Pneumonia is either the first or second most common ventilator-associated event (VAE) seen in the pediatric intensive care unit. The reported incidence varies widely among studies (from 0.3 to 45.1 per 1,000 ventilator days). The lack of a consistent, gold-standard definition for what had been traditionally referred to as ventilator-associated pneumonia (VAP) plays a large part in this variance.
The U.S. Centers for Disease Control and Prevention (CDC) defines VAP as a positive bacterial culture from a tracheal aspirate (more than 104 colony-forming units [cfu] from a sample obtained via bronchoalveolar lavage) and/or purulent secretions (more than 25 neutrophils and fewer than 10 epithelial cells per low-power field) in a patient who requires mechanical ventilation and has acutely worsening oxygenation. However, other investigators have defined VAP by the presence of pathogenic bacteria in tracheal aspirate in conjunction with new chest radiographic findings and fever or leukocytosis. Studies by Srinivasan and colleagues and Carcillo et al have found that the presence of pneumonia is associated with high antimicrobial use and increased morbidity, mortality, hospital length of stay, and costs. The Society of Critical Care Medicine, in partnership with the Critical Care Societies Collaborative, also has been working closely with the CDC to develop the VAE surveillance definition algorithm, representing a purposeful departure from VAP toward more purposeful, objective measures of conditions and complications occurring in adult patients on mechanical ventilation. The findings of the VAP Surveillance Definition Working Group, which has only focused on adult patients, were published in the November 2013 issue of Critical Care Medicine. It is clear, the development and use of a standardized definition is essential.