1. Definition

Ventilator associated pneumonia (VAP) is a lung infection that develops in a patient who has been mechanically ventilated for >48 hours and is defined by clinical, radiographic, and microbiological criteria. These criteria are subjective, leading to substantial inter-observer variability. The clinical and surveillance definitions of VAP are compiled and summarized by SHEA/IDSA in a publication from 2014 [1].

2. Burden of disease.

The prevalence and incidence of VAP are difficult to calculate since definitions are subjective and non-specific. Clinical surveys suggest that 10-20% of ventilated patients will develop VAP [1]. The attributable mortality of VAP is estimated to be approximately 10%, ranging between 3% and 17%, and varies for different kinds of patients. Critically ill patients who develop VAP appear to be twice as likely to die compared with similar patients without VAP. VAP increases direct medical costs since VAP extend patients’ duration of mechanical ventilation, increase intensive care and hospital length of stay, and are associated with increased use of antimicrobials.

3. How to prevent-specific requirements.

It has been shown that 55% of VAP cases can be prevented when evidence-based guidelines are followed [2]. General conditions must be met to prevent HAIs described elsewhere regarding education of staff, surveillance and infrastructure. VAP develops due to microbial invasion of the normally sterile lung and is a result of either impaired host defences, the presence of a high dose of microorganisms or a particularly virulent pathogen. The predisposing factor is the endotracheal tube that bypasses the body’s natural defence mechanisms against respiratory infection. The tube impairs cough and mucociliary clearance and creates an abnormal passageway between the upper airway and the trachea. In addition, the tube may facilitate the entry of bacteria by pooling and leakage of contaminated secretions around the cuff. Non-invasive mechanical ventilation is associated with a lower incidence of nosocomial infection and the overall focus of guidelines is to prevent deep sedation for long times and to encourage patients to breathe spontaneously to decrease the need of an endotracheal tube. The following recommendations are based on recently published guidelines for adults [1]. A bundled strategy with the following elements can decrease VAP incidence significantly [3,4]. 

  • Avoid intubation and unnecessary use of ventilator:

–      use noninvasive positive pressure ventilation if possible in selected populations;

–      assess possibility to extubate daily.

  • Minimize and interrupt sedation:

–      manage patients without sedation whenever possible,

–      interrupt sedation daily;

–      perform spontaneous breathing trials with sedatives turned off;

–      facilitate early mobility;

  • Ventilator and breathing circuit maintenance

–      minimize pooling of secretions above the endotracheal tube cuff. Use endotracheal tubes with subglottic secretion drainage ports for patients expected to require greater than 48 or 72 hours of mechanical ventilation;

–      change the ventilator circuit only if visibly soiled or malfunctioning;

–      follow guidelines for sterilization and disinfection of respiratory care equipment.

  • Patient care:

–      elevate the head of the bed to 30°-45°;

–      use selective oral or digestive decontamination to decrease the microbial burden of the aerodigestive tract;

–      perform regular oral care with chlorhexidine and provide mechanical tooth brushing.

References.

  1. Klompas M, Branson R, Eichenwald EC, Greene LR, Howell MD, Lee G, et al. Strategies to prevent ventilator-associated pneumonia in acute care hospitals: 2014 update. Infection control and hospital epidemiology. 2014;35 Suppl 2:S133-54.
  2. Umscheid CA, Mitchell MD, Doshi JA, Agarwal R, Williams K, Brennan PJ. Estimating the proportion of healthcare-associated infections that are reasonably preventable and the related mortality and costs. Infection control and hospital epidemiology. 2011;32(2):101-14.
  3. Talbot TR, Carr D, Lee Parmley C, Martin BJ, Gray B, Ambrose A, et al. Sustained Reduction of Ventilator-Associated Pneumonia Rates Using Real-Time Course Correction With a Ventilator Bundle Compliance Dashboard. Infection control and hospital epidemiology. 2015;36(11):1261-7.
  4. Lawrence P, Fulbrook P. The ventilator care bundle and its impact on ventilator-associated pneumonia: a review of the evidence. Nursing in critical care. 2011;16(5):222-34.