Risk Factors for the Development of Nosocomial Pneumonia and Its Clinical Impact in Cardiac Surgery

Abstract

Abstract BackgroundThe development of nosocomial pneumonia after cardiac surgery is a significant post-operative complication that may lead to increased morbidity, mortality, and hospital cost. We aimed to identify risk factors associated with it and to determine its clinical impact in terms of in-hospital mortality and morbidity.MethodsThis is a retrospective cohort study conducted among all adult patients who underwent cardiac surgery from 2014-2019 in St. Luke’s Medical Center, Quezon City, Philippines. Baseline characteristics and possible risk factors for pneumonia were retrieved from medical records. Nosocomial pneumonia was based on the Centers for Disease Control and Prevention criteria. Clinical outcomes include in-hospital mortality and morbidity. Odds ratios from logistic regression was computed to determine risk factors associated with pneumonia using STATA 15.0.ResultsOut of 373 patients included in this study, 104 (28%) patients acquired pneumonia. Most surgeries were coronary artery bypass graft (CABG) (71.58%), followed by valve repair/replacement (29.76%). Neither age, sex, BMI, diabetes, LV dysfunction, renal dysfunction, COPD/asthma, urgency of surgery, surgical time, nor smoking showed association in the development of pneumonia. However, preoperative stay of >2 days was associated with 92.3% (95%CI 18–213%) increased odds of having pneumonia (p=.009). Also, every additional hour on mechanical ventilation conferred 0.8% (95%CI, 0.3–1%) greater odds of acquiring pneumonia (p=.003).Patients who developed pneumonia had 3.9 times odds of mortality (95%CI 1.51–9.89, p=.005), 3.8 times odds of prolonged hospitalization (95%CI 1.81–7.90,p<.001), 6.4 times odds of prolonged ICU stay (95%CI 3.59–11.35,p<.001), and 9.5 times odds of postoperative reintubation (95%CI 3.01–29.76,p<.001). ConclusionAmong adult patients undergoing cardiac surgeries, prolonged preoperative hospital stay and prolonged mechanical ventilation were both associated with an increased risk for nosocomial pneumonia. Those who developed pneumonia had worse outcomes with significantly increased in-hospital mortality, prolonged hospitalization, prolonged ICU stay, and increased postoperative re-intubation. Clinicians should therefore minimize delays in surgery to avoid unnecessary exposure to pathogenic organisms. Also, timely liberation from mechanical ventilation after surgery should be encouraged.