Optimal duration of antimicrobial therapy in ventilator-associated pneumonia: What is the role for procalcitonin?

Hospital-acquired pneumonia (HAP) is the major cause of hospital-acquired infections in critically ill patients. Up to 90% of intensive care unit episodes of HAP occur in mechanically ventilated patients, who may develop what is termed ventilator-associated pneumonia (VAP). An appropriate duration of antimicrobial therapy is crucial in the management of HAP: on the one hand, delay in administration of proper therapy has been associated with an increased risk of treatment failure and mortality; on the other hand, unnecessary prolongation of antimicrobial treatment may favour the emergence of multidrug-resistant bacteria and increase healthcare costs. In this review, we discuss the evidence and recommendations from international guidelines for the management of VAP and focus on randomised controlled trials comparing the clinical efficacy of a short-course vs. an extended-course antimicrobial regimen for the treatment of VAP in adults. In these trials, short-course regimens were as effective and safe as long-course regimens for the treatment of VAP, provided that infection was not due to difficult-to-treat micro-organisms such as non-fermenting Gram-negative bacilli. In addition, strategies incorporating individualised stop-points for antibiotics, i.e. clinical features or biomarkers such as procalcitonin, were shown to reduce antibiotic exposure, healthcare costs and the risk of developing antimicrobial resistance, without negatively affecting other outcomes.