The ventilator-associated pneumonia (VAP) prevention bundle is a set of evidence-based interventions implemented together to reduce VAP incidence in mechanically ventilated patients. VAP develops in 9-27% of intubated patients, with mortality rates of 25-50%. Pathogenesis: oropharyngeal colonization with pathogenic bacteria → aspiration of contaminated secretions past the endotracheal tube cuff → lower respiratory tract infection. The ET cuff creates a reservoir of subglottic secretions above the cuff that leak around it despite inflation. Bundle components target different pathogenic steps: HOB elevation reduces gastric aspiration; oral care reduces oropharyngeal pathogen burden; subglottic secretion drainage removes pooled secretions above the cuff; DVT prophylaxis and stress ulcer prophylaxis prevent complications of immobility; daily sedation interruption (SAT) and spontaneous breathing trials (SBT) facilitate earlier extubation — every additional ventilator day increases VAP risk by 1-3%.