Surveillance of bacterial airway colonization during general anesthesia does not predict postoperative pneumonia in lung cancer patients after pulmonary resection: A retrospective analysis of risk factors

Abstract

Objectives: Postoperative pneumonia (POP) is a major cause of mortality in patients who undergo lung cancer surgery. We previously reported that bronchial colonization by potentially pathogenic microorganisms (PPMs) and chronic obstructive pulmonary disease (COPD) were both significant risk factors for POP; subsequently, the prophylactic use of antibiotics according to Centers for Disease Control and Prevention (CDC) guidelines and perioperative treatment for COPD were introduced in our institution. In this study, we investigated if airway colonization surveillance during general anesthesia could predict POP and determined risk factors for POP. Methods: Surveillance and a retrospective chart review were conducted involving 114 lung cancer patients who underwent pulmonary resection at Chiba University Hospital in 2011. For surveillance, postoperative bronchoscopy was performed to collect sputum under general anesthesia, followed by bacterial cultures for which>100-PPM colonies were recorded as positive. Results: Patients with PPM colonization did not show a significantly higher incidence of POP (2/11; 18.2%) than those without PPMs (8/103; 7.8%; p=0.55). Using multivariate analyses for POP risk factors, two significant factors were identified: smoking pack-years (odds ratio=1.04, 95% confidence interval: 1.01-1.07; p=0.009) and restrictive lung disease (odds ratio=11.0, 95% confidence interval: 1.18-102; p=0.035). Conclusions: Due to improved perioperative treatments, bronchial colonization by PPMs and COPD were no longer POP risk factors for lung cancer patients. However, for these patients, a heavy smoking history and restrictive lung disease were newly recognized POP risk factors.