Pulmonology Paediatric Critical Care Medicine Ventilator-associated pneumonia (VAP) is a type of lung infection that occurs in people who are on mechanical ventilation breathing machines in hospitals.

As such, VAP typically affects critically ill persons that are in an intensive care unit (ICU) and have been on a mechanical ventilator for at least 48 hours.

These factors include temperatures of >38 °C or <36 °C, a white blood cell count of >12 × 109/ml, purulent secretions from the airways in the lung, and/or reduction in gas exchange.

[5] People who are on mechanical ventilation are often sedated and are rarely able to communicate due to which many of the typical symptoms of pneumonia will either be absent or unable to be obtained.

The most important signs are fever or low body temperature, new purulent sputum, and hypoxemia (decreasing amounts of oxygen in the blood).

[7] Recent studies have also linked the overall oral health of a patient to the potential development of VAP; suggesting that bacteria found in plaque can "migrate to the respiratory system.

Ciliary action of the cells lining the trachea drive the mucus superiorly, leading to a build-up of fluids around the inflated cuff where there is little to no airway clearance.

[13] A combination of bacterial damage and consequences of the immune response lead to disruption of gas exchange with resulting symptoms.

[16] In recent years there has been a focus on rapid diagnostics, allowing for detection of significant levels of pathogens before this becomes apparent on microbial cultures.

[17][18] Alternatively, molecular detection of bacteria has been undertaken, with reports that amplifying the pan-bacterial 16S gene can provide a measure of bacterial load.

[19] A trial of biomarker-based exclusion of VAP (VAP-RAPID2) demonstrated test effectiveness but did not impact on clinical antibiotic prescribing decisions.

[20] Studies of pathogen-focussed molecular diagnostics have shown more promise in improving antimicrobial prescribing,[21][22] with formal findings from the INHALE randomised controlled trial awaited.

Proper hand washing, sterile technique for invasive procedures, and isolation of individuals with known resistant organisms are all mandatory for effective infection control.

Weak evidence suggests that raising the head of the bed to at least 30 degrees may help prevent VAP, however further research is required to understand the risks associated with this.

New cuff technology based on polyurethane material in combination with subglottic drainage (SealGuard Evac tracheal tube from Covidien / Mallinckrodt) showed significant delay in early and late onset of VAP.

However, when VAP is first suspected, the bacteria causing infection is typically not known and broad-spectrum antibiotics are given (empiric therapy) until the particular bacterium and its sensitivities are determined.

For patients with VAP not caused by nonfermenting Gram-negative bacilli (like Acinetobacter, Pseudomonas aeruginosa) the available evidence seems to support the use of short-course antimicrobial treatments (< or =10 days).

[33] People who do not have risk factors for MDR organisms may be treated differently depending on local knowledge of prevalent bacteria.