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1、Fat Embolism SyndromeSpeaker: Xie Xianbiao Acdemic Supervisor: Proffessor WanYongDefinitionFat embolism syndrome (FES) is a condition cha- racterized by hypoxemia bilateral pulmonary in filtrates , and mental status change , which is commonly thought of in association with long bone trauma.Pathophys
2、iology2 Theories Mechanical BiochemicalFat globules from disrupted bone marrow or adipose tissue are forced into torn venules in areas of trauma.Hormonal changes caused by trauma and/or sepsis induce systemic release of free fatty acids (FFA) as chylomicrons which cause the systemic FES.VSPathophysi
3、ologyMechanical Theories Clinical PresencenDiagnosis is made clinically NOT chemically. It does not matter how much fat globules are in the circulation, it just matters if patients have their side effects.nFES typically manifests 24 to 72 hours after the initial insult. Rarely 72 hrs.nClassic triad:
4、 Hypoxemia; Neurologic abnormalities; and a Petechial RashClinical PresencenSOB, Inc RR, Hypoxemia are early findings. 50% of pts with symptoms will need ventilation support. Respiratory dysfunction is major cause of mortality, which is about 10- 20%.nNeurologic symptoms usually develop after lung i
5、njury, and include: Confusion, altered LOC, Headaches, +/- Seizures, +/-Strokes with focal deficits.nPetechial rash is usually a late finding (frequency of 20-50% of pts). Head, neck, anterior thorax, subconjunctiva, and axillae are the most common regions.Clinical Presencen Petechiae result from th
6、e occlusion of dermal capillariesby fat globules, leading to extravasation of erythrocytes. n The rash resolves in five to seven days.n No abnormalities of platelet function have been documented.Clinical PresencenOther FindingsScotomata(Purtschers retinopathy)LipiduriaFeverCoagulation Abnormalities
7、(DIC like)Myocardial DepressionDiagnosisnFES is clinical diagnosisCXR(n) mostly. Some have patchy consolidations at periphery or bases due to alveolar hemorrhages , but not sensitive nor specific (snow storm pattern).CXRDiagnosisn Ventilation/perfusion scans may demonstrate a mottled pattern of subs
8、egmental perfusion defects with a normal ventilatory pattern. DiagnosisFocal areas of ground glass opacification with interlobular septal thick-ening are generally seen on chest CT.CTDiagnosisMRI of the brain may reveal high intensity T2 signal, which correlates with the degree of clinical neurologi
9、c impairment. MRIDiagnosisLaboratory Test (nonspecific)n ABGnThrombocytopenia, anemia, and hypofibri- nogenemia are indicative of FES, but non- specific.nUrine , blood , sputum examination with Sudan or oil red O staining detect fat glo-bules.DiagnosisnCommon misconception that the presen- ce of fat
10、 globules, either in sputum,urineis necessary to confirm the diagnosis of FESnIn 50% of fracture patients, fat globules was demonstrated in the serum, without symptoms of FES.DiagnosisnHOWEVERGrowing literatures on the use of bron-choscopy with bronchoalveolar lavage to detect fat droplets in alveol
11、ar macro- phages as a means to diagnose FES . Sensitivity and specificity are unknown, being studied in Trauma patients.DiagnosisClassic Gurds criteriaMajor criterianaxillary or subconjunctival petechia; occurs transiently (4-6 hours) in 50-60% of the cases.nhypoxemia (PaO260 mmHg)ncentral nervous s
12、ystem ( CNS ) de- pression disproportionate to hypo-xemia, and pulmonary edema.Minor criteriantachycardia (more than 110 beats per minute)npyrexia (temperature higher than 38.5 degrees)nemboli present in retina on fun- duscopic examinationnfat present in urinensudden unexplainable drop in hematocrit
13、 or platelet values(150109/L)nincreasing sed ratenfat globules present in sputum1 major criteria and at least 4 minor criteriasJ Arthroplasty . 2000 Sep;15(6):809-13.TreatmentnMedical care Supportive in nature Maintain oxygenation and ventilation Stabilize hemodynamics Blood products as needed Hydra
14、tion DVT 132:435439Treatment is supportiveTreatmentnCorticosteroids (controversial) Corticosteroids as prophylaxis for FES : Several studies have demonstrated varying results using corticosteroids in patients identified as high-risk for developing FES; while the data appear compel-ling, the optimal
15、timing, duration , and dose of corticosteroids are undetermined.TreatmentDose Model TimingDuration of StudyEffect on Disease Incidence30 mg/kg Dog Pre-event 60 min None10 mg/kg q8h for 24 hHuman traumaAt admissionNo data Declining7.5 mg/kg q6h for 12 h or placeboHuman trauma Within 12 h 2 d DeclininglOther doses: 1.5 mg/kg q8h48 hrslStatistical Significance in reduction of clinical diagnosed FESlNo major complications were noted；but potential for complications is the major concern (bleeds,infection, cardiac compromise)lKey is to initiate treatment early and for a short period of time
