Multiplex Polymerase Chain Reaction in Postoperative Pneumonia After Thoracic Surgery

Background: In thoracic surgery, postoperative pneumonia (POP) is the leading cause of postoperative morbidity and mortality. The clinical diagnosis of POP is difficult and conventional microbiological diagnostic tests perform poorly. The contribution of molecular diagnostic tests (multiplex PCR, mPCR) should be evaluated to optimize the diagnostic and therapeutic management of POP. Objectives: The main objective is to describe the microbiological relationship between the existence of pre- (if available) and intra-operative bronchial and pulmonary bacterial colonization and the occurrence of POP. The secondary objectives are to analyze the contribution of the mPCR for the diagnosis of POP and to validate the predictive factors of POP described in the literature Material and methods: A monocentric prospective non-interventional research with minimal risks and constraints. The study population is represented by all the consecutive adult patients hospitalized for lung surgical resection (except surgical resection indicated for infectious disease) during one year. The preoperative respiratory samples within the 3 preceding months (date and type, pathogen and threshold) are recorded, if available. Intra-operative bronchial aspirate is performed for direct examination and culture (pathogen and threshold) and mPCR (PCR1). A mPCR is optionally performed on the surgical specimen (PCR2). In case of postoperative clinical suspicion of POP, invasive or non invasive samples of respiratory tract secretions are obtained for direct examination and culture (pathogen, threshold) and mPCR (PCR3). A clinical pulmonary infection score (CPIS) is calculated by integrating the results of conventional tests (CPIS1) and mPCR (CPIS2). The pre / intra operative and postoperative microbiological relationship will be described qualitatively and quantitatively and analyzed using correlation tests. Concordances and discrepancies between conventional tests and mPCR will be studied to analyze the