Respiratory physiotherapy has been questioned in patients with pneumonia and recent clinical studies have shown that there is no benefit to these patients. Respiratory physical therapy in addition to manual techniques has in his repertoire instrumental resources such as therapeutic high-frequency oral oscillator (HFOO) and the mask of expiratory positive pressure (PEP). The hypothesis of this study is that physical and physiological effects of these resources may have positive effects in this population of children with acute respiratory illness. The aim of this study is to evaluate the short-term effects HFOO and mask of PEP in children hospitalized for community-acquired pneumonia.