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

Abstract

INTRODUCTION: The development of pneumonia after cardiac surgery is a significant  postoperative complication that may lead to worse clinical outcomes. We aimed to identify risk  factors associated with it and determine its clinical impact in terms of in-hospital mortality and  morbidity.  METHODS: This was a cross-sectional study among all adult patients who underwent cardiac  surgery from 2014 to 2019 in a tertiary hospital in the Philippines. Baseline characteristics and  risk factors for pneumonia were retrieved from medical records. Nosocomial pneumonia was  based on the Centers for Disease Control and Prevention criteria. Odds ratios from logistic  regression were computed to determine risk factors and clinical outcomes for pneumonia using  STATA 15.0 (StataCorp, College Station, Texas).  RESULTS: Of 373 patients included, 104 (28%) acquired pneumonia. Most surgeries were ere  coronary artery bypass grafting (71.58%). Age, sex, body mass index, diabetes, left ventricular/ renal dysfunction, chronic obstructive pulmonary disease/asthma, surgical urgency, surgical time,  and smoking did not show association with pneumonia development. However, preoperative  stay of >2 days was associated with 92.3% increased odds of having pneumonia (P = 0.009).  Also, every additional hour on mechanical ventilation conferred 0.8% greater odds of acquiring  pneumonia (P = 0.003). Patients who developed pneumonia had 3.9-times odds of mortality  (95% confidence interval [CI], 1.51–9.89; P = 0.005), 3.8-times odds of prolonged hospitalization  (95% CI, 1.81–7.90; P < 0.001), 6.4-times odds of prolonged intensive care unit stay (95% CI,  3.59–11.35; P < 0.001), and 9.5-times odds of postoperative reintubation (95% CI, 3.01–29.76;  P < 0.001).  CONCLUSION: Among adult patients undergoing cardiac surgeries, prolonged preoperative  hospital stay and prolonged mechanical ventilation were associated with an increased risk  of nosocomial pneumonia. Those who developed pneumonia had worse outcomes with  significantly increased in-hospital mortality, prolonged hospitalization/intensive care unit stay, and  increased postoperative reintubation. Clinicians should therefore minimize delays in surgery and  encourage timely liberation from mechanical ventilation after surgery.