Clinical usefulness of sputum culture on the first postoperative day to predict early postoperative pneumonia after esophagectomy for esophageal cancer

Background: Postoperative pneumonia is a serious prognostic problem that can appear after esophagectomy in patients with esophageal cancer. The past reports have considered the usefulness of perioperative culture examinations for predicting postoperative pneumonia; however, the direct relationship between these examinations and postoperative complications remains unclear. Methods: This study retrospectively analyzed esophageal cancer patients who underwent esophagectomy followed by sputum culture on the first postoperative day. The bacterial species that frequently cause hospital-acquired pneumonia were chosen as the target species in this study. The relationship between culture examination and postoperative pneumonia within one week (7 days) after esophagectomy was investigated. Results: Sputum cultures on the first postoperative day were investigated in 238 patients who underwent esophagectomy for esophageal cancer. Forty-one patients developed pneumonia within one week after surgery. The target bacterial species were detected in 26 of 238 sputum cultures (10.9%). In the univariate analysis, a Brinkman index, detection of target bacterial species, detection of Gram-positive cocci, and Gram-negative rods were significantly associated with postoperative pneumonia. In the three independent multivariate analyses, the target bacterial species, Gram-positive cocci, and Gram-negative rods (p = 0.001, 0.042, and < 0.001) were individually identified as independent risk factors of postoperative pneumonia in addition to a Brinkman index. Conclusions: Detection of target bacterial species by sputum culture on the first postoperative day after esophagectomy was an independent risk factor of postoperative pneumonia within 7 days after surgery. Prospective studies for the prevention of early postoperative pneumonia using sputum culture on the first postoperative day can be considered.