ALVEOLAR MACROPHAGES FAT STAIN IN EARLY DIAGNOSIS OF FAT-EMBOLISM SYNDROME

The aim of this study was to assess the contribution of bronchoalveola r lavage (BAL) in the diagnosis of fat embolism syndrome (FES). The pr esence of fat droplets in alveolar macrophages was addressed in 13 tra uma patients with bone fractures and 10 non-trauma patients with acute respiratory distress syndrome (ARDS). The control group was composed of 5 anesthesized patients with ischemic heart disease, immediately pr ior to cardiac surgery. Two patients with suggestive clinical and labo ratory signs of FES had 40% and 24% fat-containing alveolar cells, res pectively. The trauma patients without signs of FES displayed a wide v ariation in the percentage of fat-containing macrophages (from 3% to 9 5%). Most of the patients with ARDS who were receiving lipid emulsion as part of their parenteral nutrition, had a high percentage (>85%) of fat-containing macrophages. Patients with normal lungs had no fat-con taining macrophages. Our findings suggest that BAL Oil Red O-positive macrophages are frequently observed in trauma patients irrespective of the presence of FES. Therefore, estimation of the percentage of fat-c ontaining macrophages from BAL is an unreliable marker of FES.