatric population affected by congenital or acquired heart disease are even rarer. De Jager et al. recently conducted a retrospective analysis on 52 patients suffering from congenital and/or acquired heart disease with respiratory failure: no significant changes in hemodynamic parameters such as heart rate, blood pressure, central venous pressure and lactate level were measured. No significant changes were detected in the number of fluid boluses made when switching from one ventilatory mode to another, nor significant alterations in the administration of vasoactive drugs. Furthermore, an improvement in respiratory parameters such as paCO2 and paO2 was detected, associated with a simultaneous significant reduction in the dosage of muscle relaxants without any significant change in the dosage of sedatives. This monocentric and retrospective study is the only one in the literature that aims to analyze the hemodynamic effects of HFOV in this peculiar population of pediatric patients. It should also be underlined that the inclusion criteria were established not by considering clinical parameters, but by considering ventilatory parameters. The transition from the conventional to the oscillatory ventilation mode was carried out by adopting a protocol that was determined by the achievement of harmful ventilatory parameters, this was a cut off to use the HFOV regardless of the clinical condition and the underlying cardiac pathology. In this way it was possible to observe the effects of this ventilation mode on patients suffering from cardiac pathologies, including acquired or congenital ones [
12]. HFOV has been used profitably in the treatment of post-cardiopulmonary bypass ARDS for more than a decade now [
11,
13,
37,
40,
46,
47,
48]. Oscillatory ventilation has been shown to improve oxygen index, PaO2/FiO2 ratio, blood alveolar-arterial oxygen concentration gap, dynamic lung compliance, PaO2, PaCO2, pH, resulting in a positive impact on patient survival [
13,
40,
48,
49]. HFOV proved to be beneficial in controlling the production of inflammatory mediators during ARDS. Zheng et al. demonstrated that the use of oscillatory ventilation with protective parameters mixed with the “volume guaranteed” mode led to a significant improvement in the panel of proinflammatory mediators such as IL-6, IL-8 and TNF-α that are produced during the inflammatory response in ARDS. The reduction of these activators improved the blood gas analysis parameters significantly with a decrease in days of post-operative mechanical ventilation [
50]. Oscillatory ventilation also represents a valuable aid in the treatment of pulmonary hypertension in cardiac newborns. The use of HFOV and inhaled nitric oxide therapy is now a consolidated therapeutic option for neonatal pulmonary hypertension. Its use is also finding its place in the pediatric population affected by congenital heart disease [
39,
50,
51]. Huang et al. have demonstrated that, as in patients suffering from cardiac congenital disease, oscillatory ventilation associated with nitric oxide is a concrete and safe therapeutic option in the treatment of post-cardiac surgery pulmonary hypertension improving blood gas analysis parameters while determining a significant reduction in the days of post-operative mechanical ventilation [
39].