Prognosis of ventilator-associated pneumonia: what lies beneath

Abstract

Ventilator-associated pneumonia (VAP) continues to be a major problem in the care of intensive care unit (ICU) patients. The incidence of VAP in mechanically ventilated patients is high, ranging from 10 to 30%. The clinical symptoms of VAP are ambiguous and there is no generally accepted gold standard for the diagnosis of VAP. The associated mortality is still high at 30–40% 1, 2. Established clinical scores and biomarkers are only of limited value in terms of diagnosis and prognosis. Since VAP is an infectious disease we traditionally use biomarkers of infection for diagnostic and prognostic purposes. Inflammatory markers such as leukocyte count and C-reactive protein (CRP) are still widely used in the diagnosis of VAP, although it is well known that sensitivity in the ICU setting is highly limited. Until recently, only procalcitonin as a more accurate marker of bacterial infection turned out to be of clinical value. Procalcitonin is useful for the guidance of antibiotic therapy in community-acquired pneumonia (CAP), which has been shown by several studies of the Basel group in recent years 3, 4. Nobre et al. 5 were the first to demonstrate a median reduction of antibiotic treatment of 4 days (six versus 10) following a procalcitonin-guided strategy as opposed to a clinical strategy in patients with VAP. The ProVAP trial demonstrated that procalcitonin guidance can reduce the duration of antibiotic therapy in patients with VAP. In the ProVAP trial Stolz et al. 6 performed a multicentre, randomised, controlled trial with 101 patients with VAP. Patients were either assigned to an antibiotic discontinuation strategy according to American Thoracic Society/Infectious Diseases Society of America guidelines (control group) or to a strategy using serial serum procalcitonin measurements (procalcitonin group). The number of antibiotic-free days patients were alive 28 days after VAP onset was significantly …