Clinical, radiological and microbiological corroboration to assess the role of endotracheal aspirate in diagnosing ventilator-associated pneumonia in an intensive care unit of a tertiary care hospital, India

Abstract

Early and accurate diagnosis and follow up of Ventilator-associated pneumonia (VAP) varies considerably with the clinical, radiological and microbiological criteria employed. this study was aimed to correlate serial clinicoradiological findings with microscopy and quantitative culture of consecutive Endotracheal aspirate (ETA) from 50 mechanically ventilated patients along with the antibiogram and risk factor assessment. the results revealed the incidence of VAP to be 42% with a rate of 116/1000 ventilator days in Multidisciplinary Intensive Care Unit (MICU). Early onset VAP was seen in 8 patients and late onset VAP in 13, with no significant age or sex preponderance. the attributable mortality rate was 61.9% which rose with duration of stay. the independent risk factors were multi-organ failure, re-intubation and pleural effusion. the most commonly isolated organisms were Multidrug resistant (MDR) Acinetobacter baumannii (76%) and Pseudomonas aeruginosa (42%). All enterobacterial isolates were Extended spectrum beta lactamases (ESBL) producing organisms and all Staphylococcus aureus isolates were methicillin resistant. Colonization on day 1 resulted in development of VAP on day 4 in 66% of the population studied. Gram stain findings had a significant correlation with the quantitative culture of ETA. Quantitative culture by itself showed a significant progressive increase of specificity in diagnosing VAP on day 7. he strength of association between Clinical Pulmonary Infection Score (CPIS), the microbiological findings and the clinical diagnosis was found to be strong. This study concludes that Gram stain and quantitative culture of ETA can be considered useful for the diagnosis of VAP and a combined clinical, radiological and microbiological approach can be used successfully in the management and follow up of VAP with emphasis on stepping up the VAP prevention bundle protocols.