QUANTITATIVE CULTURES OF ENDOTRACHEAL ASPIRATES FOR THE DIAGNOSIS OF VENTILATOR-ASSOCIATED PNEUMONIA

Bronchoalveolar lavage (BAL) and protected specimen brushing (PSB) are the most commonly used methods for diagnosing ventilator-associated ( VA) pneumonia although they require bronchoscopy. Endotracheal aspirat ion (EA) is a simple and less costly technique than PSB or BAL. The pu rpose of our study was to investigate the diagnostic value of EA quant itative cultures and to compare the results obtained using EA with tho se obtained using PSB and BAL in mechanically ventilated patients with or without pneumonia. We prospectively studied 102 intubated patients divided into three diagnostic categories: Group I (definite pneumonia , n = 26), Group II (uncertain status, n = 48), and Group III (control group, n = 28). All patients received prior antibiotic treatment. EA, PSB, and BAL were obtained sequentially in all patients. When compari ng Group I with Group III and using 10(5) cfu/ml as a threshold, we fo und that EA quantitative cultures represented a relatively sensitive ( 70%) and relatively specific (72%) method to diagnose VA pneumonia. Th e specificity of BAL and PSB (87% and 93%, respectively) was better th an that of EA. The negative predictive value of EA cultures was higher (72%) when compared with that obtained using PSB (34%) (p < 0.05). EA quantitative cultures correlated with PSB and BAL quantitative cultur es in patients with definite pneumonia. Although EA quantitative cuItu res are less specific than PSB and BAL for diagnosing VA pneumonia, ou r results suggest that the former approach may be used to treat these patients when bronchoscopic procedures are not available.