The necessity for fiberbronchoscopy treatment in children with lobar MPP was designated as the dependent variable, and the maximum temperature, fever duration, presence of pleural effusion, presence of atelectasis, neutrophil count, lymphocyte count, NLR, the levels of serum CRP, LDH, ALT, D-dimer, and IgM, and sputum MUC5AC levels were considered as the independent variables. The gene discussed is MUC5AC; the disease is Pleural effusion.