Perioperative Microbiologic Monitoring of Sputum on Postoperative Day One as a Predictor of Pneumonia After Hepatectomy

BACKGROUND: The purpose of this study was to retrospectively evaluate microbial examination of sputum on postoperative day one (POD1) and to determine risk factors for postoperative pneumonia (POP) after hepatectomy. METHODS: Two hundred ninety-four patients who expectorated sputum on POD1 after hepatectomy between 2003 and 2014 were investigated. Sputum samples were submitted for microbial examination. Risk factors for POP were identified using multivariable analysis. RESULTS: One hundred fifty-eight (53.7 %) of 294 patients had bacteria in their sputum on POD1. POP was observed in 24 (8.2 %) patients, with increased mortality in the patients with POP (0.74 vs 12.5 %, p < 0.01). Multivariate analysis demonstrated that a Brinkman index of >400 and bacteria in sputum on POD1 were independent risk factors for POP. Bacterial homology in sputum obtained on POD1 and onset day of POP was found in 13 of the 24 (54.2 %) patients with POP. In particular, in 13 patients with POP caused by methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa, homology was confirmed in 9 patients (69.2 %). CONCLUSION: A Brinkman index ≥400 and bacteria in sputum on POD1 increased the risk of POP. Presence of bacteria in sputum on POD1 may be useful in determining early treatment against POP after hepatectomy.