summary Fat Embolism Syndrome is an acute respiratory disorder caused by an inflammatory response to embolized fat globules that may enter the bloodstream as a result of acute long bone fractures or intramedullary instrumentation. Patients present with hypoxia, changes in mental status, and petechial rash. Diagnosis is made clinically with presence of hypoxemia (PaO2 < 60), CNS depression, petechial rash, and pulmonary edema. Treatment is focused on prevention with early stabilization of long bone fractures. Mechanical ventilation with high levels of PEEP is the recommended treatment for acute presentation. Epidemiology Incidence 3-4% with isolated long bone trauma 10-15% with polytrauma Etiology Pathophysiology fat and marrow elements are embolized into the bloodstream during acute long bone fractures intramedullary instrumentation intramedullary nailing hip & knee arthroplasty pathophysiology two theories regarding the causes of fat embolism include mechanical theory embolism is caused by droplets of bone marrow fat released into venous system metabolic theory stress from trauma causes changes in chylomicrons which result in formation of fat emboli Diagnosis Criteria Major (1) hypoxemia (PaO2 < 60) CNS depression (changes in mental status) petechial rash pulmonary edema Minor (4) tachycardia pyrexia retinal emboli fat in urine or sputum thrombocytopenia decreased HCT Additional PCO2 > 55 pH < 7.3 RR > 35 dyspnea anxiety Presentation History symptoms usually present within 24 hours of inciting event Symptoms patient complains of feeling "short of breath" patient appears confused Physical exam tachycardia tachypnea petechiae axillary region conjunctivae oral mucosa Studies ABG hypoxemia (PaO2 < 60 mmHg) Treatment Nonoperative mechanical ventilation with high levels of PEEP (positive end expiratory pressure) indications acute fat emboli syndrome Prevention early fracture stabilization indications early fracture stabilization (within 24 hours) of long bone fracture is most important factor in prevention of FES techniques to reduce the risk of fat emboli overreaming of the femoral canal during a TKA use of reamers with decreased shaft width reduces the risk during femoral reaming for intramedullary fixation use of external fixation for definitive fixation of long bone fractures in medically unstable patients decreases the risk Prognosis Fatal in up to 15% of patients
QUESTIONS 1 of 5 1 2 3 4 5 Previous Next (OBQ09.214) An 85-year-old woman undergoes the treatment seen in Figure A for a displaced left femoral neck fracture. During wound closure, the patient becomes hypoxic and hypotensive. Despite aggressive resuscitation efforts, she passes away three hours later in the intensive care unit. The autopsy findings seen in Figure B from the patient's lungs are most likely the result of which of the following QID: 3027 FIGURES: A B Type & Select Correct Answer 1 Reaming for the femoral component 21% (390/1851) 2 Insertion of a femoral component after cement pressurization 77% (1425/1851) 3 Utilization of undersized broaches during canal preparation 1% (23/1851) 4 Inadequate beta blockade 0% (1/1851) 5 Use of spinal anesthesia 0% (5/1851) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.50) Embolic material generated during total knee arthroplasty (TKA) shown in Figure 29 is composed of which of the following substances? QID: 6010 FIGURES: A Type & Select Correct Answer 1 Fat only 7% (25/344) 2 Fat and air 7% (24/344) 3 Fat and marrow 66% (228/344) 4 Fat and cement 17% (60/344) 5 Fat and bone 1% (3/344) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ06.62) A 79-year-old female falls onto her right hip at home and sustains the injury shown in Figure A. She undergoes an uncemented unipolar hemiarthroplasty. During insertion of the stem into the femoral canal, the patient becomes hypotensive and hypoxic. Which of the following has most likely occurred? QID: 173 FIGURES: A Type & Select Correct Answer 1 Femoral shaft fracture 0% (6/3456) 2 Inadequate fluid resuscitation during surgery 1% (23/3456) 3 Acute myocardial infarction 1% (24/3456) 4 Pulmonary embolism caused by dislodging of deep venous thrombosis during hip exposure 2% (82/3456) 5 Intramedullary fat and marrow embolization 96% (3307/3456) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ05.194) In a patient undergoing total knee arthroplasty, the femoral and tibial bone resections can be done using intra-or extra-medullary alignment systems. Extra-medullary guidance systems have what benefit over intra-medullary guidance systems? QID: 1080 Type & Select Correct Answer 1 Decreased fracture risk 14% (366/2532) 2 Decreased embolization risk 80% (2024/2532) 3 Decreased surface area available for cement interdigitation 2% (42/2532) 4 Increased risk of blood loss and/or transfusion requirement 4% (91/2532) 5 Increased rates of cerebral ischemia 0% (3/2532) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (OBQ04.147) A 20-year-old male sustains bilateral humeral shaft fractures and bilateral femoral shaft fractures from a motor vehicle collision. While awaiting surgery, the patient suddenly becomes tachycardic, hypoxemic and experiences mental status changes; physical exam demonstrates multiple petechiae in his bilateral axilla. CT angiography is ordered and is negative for pulmonary embolus. What is the most likely diagnosis? QID: 1252 Type & Select Correct Answer 1 hypovolemic shock 2% (35/1446) 2 stroke 0% (4/1446) 3 fat embolism syndrome 97% (1398/1446) 4 sundown syndrome 0% (2/1446) 5 narcotic overdose 0% (1/1446) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic
All Videos (0) Podcasts (1) Basic Science⎪Fat Embolism Syndrome Basic Science - Fat Embolism Syndrome Listen Now 12:57 min 8/13/2020 281 plays 5.0 (2)