Studies on the genesis of traumatic fat embolism in man.

Two mAnq viEws are held with regard to the pathogenesis of traumatic fat embolism. The classic view is that such embolism follows the intravenous incursion of fat droplets liberated from traumatized adipose tise and bone marrow. The mode of entrance of embolic fat globules into the bloodstream from a fracture site can be satisfactorily explained by analogy with the hydrodynamic model of Young and Griffith' This view is also supported by the observation that pulmonary fat emboli are sometimes accompanied by embolic fragments of bone marrow 2 or even by spicules of bone.3 Nevertheless, it is diflicult to conceive that in all cases sufficient fat can be liberated from localized areas of trauma to account for the severity of the subsequent fat embolism.4A Again, fat embolism has been reported in circumstances in which there is no overt tissue damage-for example, following decompression in low pressure chambers or in flying accidents.8'7 These considerations and others of a more positive nature have prompted an alternative view that the embolic fat globules are derived mainly or entirely from the lipids normally present in the plasma.8'9 This view has been the subject of much controversy and we are inclined to agree with Sevitt 10 that it remains unproven. A relatively neglected approach, the investigation of the physical properties and chemical composition of the embolic fat, might be expected to provide some clues as to its origin The intense sudanophilia of the emboli and their stainability with osmium tetroxide are in keeping with the reactions given by the triglycerides in adipose tissue cells. Evidence for the presence of free fatty acids is inconclusive, owing to the unreliability of the available techniques." Beyond this, little attention seems to have been given to the nature of the embolic fat until the important observations of LeQuire et aL'I These workers reported that the emboli in 9 cases of human pulmonary fat embolism often included masses of birefringent acicular