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[Ventilator-associated pneumonia; controversies with respect to diagnosis, pathogenesis, therapy and prevention]
M J Bonten1, D C Bergmans, I M Hoepelman
1Afd. Interne Geneeskunde, onderafd, Infectieziekten & Aids, Academisch Ziekenhuis, Utrecht. m.bonten@wxs.nl
Abstract:
Ventilator-associated pneumonia (VAP) is the most frequent nosocomial infection among intensive care patients; it is associated with increased morbidity and mortality. VAP is always preceded by colonization of the upper respiratory tract with potentially pathogenic micro-organisms. Oropharyngeal colonization is pivotal in the pathogenesis of VAP, while gastric and intestinal colonization appear to be less important than generally believed. The diagnosis is difficult and usually relies on a combination of clinical, microbiological and radiographic criteria. This combination of criteria may have a high sensitivity for VAP, but specificity is low. As a result, many patients receive antibiotics unnecessarily. Bronchoscopic sampling of lower airways can increase specificity, but whether these relatively expensive techniques are cost-effective remains to be established. The best antibiotic therapy for VAP is unknown. General infection control measures remain the cornerstone of infection prevention in each intensive care unit (ICU). Selective digestive decontamination (SDD) was associated with a reduction in the incidence of VAP, but mortality rates remained largely unaffected, and selection of antibiotic-resistant pathogens remains a potential disadvantage. Routine SDD in ICU is discouraged. Decontamination of the oropharynx appears to be equally effective.
Insights
Ventilator-associated pneumonia (VAP), a common ICU infection, stems from upper airway colonization. Oropharyngeal decontamination shows promise for prevention, potentially reducing unnecessary antibiotic use.
Area of Science:
- Critical Care Medicine
- Infectious Diseases
- Hospital Epidemiology
Context:
- Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care units (ICUs), leading to significant morbidity and mortality.
- VAP pathogenesis is linked to the colonization of the upper respiratory tract by pathogenic microorganisms.
- Oropharyngeal colonization plays a critical role, whereas gastric and intestinal colonization are less significant than previously thought.
Purpose:
- To review the pathogenesis, diagnosis, and prevention strategies for VAP.
- To evaluate the effectiveness and limitations of current diagnostic criteria and treatment approaches for VAP.
- To discuss the role of infection control measures, including selective digestive decontamination (SDD), in managing VAP.
Summary:
- VAP diagnosis is challenging, often relying on clinical, microbiological, and radiographic criteria, which can lead to low specificity and unnecessary antibiotic administration.
- Bronchoscopic sampling offers higher specificity but its cost-effectiveness is debated.
- While general infection control is crucial, selective oropharyngeal decontamination appears effective in reducing VAP incidence without significantly impacting mortality, though antibiotic resistance is a concern with routine SDD.
Impact:
- Highlights the importance of oropharyngeal colonization in VAP development.
- Suggests that oropharyngeal decontamination may be a viable strategy for VAP prevention.
- Discourages routine selective digestive decontamination in ICUs due to potential disadvantages like antibiotic resistance, while emphasizing the value of general infection control measures.