Fat embolism.

OBJECTIVE To review the pathophysiology and management of patients with clinical manifestations of fat embolism. DATA SOURCES A review of studies reported from 1976 to 1998 and identified through a MEDLINE search of the literature on fat embolism and fat embolism syndrome. SUMMARY OF REVIEW Fat embolism occurs when bony or soft tissue trauma has caused fat to enter the circulation, or in atraumatic disorders where circulating fat particles have coalesced abnormally within the circulation. The fat particles deposit in the pulmonary and systemic circulations, although only 1 - 2% develop a clinical disorder with respiratory, cerebral and dermal manifestations known as the fat embolism syndrome. Rarely, fat embolism produces a fulminant fat embolism syndrome due to mechanical obstruction within the pulmonary circulation causing a severe right heart failure. The fat embolism syndrome is believed to be caused by the toxic effects of free fatty acids liberated at the endothelial layer which cause capillary disruption, perivascular haemorrhage and oedema. The clinical manifestations of respiratory failure, petechiae and a diffuse or focal cerebral disturbance, are characteristic but not pathognomonic of the syndrome. The syndrome is largely self limiting with treatment being symptomatic. Therapy is directed at maintaining respiratory function and largely follows the same principles of management used in patients who have the acute respiratory distress syndrome. Early immobilization of fractures and methods to reduce the intramedullary pressure during total hip arthroplasty have reduced the incidence of operative fat embolisation. Corticosteroids either before or after the development of respiratory or cerebral symptoms have not been shown to be of any benefit. CONCLUSIONS Fat embolism occurs in many traumatic and atraumatic conditions and is largely asymptomatic. Preventative measures include early immobilization of fractures and methods to reduce intramedullary pressure during surgical manoeuvres. Treatment is largely symptomatic with therapy for respiratory failure similar to that used in management of acute respiratory distress syndrome. Corticosteroids have not been found to be of significant benefit.