Aspiration Pneumonia in Cardiac Surgery: APredictive Model

Background: Aspiration pneumonia is a rare but serious complication that carries significant morbidity following surgery. This study was undertaken to identify pre-operative and operative risk factors and develop a predictive model for aspiration pneumonia in cardiac surgery patients. Methods: This study was a retrospective analysis of our institution’s Society of Thoracic Surgeons’ (STS) cardiac surgery database. Analysis was limited to adult patients (Age ≥ 18) who underwent cardiac surgery from January 2008 through July 2014. The cohort was divided into a derivation cohort (Jan 2008-Dec 2011) and a validation cohort (Jan 2012-July 2014). Logistic regression was used to identify significant predictors of aspiration pneumonia, and receiver operator characteristic (ROC) analysis was used to assess model performance. Results: Of the 4,741 patients who underwent cardiac surgery during the study period, 70 cases of aspiration pneumonia were identified (1.5%). Multivariable analysis revealed preoperative dialysis, chronic lung disease, percutaneous coronary intervention, congestive heart failure, and urgent/emergent status as significant predictors of post-operative aspiration. The subsequently derived model had 73% sensitivity and 64% specificity across both cohorts when two or more factors were used as a cutoff. Aspiration pneumonia was associated with greater mechanical ventilation time, intensive care unit stay, and hospital length of stay (all p < 0.001). Conclusions: Aspiration pneumonia is associated with significant morbidity after surgery. The developed model may help identify cardiac surgery patients at high-risk for post-operative aspiration pneumonia. Subsequent strategies for prevention of aspiration may thus be tailored accordingly.