FAT EMBOLISM : Clinical features Early warning signs of fat embolism (usually within 72 hours of injury) are a slight rise of temperature and pulse rate. In more pronounced cases there is breathlessness and mild mental confusion or restlessness. Pathognomonic signs are petechiae on the trunk, axillae and in the conjunctival folds and retinae. In more severe cases there may be respiratory distress and coma, due both to brain emboli and hypoxia from involvement of the lungs. The features at this stage are essentially those of ARDS. There is no infallible test for fat embolism; however, urinalysis may show fat globules in the urine and the blood PO2 should always be monitored; values below 8 kPa (60 mmHg or less) within the first 72 hours of any major injury must be regarded as suspicious. REF:Apley&;s system of ohopaedics - 9th edn - pg no 681.