Blog post: Nebulized amikacin – preventing positive cultures or VAP?

A long time ago (previous century!) I did a PhD on just this topic, prevention of VAP. Part of my thesis was a review entitled “Problems in diagnosing nosocomial pneumonia in mechanically ventilated patients” (Crit Care Med 1994; 22: 1683-91). The problem: VAP was diagnosed upon several clinical criteria (fever, leukocytosis), abnormalities on chest X-ray and microbiological culture results from endotracheal aspirates. Each - and even in combination – had low specificity for VAP; implying many false-positive diagnoses, overestimation of incidence, and unnecessary antibiotic use. Moreover, an intervention that would result in negative culture results would also reduce the incidence of VAP, regardless of clinical symptoms. 

The possible solution was invasive diagnostics – bronchoscopy to obtain samples from deep inside the lungs (instead of the upper endotracheal part) combined with quantitative cultures. Famous French investigators, Jean-Yves Fagon and Jean Chastre, demonstrated that this approach reduced the incidence of VAP by 50% without affecting patient outcome. Yet the invasive approach did not survive due to the fear of missing out (sensitivity may not be 100%) and the hassle of performing bronchoscopy. So-called deep non-bronchoscopic endotracheal aspirates became the standard.