Study objectives: To evaluate the risk factors associated with postoperative respiratory infection in patients undergoing lung cancer surgery, with special emphasis on the perioperative pattern of airway colonization.
Design: Prospective cohort study.
Setting: Department of Pneumology and Thoracic Surgery of a tertiary hospital.
Patients: Seventy-eight consecutive patients undergoing lung cancer surgery were evaluated. Patients were followed up until hospital discharge or death.
Interventions: Fiberoptic bronchoscopies with bilateral protected specimen brush or bronchial aspirates were performed during anesthesia prior to the initiation of the surgical procedure.
Results: Sixty-five patients (83%) had perioperative bronchial colonization by either potentially pathogenic microorganisms (PPMs) [28 patients, 36%] or non-potentially pathogenic microorganisms (56 patients, 72%). The 24 patients (31%) with a postoperative respiratory infection (pneumonia, purulent tracheobronchitis, or pleural empyema) had significantly higher perioperative bronchial colonization by PPMs (15 patients [63%] vs 13 patients [24%], p = 0.003) and a higher bacterial index (mean +/- SD, 3.6 +/- 3.3 vs 0.9 +/- 1.4; p = 0.003), compared to patients without infection. The agreement between pathogens found in perioperative evaluation and during postoperative infection was total in 5 patients (21%), partial in 5 patients (21%), and no concordance in 14 patients (58%). In the multivariate analysis, the presence of perioperative airway colonization by a PPM (odds ratio [OR], 6.9; p = 0.001) and a higher postoperative pain score (OR, 4.1; p = 0.014) were independent predictors of postoperative respiratory infection.
Conclusion: Adequate control of postoperative pain, as well as the conditions that potentially cause airway colonization by PPMs, could be beneficial in preventing postoperative respiratory infections after lung cancer surgery.