Effects of bronchoalveolar lavage volume on arterial oxygenation in mechanically ventilated patients with pneumonia.

Abstract

To assess the effect of bronchoalveolar lavage (BAL) volume on arterial oxygenation in critically ill patients with pneumonia. Randomized clinical comparison. Six-bed respiratory intensive care unit of a 850-bed tertiary care university hospital. Thirty-seven intubated and mechanically ventilated patients with clinical suspicion of pneumonia. Bronchoscopically guided protected specimen brush (PSB) followed by either a "high volume" BAL (n = 16, protected catheter, mean volume: 131 +/- 14 ml) or a "low volume" BAL (n = 21, protected double-plugged catheter, 40 ml volume for all patients). Arterial oxygen tension/fractional inspired oxygen (PaO2/FIO2) and mean arterial pressure (MAP) before and up to 24 h after the intervention. Bacterial growth in quantitative cultures. Analysis of variance for repeated measurements with inter-subject factors. All patients showed a lower PaO2/FIO2 ratio and higher MAP after the diagnostic procedure, without differences between the study arms (p = 0.608 and p = 0.967, respectively). Patients with significant bacterial growth (p = 0.014) and patients without preemptive antibiotic (p = 0.042) therapy showed a more profound and longer decrease in arterial oxygenation after the diagnostic procedure. A decrease in the PaO2/FIO2 ratio was observed in all patients after a combined diagnostic procedure, independent of the BAL volume used. A significant bacterial burden recovered from the alveoli and no preemptive antibiotic therapy were associated with a larger and longer-lasting decrease in arterial oxygenation.