Discuss the causes and management of fat embolus syndrome

Discuss the causes and management of fat embolus syndrome.

Microscopic fat emboli are very common in patients who sustain long bone fractures or who undergo total joint replacement. Less commonly fat embolus syndrome (FES) may present. It should be suspected during total joint replacement surgery if the patient develops hypoxia or agi-tation. FES is present in 0.1% of patients having a total hip arthroplasty and 7% of patients having a total knee arthro-plasty. It may also occur during liposuction, osteomyelitis, sickle cell anemia, and burns.

The diagnostic criteria for FES were described by Gurd (Table 54.1). In order to make the diagnosis, the patient must have one major and four minor criteria.

There are two theories to describe the development of FES. One theory postulates a mechanical phenomenon. Fat cells released into the venous circulation secondary to long bone trauma are transported to the pulmonary circu-lation where they act as microemboli. The second theory postulates a biochemical phenomenon. Free fatty acids released during trauma may directly cause pulmonary damage and adult respiratory distress syndrome. In addi-tion, the release of stress catecholamines during trauma results in further free fatty acid release.

There is no definitive treatment for FES. Many drugs, such as heparin, albumin, and hypertonic glucose, have been used without success. Steroids may be beneficial in certain high-risk patients. Currently, supportive measures to maintain hemodynamic stability and optimal oxygena-tion and ventilation are the only options available. FES usually resolves in 3–5 days.