The use of point-of-care ultrasound (POCUS) has become significantly more widespread over the past 20 years and is now a regular part of residency training in specialties such as obstetrics and gynecology, emergency medicine, and anesthesia. Ultrasound technology was originally introduced in the 1950s, with portable devices making their appearance in the adult emergency medicine arena in the 1980s.1 Since then, the convenience and portability of these devices have greatly increased. The US Food and Drug Administration has even approved devices to attach to a smart phone.2
The use of POCUS in clinical care by non-radiologists has greatly increased over the past few decades, partially due to improvement of technology but also because of increasing awareness of the harm of ionizing radiation to patients.3,4 In 1999, the American Medical Association (AMA) released a statement supporting the use of POCUS for non-radiologists, saying that the “AMA policy on ultrasound acknowledges that broad and diverse use and application of ultrasound imaging technologies exists in medical practice” and that it is “within the scope of practice of appropriately trained physicians.”5
Children in particular are prime candidates for ultrasound as they are both usually thinner than adults and are particularly at risk for the harmful effects of ionizing radiation.6 Many applications of POCUS have been described for use in pediatric emergency medicine, in the pediatric intensive care unit, and neonatal intensive care unit. Recently, there has been a push for the use of POCUS in the outpatient setting by primary care providers.7 The American College of Physicians (ACP) even offers continuing medical education credit and credentials for learning ultrasound techniques.8
In this article, we propose uses of POCUS that pediatric generalists can use to help their practice. We present 10 clinical questions (in a two-part article) that can potentially be answered using POCUS in the inpatient or outpatient pediatric setting. The list is not exhaustive, and POCUS applications were chosen based on usefulness, ease of performing, and/or published evidence. The purpose of this article is to make the case for pediatricians to learn more about these POCUS techniques and is not meant as a substitute for training to learn these applications at a competent level. The first five clinical questions are presented in this article.
Does this Patient Have an Abscess or Cellulitis?
It is important for the general pediatrician to distinguish cellulitis from a cutaneous abscess, as the two have different recommended interventions and have a different prognosis. Several articles point out the limitations of history and physical examination in making this distinction.9,10 An abscess may have edema and overlying erythema similar to cellulitis, which limits the examination.11 Excluding an abscess can avoid an unnecessary attempted incision and drainage procedure, sedation, and anxiety.
Cellulitis and an abscess appear differently with ultrasound. Cellulitis appears as thickening of the subcutaneous layer of the skin with a cobblestone appearance, whereas abscesses appear as an anechoic or heterogeneous hypoechoic fluid collection lacking vascularity (Figure 1). Several articles demonstrate that POCUS is superior to clinical examination alone in differentiating between abscess and cellulitis, as seen in a systematic review and meta-analysis.12–15 In the systematic review, six studies with 800 patients were included. Two of the studies reviewed had physicians perform a clinical examination and POCUS, and the remaining four had physicians only perform POCUS while being blinded from the clinical examination.15 The sensitivity of POCUS in diagnosing abscesses versus cellulitis ranged from 90% to 98%, and the specificity ranged from 67% to 88%, whereas in clinical examination alone the sensitivity was 75% to 95% and the specificity was 60% to 84%.15 For most of the studies included in this review, POCUS was performed by physicians with minimal ultrasound training (ie, the most extensive training described being a 1- or 2-day course with 25 POCUS examinations performed). Overall, POCUS may prove to be an invaluable tool to improve the safety and efficiency of care for patients presenting with soft tissue infections.
Skin and soft tissue infection: (A) abscess versus (B) cellulitis. Star indicates the anechoic fluid collection, which represents an abscess. Arrows indicate where intracellular edema and cobblestoning is present.
Does this Patient Have Pneumonia?
Pediatric community-acquired pneumonia (pCAP) is one of the leading causes of morbidity and mortality in children worldwide.16 Consensus guidelines for the diagnosis of pCAP are nonspecific and vary widely based on the patient's age and the infectious organisms involved. Classic symptoms and signs include tachypnea, cough, hypoxia, and fever. However, none of these findings are specific to pneumonia and may be seen in other lung pathologies such as bronchiolitis, bronchitis, or even asthma. Often a chest radiograph (X-ray) is used as an imaging screening tool. Although chest X-ray is a helpful adjunct for the diagnosis of pCAP, it may not be readily be available in the primary care setting, and it also exposes the child to radiation.
The role of POCUS in identifying pneumonia in the pediatric population has been well described in the medical literature.17,18 Consolidations with or without bronchograms seen on POCUS are specific for pneumonia. In fact, in a recent systematic analysis of 12 prospective studies, POCUS was found to have a pooled sensitivity and specificity of 95.5% (93.6%−97.1%) and 95.3% (91.1%−98.3%), respectively, compared to chest X-ray, which had a sensitivity of 86.8% (83.3%−90% and specificity of 98.2% (95.7%−99.6%).17 Another study that included novice and expert sonographers showed that even the novice group was quite accurate at diagnosing pneumonia with POCUS, although slightly less than experts.19
Several sonographic findings have been suggested for diagnosis of pCAP, but the most commonly described finding is a hypoechoic tissue-like consolidation with associated hyperechoic markings present, known as sonographic air bronchograms (Figure 2). The combination of these two findings appear as liver tissue and is often referred to as hepatization (Figure 2). Other sonographic findings associated with pCAP are pleural irregularities and focal b-lines, but these are often noted as other disease processes such as bronchiolitis/viral pneumonia. When evaluating for lung pathology, such as pneumonia in pediatric patients, POCUS is an indispensable tool in aiding diagnosis, although more literature is still needed to differentiate viral from bacterial pneumonia.
Lung imaging. (A) Normal lung versus (B) pneumonia. Just below the asterisk is the pleural line, where line sliding is present between the ribs (R). The arrow on Panel A shows an “A-line,” which is a normal reverberation artifact that mirrors the pleural line. Panel B shows lung hepatization and the arrow is pointing to air bronchograms, which are classic findings in pneumonia.
Is this Patient's Bladder Full?
Point-of-care bladder ultrasound is a quick method to assess bladder fullness and, therefore, can help with urethral catheterizations.20,21 On ultrasound, the bladder appears as an anechoic structure with a three-layer wall in the anterior inferior pelvis; it will have a smooth contour and appear large when filled with urine (Figure 3). Bladder volume can be estimated in infants by the product of anterior-posterior and transverse bladder diameters, or with a prolate ellipsoid equation in older people.22 POCUS can be repeated to reassess bladder volume with minimal to no harm to the patient. Clinicians can repeat ultrasound every 30 minutes until adequate urine volume (2.4 cm2 or 2 mL) is present before attempting invasive procedures such as catheterization.20,21 Bladder volume is not only important for catheterization, but for measurement of post-void residual volume when concerned for a neurologic issue or obstruction. Additionally, POCUS can look for abnormalities in the structure of the bladder and its contents when investigating oliguria, bladder stones, or other pathologies. It has recently even been shown that bladder debris on ultrasound may be a predictor of positive urine culture.23 Overall, bladder ultrasound can reduce catheterization attempts, be performed quickly, decrease time to antibiotic administration, and theoretically lead to higher patient satisfaction and shorter lengths of stay.21
Bladder volume is calculated by measuring the bladder in three dimensions: height, width, and depth. (A) First, depth is calculated with the transducer toward the patient's head. (B) Then, the height and width are calculated with the transducer toward the patient's right. Many machines have an automatic program to calculate the bladder volume.
Is this Patient's Abdominal Pain Due to Gallstones?
Although gallstones are not common in children, certain populations are more at risk, such as patients with obesity or hemolytic disease.24 History and physical examination alone have proven to be insufficient at identifying gallbladder pathology, especially as the pediatric population may present without many of the classic symptoms.25 Additionally, only 15% to 20% of gallstones contain enough calcium to be visible on plain radiographs.26 However, ultrasound has a high sensitivity for identifying gallbladder pathology such as gallstones, is noninvasive, lacks ionizing radiation, has a lower cost, and can be performed at the bedside.27
On ultrasound, the gallbladder appears as an oval-shaped anechoic structure in the liver, and gallstones appear as hyper-echoic structures in the gallbladder with posterior acoustic shadowing (Figure 4). Imaging of the gallbladder was studied in a meta-analysis including 1,019 patients in which POCUS was compared to radiologic ultrasound and pathological examination, and POCUS was found to have a combined sensitivity of 96% (with a 95% confidence interval [CI]) and a specificity of 99% (with a 95% CI).28 In another study of 575 patients receiving bedside POCUS and radiology ultrasounds, emergency physicians diagnosed gallstones in 57.7% of patients and radiologists in 60%, making POCUS bedside interpretation 88% sensitive (95% CI) and 87% specific.29 This evidence suggests that the use of POCUS can be quickly performed at bedside in an inpatient or outpatient setting, with sensitivity and specificity similar to radiologically performed ultrasound.30 Patients could be diagnosed and treated more quickly and with fewer complications.
(A) Normal gallbladder versus (B) cholecystitis. Panel A shows normal gallbladder anatomy as labeled. On Panel B, see the white arrow pointing to multiple small stones in the gallbladder and the shadow cast down posterior to it. The black arrow shows where there is pericholecystic fluid. GB, gallbladder; PV, portal vein.
Does this Patient Have Splenomegaly?
Knowing if a patient has splenomegaly can be of particular importance in conditions including infectious mononucleosis, sickle cell disease, and oncologic processes. Evaluation is difficult with physical examination alone, as spleen size can vary widely by age and gender.31 Several published articles have demonstrated greater diagnostic accuracy of POCUS in assessing splenomegaly as compared to physical examination, although these studies were done on adults.32,33 In a prospective trial of diagnostic accuracy, POCUS plus physical examination versus physical examination alone found increase in sensitivity of 100% versus 40%, respectively, with a slight drop in specificity of 74% versus 88%, respectively.34
Splenomegaly is evaluated using the curvilinear, lower-frequency probe between the ribs in a posterolateral approach. Another study in adults demonstrated that the sonographic Castell's method had greater sensitivity (91.7%) versus the traditional Castell's method of physical examination maneuvers (83.3%).33 One study found that even with a limited 1-hour ultrasound training session, novice internal medicine residents achieved a high level of accuracy in splenomegaly assessment with hand-held POCUS when compared to sonographer measurements.32 The spleen on ultrasound appears as a homogenous, “inverted comma” or an “exclamation point” (Figure 5); when it expands and shape is lost, it becomes rounded and appears as an egg shape extending beyond the left kidney. Using POCUS as an adjunct to physical examination in detection of splenomegaly is both accurate and noninvasive.
Spleen measurement measured across the longest length of the spleen.
This article is meant to inform the general pediatrician about the potential impact POCUS can make on his or her practice, and to inspire pursuit of further training in these techniques. Although this article discusses several applications, it is by no means exhaustive. In part 2 of this article we will cover five more clinical questions that can be answered by POCUS.
There are many organizations that provide formal, in person, hands-on courses for POCUS. Alternatively, there are several online options for learning more about POCUS such as lectures, webinars, and training modules. Some training options are broad in scope (ie, applicable to many specialties). However, in the process of writing this article we were able to identify several pediatric-specific options such as through 3rd Rock Ultrasound LLC ( https://emergencyultrasound.com), Gulfcoast Ultrasound Institute ( https://www.gcus.com), or the American Institute of Ultrasound Medicine (AIUM) ( https://www.aium.org) to name a few (please note that the authors have no relationships, financial or otherwise, with these companies).
Prior to incorporating POCUS into clinical practice, the pediatrician should have consensus among his or her practitioners regarding scope and training. Ultimately, clinical privileges in the hospital setting are determined by the institute's credentialing committee, usually in the form of hospital by-laws. In 1999, the American Medical Association House of Delegates recommended that the hospital credentialing committee follow specialty-specific guidelines for hospital credentialing decisions. As of the writing of this article, no such universally agreed upon guidelines exist for general pediatrics. Specialties such as pediatric emergency medicine are trying to create consensus guidelines and policies to assist with integrating POCUS into clinical care.35
Because no specialty-specific guidelines exist, some providers prefer to use external entities to validate their competency in ultrasound. Although there are several organizations that offer certification of ultrasound skills, (ie, American Registry for Diagnostic Medical Sonography [ https://www.ardms.org], Society of Diagnostic Medical Sonography [ https://www.sdms.org], AIUM), there is no organization that certifies skills for POCUS. However, the American Board of Medical Specialties is considering making POCUS a focused practice designation for certain medical specialties.36
As highlighted in this article, POCUS provides a wonderful adjunct to physical examination without unnecessary radiation exposure, a consideration particularly important for pediatrics. Taking the time to learn POCUS will most certainly result in improved patient care.
- Doniger SJ, ed. Pediatric Emergency and Critical Care Ultrasound. New York, NY: Cambridge University Press; 2013.
- Comstock J. Butterfly IQ gets FDA clearance for chip-based, smartphone-connected ultrasound. http://www.mobihealthnews.com/content/butterfly-iq-gets-fda-clearance-chip-based-smartphone-connected-ultrasound. Accessed February 14, 2020.
- Pearce MS, Salotti JA, Little MP, et al. Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. Lancet.2012;380(9840):499–505. doi:10.1016/S0140-6736(12)60815-0 [CrossRef] PMID:22681860
- Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med. 2007;357(22):2277–2284. doi:10.1056/NEJMra072149 [CrossRef] PMID:18046031
- Melniker L. Update on drafts of new AMA resolutions to promote point-of-care, clinical ultrasound. https://www.acep.org/how-we-serve/sections/emergency-ultrasound/news/august-2017/update-on-drafts-of-new-ama-resolutions-to-promote-point-of-care-clinical-ultrasound/#sm.0000qf4wumkyudiewkc21cmmb4c5u. Accessed February 14, 2020.
- Brody AS, Frush DP, Huda W, Brent RLAmerican Academy of Pediatrics Section on Radiology. Radiation risk to children from computed tomography. Pediatrics. 2007;120(3):677–682. doi:10.1542/peds.2007-1910 [CrossRef] PMID:17766543
- Hoppmann R. AIUM/ACP/SUSME webinar: primary care office-based ultrasound. https://www.youtube.com/watch?v=RT4fqpf1Iok. Accessed February 19, 2020.
- American College of Physicians. Point of care ultrasound (POCUS) for internal medicine. https://www.acponline.org/meetings-courses/focused-topics/point-of-care-ultrasound. Accessed February 14, 2020.
- Giovanni JE, Dowd MD, Kennedy C, Michael JG. Interexaminer agreement in physical examination for children with suspected soft tissue abscesses. Pediatr Emerg Care. 2011;27(6):475–478. doi:10.1097/PEC.0b013e31821d8545 [CrossRef] PMID:21629150
- Marin JR, Bilker W, Lautenbach E, Alpern ER. Reliability of clinical examinations for pediatric skin and soft-tissue infections. Pediatrics. 2010;126(5):925–930. doi:10.1542/peds.2010-1039 [CrossRef] PMID:20974788
- Chau CLF, Griffith JF. Musculoskeletal infections: ultrasound appearances. Clin Radiol. 2005;60(2):149–159. doi:10.1016/j.crad.2004.02.005 [CrossRef] PMID:15664569
- Adams CM, Neuman MI, Levy JA, Neuman MI, Levy JA. Point-of-care ultrasonography for the diagnosis of pediatric soft tissue infection. J Pediatr. 2016;169:122–127.e1. doi:10.1016/j.jpeds.2015.10.026 [CrossRef]
- Iverson K, Haritos D, Thomas R, Kannikeswaran N. The effect of bedside ultrasound on diagnosis and management of soft tissue infections in a pediatric ED. Am J Emerg Med. 2012;30(8):1347–1351. doi:10.1016/j.ajem.2011.09.020 [CrossRef] PMID:22100468
- Barbic D, Chenkin J, Cho DD, Jelic T, Scheuermeyer FX. In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? A systematic review and meta-analysis. BMJ Open. 2017;7(1):e013688. doi:10.1136/bmjopen-2016-013688 [CrossRef] PMID:28073795
- Subramaniam S, Bober J, Chao J, Zehtabchi S. Point-of-care ultrasound for diagnosis of abscess in skin and soft tissue infections. Acad Emerg Med. 2016;23(11):1298–1306. doi:10.1111/acem.13049 [CrossRef] PMID:27770490
- World Health Organization. Pneumonia. http://www.who.int/news-room/fact-sheets/detail/pneumonia. Accessed February 14, 2020.
- Balk DS, Lee C, Schafer J, et al. Lung ultrasound compared to chest X-ray for diagnosis of pediatric pneumonia: a meta-analysis. Pediatr Pulmonol. 2018;53(8):1130–1139. doi:10.1002/ppul.24020 [CrossRef] PMID:29696826
- Pereda MA, Chavez MA, Hooper-Miele CC, et al. Lung ultrasound for the diagnosis of pneumonia in children: a meta-analysis. Pediatrics.2015;135(4):714–722. doi:10.1542/peds.2014-2833 [CrossRef] PMID:25780071
- Shah VP, Tunik MG, Tsung JW. Prospective evaluation of point-of-care ultrasonography for the diagnosis of pneumonia in children and young adults. JAMA Pediatr. 2013;167(2):119–125. doi:10.1001/2013.jamapediatrics.107 [CrossRef] PMID:23229753
- Chen L, Hsiao AL, Moore CL, Dziura JD, Santucci KA. Utility of bedside bladder ultrasound before urethral catheterization in young children. Pediatrics. 2005;115(1):108–111. doi:10.1542/peds.2004-0738 [CrossRef] PMID:15629989
- Witt M, Baumann BM, McCans K. Bladder ultrasound increases catheterization success in pediatric patients. Acad Emerg Med. 2005;12(4):371–374. doi:10.1197/j.aem.2004.11.023 [CrossRef] PMID:15805331
- Milling TJ Jr, Van Amerongen R, Melville L, et al. Use of ultrasonography to identify infants for whom urinary catheterization will be unsuccessful because of insufficient urine volume: validation of the urinary bladder index. Ann Emerg Med. 2005;45(5):510–513. doi:10.1016/j.annemergmed.2004.11.010 [CrossRef] PMID:15855948
- Stevenson SM, Lau GA, Andolsek WC, Presson AP, Cartwright PC. Bladder debris on ultrasound as a predictor for positive urine culture in a pediatric population. J Pediatr Urol. 2018;(3):254.e5. doi:10.1016/j.jpurol.2017.11.025 [CrossRef]
- Walker S, Maki AC, Cannon RM, et al. Etiology and incidence of pediatric gallbladder disease. Surgery. 2013;154(4):927–933. doi:10.1016/j.surg.2013.04.040 [CrossRef]
- Hwang H, Marsh I, Doyle J. Does ultrasonography accurately diagnose acute cholecystitis? Improving diagnostic accuracy based on a review at a regional hospital. Can J Surg.2014;57(3):162–168.
- Pinto A, Reginelli A, Cagini L, et al. Accuracy of ultrasonography in the diagnosis of acute calculous cholecystitis: review of the literature. Crit Ultrasound J. 2013;5(S1)(suppl 1):S11. doi:10.1186/2036-7902-5-S1-S11 [CrossRef] PMID:23902680
- Bortoff GA, Chen MY, Ott DJ, Wolfman NT, Routh WD. Gallbladder stones: imaging and intervention. Radiographics.2000;20(3):751–766. doi:10.1148/radiographics.20.3.g00ma16751 [CrossRef] PMID:10835126
- Carroll PJ, Gibson D, El-Faedy O, et al. Surgeon-performed ultrasound at the bedside for the detection of appendicitis and gallstones: systematic review and meta-analysis. Am J Surg. 2013;205(1):102–108. doi:10.1016/j.amjsurg.2012.02.017 [CrossRef] PMID:22748292
- Scruggs W, Fox JC, Potts B, et al. Accuracy of ED bedside ultrasound for identification of gallstones: retrospective analysis of 575 studies. West J Emerg Med. 2008;9(1):1–5. PMID:19561694
- Summers SM, Scruggs W, Menchine MD, et al. A prospective evaluation of emergency department bedside ultrasonography for the detection of acute cholecystitis. Ann Emerg Med. 2010;56(2):114–122. doi:10.1016/j.annemergmed.2010.01.014 [CrossRef] PMID:20138397
- Rosenberg HK, Markowitz RI, Kolberg H, Park C, Hubbard A, Bellah RD. Normal splenic size in infants and children: sonographic measurements. AJR Am J Roentgenol. 1991;157(1):119–121. doi:10.2214/ajr.157.1.2048509 [CrossRef] PMID:2048509
- Arishenkoff S, Eddy C, Roberts JM, et al. Accuracy of spleen measurement by medical residents using hand-carried ultrasound. J Ultrasound Med. 2015;34(12):2203–2207. doi:10.7863/ultra.15.02022 [CrossRef] PMID:26507695
- Cessford T, Meneilly GS, Arishenkoff S, et al. Comparing physical examination with sonographic versions of the same examination techniques for splenomegaly. J Ultrasound Med. 2018;37(7):1621–1629. doi:10/1002/jum.14506 [CrossRef] PMID:29219201
- Olson AP, Trappey B, Wagner M, Newman M, Nixon LJ, Schnobrich D. Point-of-care ultrasonography improves the diagnosis of splenomegaly in hospitalized patients. Crit Ultrasound J. 2015;7(1):13. doi:10.1186/s13089-015-0030-8 [CrossRef] PMID:26383010
- American Academy of PediatricsCommittee on Pediatric Emergency MedicineSociety for Academic Emergency MedicineAcademy of Emergency UltrasoundAmerican College of Emergency PhysiciansPediatric Emergency Medicine CommitteeWorld Interactive Network Focused on Critical Ultrasound et al. Point-of-care ultrasonography by pediatric emergency medicine physicians. Pediatrics. 2015;135(4):e1113–e1122. doi:10.1542/peds.2015-0343 [CrossRef] PMID:25825532
- American Board of Emergency Medicine. Recognition for clinical ultrasonography expertise: frequently asked questions. https://www.abem.org/public/docs/default-source/default-document-library/clinical-ultrasonography-fact-sheet.pdf?sfvrsn=8. Accessed February 14, 2020.