Diagnostic Point-of-Care Ultrasound: Assessment Techniques for the Pediatric Trauma Patient - Trauma EXTRA Supplement

Table of Contents

 

Diagnostic POCUS can help emergency clinicians make management decisions for pediatric trauma patients quickly at the bedside, without the risks associated with exposure to ionizing radiation from CT scans. This supplement reviews the evidence for the use of diagnostic ultrasound in the pediatric emergency setting and discusses techniques for common applications of POCUS for the assessment of trauma in pediatric patients. You will learn:

How to perform the FAST and E-FAST examinations to detect free fluid, pneumothorax, and hemothorax

How skull fractures are differentiated from sutures on ultrasound

How to use ultrasound to identify forearm fractures and guide fracture reductions

The pediatric-specific cardiac ultrasound views to obtain when assessing for pericardial effusion, cardiac tamponade, and left ventricular ejection fraction

The applications of intra-arrest cardiac ultrasound in pediatric patients

How to take measurements of the inferior vena cava on ultrasound for intravascular volume assessment

The signs to look for when using ultrasound to assess for testicular torsion

1. Abstract
2. Introduction
3. Critical Appraisal of the Literature
4. Prehospital Ultrasound
5. Emergency Department Assessment Using Ultrasound
   1. FAST Examination
      1. Future Applications
   2. E-FAST Examination
      1. E-FAST to Detect Pneumothorax
      2. E-FAST to Detect Hemothorax
   3. Assessment for Skull Fractures
      1. Technique
      2. Future Applications
   4. Update: Assessment for Forearm Fractures
      1. Technique
      2. Future Applications
   5. Lung Ultrasound
      1. Technique
   6. Cardiac Ultrasound
      1. Technique
         • Subxiphoid View
         • Apical 4-Chamber View
         • Parasternal Long-Axis View
         • Parasternal Short-Axis View
         • Other Cardiac Views
      2. Indications for Cardiac Ultrasound
         • Pericardial Effusion and Tamponade
         • Assessment of Left Ventricular Ejection Fraction
         • Cardiac Arrest
   7. Assessment of Intravascular Volume
      1. Technique
      2. Future Applications
   8. Assessment for Testicular Torsion
      1. Technique
6. Controversies and Cutting Edge
7. Summary
8. Acknowledgement
9. Editor’s Note
10. Figures
    1. Figure 1. Right Upper Quadrant View in the FAST Examination
    2. Figure 2. Left Upper Quadrant View in the FAST Examination
    3. Figure 3. Pelvic View in the FAST Examination
    4. Figure 4. Subxiphoid Cardiac View in the FAST Examination
    5. Figure 5. Lung View in the E-FAST Examination for Assessment of Pneumothorax
    6. Figure 6. Skull Fracture on Ultrasound
    7. Figure 7. Transducer Placement for Posteroanterior View
    8. Figure 8. Transducer Placement for Anteroposterior View
    9. Figure 9. Transducer Placement for Lateral View
    10. Figure 10. Nondisplaced Radius Fracture
    11. Figure 11. Minimally Displaced Radius Fracture
    12. Figure 12. Significantly Displaced Radius Fracture
    13. Figure 13. Buckle Fracture of the Distal Radius
    14. Figure 14. Wrist Joint
    15. Figure 15. Cardiac Ultrasound in the Subxiphoid View
    16. Figure 16. Cardiac Ultrasound in the Apical 4-Chamber View
    17. Figure 17. Cardiac Ultrasound in the Parasternal Long-Axis View
    18. Figure 18. Cardiac Ultrasound in the Parasternal Short-Axis View, Mitral Valve Level, in the Cardiology Orientation
    19. Figure 19. Pericardial Effusion Seen Through the Subxiphoid Window
    20. Figure 20. Pericardial Effusion Seen Through the Parasternal Long-Axis View
    21. Figure 21. Inferior Vena Cava in the Long Axis
    22. Figure 22. Inferior Vena Cava and Aorta in the Short Axis
11. Videos
    1. Ultrasound assessment of the peritoneum for free fluid
    2. Tutorial on performing the E-FAST examination on pediatric patients
    3. Tutorial on performing focused cardiac ultrasound on pediatric patients
12. References

Abstract

Emergency ultrasound is performed at the point of care to quickly answer focused clinical questions. Over the last 25 years, the use of this technique has expanded rapidly. The use of emergency ultrasound in the pediatric setting is increasing because it does not expose the patient to ionizing radiation, as compared to computed tomography (CT). Utilizing diagnostic point-of-care ultrasound (POCUS) for pediatric trauma patients in the emergency department (ED) can facilitate diagnosis at the bedside rather than sending the patient out of the department for another study. This supplement focuses on some of the common indications for diagnostic POCUS that may be useful in the setting of trauma, as found in the pediatric literature, or extrapolated from adult literature where pediatric evidence is scarce.

Introduction

The use of ultrasound at the point of care by emergency clinicians, as well as by other specialists, has become increasingly common over the last 25 years. Emergency POCUS can be used as a diagnostic test and also to visualize anatomy for procedural guidance. It allows the emergency clinician to rapidly rule in or rule out disease processes and guide ongoing investigation and management of patients in the ED. POCUS is a skill required by the Accreditation Council for Graduate Medical Education for emergency medicine residency training,¹ and it is supported by many organizations, including the American Medical Association, the American Academy of Pediatrics, the American College of Emergency Physicians, the American Board of Emergency Medicine, and the American Institute for Ultrasound in Medicine.

Pediatric emergency ultrasound has been slower to progress than adult emergency ultrasound. Of the more than 120 emergency ultrasound fellowships currently listed on the Society for Clinical Ultrasound Fellowships website, only 14 are pediatric-specific. However, the use of emergency ultrasound for pediatric patients has recently begun to formalize. The American Academy of Pediatrics, along with several emergency medicine and ultrasound societies, released a policy statement in 2015 that supported the use of POCUS by pediatric emergency physicians.² In 2016, a review was published that reported guidelines and training objectives for pediatric-specific POCUS applications.³ Most pediatric emergency medicine fellowship directors now consider POCUS to be an essential skill and many include formal POCUS training in their curricula.⁴

The pediatric patient is arguably more suited for emergency ultrasound than the adult patient. Children generally have a smaller body habitus than adults and, therefore, less tissue for the ultrasound beams to penetrate. This often leads to clearer images of the different organ systems, which should yield better diagnostic accuracy. There has been sparse data to support this assumption, due to a lack of comparative studies of the populations. The largest meta-analyses pooled together adult and pediatric patients without separately assessing the diagnostic accuracy of this testing in adults and children, even for the most basic emergency ultrasound technique, the focused assessment with sonography for trauma (FAST) examination.^5-10

Children are an ideal target population in which to increase the use of emergency ultrasound. Exposure to ionizing radiation from CT scans may lead to an increased incidence of cancer.^11-13 Pediatric cells divide at a faster rate than adult cells, so pediatric patients have a greater risk of harm from ionizing radiation compared to adults. The number of CT scans performed overall has increased 5-fold over the last 20 years, and it is widely believed that an increased incidence of cancer directly linked to medical imaging will be seen.¹⁴ One large retrospective epidemiological study found a small, but significant, increase in cancer related to CT scanning in the first decade of life. The study predicted that, among patients aged < 10 years who received a CT scan, there would be 2 cases of excess cancer (cancer that would not have occurred without the CT scans) per 10,000 CT scans in the decade following the scan.¹⁵ With an estimated 4 million CT scans being performed annually in pediatric patients,¹⁶ it is incumbent on healthcare providers to find alternate diagnostic methods for these patients. Ultrasound has been shown to have a high diagnostic accuracy for many pathologies, without the associated risks of ionizing radiation.

Diagnostic ultrasound for pediatric patients has traditionally been in the domain of pediatric radiologists and technicians who are skilled in the interpretation of ultrasound for pediatric-specific pathologies. Many centers do not have access to pediatric radiologists or do not have access to pediatric ultrasound during evening and night hours. These centers generally transfer pediatric patients who need medical and surgical care to tertiary care centers with pediatricians and pediatric surgeons. However, ultrasound technology has improved to include portable ultrasound machines and ultrasound transducers that can be attached to smartphones. If the emergency clinician can make or rule out a diagnosis at the bedside, transfer to the appropriate facility can be expedited and unnecessary transfers avoided.

Critical Appraisal of the Literature

A literature search was performed in PubMed to identify relevant articles pertaining to each of the modalities discussed, utilizing combinations of the following search terms: diagnostic emergency ultrasound, pediatric, cardiac, pericardial effusion, tamponade, cardiac arrest, ejection fraction, focused assessment with sonography in trauma, FAST, pelvic trauma, extended focused assessment sonography in trauma, E-FAST, skull, forearm, lung, and testicular torsion. Original research, systematic reviews, and meta-analyses were the primary literature reviewed. If there was a lack of original research, case reports and case series were evaluated and presented. Additionally, previous reviews were used to identify relevant literature. Critical appraisal for specific indications will be discussed in the relevant sections.

Before pediatric data became available, most of the evidence for the utility of pediatric emergency ultrasound was derived from adult literature. However, there are important differences in the efficacy of pediatric emergency ultrasound compared to adult emergency ultrasound. While the FAST examination is the most widely used and accepted emergency ultrasound modality in adults, its diagnostic accuracy in children has been shown to be poor.^5,17 Fortunately, the emergency ultrasound field is expanding very rapidly, and more emergency ultrasound research is being conducted than ever before. It is, therefore, expected that more pediatric emergency ultrasound data will be available in the near future. This supplement will focus on the pediatric-specific emergency ultrasound literature. Where there is a paucity of pediatric data in the emergency setting, adult emergency ultrasound data or pediatric radiology data will be presented.

Prehospital Ultrasound

Ultrasound has been investigated for use in the prehospital setting. It is used widely in Europe,¹⁸ but is less often used in this setting in North America.¹⁹ In a recent survey of emergency medical services (EMS) directors in the United States and Canada, the most common reasons for not implementing prehospital ultrasound were equipment and training costs, as well as a lack of evidence that it reduces patient morbidity and mortality.¹⁹ Two systematic reviews, 1 for trauma and 1 for nontrauma, concluded that there was insufficient evidence that prehospital ultrasound improves patient outcomes.^20,21 There are no randomized controlled trials in this area, and there are no studies in the pediatric setting in particular. Most of the studies are from the trauma setting and assessed patients of all ages, while some excluded pediatric patients.

Despite the lack of evidence on patient outcomes, there is evidence that ultrasound is feasible and accurate in the prehospital setting when performed either by physicians or nonphysician clinicians, especially in the context of trauma.²¹ Studies evaluating the feasibility of ultrasound included adult patients, and, therefore, may not reflect feasibility in pediatric patients. A prospective multicenter British study looked at FAST performed by EMS personnel and physicians on adults and children with suspected blunt or penetrating abdominal trauma. For the 202 patients completing the protocol, they found a sensitivity of 93% and a specificity of 99% as confirmed by hospital ultrasound or CT. Furthermore, prehospital management was altered in 30% of cases and the choice of admitting to the hospital changed in 22% of cases.²² Of note, because FAST has been shown to be less accurate in pediatric patients as compared to adult patients and because the results of this study were not separated between pediatric patients and adult patients, the accuracy of FAST in this study cannot be extrapolated to the pediatric population. In a Korean study, FAST performed by EMS personnel was found to have a similar diagnostic accuracy compared to FAST performed by physicians.²³ Lyon et al randomized a cadaver to tracheal or esophageal intubations to assess prehospital critical care clinician accuracy in the diagnosis of lung sliding on ultrasound. After a 9-month period without additional teaching, the prehospital clinicians maintained a sensitivity and specificity of 100%.²⁴

Retrospective studies and case series have evaluated the use of prehospital ultrasound in the mass casualty setting, both for earthquakes and war zones. These reports use ultrasound as an adjunct to the simple triage and rapid treatment (START) protocol in the prehospital setting and as an adjunct to clinical care in the hospital setting.^25-29 In a report on casualty management of victims of an earthquake in China, patient statuses were successfully upgraded from yellow to red based on the FAST.²⁸ Whether or not ultrasound changes outcomes in this setting requires further study.

Editor’s Note

For a detailed review of additional diagnostic ultrasound applications for pediatric patients, including assessment for pneumonia, appendicitis, intussusception, pyloric stenosis, and pregnancy in the first trimester, see the January 2016 issue of Pediatric Emergency Medicine Practice titled, “Diagnostic Emergency Ultrasound: Assessment Techniques In The Pediatric Patient.”

For a detailed review of procedural ultrasound applications for pediatric patients, including the use of ultrasound guidance for peripheral line placement, bladder catheterization, lumbar puncture, and foreign body removal, see the June 2016 issue of Pediatric Emergency Medicine Practice titled, “Procedural Ultrasound In Pediatric Patients: Techniques And Tips For Accuracy And Safety.”

Figures

Videos

Ultrasound assessment of the peritoneum for free fluid

Tutorial on performing the E-FAST examination on pediatric patients

Tutorial on performing focused cardiac ultrasound on pediatric patients

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study will be included in bold type following the references, where available.

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77. Rozycki GS, Feliciano DV, Ochsner MG, et al. The role of ultrasound in patients with possible penetrating cardiac wounds: a prospective multicenter study. J Trauma. 1999;46(4):543-551. (Prospective cohort study; 225 patients)
78. Jones AE, Tayal VS, Kline JA. Focused training of emergency medicine residents in goal-directed echocardiography: a prospective study. Acad Emerg Med. 2003;10(10):1054-1058. (Prospective observational educational study; 21 participants)
79. Mayron R, Gaudio FE, Plummer D, et al. Echocardiography performed by emergency physicians: impact on diagnosis and therapy. Ann Emerg Med. 1988;17(2):150-154. (Case series; 156 patients)
80. Mandavia DP, Hoffner RJ, Mahaney K, et al. Bedside echocardiography by emergency physicians. Ann Emerg Med. 2001;38(4):377-382. (Prospective study; 103 patients)
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