Usefulness of Airway Visualization in the Diagnosis of Nosocomial Pneumonia in Ventilated Patients

Abstract

Clinical diagnosis of nosocomial pneumonia in ventilated patients remains a challenge in the ICU as none of the clinical biological and radiologic parameters can predict its diagnosis. To our knowledge, however, the accuracy of direct visualization of the bronchial tree has never been investigated. To evaluate the interest of airway visualization and to select independent parameters that predict nosocomial pneumonia in ventilated patients. A ten-bed medical-surgical ICU. All consecutive patients suspected of having nosocomial pneumonia who underwent bronchoscopy with protected specimen brush, culture examination of BAL, and direct examination of BAL were studied. Clinical and biological data and airways findings were recorded prospectively. Patients were classified as having pneumonia or not according to the results of distal bacteriologic samples, follow-up, and histologic study. Respective accuracies of each variable were calculated using univariate analysis and stepwise logistic regression. Ninety-one patients with suspected nosocomial pneumonia were studied. Patients were randomly assigned to a construction group (n = 46) and a validation group (n = 45). Using multivariate analysis, 3 factors were associated with pneumonia (a decrease in PaO2/fraction of inspired oxygen ratio > or = 50 mm Hg, odds ratio [OR] = 9.97, p = 0.026; the presence of distal purulent secretions, OR = 7.46, p = 0.044; the persistence of distal secretions surging from distal bronchi during exhalation, OR = 12.25, p = 0.013). These three factors remained associated with pneumonia in the validation group. Interobserver repeatability of the bronchoscopic parameters was good. Having 2 or more of these 3 independent factors was able to predict pneumonia with a 94% sensitivity and a 89% specificity in the construction group and with a 78% sensitivity and a 89% specificity in the validation group. We conclude that direct visualization of the bronchial tree can immediately and accurately predict nosocomial pneumonia in ventilated patients before obtaining definite results of protected samples.