Changes in airway resistance and its correlation with disease severity in children with Mycoplasma pneumoniae pneumonia.

Background: Mycoplasma pneumoniae pneumonia (MPP) can cause lung function damage; however, few studies have examined the correlation between airway resistance and MPP severity. This study aimed to investigate changes in airway resistance related to severe MPP (SMPP) in children and evaluate its role in assessing disease severity.

Methods: A total of 96 children with MPP, admitted to Chengdu Women's and Children's Center Hospital from December 2022 to December 2023, were recruited for the study. The children were allocated to the mild MPP (MMPP) group (n=39) and the SMPP group (n=57) based on disease severity. Indices derived from impulse oscillometry (IOS) were compared, and receiver operating characteristic (ROC) curves were generated to assess the predictive value of various indicators for SMPP.

Results: The results revealed significant increases in respiratory resistance at 5 Hz (R5), respiratory resistance at 20 Hz (R20), reactance at 5 Hz (X5), and resonant frequency (Fres) in the SMPP group compared to the MMPP group (P<0.05). Compared to the children in the MMPP group, those in the SMPP group had a significantly longer hospital length of stay, and a higher proportion were admitted to the intensive care unit (ICU) and received mechanical ventilation (P<0.05). A positive correlation was found between MPP severity and R5, R20, X5, Fres, and hospital length of stay, of which R5 showed the strongest correlation. The ROC curve analysis indicated that R5 was the most effective predictor of SMPP, with an area under the curve (AUC) indicating good predictive ability [R5 > R20 > hospital length of stay > X5 (0.70)]. R5 had the highest predictive value for SMPP, with a sensitivity of 82.46%, a specificity of 87.18%, a cut-off value of 123.80%, a positive predictive value (PPV) of 90.38%, and a negative predictive value (NPV) of 77.27%.

Conclusions: The airway resistance of the children with SMPP was significantly higher than that of the children with MMPP. The primary increase was observed in small airway resistance, which might be accompanied by an increase in large airway resistance, along with a decrease in lung compliance. R5, R20, and X5 were found to be correlated with the severity of MPP, indicating that IOS is a valuable tool for assessing MPP severity.