Advances in infection control: ventilator-associated pneumonia

Mechanically ventilated patients are 6-21 times more likely to develop nosocomial pneumonia. It is estimated that between 6% and 52% of ventilated patients develop ventilator-associated pneumonia (VAP) with attributable mortality of 27-51%. Certain high risk organisms carry higher mortality (e.g., Pseudomonas aeruginosa and Acinetobacter spp.). Aspiration of colonized orodigestive secretions is the commonly recognized route of infection, whereas inhalation of contaminated aerosol hematogenous spread and direct infection are less common. Gram-negative pathogens are responsible for 40-60% of VAP, whereas gram-positive pathogens cause 15-20%, and it is commonly polymicrobial. Diagnosis remains difficult, and studies showed that early appropriate treatment can improve patient outcome. Better understanding of the pathogenesis and risk factors is important for implementing more effective infection control measures. Clinical trials evaluating outcome will help in assessing current and future preventive and therapeutic measures.