DIAGNOSING PNEUMONIA IN MECHANICALLY VENTILATED TRAUMA PATIENTS - ENDOTRACHEAL ASPIRATE VERSUS BRONCHOALVEOLAR LAVAGE

We prospectively investigated the diagnostic value of semiquantitative (semiQC) and quantitative (QC) cultures of endotracheal aspirate (ETA ) compared with QC of bronchoalveolar lavage (BAL) fluids in 18 mechan ically ventilated trauma patients with clinical signs of pneumonia. Th e general agreement between QC of ETA and BAL was 89% when conventiona l cutoffs for the QC were used and 94% if the cutoffs were adjusted fo r previous antibiotic therapy. In all six patients whose clinical diag noses of pneumonia were considered definite, both QC of ETA and QC of BAL were positive; however, standard semiQC of ETA showed comparable r esults in this group. On the contrary, in the 12 patients whose clinic al diagnoses were uncertain, QC of BAL and ETA were negative in ten pa tients and in five (50%) of these, pneumonia was eventually excluded. Semiquantitative cultures of ETA were positive in all these patients. Five (28%) patients experienced a decrease in PaO2/FiO2 (> 15% of prev ious value) 2 hours after BAL, and in three (17%) this derangement per sisted for 24 hours. These data suggest that BAL may be hazardous in m echanically ventilated trauma patients and that its use should be rest ricted to patients in whom the diagnosis is in doubt.