Incidence and risk factors for ventilator-associated pneumonia after major heart surgery

Purpose: Major heart surgery (MHS) patients are a particularly high-risk population for nosocomial infections. Our objective was to identify risk factors for ventilator-associated pneumonia (VAP) in patients undergoing MHS. Methods: Prospective study including 1,844 patients operated from 2003 to 2006. Results: Overall 106 patients (140 episodes) developed one or more episodes of VAP (5.7%, 22.2 episodes per 1,000 days of mechanical ventilation). VAP incidence was 45.9% in those patients requiring more than 48 h of MV. Enterobacteriaceae (32.8), Pseudomonas aeruginosa (28.6%) and Staphylococcus aureus (27.1%, of which 65.8% were methicillin resistant) were the principal microorganisms causing VAP. The independent risk factors for VAP were: age >70, perioperative transfusions, days of mechanical ventilation, reintubation, previous cardiac surgery, emergent surgery and intraoperative inotropic support. Median length of stay in the ICU for patients who developed VAP or not was, respectively, 25.5 versus 3 days (P < 0.001), and mortality was, respectively, 45.7 versus 2.8% in both populations (P < 0.001). We developed a predictive preoperative score with a sensitivity of 93% and a specificity of 40%. Conclusions: VAP is common in patients undergoing MHS that require more than 48 h of MV. In that "high-risk" population, innovative preventive measures should be developed and applied.