Fat embolism pathophysiology PDF

Preview

Summary

Download Fat embolism pathophysiology PDF

Description

Fat Embolism Syndrome

1

Fat Embolism Syndrome Thomas Hudson Lansing Community College

Fat Embolism Syndrome

2

Pathophysiology Fat embolisms syndrome (FES) is a condition where fat globules are released from the bone marrow and into vascular circulation. It is often the result of long bone injuries but has also been observed in patients who have had pelvic fractures, blunt trauma, severe burns, pancreatitis, liposuction, and orthopedic surgeries [ CITATION Wal02 \l 1033 ]. The release of fat globules from bone marrow into circulation results in direct tissue damage to organs and creates a systemic inflammatory response. The first case of FES was documented over 150 years ago but many aspects of how fat emboli develop are not completely understood [ CITATION Kwi13 \l 1033 ]. The two main theories that have emerged to describe the formation of fat emboli are termed the mechanical theory and the biochemical theory. The mechanical theory suggests that long bone trauma directly releases yellow bone marrow components into the venous system. Trauma causes increased intramedullary pressure resulting in leaky venous sinusoids [ CITATION Wal02 \l 1033 ]. The fat globules can then travel through venous circulation resulting in the obstruct pulmonary capillaries. The biochemical theory gives insight into how fat embolisms can develop and occlude more systemic capillaries as FES has been observed to also cause damage in brain, kidneys, retina, and skin. The biochemical theory suggests that the inflammatory response to trauma and increase in circulating catecholamines causes the mobilization of free fatty acids which damages capillary beds. The chemical process results in platelet aggregation, the formation of fat globules, and potential widespread tissue damage (Walls, 2002). There is evidence that most patients who suffer orthopedic trauma develop fat embolisms; however, it is usually subclinical and without complication. The development of FES is less likely with recent studies suggesting the incidence is between 0.9 and 11% [ CITATION Kwi13 \l 1033 ]. Body Systems Affected Fat emboli can travel throughout the vasculature of the body and therefore it is potentially a multiorgan disease. Fat emboli have been found in the lungs, brain, skin, retina, kidneys, liver, and heart [ CITATION Kwi13 \l 1033 ]. The most common area affected by FES is the lungs. Fat emboli enter venous circulation, return to the heart, and travel to lung tissue potentially causing a pulmonary embolism. Affected lung tissue from FES can result in mild hypoxemia to acute lung injury and acute respiratory distress syndrome. Signs and symptoms might include tachypnea, dyspnea, shortness of breath, tachycardia, hypoxemia, cyanosis, lung crackles, change in mental status, restlessness, and anxiety related to impaired gas exchange caused by the fat embolism. Other common organs that

Fat Embolism Syndrome

3

are affected by fat emboli include the brain and skin. The symptoms associated with the central nervous system are non-specific and believed to be the result of cerebral edema cause by the fat emboli as opposed to ischemia. Clinical presentation may include change in mental status, fever, lethargy, and restlessness. Petechiae or round, pinpoint spots that can be brown, red, or purple in color, can be observed on the skin. Petechiae is is the result of the fat emboli occluding the dermal capillaries and causing damage and bleeding [ CITATION Wal02 \l 1033 ]. Overall, the body systems affected by FES vary greatly. Subjective and Objective Assessment Onset of FES typically takes place within hours to several days after orthopedic trauma. It is important to get a baseline on the patient in order to quickly detect changes that may be indicative of a fat embolism development. Vitals, oxygen saturation, level of consciousness, and a full head-to-toe assessment should be completed. Blood analysis that includes CBC, ABGs, electrolytes, and serum lipid levels should also be monitored to aid in the detection of FES [ CITATION Har04 \l 1033 ]. The assessment should include asking the patient about the time of injury, if he or she has been able to immobilize the affected extremity since injury, and if the patient has noticed any new onset difficulty in breathing, mental status, or rashes. The nurse should also complete a respiratory assessment including auscultation for crackles and monitor for hypoxemia and tachypnea. Changes in neurological and cognitive status could give insight into potential cerebral fat emboli; also hyperthermia is thought to result from a fat emboli affecting the hypothalamus [ CITATION Wal02 \l 1033 ]. Diagnostic Tests There is no specific diagnostic test to identify FES. FES is typically a diagnosis of exclusion based on symptoms and findings. Microscopic examination of blood, urine, and sputum can reveal fat globules and can aid in diagnosis but is overall nonspecific to FES. If vision is affected and FES is suspected, a fundoscopic examination of the retina can be completed to assess for blockages and vascular hemorrhages [ CITATION Gor05 \l 1033 ]. The absence of specific tests makes FES challenging to diagnose. Other Associated Tests Changes in lab values that include a complete blood cell count, sedimentation rate and, basic metabolic profile can aid in diagnosis but are non-specific. Some abnormal lab findings related to FES are not completely understood. Infiltrates that can be seen from chest x-rays and chest CT scans can show signs of pulmonary edema but again, are non-specific to FES [ CITATION Kwi13 \l 1033 ].

Fat Embolism Syndrome

4

Risk Factors Risk factors for the development of a fat embolism increase for anyone with long bone trauma, hip and pelvis fractures. The risk of developing FES is more likely to occur within hours to a few days from the time of injury or trauma. FES is more common in males 20-40 years in age and older adults 70-80 years of age. [ CITATION Ign18 \l 1033 ]. Complications As a fat emboli can travel throughout the body, it has the potential to create a variety of complications and can result in multiorgan dysfunction. The most potentially significant and common complication of FES is an impact on pulmonary circulation. Up to 75% of patients with FES experience respiratory depression. The complications from affected lung tissue can range from milder hypoxemia to acute respiratory distress syndrome requiring intubation. The mortality rate associated with FES is between 7% and 10% [ CITATION Kwi13 \l 1033 ]. Another common complication that can help aid in the diagnosis of FES is Petechiae, where dermal capillaries are damaged causing bleeding [ CITATION Wal02 \l 1033 ]. Overall, complications from FES are dependent on where the fat embolism is formed and where the circulatory system allows the fat embolism to travel. Medical Treatments Pharmacological treatments for specifically treating fat emboli have largely been unsuccessful. Anticoagulation with Heparin and the use of dextrose to clear free fatty acids are no longer used clinically because their benefits are unproven. Corticosteroids have been used to reduce inflammation and aid in clearing free fatty acids after long bone fractures and trauma. Studies have found corticosteroids can significantly reduce FES formation. However, they remain controversial due to potential side effects and have not been found to reduce mortality [ CITATION Kwi13 \l 1033 ]. Albumin 25% has been used to maintain intravascular volume and decrease the risk of lung injury by binding with free fatty acids. High-risk patients may have a vena cava filter placed following a bone fracture to stop the fat emboli from traveling to the lungs [ CITATION Lip19 \l 1033 ].

Fat Embolism Syndrome

5

Potential Health-Related Problems A patient with a fat embolism has the potential to experience impaired gas exchange due to emboli traveling through venous circulation and through the right side of the heart. The embolus becomes lodged in a smaller pulmonary artery causing a blockage in the lung that can cause damage and impair gas exchange. Another potential health related problem of fat emboli is ineffective cerebral tissue perfusion. The fat embolus can impair blood flow to cerebral tissue causing ischemia but is often thought to cause cerebral edema where neurological symptoms are non-lateralizing [ CITATION Kwi13 \l 1033 ]. Nursing Interventions The nurse should monitor vitals, oxygen saturation, level of consciousness, and perform regular respiratory assessments to identify signs and symptoms of impaired gas exchange with the FES patient. Administration of supplemental oxygen for hypoxic patients and quickly recognizing the often rapidly developing signs and symptoms of respiratory failure are key. The nurse should also regularly assess neurocognitive status and level of consciousness to detect any changes that could be indicative of decreased cerebral perfusion and/or cerebral edema. The nurse would want to obtain a baseline Glasgow Coma Scale measurement and reassess for any changes from baseline. A key intervention to avoid complications of fat emboli is to keep the affected extremity mobilized with proper splinting and using proper techniques and devices to safely move and transport the patient. Related Concepts Clinical judgment is an important nursing concept related to FES. This is due to the nature of fat emboli having the ability to affect tissues and organs all throughout the body and the lack of specific tests that can diagnosis FES. The nurse must use critical thinking skills and assess the overall clinical picture to recognize FES and provide interventions sooner to improve patient outcomes. This would involve a thorough review of the patient’s medical history and regular assessments to detect changes from baseline indicative of FES. Another important nursing concept related to FES is safety. The nurse should promote safety and collaborate with patients on measures that can be taken to avoid trauma and fractures, and subsequently potential fat emboli. This may involve teaching elderly patients to declutter and remove tripping hazards from their home or teaching a younger patient about the use of protective gear while playing sports. Overall, avoiding injury would be the best way to avoid the development of FES.

Fat Embolism Syndrome

6

Evidence-Based Practice Intravenous corticosteroids have long been used for prophylactic treatment of FES in patients that have experienced skeletal trauma, but its use is limited by surgeons due to its systemic effects. A recent study reviewed the effectiveness and safety for using an inhaled corticosteroid in preventing FES and improving hypoxia in patients with isolated skeletal trauma. Upon admission the trial group received 640 mcg of ciclesonide with a metered dose inhaler while the control group did not. In the trial group 5.71% of the patients developed FES as compared to 25.71% in the control group. Additionally, 9% of the trial group developed hypoxia compared to 22.85% in the control group [CITATION Sen16 \l 1033 ]. This study is important because it highlights the fact that there may be effective prophylactic measures that clinicians can take to decrease the occurrence of FES and its complications. Of course, more research is needed surrounding FES and its treatments.

Fat Embolism Syndrome

7

References Gore, T., & Lacey, S. (2005). Bone up on fat embolism syndrome. Nursing, 35(8): 32hn1-32hn4. doi:http://dx.doi.org.lcc.idm.oclc.org/10.1097/00152193-200508000-00026 Harris, H. R. (2004). Fat embolism. Nursing2004: June 2004 - Volume 34 - Issue 6, 96. doi:https://doiorg.lcc.idm.oclc.org/10.1097/00152193-200406000-00064 Ignatavicius, D. D., Workman, L., & Rebar, C. (2018). Medical-Surgical Nursing: Concepts for Interprofessional Collaborative Care, 9th Edition. St. Louis: Elsevier. Kwiatt, M., & Seamon, M. (2013). Fat embolism syndrome. International Journal of Critical Illness and Injury Science (Vol. 3, Issue 1). Retrieved from Fat embolism syndrome: https://go-galecom.lcc.idm.oclc.org/ps/i.do?p=AONE&u=lom_lansingcc&id=GALE| A325409267&v=2.1&it=r&sid=AONE&asid=5446265d Lipincott Advisor. (2019, October 4). Fat embolism syndrome. Retrieved from Lipincott Advisor: https://advisor-edu.lww.com/lna/document.do?did=815200 Sen, R. P. (2016). Inhalational Ciclesonide found beneficial in prevention of fat embolism syndrome and improvement of hypoxia in isolated skeletal trauma victims. European Journal of Trauma and Emergency Surgery, 313-318. doi:https://doi-org.lcc.idm.oclc.org/10.1007/s00068-016-0633-1 Walls, M. (2002). Orthopedic trauma! RN, 65(7), 52–58....