Effect of metagenomic next-generation sequencing on clinical outcomes in adults with severe pneumonia post-cardiac surgery: a single-center retrospective study

Reports on the application of metagenomic next-generation sequencing (mNGS) in adult patients with severe pneumonia after cardiac surgery remain limited. This study aimed to evaluate the clinical outcomes of mNGS analysis of bronchoalveolar lavage fluid (BALF) in such patients.A retrospective cohort study was conducted on adult patients with severe pneumonia after cardiac surgery. Samples were collected from patients in the surgical intensive care unit (SICU) of Sichuan Provincial People’s Hospital between January 2019 and March 2024. Upon diagnosis of severe pneumonia, bronchoalveolar lavage fluid was obtained via bronchoscopy within 24 h. The mNGS group was composed of patients tested using mNGS and conventional microbiological tests. BALF was detected only by the conventional microbiological test (CMT) method in the CMT group, which involved examining bacterial and fungal smears and cultures at least. We reviewed a total of 4,064 cardiac surgeries, and based on the inclusion criteria, a total of 113 adult patients with severe pneumonia after cardiac surgery were included in this study. The overall positive rate detected by mNGS was significantly higher than that of the culture method (98% vs. 58%, P