Abstract
Intensive care unit (ICU) acquired pneumonia is one of the most common and morbid
health care-associated infections. Despite decades of work developing and testing
prevention strategies, ICU-acquired pneumonia remains stubbornly pervasive. Pneumonia
prevention studies are difficult to interpret because all are at risk of bias due
to the subjectivity and poor specificity of pneumonia definitions. Interventions associated
with improvements in objective outcomes in addition to pneumonia, such as length of
stay or mortality, should therefore be prioritized. Avoiding intubation, minimizing
sedation, implementing early extubation strategies, and mobilizing patients do appear
to improve some of these objective outcomes. Many of our other assumptions about how
best to prevent ICU-acquired pneumonia, however, have recently been challenged. Elevating
the head of the bed is supported by very little randomized trial data. Early reports
suggested that subglottic secretion drainage may decrease time to extubation and ICU
length of stay, but more recent analyses refute these findings. Novel endotracheal
tube cuff designs do not clearly lower pneumonia rates. A large randomized trial of
selective digestive decontamination in ICUs with high baseline rates of antimicrobial
resistance did not identify any benefit. Oral care with chlorhexidine may increase
mortality risk and stress ulcer prophylaxis may facilitate pneumonia. Early data on
probiotics suggest a possible effect but there is no clear signal yet that they shorten
duration of mechanical ventilation or lower mortality. Ventilator bundles on balance
do appear to be beneficial but it is not clear which components are most important
nor how best to implement them. This article will review recent studies that have
challenged, refined, or complicated our understanding of how best to prevent ICU-acquired
pneumonia.
Keywords
ventilator-associated pneumonia - ICU-acquired pneumonia - spontaneous breathing trials
- oral care with chlorhexidine - subglottic secretion drainage - stress ulcer prophylaxis
- endotracheal tube cuff design - selective digestive decontamination - probiotics
