Ventilator-associated pneumonia

Ventilator-associated-pneumonia (VAP) is a major morbid outcome among critically ill patients. Risk of developing it increases over time, with a cumulative rate of approximately 15 cases per 1,000 ventilator-days. However, the conditional risk actually decreases over time, reflecting the high rate of early-onset VAP. The microbial etiology of VAP is profoundly influenced by prior antimicrobial therapy and by the duration of mechanical ventilation, which predispose to Gram-negative bacilli and late-onset VAP. Ventilator-associated pneumonia is associated with an approximately 4-day increase in length of intensive care unit stay and an attributable mortality of approximately 20-30%. Fixed VAP risk factors include underlying cardiorespiratory disease, neurologic injury, and trauma. Modifiable VAP risk factors include supine body position, witnessed aspiration, paralytic agents, and antibiotic exposure. Modifiable risk factors, such as semirecumbancy versus supine positioning, were found to lower VAP rates in randomized trials, and may represent effective VAP prevention strategies.