Acute respiratory distress syndrome (ARDS) against the background of a lung infection is one of the chief reasons for a fatal outcome in children with oncohematological and immunological diseases. This is due to the fact that in 16-24% of these patients, it is not possible to treat critical hypoxemia successfully using the traditional methods of mechanical ventilation (MV) of the lungs. For patients with ARDS, the method of choice for treating critical hypoxemia is extracorporeal membrane oxygenation (ECMO), but pronounced cytopenia, immunosuppression and hemostatic system disorders constitute absolute contraindications for ECMO, owing to a high risk of numerous fatal complications. Therefore, there remains currently a rather relevant problem: Specifically, the search for alternative methods of mechanical ventilation, which would aim to improve oxygenation and gas exchange during severe forms of ARDS in children with oncohematological and immunological diseases. One of such methods is superimposed high-frequency jet ventilation (SHFJV).