Blood eosinophil count and risk of postoperative pneumonia following coronary artery bypass graft surgery

AIM:To investigate the relationship between blood eosinophil count and risk of postoperative pneumonia in patients with coronary artery bypass graft (CABG) surgery. METHODS: The medical records of 613 patients who underwent CABG surgery from January 2008 to December 2017 in our hospital were collected and reviewed. The incidence of postoperative pneumonia and hospital mortality were compared in the patients with low or high blood eosinophil count. The risk factors for postoperative pneumonia following CABG surgery were analyzed by multiple logistic regression. RESULTS: The patients enrolled in the study were 582, in which 220 patients had preoperative blood eosinophil counts of less than 2% (low blood eosinophil count) and 362 patients had eosinophil counts of 2% or more (high blood eosinophil count). The incidence of postoperative pneumonia in the patients with low blood eosinophil count was 14.1% (31/220), significantly higher than that (6.4%, 23/362) in the patients with high blood eosinophil count (P=0.002). However, the hospital mortality of the patients with high or low blood eosinophil count had no difference. Low blood eosinophil count (OR=3.521, 95% CI:1.213~10.223, P=0.021), nasogastric tube (OR=6.490, 95% CI:2.757~15.280, P<0.001) and mechanical ventilation ≥ 24 h (OR=3.496, 95% CI:1.156~10.178, P=0.035) were identified as independent risk factors for postoperative pneumonia following CABG surgery. CONCLUSION: Low blood eosinophil count is associated with increased risk of postoperative pneumonia following CABG surgery.