Diagnostics of VAP relies on two complementary strategies: meeting pre-defined clinical criteria and evidence of pathogens in the lower respiratory tract. Mere reliance on clinical symptoms, such as radiologic evidence, systemic signs of inflammation and indices of compromised pulmonary function reportedly lead to misdiagnosis. Current diagnostic procedures recommend gathering of evidence for new or progressive lung infiltrates from serial chest radiographies, together with co-existing clinical signs of impaired respiratory function. Microbiological confirmation of pathogen presence requires examination of airway secretions collected by invasive bronchoalveolar lavage which demands specific technical skills and staff training. Although verification of causal pathogens is essential for the introduction of targeted antibiotic therapy, the procedure is time-consuming and qualitative in reportedly less than 30 % of the cases. Furthermore, the currently adopted diagnostic approaches are based on sporadic information sampling and do not support continuous monitoring and evaluation of the effect of therapeutic interventions. All above-listed flaws and shortcomings emphasize the need for rapid, reliable and non-invasive recognition of VAP, preferably in a setting that would permit continuous bedside monitoring and timely introduction of targeted drug therapy.