Diagnosis of Nosocomial Pneumonia in Mechanically Ventilated Patients: Comparison of a Plugged Telescoping Catheter with the Protected Specimen Brush

Abstract

Protected samples of lower respiratory tract secretions processed by quantitative culture techniques are recommended to diagnose nosocomial bacterial pneumonia in intubated, mechanically ventilated patients. To evaluate the accuracy of a simple and inexpensive sampling device in this setting, we compared quantitative cultures of paired single-sheathed plugged telescoping catheter (PTC) and protected specimen brush (PSB) samples in 55 patients during 78 suspected episodes of nosocomial pneumonia. PTC and PSB samples were taken in randomized order, and patients were also randomized to have PTC samples taken "blindly" or via a fiberoptic bronchoscope. Fifteen PSB and 27 PTC samples were culture positive (greater than or equal to 10(3) cfu/ml). The two sampling procedures gave similar results in 58 (74%) episodes. A major discrepancy occurred in 20 episodes, including six false negatives of PSB in episodes of proved pneumonia, four possible false positives of PSB, and 10 possible false positives of PTC (three of which rapidly evolved towards overt pneumonia). The sensitivity and specificity of PTC were 100 and 82.2%, and those of PSB were 64.7 and 93.5%, respectively. Blinded or directed PTC samples had similar concordance with PSB samples taken via bronchoscopy. We conclude that PTC is at least as accurate as PSB in the bacteriologic diagnosis of nosocomial pneumonia in intubated patients, and that its use can result in substantial cost savings, especially when fiberoptic bronchoscopy is not otherwise indicated.

Diagnostic accuracy of protected catheter sampling in ventilator-associated bacterial pneumonia

“…[22]. Their accuracy for the diagnosis of ventilatorassociated bacterial pneumonia has been challenged recently in several studies that also show that noninvasive blind methods can be as accurate [12,23,24]. Blind protected telescoping catheter avoids contamination by the upper tracheobronchial tree and thus could improve specificity in comparison with other blind methods.…”

“…[13,14] for mini-bronchoalveolar lavage and give new information concerning protected distal aspiration. The study of PHAM et al [12] which was performed to validate protected distal aspiration, had the advantage of targeting a large population of ventilated patients whose outcome was representative of ICUs (51% survivors). Nevertheless, the reference diagnosis in this work was in part based on the results of the method that was evaluated (in association with the results of protected specimen brush cultures).…”

“…In order to avoid the spread of diluted secretions resulting from minibronchoalveolar lavage, protected distal aspiration was performed first, followed by lavage. Protected distal aspiration was performed via a double polyethylene catheter (Combicath TM ; Plastimed, Saint-Leu-La-Foret, France), according to the technique described by PHAM et al [12]. Mini-bronchoalveolar lavage was performed using a double polyethylene catheter (Combicath TM ; Plastimed, Saint-Leu-La-Foret, France) according to the technique described by ROUBY et al [13].…”

“…A noninvasive strategy based on blind methods has also been proposed [9±11]. Among noninvasive sampling methods, some authors have proposed a protected telescoping catheter inserted blindly into the respiratory tract in order to avoid contamination of the sample with pathogens from the upper tracheobronchial tree [12,13]. A protected telescoping catheter can be used in two ways, either by simple distal protected aspiration or instillation of sterile saline, i.e.…”

Diretrizes brasileiras para tratamento das pneumonias adquiridas no hospital e das associadas à ventilação mecânica - 2007

“…(52) (53) Outros autores demonstraram que bactérias presentes no parênquima pulmonar, a julgar por seu isolamento em culturas de amostras de EP, estão presentes também nas culturas do AET. (54) Baseando-se em vários estudos, os índices operacionais encontrados para o AET, no diagnóstico da PAVM, variam de 38 a 100% de sensibilidade, e 14 a 100% de especificidade, de acordo com os pontos de corte utilizados.…”