Purpose: Pneumonia is the most prevalent healthcare-associated infection following isolated coronary artery bypass surgery (CABG) and is associated with increased length of stay and mortality. Bundled infection prevention practices have been proposed as a tool for quality improvement, however the extent to which their adoption is associated with reducing risk of pneumonia is unknown.
Method: We undertook a cohort study of 2,482 patients undergoing CABG from 2016 to 2017 across 18 centers participating in a statewide collaborative. Three pneumonia prevention practices were identified via structured literature review and benchmarking site visits: 1) preoperative nasal and oral antibiotic prophylaxis, 2) lung protective ventilation, and 3) goal-directed postoperative ambulation. These practices were implemented as a bundle, with a composite (bundle) score calculated as the total number of practices received by each patient. We estimated the association between composite score and development of pneumonia using logistic regression, adjusting for baseline risk (using a published risk model). Sensitivity analyses were conducted by age, sex, chronic lung disease, and operative status.
Results: Pneumonia occurred in 2.4% (n/N = 60/2482) of patients. Bundle scores ranged from 0 to 3, with 75% of patients receiving a score of 1 or 2, and 22% having a score of 3. Crude and adjusted rates of pneumonia were lower in patients with higher scores (p-trend < 0.01; Figure); this finding was consistent across clinically important subgroups. Lung protective ventilation (ORadj: 0.42) and goal-directed postoperative ambulation (ORadj: 0.11) were significantly associated with lower odds of pneumonia (both p < 0.01); preoperative nasal and oral antibiotic prophylaxis was non-significantly protective of pneumonia (ORadj: 0.63, p = 0.11). Each 1-unit increase in bundle score was associated with a 57% decrease in operative mortality, and a more than 1 day reduction in (i.e., -27 hours) ICU length of stay (both p < 0.01).
Conclusion: In this statewide study, we identified components of a bundle associated with reduced odds of pneumonia. Broader adoption of this bundle may serve as an effective strategy for improving value for cardiac surgical patients.