Emergency ultrasound

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Emergency ultrasound is the application of ultrasound at the point of care to make immediate patient-care decisions. It is performed by the health care professional caring for the injured persons. This point-of-care use of ultrasound is often to evaluate an emergent medical condition, in settings such as an emergency department, critical care unit, ambulance, or combat zone.[1][2]

Setting[edit]

Emergency ultrasound is used to quickly diagnose a limited set of injuries or pathologic conditions,[3] specifically those where conventional diagnostic methods would either take too long or would introduce greater risk to a person (either by transporting the person away from the most closely monitored setting, or exposing them to ionizing radiation and/or intravenous contrast agents).[4][5]

Point of care ultrasound has been used in a wide variety of specialties and has increased in use in the last decade as ultrasound machines have become more compact and portable.[6] It is now used for a variety of exams in various clinical settings at the person's bedside. In the emergency setting, it is used to guide resuscitation and monitor critically ill persons, provide procedural guidance for improved safety and confirm clinical diagnosis.

Scope[edit]

Resuscitation of the critically ill[edit]

Point of care ultrasound is sometimes the only option in the evaluation of injured persons who are too ill for transport to other imaging modalities (i.e. computed tomography, or CT scan) or whose illness is so acute that medical decisions in their care need to be made in seconds to minutes. It is also increasingly used to guide and triage care in resource-limited situations, in rural or medically underserved areas.[7]

In people who present with a traumatic injury, The focused assessment with sonography for trauma or FAST exam is used to assess hypotensive person for occult bleeding. Traditionally used by emergency physicians and surgeons treating trauma persons, it has also been used by paramedics[8] in combat zones,[2] and for non-traumatic problems such as ruptured ectopic pregnancy. Similarly, emergency ultrasound can also evaluate the lungs for hemothorax (bleeding in the chest), and pneumothorax (a puncture resulting in air trapped in the chest and lung collapse).

People presenting with hypotension of unknown cause, ultrasound has been utilized to determine the cause of shock.[9][10] Evaluation of the heart and inferior vena cava (IVC) can help the clinician at the bedside choose important treatments and monitor the response to the interventions.[11][12]

A person who has hypotension and a bedside ultrasound showing hyperdynamic left heart with a flat, collapsible IVC indicates low blood volume. If the person also has a fever, the clinician may determine sepsis, or severe infection is causing the problem. If that same hypotensive person has back pain instead of a fever, the clinician may see an abdominal aortic aneurysm that is leaking or ruptured. Conversely, weak heart activity and a very full, non-collapsible IVC would indicate a cardiac cause for low blood pressure.

For those presenting with acute shortness of breath, ultrasound assessment of the lung, heart, and IVC can evaluate for potentially life-threatening diseases, including pneumothorax, significant pleural effusions, congestive heart failure, pulmonary edema, pericardial effusion, and some large pulmonary emboli.[11][13]

With its increased availability, ultrasound is now frequently used more in code situations, in which a person have lost most or all signs of life.[14] Practitioners may use the ultrasound to see if the heart is moving, beating in organized fashion or if it has a pericardial effusion or fluid around it. Pericardiocentesis, a procedure in which a needle is used to drain the effusion, can utilize ultrasound guidance of a needle to decrease the risk of hitting lungs, heart or other vital organs[15]

Monitoring therapy[edit]

Emergency ultrasound can not only diagnose, but also monitor a persons response to therapeutic interventions. Ultrasound can be utilized to assess a persons intravascular volume status and response to intravenous fluid therapy by measuring the size and respiratory change in the diameter of the IVC.[11] Ultrasound of the lungs may demonstrate resolution of pulmonary edema from congestive heart failure.[16]

Procedural guidance[edit]

Using ultrasound to guide needles during procedures may improve success and decrease complications in procedures performed by multiple specialties, including central[17] and venous access,[18][19] thoracentesis,[20] paracentesis, pericardiocentesis,[21] arthrocentesis, regional anesthesia, incision and drainage of abscesses,[22][23] localization and removal of foreign bodies, lumbar puncture, biopsies, and other procedures.[17]

Diagnostic[edit]

Point-of-care ultrasound is being increasingly used to speed patient care and to avoid ionizing radiation. Quick diagnosis is still valuable for both an injured and healthcare professional. The efficiency of obtaining the answer to a focused question within minutes is one of the driving forces of the popularity of bedside ultrasound. Use of this modality in settings such as the emergency department can decrease waiting times and improve satisfaction among those served.[24]

Cardiac: Chest pain is one of the most common complaints presenting to the emergency department. Those presenting with chest pain, focused cardiac ultrasound can be helpful in the evaluation of persons with potentially life-threatening disease such as a pericardial effusion, a severe pulmonary embolus (or blood clot in the lungs), or in screening those with suspected aortic dissection.[11] The use of ultrasound is also helpful in persons with chest pain due to suspected heart ischemia, especially when the baseline electrocardiogram or EKG, is nondiagnostic.[11] The more technically demanding aspects of echocardiographic interpretation, and should be reserved for more formal comprehensive echocardiography.[11]

Abdominal complaints: Abdominal pain is also a common complaint in the primary care and emergency department setting. Gallbladder disease is a frequent cause of abdominal pain, but can also result in critical illness. Bedside ultrasound assesses the gallbladder for presence of gallstones that cause the majority of gallbladder illness. Emergency ultrasound of the gallbladder can help speed diagnosis and care.[25]

Flank pain can indicate obstructing kidney stones or abdominal aortic aneurysm.[26] If obstructing kidney stones are suspected, the kidneys can be evaluated by ultrasound for signs of obstruction, called hydronephrosis.[27][28] A common use of ultrasound is identifying or evaluating the fetus in a person who is pregnant. Women in the first trimester of pregnancy can have a tubal or ectopic pregnancy outside the uterus that is life-threatening if not identified.[29] A more advanced fetus may be evaluated for normal heart rate and movement and gestational age to help guide care of both the fetus and the pregnant mother.

Other symptom-oriented diagnostic exams: Blood clots that form in deep veins of the body can break off and block blood vessels in the lungs, resulting in low oxygen, heart strain and death. The most common location of these deep vein thromboses (DVTs) is in the legs. A bedside ultrasound can determine the presence or absence of blood clots and their location in the proximal lower extremity to behind the knee.[30][31] Those presenting with eye pain or visual loss, ultrasound of the eye can be used for the detection of orbital pathology.[32] Ultrasound has been described to detect retinal detachments, vitreous hemorrhage, dislocation of the lens, as well as evaluating optic nerve sheath diameters as a potential indicator of other diseases in the central nervous system.[33][34]

Now that ultrasound is available in portable units that are smaller than laptop computers and handheld models, it is being used more and more in many clinical settings. Many practitioners use point-of-care ultrasound in diagnosing other urgent and emergent problems, including appendicitis, testicular torsion, and abscesses. To describe each of these fully is beyond the scope of this entry, and impossible as the use of ultrasound is expanding rapidly:

Training[edit]

Emergency and point-of-care ultrasound is taught in a variety of settings. Many physicians are currently taught bedside ultrasound during the emergency medicine residency training programs in the United States. It can also be learned as part of the continuing education process, through formal didactics, one-on-one training, and clinical application and practice. Other specialists may learn during their residency or fellowship training programs. There are specialized fellowship training programs for bedside ultrasound in emergency medicine, but these are not required nor expected for the use of this tool in practice.

References[edit]

  1. ^ ACEP Policy Statement: Emergency Ultrasound Guidelines. Ann Emerg Med. 2009;53:550-570.
  2. ^ a b Beck-Razi N, Fischer D, Michaelson M et al. The utility of focused assessment with sonography for trauma as a triage tool in multiple-casualty incidents during the second Lebanon war. J Ultrasound Med 2007;26:1149–1156.
  3. ^ Atlas of Emergency Medicine. Kevin J. Knoop, Lawrence B. Stack, Alan B. Storrow. McGraw-Hill Professional, 2002.ISBN 0071352945, ISBN 978-0-07-135294-9.
  4. ^ Emergency Ultrasound: Principles and Practice. Romolo Joseph Gaspari, J. Christian Fox, Paul R. Sierzenski. Mosby, 2005. ISBN 0-323-03750-X, 9780323037501.
  5. ^ http://www.sonoguide.com/introduction.html
  6. ^ Levin DC, Rao VM, Parker L, Frangos AJ. Noncardiac point-of-care ultrasound by non-radiologist physicians: How widespread is it?. JACR 2011; 8(11):772-775.
  7. ^ Dean AJ, Ku BS, Zeserson EM. The utility of handheld ultrasound in an austere medical setting in Guatemala after a natural disaster. Am J Disaster Med. 2007;2(5):249–256.
  8. ^ Walcher F, Weinlich M, Conrad G, Schweigkofler U, Breitkreutz R, Kirshning T. Marzi I. Prehospital ultrasound imaging improves management of abdominal trauma. Br J Surg 2006;93(2): 238-42.
  9. ^ Rose JS et al. The UHP Ultrasound Protocol: A Novel Ultrasound Approach to the Empiric Evaluation of the Undifferentiated Hypotensive Patient. AJEM; 19(4):299-301.
  10. ^ Jones AE et al. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Critical Care Med. 2004;32(8):1703-1708.
  11. ^ a b c d e f Labovitz AJ et al. Focused Cardiac Ultrasound in the Emergent Setting: A Consensus Statement of the American College of Emergency Physicians. JASE 2010; 23(12):1225-1230.
  12. ^ Hernandez C et al. C.A.U.S.E.:Cardiac arrest ultrasound exam—a better approach to managing patients in primary non-arrhythmogenic cardiac arrest. Resuscitation 2008; 76:198-206.
  13. ^ Litchenstein DA, Meziere GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure. The BLUE Protocol. Chest 2008; 134(1):117-125.
  14. ^ Blaivas M, Fox J. Outcome in cardiac arrest patients found to have cardiac standstill on bedside emergency department echocardiogram. Acad Emerg Med. 2001;8:616-621.
  15. ^ Salem K, Mulji A, Lonn E. Echocardiographically guided pericardiocentesis -- the gold standard for the management of pericardial effusion and cardiac tamponade. Can J Cardiol 1999;15:1251-1255.
  16. ^ Noble VE et al. Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis: time course for resolution. CHEST. 2009; 135(6) 1433-1439.
  17. ^ a b Moore CL, Copel JA. Point-of-Care Ultrasonography. NEJM 2011; 462(8):749-757.
  18. ^ Constantino TG et al. Ultrasonography-guided peripheral intravenous access versus traditional approaches in persons with difficult intravenous access. Ann Emerg Med. 2005; 46:456-61.
  19. ^ Blaivas M, Lyons M. The Effect of Ultrasound Guidance on the Perceived Difficulty of Emergency Nurse-Obtained Peripheral IV Access. Journal of Emergency Medicine 31(4):407-410.
  20. ^ Tayal VS, Nicks BA, Norton HJ. Emergency ultrasound evaluation of symptomatic nontraumatic pleural effusions. American Journal of Emergency Medicine. 2006. 24, 782-786.
  21. ^ Nazeer SR, Dewbre H, Miller AH. Ultrasound-assisted paracentesis performed by emergency physicians vs the traditional technique: a prospective, randomized study. Amer J Emerg Med. 2005; 23:363-367.
  22. ^ Squire BT, Fox JC, Anderson C. ABSCESS: Applied Bedside Sonography for Convenient Evaluation of Superficial Soft Tissue Infections. Acad Emerg Med 2005; 12(7): 601-606.
  23. ^ Vivek S. Tayal, MD, Nael Hasan, MD, H. James Norton, PhD, Christian A. Tomaszewski, MD The Effect of Soft-tissue Ultrasound on the Management of Cellulitis in the Emergency Department. Acad Emerg Med 2006; 13(4):384-388.
  24. ^ Lindelius A, Torngren S, Nilsson L, Pettersson H, Adami J. Randomized clinical trial of bedside ultrasound among patients with abdominal pain in the emergency department: impact on patient satisfaction and health care consumption. Scand J Trauma Resusc Emerg Med. 2009 Nov 27;17:60.
  25. ^ Blaivas M, Harwood M, Lambert M. Decreasing length of stay with emergency ultrasound examination of the gallbladder. Ultrasonography 1999; 6:1020-1023
  26. ^ Kuhn M, Bonnin RLL, Davey MJ, et al. Emergency department ultrasound scanning for abdominal aortic aneurysm: Accessible, accurate, and advantageous. Ann Emerg Med. 2000; 36:219-223
  27. ^ Gaspari RJ, Horst K. Emergency ultrasound and urinalysis in the evaluation of flank pain. Acad Emerg Med. Dec 2005;12(12):1180-4
  28. ^ Kartal M, Eray O, Erdogru T, Yilmaz S. Prospective validation of a current algorithm including bedside US performed by emergency physicians for patients with acute flank pain suspected for renal colic. Emerg Med J. May 2006;23(5):341-4
  29. ^ Durham B, Lane B, Burbridge L, Balasubramaniam S. Pelvic Ultrasound Performed by Emergency Physicians for the Detection of Ectopic Pregnancy in Complicated First-Trimester Pregnancies. Ann Emerg Med. 1997; 29:338-347
  30. ^ Burnside PR, Brown MD, Kline JA. Systematic review of emergency physician-performed ultrasonography for lower extremity deep vein thrombosis. Acad Emerg Med. 2008;15:493-498
  31. ^ Theodoro DL, Blaivas M, Duggal D, et al. Emergency physician performed lower extremity doppler results in significant time savings. Acad Emerg Med. 2002; 9:541 Abstract.
  32. ^ Blaivas M. Bedside emergency department ultrasongraphy in evaluation of ocular pathology. Acad Emerg Med. 2000; 7:947-950
  33. ^ Kimberly HH et al. Correlation of Optic Nerve Sheath Diameter with Direct Measurement of Intracranial Pressure. Acad Emerg Med. 2008: 15(2):201-204
  34. ^ Tayal V, Neulander M, Norton H, et al. Emergency department sonographic measurement of optic nerve sheath diameter to detect findings of increased intracranial pressure in adult head injury patients. Ann Emerg Med. 2007;49:508-514

See also[edit]