Background Mycoplasma pneumoniae infection accounts for a high proportion of community-acquired pneumonia and the incidence rate of severe M. pneumoniae pneumonia (MPP) has increased year by year. This study investigated the changes in lung diffusion function after M. pneumoniae infection, compared the lung diffusion and ventilation function of children with mild (MMPP) or severe M. pneumoniae pneumonia (SMPP) infections, and explored their clinical significance. Objective To study the changes in pulmonary ventila…