The role of quantitative cultures of non-bronchoscopic samples in ventilator associated pneumonia

The objective of this study is to determine the role of quantitative cultures of non-bronchoscopic samples such as blinded bronchial sampling (BBS) and endotracheal aspirates (ETA) in the management of ventilator associated pneumonia (VAP). The study also evaluates the clinical diagnosis of VAP based on the inclusion of Gram stain results of BBS/ETA samples into modified clinical pulmonary infection score (CPIS).

Fifteen out of the 120 patients admitted to respiratory intensive care unit under mechanical ventilation for more than 48 hours with a clinical suspicion of VAP, were included in this study. Quantitative cultures of BBS and ETA were performed from all the 15 patients.

VAP was confirmed in 11 out of 15 cases by quantitative cultures of either the BBS or ETA samples. The condition of 8/11 VAP confirmed patients improved significantly with the change in antibiotic therapy. The overall mortality rate was found to be 18%. The agreement between BBS and ETA results was found to be 83.3%. Modified-clinical pulmonary infection score (CPIS) increased significantly when Gram stain results of BBS/ETA samples were included, thereby strengthening the clinical diagnosis of VAP.

Quantitative culture of lower respiratory tract samples obtained by non-bronchoscopic methods may be a useful alternative to bronchoscopy, in the diagnosis of VAP. Inclusion of Gram stain results of BBS/ETA into modified-CPIS may augment the diagnostic evaluation of VAP.