Bedside ultrasound has become the standard tool for clinical evaluation in the emergency room. It is considered so vital that the American College of Emergency Physicians (ACEP) considers emergency, clinical Point of Care Ultrasound (POCUS) to be a fundamental skill for emergency medicine physicians and should be included in the residency training curriculum.1 Likewise, the European Society for Emergency Medicine (EUSEM) includes POCUS as a key part of its curriculum.2
The widespread use of emergency ultrasound carries benefits for patients and hospitals for faster, more cost-effective first-line assessment. Its clinical uses range from evaluating fractures, ectopic pregnancy, appendicitis to shock, heart attack, assessing internal bleeding after trauma, and guiding needle procedures.
What are the common applications of emergency ultrasound, and how might emergency physicians use them to make more informed decisions? Here's what the literature suggests.
Benefits of POCUS in Emergency Medicine
In the emergency department, it's essential to evaluate and triage patients quickly. Emergency medicine physicians use POCUS for immediate answers to guide treatments or rule out differential diagnoses. The ACEP notes that ultrasound use is associated with procedural safety, faster care, more accurate diagnoses, and reduced costs. It also supports the "staged imaging" concept, which aims to answer the most pressing clinical questions first before referring patients for more expensive imaging or invasive procedures that carry their own risks.1
Common Emergency Ultrasound Uses
The American College of Cardiology (ACC) highlights six areas in which POCUS is critical in the emergency department (ED) as a fast, reliable diagnostic tool:3
Undifferentiated shock. POCUS allows clinicians to quickly identify the cause of shock and determine the type of shock in an average of six minutes. This has led to an overall improvement in diagnostic accuracy.
Cardiac arrest. Ultrasound findings can help determine prognosis and guide the use of cardiac resuscitation efforts.
Trauma. The extended focused assessment with sonography for trauma (eFAST) is a standardized approach to evaluating trauma patients, primarily to assess internal bleeding. Ultrasound findings from eFAST help clinicians determine treatment approaches and can sometimes reduce the need for computed tomography (CT) scans.
Chest pain. Chest pain is a non-specific complaint in the ED that can have a wide range of causes. POCUS helps narrow down possible causes to reach a diagnosis, so doctors can act fast.
Dyspnea or shortness of breath. Similar to chest pain, difficulty breathing can be caused by many conditions. Ultrasound findings can help determine whether the cause is cardiac or pulmonary.
Abdominal pain. Many causes of abdominal pain can be seen with POCUS, making this an essential tool for narrowing down a diagnosis. POCUS can look for kidney stones, gallstones, abdominal aortic aneurysms, appendicitis, or bowel obstruction, among others.
Arterial Access with Ultrasound
Peripheral intravenous catheter (PIV) and central venous catheter (CVC) insertion are common procedures in the ED, but they carry a risk of complications and infection, which may be reduced with the use of ultrasound.4,5 A PIV line is inserted in a peripheral vein to administer medications, fluids, blood, or other therapies. A CVC is more invasive and may be needed in some treatment circumstances to deliver therapy or if the PIV has failed. It involves inserting a line in a large vein in the neck, chest, groin or arm. The line is longer and thicker than a PIV and can stay in longer for people who need repeat therapy.
Accurately locating the vein and inserting the needle is key to a successful procedure. Traditionally, a PIV is inserted by looking for and palpating the vein, but this can be challenging in some patients. Failure to access the vein with PIV can lead to patients needing a more invasive CVC. Using ultrasound to guide the insertion can improve safety and accuracy.
The ACEP and the Society of Hospital Medicine (SHM) recommend using real-time ultrasound guidance for PIV and CVC insertion. In addition, numerous professional societies, including the Society of Cardiovascular Anesthesiologists, recommend using real-time ultrasound for specific CVC placements.6
PIV Access
The ACEP recommends using ultrasound for PIV line insertion and considers this process an "essential skill" for emergency physicians.4 PIV access can be challenging in patients with obesity, chronic illness, previous venous surgery or vascular pathology, or from drug use or chemotherapy. For these patients, a physician may opt to do a central line placement instead, which is more invasive and carries more complications.
Using bedside ultrasound to guide PIV line insertion helps overcome visual limitations and prevent unnecessary CVCs.4 One challenge, however, is the lack of standardized guidance for performing the procedure. Although the ACEP has not recognized the superiority of a short-axis or long-axis approach, it recommends physicians know how to perform both and summarizes best practices for the procedure, highlighting that clinicians should carefully choose the site, position the patient appropriately and comfortably, and know both approaches.4
CVC Insertion
Millions of patients annually have a central line inserted, but despite how common the procedure is, it still carries risks for critically ill patients. Some of these risks include accidental lung puncture, injury to the artery, and hemorrhage. Without ultrasound, physicians use a technique that involves anatomic 'landmarks' to locate the blood vessel. But in 35% of cases studied, this method was unsuccessful and had a complication rate of 19%.7
CVCs have an overall complication rate of 15%, most commonly pneumothorax alongside other mechanical complications, and infections.8 Research has found a large reduction in complications and errors with ultrasound guidance, including a 35% lower risk of central line-associated bloodstream infection (CLABSI).7
The SHM recommends physicians use real-time ultrasound for subclavian vein CVCs, internal jugular vein catheterization, femoral venous access, and peripherally inserted central catheters5. International guidelines also recommend using ultrasound for CVC insertion, particularly for internal jugular and femoral vein access. These recommendations are based on evidence that ultrasound guidance led to fewer complications, fewer needle passes, and higher procedure success rates when compared with landmark-based techniques.,9
CVC insertion may be done through a short-axis (transverse) or long-axis (longitudinal) approach. Each approach has its pros and cons, and the SHM doesn't promote one approach over another.5 However, the American College of Critical Care Medicine weighs in to recommend using the short-axis approach for CVC.6
As ultrasound technology continues to advance with artificial intelligence (AI) and machine learning applications, POCUS continues to remain one of the top imaging modalities for emergency care. Continued training ensures the use of best practices, but advancing technology also provides clinicians with an ever-increasing array of clinical decision support tools, providing fast, accurate answers to get patients the care they need at the right time.
References:
1. American College of Emergency Physicians. Ultrasound guidelines: Emergency, point-of-care, and clinical ultrasound guidelines in medicine. https://www.acep.org/globalassets/new-pdfs/policy-statements/ultrasound-guidelines---emergency-point-of-care-and-clinical-ultrasound-guidelines-in-medicine.pdf. Accessed April 20, 2022.
2. European Society for Emergency Medicine. European Curriculum of Emergency Medicine. Eusem.org. https://eusem.org/education/curriculum/european-curriculum-of-emergency-medicine. Accessed June 3, 2022.
3. Melgarejo S, Schaub A, Noble V. Point of care ultrasound: An overview. American College of Cardiology. https://www.acc.org/latest-in-cardiology/articles/2017/10/31/09/57/point-of-care-ultrasound. Accessed April 20, 2022.
4. Preiksaitis C, Ashenburg N. Tips and tricks: Best practices for ultrasound-guided IV placement. American College of Emergency Physicians. https://www.acep.org/emultrasound/newsroom/jul2021/tips-and-tricks-best-practices-for-ultrasound-guided-iv-placement/Accessed April 20, 2022.
5. Franco-Sadud R, Schnobrich D, Mathews B, et al. Recommendations on the use of ultrasound guidance for central and peripheral vascular access in adults: A position statement of the society of hospital medicine. Journal of Hospital Medicine. 2019 Sep;14:E1-E22. https://pubmed.ncbi.nlm.nih.gov/31561287/.
6. Saugel B, Scheeran T, Teboul JL. Ultrasound-guided central venous catheter placement: A structured review and recommendations for clinical practice. Critical Care.
2017 Aug;21. https://ccforum.biomedcentral.com/articles/10.1186/s13054-017-1814-y.
7. Mandavia D. Ultrasound-guided procedures: Financial and safety benefits. ICU Management & Practice. 2015;15(2). https://healthmanagement.org/c/icu/issuearticle/ultrasound-guided-procedures-financial-and-safety-benefits.
8. Odendaal J, Kong VY, Sartorius B, et al. Mechanical complications of central venous catheterisation in trauma patients. Annals of The Royal College of Surgeons of England. 2017 May;99(5):390-393. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5449698/.
9. Frankel H, Kirkpatrick A, Elbarbary M. Guidelines for the Appropriate Use of Bedside General and Cardiac Ultrasonography in the Evaluation of Critically Ill Patients—Part I. Critical Care Medicine. 2015 November; 43(11):2479-2502. https://dx.doi.org/10.1097/CCM.0000000000001216.
