Background: Postoperative pneumonia (POP) is a life-threatening complication of lung resection. The incidence, causative bacteria, predisposing factors, and outcome are poorly understood.

Design: Prospective observational study.

Methods: A prospective study of all patients undergoing major lung resections for noninfectious disease was performed over a 6-mo period. Culture of intraoperative bronchial aspirates was systematically performed. All patients with suspicion of pneumonia underwent bronchoscopic sampling and culture before antibiotherapy.

Results: One hundred and sixty-eight patients were included in the study. Bronchial colonization was identified in 31 of 136 patients (22.8%) on analysis of intraoperative samples. The incidence of POP was 25% (42 of 168). Microbiologically documented and nondocumented pneumonias were recorded in 24 and 18 cases, respectively. Haemophilus species, Streptococcus species, and, to a much lesser extent, Pseudomonas and Serratia species were the most frequently identified pathogens. Among colonized and noncolonized patients, POP occurred in 15 of 31 and 20 of 105 cases, respectively (p = 0.0010; relative risk, 2.54). Death occurred in 8 of 42 patients who developed POP and in 3 of 126 of patients who did not (p = 0.0012). Patients with POP required noninvasive ventilation or reintubation more frequently than patients who did not develop POP (p < 0.0000001 and p = 0.00075, respectively). POP was associated with longer intensive care unit and hospital stay (p < 0.0000001 and p = 0.0000005, respectively). Multivariate analysis showed that chronic obstructive pulmonary disease, extent of resection, presence of intraoperative bronchial colonization, and male sex were independent risk factors for POP.

Conclusions: Pneumonia acquired in-hospital represents a relatively frequent complication of lung resections, associated with an important percentage of postoperative morbidity and mortality.