Controversies on diagnosis and prevention of ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) is the most frequent infection among intensive care patients. There is a great deal of controversy about the methods for diagnosis and prevention of this infection. VAP is usually diagnosed on a combination of clinical, microbiological, and radiographic criteria. Although these criteria have a high sensitivity, specificity is low, resulting in unnecessary antibiotic use in many patients. Bronchoscopic techniques, suh as protected specimen brush and bronchoalveolar lavage, in combination with quantitative culture techniques, do have a higher specificity. However, whether implementation of these techniques influences patient care, and to what costs, remains to be determined. Prevention of VAP relies on basic infection control practices. Many specific strategies interfering with colonization routes have been studied. So far, only the use of topical nonabsorbable antibiotics, either of the whole digestive tract or the oropharynx only, consistently reduced the incidence of VAP. However, the effects on patient survival were disappointing and the possibility of selection of antibiotic-resistant bacteria limit the widespread use of these strategies.