Background: The pneumonias associated to mechanical ventilation present great difficulty in diagnosis and have a high mortality. The invasive diagnostic technique of choice in these patients is bronchial curettage by a double telescopic catheter with distal occlusion (OTC) based on its good sensitivity/specificity relation. Recently, the use of a variant of the classical bronchoalveolar lavage (BRL), bronchoalveolar lavage or protected alveolar lavage (PAL) has appeared in the diagnosis of conventional bacterial pneumonia. This new technique provides good specificity of OTC by its use with "protected" catheters and a high sensitivity due to exploration of a greater area of the lung.
Methods: Twenty patients receiving mechanical ventilation (MV) suspected of pneumonia in whom 21 fibrobronchoscopies (FB) were performed with OTC and PAL were studied with quantification of the cultures obtained being carried out. The OTC was performed according to the usual technique and PAL by the instillation of 40 ml of saline serum administered through a Combicath type catheter.
Results: OTC and PAL provided diagnostic results which coincided in 8 cases: the same germs were isolated at significant concentrations in six patients and in the two remaining cases direct immunofluorescence for Legionella was positive. PAL was diagnosed in 4 more cases with the diagnosis of viral inclusion bodies being possible in one upon cytologic examination. The count of cells with intracellular bacteria (ICB) was greater than 7% and was always related with positivity in the PAL.
Conclusions: A greater sensitivity was observed with the protected alveolar lavage technique. Moreover, this technique makes virologic investigation and the counting of cells with intracellular bacteria, which may be a marker of rapid diagnosis of bacterial pneumonia, possible.