Initial empirical antibacterial therapy of ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) is the most frequently occurring nosocomial infection, accounting for considerable morbidity and mortality. Diagnosis can be difficult, creating important therapeutic challenges for intensivists. Early therapy is important in maximizing outcomes, but inappropriate antibacterial treatment has its own risks. A balance needs to be struck between the necessary therapeutic benefits and the negative effects (selection of resistant pathogens, costs, and adverse effects) of antibacterials. Several studies have indicated, in various groups of critically ill patients including those with VAP, that starting treatment with an ineffective antibacterial can increase hospital and intensive care unit length of stay and mortality. When the responsible microorganisms cannot be defined, it may be better to start treatment with a broad-spectrum antibacterial regimen, taking into account individual patient factors and local bacteriology patterns, including antibacterial resistance. As soon as the nature of the pathogen has been defined, the antibacterial agent(s) should be modified accordingly, with the primary aim to reduce the antibacterial spectrum. The optimal duration of therapy is controversial and probably best tailored to the individual patient depending on clinical response and resolution of the factors used to diagnose VAP in that patient. Consultation with an infectious disease specialist may facilitate these therapeutic decisions. With the high morbidity and mortality associated with VAP, prevention is an important issue. General measures include adequate hand hygiene. Physicians must be aware of the risk factors for VAP and of accepted and effective strategies of prevention.