The authors describe a new and interesting method for the detection of fat droplets in blood. The topic itself and the problem of fat in salvaged orthopedic wound blood is rather hypothetical. There are no reports that show that “fat particles in the shed blood may increase the risk of fat embolism after bone surgery.” The cases of fat embolism in these patients are best explained by the surgical procedure. There are no studies that show retransfusion of blood salvaged during or after orthopedic surgery to cause mental disturbances.

In the discussion presented in this paper, two things are unjustifiably mixed: the demonstration of fat droplets in orthopedic wound blood, and the occurrence of membrane vesicles from cell lysis or extracorporeal circulation that can cause cerebral microembolization and postoperative neuropsychological disturbances. Biochemically, both substances represent “lipids,” but the characteristics of fat and membrane lipids are different. Unfortunately, this mix-up is often not due to innocent not-knowing. The clinical relevance of fat in orthopedic wound blood awaits clarification ― and this paper may support such studies ― but clarification would also strongly benefit from discrimination of the scientific facts.

– E. Hansen.