Ventilator-associated pneumonia: an evaluation of definitions from their components

Abstract

Ventilator-associated pneumonia (VAP) is a known complication of mechanical ventilation within the intensive care unit (ICU) that frequently negatively impacts ICU length of stay, morbidity, and mortality of the critically ill. Characterising VAP within ICUs is difficult due to varying definitions, definition component sensitivity, and the subtle pathophysiology of VAP. The extent of VAP morbidity and mortality is not fully known and is a strain in the critically ill population with low physiological reserve. Many detection-prevalence studies exist in parallel with numerous meta-analyses evaluating select components of definitions. Definitions for VAP (and criteria for) exist around the globe in various forms and are often composed of differing components or criteria. Most definitions combine changing oxygenation or ventilatory status, laboratory tests suggestive of infection, duration of ventilation, and microbiology to determine a ventilator-associated event. This narrative review seeks to compare the most common definitions of VAP published in the literature, evaluate VAP definition components, and determine VAP definition usefulness in clinical practice to diagnose VAP accurately.