Oropharyngeal decontamination with antiseptics to prevent ventilator-associated pneumonia: Rethinking the benefits of povidone-iodine

摘要

"The colonization of the oropharynx plays a pivotal role in the pathogenesis of ventilator-associated pneumonia (VAP). Analysis of the oropharyngeal microbiota of healthy humans, using real-time PCR, demonstrated an extensive bacterial diversity comprising species of Streptococcus, Gemella, Eubacterium, Selenomonas, Veillonella, Actino-myces, Atopobium, Rothia, Neisseria, Eikenella, Campylobacter, Porphyromonas, Prevotella, Capnocytophaga, Fusobacterium, and Leptotrichia (1). Oropharyngeal colonization with respiratory pathogens is prevented by the physical-chemical properties of the oral mucosa surface, the salivary enzymatic content, and specific proteases and immunoglobuiins. Conversely, in the critically ill tracheally intubated patient, the oral flora shifts to a predominance of Gram-negative and Gram-positive aerobic pathogens, that is, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (2). The main reasons for such overgrowth of pathogens are difficulties in oral hygiene, changes in salivary properties during critical illness, and antibiotic therapy (2, 3). Once the oropharynx becomes colonized, microbes translocate into the airways because of endotracheal tubes (ETTs) comprising high-volume low-pressure cuffs. These cuffs are not leak-proof and promote a continuous seepage of bacteria-laden oropharyngeal contents into the airways (4).