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Trick of the Trade: Gel-free ultrasound-guided peripheral IV technique

Ever finally step away from a busy resuscitation and someone stops you for peripheral IV access? You set up everything, have the patient positioned, and then notice there is no sterile ultrasound gel. No gel? No problem. The trick is to eliminate anything of poor acoustic impedance between the ultrasound probe and the patient’s skin.

Trick of the Trade

1. Apply a transparent adhesive dressing with a thin alcohol layer on the probe

Instead of using gel, we squeeze alcohol pads to create a thin alcohol layer and place a transparent adhesive cover, such as Tegaderm ©. The thin alcohol layer serves to eliminate any air bubbles under the adhesive cover as well as minimizes residual adhesive material sticking to the probe when removing the cover. The adhesive cover itself serves as a sterile barrier and a slick surface to improve probe maneuverability. Note that some ultrasound manufacturers do not recommend the use of isopropyl alcohol on their transducers. Therefore check your specific ultrasound’s recommendations before trying [1, 2].

2. Use sterile saline instead of gel on the patient’s skin

Squirt normal saline flush on the patient’s skin to create a coupling medium between the probe and the patient.

Why it works:

Ultrasound procedures use a range of frequencies (1.5-20 MHz) to visualize internal structures and require a medium to replace air, which has a poor acoustic impedance for the ultrasound waves [3]. Acoustic impedance is defined as the resistance of the propagation of ultrasound waves through tissues and is the product of the density and speed of sound in the tissue [4]. Ultrasound gel has an acoustic impedance that is similar to soft tissue and is therefore considered the ideal medium [3]. Because most soft tissue is comprised of water, the acoustic impedance of water, and therefore 0.9% saline, is actually pretty similar [5], as demonstrated by water bath techniques for ultrasounding distal extremity injuries [6].

We find great visual clarity for performing ultrasound-guided peripheral IVs using this trick, as shown in Figure 1.

Peripheral IV ultrasound screen without gel

Figure 1: Peripheral IV ultrasound using alcohol under transparent film dressing and topical saline flush – all without ultrasound gel

Read other Tricks of the Trade articles.

References

  1. Cleaning and Disinfecting FUJIFILM SonoSite Products User Guide [PDF]. Sonosite. 2015. Accessed April 5, 2023.
  2. Disinfectants and Cleaning Solutions for Ultrasound Systems and Transducers [PDF]. Philips. 2021. Accessed April 5, 2023
  3. Afzal S, Zahid M, Rehan ZA, et al. Preparation and Evaluation of Polymer-Based Ultrasound Gel and Its Application in Ultrasonography. Gels. 2022 Jan 6;8(1):42. doi: 10.3390/gels8010042. PMID: 35049577; PMCID: PMC8774352
  4. Suzuko S, Peter G, Philipp L. 20 – Local Anesthetics, Ed(s): Hugh C. Hemmings, Talmage D. Egan, Pharmacology and Physiology for Anesthesia (Second Edition), Elsevier, 2019, Pages 390-411, ISBN 9780323481106. DOI: 10.1016/B978-0-323-48110-6.00020-X
  5. R. Alkins, K. Hynynen, 10.08 – Ultrasound Therapy, Editor(s): Anders Brahme, Comprehensive Biomedical Physics, Elsevier, 2014, Pages 153-168, ISBN 9780444536334. DOI 10.1016/B978-0-444-53632-7.01010-8
  6. LeDonne S, Sengupta D. US Probe: Ultrasound Water Bath for Distal Extremity Evaluation. Alerhand S, Singh M, editors. emDOCs.net – Emergency Medicine Education. 2017.
By |2023-04-06T20:53:38-07:00Apr 12, 2023|Radiology, Tricks of the Trade, Ultrasound|
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SAEM Clinical Images Series: An 8-year-old Male with Dysuria

dysuria

An 8-year-old Caucasian male with no significant past medical history presented to the pediatric emergency department (ED) with complaints of three days of abdominal pain and dysuria, accompanied by nausea, vomiting, and poor oral intake. The patient had previously presented to his pediatrician, where he was found to have microscopic hematuria and subsequently sent to the ED. Microscopic hematuria and increased abdominal pain in the ED prompted a point of care ultrasound (POCUS).

GI: Soft on palpation, normal bowel sounds, tender to palpation at midline below the umbilicus.

GU: No trauma or erythema of the penis.

Remaining exam wnl.

Urinalysis (UA): Yellow; Cloudy; Ketones: 15; Protein >=300; Leukocyte esterase: large; Nitrite: positive; WBC/HPF: Packed; RBC/HPF:51-100

Urine Culture: >100,000 staphylococcus CFU/mL

The most likely site of abnormality in this patient is the urethra. Image 1 shows massive bilateral hydronephrosis while image 2 shows hydroureter and bladder wall thickening. This presentation in a male, together with the lab findings suggestive of a UTI, should raise concerns for posterior urethral valves (PUV). PUV, a congenital obstruction of the urethra, is one of the most common causes of lower urinary tract obstruction in males. [1]

The next step in management for patients with probable PUV is a referral to a urologist for a voiding cystourethrogram (VCUG) and cystoscopy to assess for vesicoureteral reflux and valvular obstruction. Patients who are found to have PUV can then undergo incision and correction of the urethral valve. PUV typically presents in the newborn period in males with a poor urinary stream, urinary tract infections, and other voiding complaints and can be corrected with bladder catheterization or valvular ablation [1,2].

Take-Home Points

  • While rare, PUV should be considered in the differential for any pediatric patient presenting with urinary tract-related complaints, abdominal pain, and unexplained nausea or vomiting, particularly in school-aged males.
  • A school-aged male without an underlying diagnosis presenting to the hospital with a UTI should prompt clinicians to look for underlying predisposing conditions, such as PUV – an undertaking in which bedside ultrasound can be extremely useful.
  • Point of care ultrasound (POCUS) is a tool used in real time by emergency physicians to provide evidence for hydronephrosis, which can lead to the diagnosis of PUV.

  • Hodges SJ, Patel B, McLorie G, Atala A. Posterior urethral valves. ScientificWorldJournal. 2009 Oct 14;9:1119-26. doi: 10.1100/tsw.2009.127. PMID: 19838598; PMCID: PMC5823193.
  • Shields LBE, White JT, Mohamed AZ, Peppas DS, Rosenberg E. Delayed Presentation of Urethral Valves: A Diagnosis That Should Be Suspected Despite a Normal Prenatal Ultrasound. Glob Pediatr Health. 2020 Oct 15;7:2333794X20958918. doi: 10.1177/2333794X20958918. PMID: 33117862; PMCID: PMC7570289.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2023-03-18T23:28:39-07:00Mar 27, 2023|Genitourinary, Pediatrics, SAEM Clinical Images, Ultrasound|
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SAEM Clinical Images Series: Incidental Finding on Bedside Echo

echo

A 48-year-old female with a past medical history of opioid use disorder on suboxone presents with abdominal pain for one day. The patient developed sharp diffuse upper abdominal pain the evening prior to arrival that resolved. The pain recurred again today and was associated with bilious emesis. The patient notes persistent upper abdominal pain with paroxysmal exacerbation. She has a history of a hysterectomy, but no other abdominal surgeries. No history of gallstone pathology.

Vitals: HR 38; BP 120/63; RR 14; SpO2 100%

HEENT: No jugular venous distention, no scleral icterus.

CV: Normal S1, S2, regular rhythm.

Respiratory: Clear breath sounds bilaterally.

Abdominal: Mild tenderness to palpation in the epigastrium, without rebound or guarding.

Extremities: Warm and well perfused, no edema.

White blood cell (WBC) count: 11

Alk phos: 123

Total Bilirubin: 0.5

Lipase: 24

Troponin: 0

Lactate: 1

An echo was performed for bradycardia and a brief episode of hypoxia in the emergency department. A large, tethered mass is seen likely originating from the left atrium. This finding is most consistent with an atrial myxoma, though it can also represent a clot. The patient was ultimately diagnosed with gallstone ileus and an atrial myxoma.

Take-Home Points

  • Myxomas are the most common type of cardiac mass. They occur more commonly in females, arising between the fourth and sixth decade of life. They are most commonly located in the left atrium.
  • Patients can experience obstructive and thromboembolic symptoms. Distal embolic events can cause neurologic deficit, visceral ischemia, STEMI, and limb ischemia amongst other critical presentatations.

  • Bernatchez, J., Gaudreault, V., Vincent, G., & Rheaume, P. (2018). Left atrial myxoma presenting as an embolic shower: a case report and review of literature. Annals of vascular surgery, 53, 266-e13.
  • Nguyen T, Vaidya Y. Atrial Myxoma. 2022 Jul 4. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 32310500.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2023-02-25T21:21:37-08:00Mar 6, 2023|Cardiovascular, SAEM Clinical Images, Ultrasound|
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PEM POCUS Series: Pediatric Focused Assessment with Sonography for Trauma (FAST)

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for Pediatric Focused Assessment with Sonography for Trauma. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Module Goals

  1. Summarize the indications and role of the FAST in the evaluation of injured children
  2. Describe the technique for performing the pediatric FAST
  3. Identify anatomical views and landmarks necessary for a complete pediatric FAST
  4. Accurately interpret each pediatric FAST anatomic view and corresponding landmarks
  5. Describe the literature on the pediatric FAST

Case Introduction

You receive an emergency medical services (EMS) notification that they are 2 minutes out from your ED with a 3-year-old boy who fell down a flight of 10 concrete stairs. He is awake and breathing spontaneously but irritable and crying with an obvious deformity to his right arm. EMS placed him in a cervical-collar and are bringing him to your ED.

Vital SignFinding
Temperature37.5oC
Heart Rate158 bpm
Blood Pressure86/48
Respiratory Rate32
Oxygen Saturation98% room air

You conduct your primary assessment:

Trauma AlgorithmAssessment
AirwayPatent: Audibly crying; cervical collar in place
BreathingBilateral breath sounds heard
CirculationSymmetric radial pulses palpable bilaterally; capillary refill 2-3 seconds
DisabilityHis eyes are open, but he is irritable and withdraws to touch (GCS= 13)
ExposureDiffuse superficial abrasions to face and extremities; tenderness and swelling to right forearm; abdomen soft without distension although difficult to appreciate tenderness as patient is crying

You call a trauma consult, connect the patient to the monitor, establish IV access, and reach for your ultrasound probe to perform a FAST.

Trauma remains the leading cause of childhood death and disability in children >1 year of age [1]. While head and thoracic trauma account for most death and disability in children, missed abdominal injuries are a common cause of mortality [2]. Particularly in polytrauma scenarios, it can be difficult for children to locate the exact area of pain and assessing for abdominal injury can be difficult.

FAST is a rapid ultrasound examination of 4 locations (Figure 1) with the primary objective of detecting free fluid within the abdomen, pleural space, and pericardial sac. In injured adults, FAST is useful in rapidly triaging hemodynamically unstable patients to expedite operative management [3]. Free fluid in any one view deems the FAST positive. However, for a FAST to be determined as negative, each of the landmarks in each individual view must be interrogated and evaluated for the presence of free fluid. The role of FAST in the hemodynamically stable child after blunt abdominal trauma is nuanced.

FAST ultrasound probe locations surface anatomy

Figure 1. Location of the 4 FAST views: Right upper quadrant (A), left upper quadrant (B), pelvic (C), subxiphoid (D). Illustration by Dr. Maytal Firnberg.

FAST Technique

The FAST can be performed in parallel with the rest of the trauma evaluation. Serial FAST exams can be repeated as needed throughout the child’s ED stay, particularly if the child has an unexplained change in clinical status. For a complete FAST, each of the views needs to be assessed and every landmark in each view must be visualized. In addition to intra-abdominal hemorrhage and pericardial effusion, point-of-care ultrasound can be used to evaluate the thorax for hemothorax and pneumothorax. When included together, this exam is referred to as the extended FAST (E-FAST).

In general, the child should be positioned supine as free fluid will pool in dependent areas (Figure 2). In children, the recto-vesicular or recto-uterine pouch is the most common place for fluid to collect depending on the patient’s sex [4]. Fluid in the abdomen can move freely up the right pericolic gutter into the right upper quadrant. The left pericolic gutter is higher and the phrenicocolic ligament blocks the flow; consequently, fluid tends to flow to the right pericolic area over the left, regardless of injury type.

Some controversy exists about how much free fluid can be detected by the FAST, and most studies focused on adults. For pediatric patients, we are using 100 mL as it was the median quantity of fluid needed for ultrasound detection of the pelvic view [5].

Free fluid collection areas FAST

Figure 2. Free fluid accumulates in dependent areas. In a supine patient, this is the hepato-renal pouch (right upper quadrant view), the spleno-renal pouch (left upper quadrant view), and recto-vesicular or recto-uterine pouch (pelvic view). Illustration by Dr. Maytal Firnberg.

Use a low frequency ultrasound probe: phased array probe (Figure 3) or curvilinear probe (Figure 4).

    • Phased array probes can generally achieve adequate penetration particularly for smaller pediatric patients and have a smaller footprint allowing for easier intercostal views.
    • Curvilinear probes allow for further penetration and greater depth of abdominal views and may be useful in larger children.

In order to obtain each landmark in the views discussed below, the ultrasound probe will often need to be manipulated in a number of orientations.

probe types

Figure 3 (left): Phased array ultrasound probe; Figure 4 (right): Curvilinear ultrasound probe

For the 4 scanning areas, each view must be interrogated completely, and the clinician should identify all key landmarks. The red dot on the probe correlates with the probe marker.

Right ​​Upper Quadrant (RUQ) View
Probe Placement
RUQ probe placement

Figure 5. Place the probe in the right mid axillary line (around ribs 8-10) with the probe marker towards the head. Fan anterior and posterior and slide up or down a rib space to view the key landmarks.

Normal View and Landmarks
RUQ normal ultrasound view

Figure 6. Normal RUQ ultrasound view with labeled landmarks

  • Diaphragm (including the subdiaphragmatic intraperitoneal space and supradiaphragmatic intrathoracic space)
  • Liver (including the caudal tip of the liver)
  • Kidney (including superior and inferior poles)
  • Hepatorenal Recess (Morison’s Pouch) – A potential space between the liver and kidney where free fluid can collect
Normal Ultrasound Video

Video 1. Normal RUQ ultrasound view
Left ​​Upper Quadrant (LUQ) View
Probe Placement
LUQ probe placement

Figure 7. Place the probe in the left mid or posterior axillary line (around ribs 7-9) with the probe maker towards the head. Fan anterior and posterior and slide up or down a rib space to view the landmarks. In infants and smaller children, the midaxillary line generally provides the best view.

Normal View and Landmarks
Normal LUQ ultrasound view

Figure 8. Normal LUQ ultrasound view with labeled landmarks

  • Diaphragm (including the sub- and supradiaphragmatic areas)
  • Spleen (including splenic tip)
  • Kidney (including superior and inferior poles)
  • Splenorenal Recess – a potential space between the spleen and kidney where free fluid can collect
Normal Ultrasound Video

Video 2. Normal LUQ ultrasound view
Pelvic View
Probe Placement
pelvic probe placement

Figure 9. Place the probe in the midline below the umbilicus and fan or rock the probe down towards the feet until the bladder comes into view. Fan through the entire bladder in both transverse and sagittal orientations. For the transverse and sagittal views, the probe marker should be towards the patient’s right and head, respectively.

Normal View and Landmarks
Normal pelvic ultrasound views

Figure 10. Normal sagittal (left) and transverse (right) views of the pelvic ultrasound with labeled bladder

  • Bladder (including anterior and posterior walls)
    • In patients with uteruses, make sure to visualize the uterus and the recto-uterine space as fluid can collect between the bladder and uterus and also behind the uterus.
Normal Ultrasound Video

Video 3. Normal pelvic ultrasound view (sagittal)

Video 4. Normal pelvic ultrasound view (transverse)
Pericardial View
Probe Placement
pericardial ultrasound probe

Figure 11. Place the probe under the sternum for a subxiphoid view. Point the probe towards the left shoulder and the probe marker towards the right shoulder. This view requires gentle downward pressure as you drop the angle of the probe down towards the patient. If unable to obtain this subxiphoid view, look parasternally.

Normal View and Landmarks
Normal pericardial ultrasound view

Figure 12. Normal pericardial subxiphoid ultrasound view with labeled landmarks

  • Hepatic-pericardial interface
  • Left and right ventricles (atria may also be visible)
  • Pericardial space
Normal Ultrasound Video

Video 5. Normal pericardial ultrasound view (no pericardial effusion and normal contractility)

Overarching Goal

The aim of the FAST is to identify free fluid in the abdomen, pelvis, pleural, and pericardial spaces.

Free fluid will appear anechoic (black) and will pool in dependent, unobstructed areas. On the right side, fluid in the abdomen can move freely up the pericolic gutter into the right upper quadrant. On the left, the pericolic gutter is higher and the phrenicocolic ligament may impede its flow. The RUQ view is the most sensitive view in adults while the pelvic view is the most sensitive view in children [4]. The following are examples of free fluid identified within the various views of the FAST scan.

free fluid ultrasound labelled

Figure 13. RUQ ultrasound view demonstrating free fluid in Morrison’s pouch in an unlabelled (A) and labelled (B) image

Abnormal RUQ Views

RUQ Free Fluid ultrasound

Figures 14 (left) and 15 (right). Abnormal RUQ ultrasound views with free fluid. Note that the right image demonstrates free fluid both above and below the diaphragm, meaning fluid that is in the peritoneal and pleural cavities, respectively.

Video 6. Abnormal RUQ ultrasound view with free fluid in the pleural space and Morison’s pouch

Abnormal LUQ Views

Tip: In the LUQ view, the free fluid tends to collect just under the diaphragm. Be sure to look at the diaphragm-spleen interface.

LUQ free fluid ultrasound

Figure 16. Abnormal LUQ view with free fluid below the diaphragm and above the spleen

Video 7. Abnormal LUQ ultrasound view with free fluid under the diaphragm

Abnormal Pelvic Views

Tip: Free fluid can collect between the bladder and colon in male patients. In female patients, fluid can collect between the bladder and uterus or between the uterus and colon.

pelvic free fluid ultrasound

Figure 17. Abnormal pelvic view showing free fluid between the bladder and colon

Video 8. Abnormal pelvic ultrasound on sagittal view showing free fluid

Abnormal Pericardial Views

abnormal pericardial FF ultrasound

Figure 18. Abnormal pericardial view showing pericardial free fluid

Video 9. Abnormal pericardial ultrasound view showing free fluid

ArtifactUltrasound Image
Mirror Artifact

These artifacts are cast above the diaphragm in the RUQ and LUQ views.

ultrasound spine sign artifact

Figure 19. The RUQ view shows liver parenchyma architecture cephalad of the diaphragm as a mirror artifact.

Spine Sign

The spine is not typically seen cephalad to the diaphragm by ultrasound due to air artifact. If the spine is visualized above the diaphragm, this indicates the lungs are no longer filled with air, which normally causes the refraction/reflection of ultrasound waves. This occurs in instances where air is replaced by fluid, such as a pleural effusion or hemothorax, or by a dense consolidation or contusion.

Figure 20. A – The spine is not visualized cephalad to the diaphragm in a normal RUQ ultrasound view. B – A pleural effusion results in a “spine sign” where the spine can be seen extended beyond the diaphragm.

Posterior Acoustic Enhancement

Since the bladder is a fluid filled structure which transmits ultrasound waves well, the waves illuminate the posterior wall of the bladder in a phenomenon called posterior acoustic enhancement. This brightness can hide free fluid settled in the pelvis. Thus, decrease the far field gain (brightness) behind the bladder to avoid missing obscured free fluid.

posterior acoustic enhancement

Figure 21. Bladder view with posterior acoustic enhancement artifact

Old Blood

As blood pools, the ultrasound appearance of clotted blood may have similar echotexture to surrounding soft tissue or organs rather than appear anechoic (black) as typical free fluid.

clotted blood artifact

Figure 22. Bladder view showing hypoechoic clotted blood that may be confused as soft tissue

Edge Artifact

Due to ultrasound physics and sound wave transmission between structures of different densities, edge artifacts are seen as a dark thin line tracing off the edge of this interface extending to the bottom of the screen. It can be misinterpreted as free fluid.

edge artifact ultrasound

Figure 23. RUQ view with an edge artifact

Stomach Sabotage

A full stomach will appear as a rounded collection of fluid and air anterior to the spleen. It may mimic a free fluid collection. Fan posterior of the stomach to visualize the spleen and perisplenic spaces.

Stomach sabotage artifact

Figure 24. The stomach obscures the LUQ view. Note the mix of bright (air) and dark (other gastric contents) inside the stomach.

Seminal Vesicles

Seminal vesicles can appear as hypoechoic, contained, symmetric structures posterior to the bladder in the transverse view and can be mistaken for free fluid.

Seminal vesicle artifact

Figure 25. Bladder view showing hypoechoic seminal vesicles  posterior to the bladder

  • The FAST evaluates for the presence free fluid only [6].
    • In trauma, the assumption is that free fluid is due to hemorrhage; however, the FAST cannot adequately distinguish between blood and other types of free fluid, such as ascites or physiologic free fluid.
    • It does not directly evaluate for injury to solid organs, bowel, diaphragm, or retroperitoneum​.
  • In isolation, the FAST cannot rule out intra-abdominal injury [7].
  • The FAST can not detect tiny amounts of hemorrhage.
    • The scan may appear initially negative with a free fluid volume under a threshold of about 100 mL [5].
    • Repeat FAST scans may help detect an accumulation of fluid over time throughout a child’s evaluation.
  • Trace pelvic free fluid may be physiologic in children, thus limiting specificity [8].

For adults, the FAST is integral in the diagnostic evaluation after blunt and penetrating trauma [9]. It improves outcomesby decreasing the time to surgical intervention, patient length of stay, surgical complications, CT scan, and diagnostic peritoneal lavage rates [3].

For children, however, the literature is less clear cut. Pediatric injury patterns commonly result in solid organ lacerations without hemoperitoneum, making the FAST a less sensitive means for detecting important intra-abdominal injury [7]. Further, the test characteristics of the FAST have variable reliability and accuracy in children [7,10,11]. This variation contributes to uncertainty of how to use results of the FAST and decreases its impact on potentially important clinical outcomes such as rates of CT scans and ED length of stay [12]. However…

  • The FAST is able to identify injuries that the physical exam can miss. When combined with the physical exam, the FAST scan has been found to have better test characteristics than the physical exam alone [13].
  • The improvement in POCUS technology, widespread pediatric-specific POCUS expertise, and a focus on clinically relevant outcomes have allowed clinicians to integrate the FAST into novel diagnostic strategies for children after blunt torso trauma [14].
  • The pediatric FAST may be used in combination with signs, symptoms, and other diagnostic testing as a screening algorithm to decrease unnecessary CTs. Investigators will need to conduct larger validation trials to confirm and clarify the algorithm.

Studies that have shaped the pediatric FAST literature landscape:

StudyStudy Type, Location (Time Frame)N, AgesNotes
Menaker et al., J Trauma Acute Care Surg 2014 [7]

Secondary Analysis of a Prospective Observational Study

Multicenter (May 2007 to January 2010)

6,468

Median age, 11.8 yrs; interquartile range (IQR) 6.3-15.5 yrs

  • Evaluated the variability of clinician-performed FAST examinations and the use of abdominal CT following FAST examination in children with blunt trauma
  • 373 (5.8%) were diagnosed with intra-abdominal injury
  • 3,015 (46.6%) underwent abdominal CT scanning. Only 887 (13.7%) underwent FAST examination before CT scan.
  • Use of the FAST increased as clinician suspicion for intra-abdominal injury increased. When clinicians had a lower suspicion, they were significantly less likely to order a CT scan, if a FAST examination was performed.
Holmes et al., JAMA 2017 [12]

Randomized Clinical Trial

University of California, Davis Medical Center (April 2012-May 2015)

925

Mean 9.7 yrs; SD 5.3 yrs

  • Studied the impact of the FAST scan on on multiple patient centered outcomes
  • Hemodynamically stable patients with blunt torso trauma were randomized a FAST or no FAST scan.
  • 50 had intra-abdominal injury, including 40 patients (80%) with intraperitoneal fluid and 9 patients underwent laparotomy.
  • No difference in the proportion obtaining CT, missed intra-abdominal injuries, length of stay, or cost.
Kornblith et al., Acad Emerg Med 2020 [13]

Retrospective Review

University of California, Benioff Children’s Hospital Oakland (November 2013 to July 2015)

354

Median age 8 yr; IQR 4-12 yr

  • Query of trauma database for children who met institutional trauma activation criteria and who also had a FAST performed.
  • 50 (14%) patients were found to have an intra-abdominal injury with 13 (4%) requiring intervention.
  • Positive FAST and positive physical exam were found to be independent predictors of intra-abdominal injury, both with a 74% sensitivity.
  • When combined, FAST and physical exam (FAST-enhanced physical exam) improved sensitivity to 88% (NPV 97.3%).
Liang et al., Pediatr. Emerg Care 2021 [11]

Systematic Review and Meta-Analysis

Multicenter (January 1966- March 2018)

2,135

Study dependent

  • Based on 8 studies, the FAST had a pooled sensitivity of 35% and specificity 96% for intra-abdomianal injury.
  • All 8 studies were prospective; 1 of the 8 was the 2017 Holmes paper mentioned above [12].
  • Conclusion: For a positive FAST, the post-test probability of an intra-abdominal injury was 63% meaning that those patients should get a CT to characterize injury. If the FAST is negative, you may still need a CT, because the post-test probability of intra-abdominal injury was still relatively high at 9%.
  • None of the studies had low enough negative likelihood ratios to obviate the need for CT.
  • Although a negative FAST alone does not exclude an intra-abdominal injury, it can identify low-risk patients with a reassuring physical exam and GCS 14-15.
Kornblith et al., JAMA 2022 [15]

Expert, consensus–based Modified Delphi

International multicenter (May 2021 to June 2021)

n/a
  • Generated definitions for complete pediatric FAST and E-FAST studies in the context of blunt trauma

Future Directions

The use of FAST in pediatric trauma is an evolving area of active research. A clear consensus on the way the FAST fits into pediatric trauma protocols is yet to be determined. Studies will need to be performed to examine the benefits of serial FAST, patient factors that may influence its test characteristics, and effect on patient centered outcomes.

There are a number of strategies to incorporate the above studies into clinical care, and one example is illustrated in the algorithm below. Keep in mind that FAST should be used in conjunction with other signs and symptoms of intra-abdominal injury (vomiting, decrease breath sounds, abdominal pain, thoracic wall trauma). Also consider laboratory testing such as liver function tests and urinalysis, depending on the clinical context and consulting your surgical colleagues.

Sample Algorithm for Pediatric Blunt Torso Trauma

Zuckerberg San Francisco General Pediatric Blunt Torso Trauma Algorithm (shared with permission)

Case Resolution

The primary survey is completed with airway, breathing, and circulation noted to be intact. As someone starts the secondary survey, you grab a phased array probe and perform a FAST . You observe the following:

RUQ View

LUQ View

Pelvis View, Sagittal

Pelvis View, Transverse

Pericardial View

You call out ‘FAST negative’ to the documenting nurse and team leader.

ED Course

The patient has radiographs performed of his chest, pelvis, neck, and right forearm. He is diagnosed with a type 3 supracondylar humeral fracture but the other radiographs are negative for fracture and pneumothorax. The rest of his evaluation is reassuring. Orthopedics is consulted and they admit him for surgery. He is discharged home the next day with pediatrician follow up.

Pediatrician Clinic Follow-Up

At her pediatrician clinic visit 1 week later, he is playful and active with his arm in a cast. He has been eating and drinking normally without any complaints of abdominal pain. He has orthopedics follow up scheduled for the following week.

Learn More…

References

  1. Leading Causes of Death by Age Group United States 2018. Centers for Disease Control and Prevention. Accessed September 28, 2022
  2. Kenefake ME, Swarm M, Walthall J. Nuances in Pediatric Trauma. Emerg Med Clin North Am. 2013;31(3):627-652. doi:10.1016/j.emc.2013.04.004
  3. Melniker LA, Leibner E, McKenney MG, Lopez P, Briggs WM, Mancuso CA. Randomized controlled clinical trial of point-of-care, limited ultrasonography for trauma in the emergency department: the first sonography outcomes assessment program trial. Ann Emerg Med. 2006;48(3):227-235. doi:10.1016/j.annemergmed.2006.01.008
  4. Brenkert TE, Adams C, Vieira RL, Rempell RG. Peritoneal fluid localization on FAST examination in the pediatric trauma patient. Am J Emerg Med. 2017;35(10):1497-1499. doi:10.1016/j.ajem.2017.04.025
  5. Jehle DVK, Stiller G, Wagner D. Sensitivity in Detecting Free Intraperitoneal Fluid With the Pelvic Views of the FAST Exam.
  6. Netherton S, Milenkovic V, Taylor M, Davis PJ. Diagnostic accuracy of eFAST in the trauma patient: a systematic review and meta-analysis. CJEM. 2019;21(6):727-738. doi:10.1017/cem.2019.381
  7. Menaker J, Blumberg S, Wisner DH, et al. Use of the focused assessment with sonography for trauma (FAST) examination and its impact on abdominal computed tomography use in hemodynamically stable children with blunt torso trauma. J Trauma Acute Care Surg. 2014;77(3):427-432. doi:10.1097/TA.0000000000000296
  8. Berona K, Kang T, Rose E. Pelvic Free Fluid in Asymptomatic Pediatric Blunt Abdominal Trauma Patients: A Case Series and Review of the Literature. J Emerg Med. 2016;50(5):753-758. doi:10.1016/j.jemermed.2016.01.003
  9. Bloom BA, Gibbons RC. Focused Assessment with Sonography for Trauma. In: StatPearls. StatPearls Publishing; 2021. Accessed November 14, 2021.
  10. Holmes JF, Gladman A, Chang CH. Performance of abdominal ultrasonography in pediatric blunt trauma patients: a meta-analysis. J Pediatr Surg. 2007;42(9):1588-1594. doi:10.1016/j.jpedsurg.2007.04.023
  11. Liang T, Roseman E, Gao M, Sinert R. The Utility of the Focused Assessment With Sonography in Trauma Examination in Pediatric Blunt Abdominal Trauma: A Systematic Review and Meta-Analysis. Pediatr Emerg Care. 2021;37(2):108-118. doi:10.1097/PEC.0000000000001755
  12. Holmes JF, Kelley KM, Wootton-Gorges SL, et al. Effect of Abdominal Ultrasound on Clinical Care, Outcomes, and Resource Use Among Children With Blunt Torso Trauma: A Randomized Clinical Trial. JAMA. 2017;317(22):2290-2296. doi:10.1001/jama.2017.6322
  13. Kornblith AE, Graf J, Addo N, et al. The Utility of Focused Assessment With Sonography for Trauma Enhanced Physical Examination in Children With Blunt Torso Trauma. Acad Emerg Med Off J Soc Acad Emerg Med. 2020;27(9):866-875. doi:10.1111/acem.13959
  14. Riera A, Hayward H, Torres Silva C, Chen L. Reevaluation of FAST Sensitivity in Pediatric Blunt Abdominal Trauma Patients: Should We Redefine the Qualitative Threshold for Significant Hemoperitoneum? Pediatr Emerg Care. 2021;37(12):e1012. doi:10.1097/PEC.0000000000001877
  15. Kornblith AE, Addo N, Plasencia M, et al. Development of a Consensus-Based Definition of Focused Assessment With Sonography for Trauma in Children. JAMA Netw Open. 2022;5(3):e222922. Published 2022 Mar 1. doi:10.1001/jamanetworkopen.2022.2922
By |2022-10-12T10:48:28-07:00Oct 7, 2022|Expert Peer Reviewed (Clinical), Pediatrics, PEM POCUS, Radiology, Ultrasound|
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IDEA Series: Ultrasound-capable, 3D-printed central line trainer

Problem: Central venous line (CVL) placement is a key skill for emergency medicine providers. Sites for central line placement include the internal jugular vein, subclavian vein, and femoral vein. Indications include, but are not limited to fluid resuscitation, medication administration, central venous pressure monitoring, pulmonary artery catheter introduction, and transvenous pacing wire placement. Procedural complications can include catheter-associated infection and arterial puncture. Success rates for CVL placement vary based on location and provider experience [1-3]. Point-of-Care Ultrasound (POCUS) increases both success rate and patient safety when used to guide CVL placement [4].

central line trainer 3d idea

Figure 1. Setup for ultrasound-capable, 3D-printed central line trainer

The Innovation

The ultrasound-capable, 3D-printed central line trainer was created to facilitate realistic training of POCUS-guided CVL placement, specifically utilizing the internal jugular vein. The trainer uses a ballistic gel insert that is ultrasound-capable and replaceable, as needed.

The Learners

The model can be utilized by anyone needing practice and training on central line placement. This includes medical and physician assistant students, residents, and fellows. It will be particularly useful with students familiar with POCUS basics.

Group Size

In our experience, 4-5 students were able to utilize the model before the wear from repeated use began to impact the imaging and structure of the model, necessitating replacement of the insert. The dilation step of the Seldinger technique can be skipped or simulated in order to prolong the life of the gel insert.

Equipment

Description of the Innovation

  • The initial head model was designed using 2 common 3D modeling software systems: Tinkercad and  Meshmixer
  • A generic head and neck model was imported into Meshmixer. Using the available tools in Meshmixer, the head was rotated to the side and the neck was manipulated to enhance the appearance of an extended neck with close attention to the sternocleidomastoid muscle and clavicle.
  • The model was then imported into Tinkercad and a section of the neck was removed, inverted, and manipulated inside of a box to create a negative (mold).

central line trainer tinkercad

Figure 2. Screenshot of head being edited in Tinkercad software

central line trainer tinkercad neck

Figure 3. Screenshot of neck mold being edited in Tinkercad software

  • The head was printed with Polylactic acid (PLA) filament in 2 sections that were then glued together with superglue. The seam was sealed and smoothed with latex caulk. The files for both the head and the mold can be found in this Google Drive folder.
  • A hole was drilled from the base of the neck through the top of the head. A second hole was drilled in the base of the model.
  • To make a suitable tray for the ballistic gel insert, a thin plate was printed and then cut to fit the shape of the neck. Finally, that piece was glued to the bottom of the model.
  • The model was painted using matte spray paint.

central line trainer spray paint

Figure 4. Use of matte spray paint to paint the model

  • The mold was printed next. Two holes were drilled on either side to allow for insertion of latex tubing.
  • The ballistic gel was heated according to the directions on the box. The gel can be colored using dye or acrylic paint. Caution should be practiced when using acrylic paint. The heated gel can foam up, increasing the possibility of injury from burn.
  • While the gel was heating, the mold was prepared. The bottom was coated with a thin layer of dish soap to assist with gel release. Two sections of latex tubing, approximately 2 feet each were inserted into the mold. Modeling clay was used to fill the gaps.
  • Once colored and thoroughly heated, the gel was poured into the mold.

central line trainer mold internal jugular vein

Figure 5. Preparation of the mold in which the heated gel will be poured

central line trainer mold pour

Figure 6. The heated, colored gel is poured into the mold

  • After curing, the latex tubes were removed. The gel neck model was then removed and placed into the accompanying space on the 3d printed trainer.
  • The latex tubing was fished back through the available holes, and filled with water. As an optional step, a 30 cc syringe was attached to one end of the thicker tube. Tube stoppers can also be printed and used in place of hemostats. Pumping the syringe plunger simulates the appearance of arterial flow on ultrasound.

Video Demonstration of Final Product

Lessons learned

We are currently investigating how best to research this model. The model is inexpensive compared to available commercial CVL trainers. We estimate the cost at approximately $80 per model in materials. This, of course, does not include the price of a 3d printer, 18v drill, or drill bit. Two comparable models available for purchase are both listed for over $1000 [5, 6]. The build time is approximately 1 week with time spent printing, glue-drying, and ballistic gel setting. The model can be used repeatedly and the insert remade many times over.

If another model were to be designed, the top of the head could be sacrificed in favor of an elongated neck section. The top of the head provides no value and consumes 3d printing filament. Furthermore, an elongated neck may be preferable for a new learner by allowing more room to practice probe and hand placement.

Theory behind the innovation

Simulation as a means of teaching has been a firmly established practice across the landscape of medical education. The model in question is high-fidelity and offers the user a realistic experience in a low-stress environment. The model is small enough to be portable and can be used with little preparation, making it an ideal tool for just-in-time training in the emergency department.

Tools that allow the learner to practice multiple steps of a skill during one exercise are invaluable for skill development, competency-based medical education and mastery learning.

Idea Series Logo debriefing

Led by series editor, Dr. Mary Haas, the IDEA series showcases examples of what programs worldwide have been doing to make residency conference more entertaining, engaging, and most of all, educational for residents. Read more publications from the series.

References

  1. McGee DC, Gould MK. Preventing complications of central venous catheterization. New England Journal of Medicine. 2003;348(12):1123-1133. doi:10.1056/nejmra011883
  2. Schummer W, Köditz JA, Schelenz C, Reinhart K, Sakka SG. Pre-procedure ultrasound increases the success and safety of central venous catheterization. British Journal of Anaesthesia. 2014;113(1):122-129. doi:10.1093/bja/aeu049
  3. E Portalatin M, Fakhoury E, Brancato R, et al. Factors contributing to unsuccessful central line placement in the neck and chest. Surgery: Current Trends and Innovations. 2019;3(2):1-5. doi:10.24966/scti-7284/100015
  4. Saugel B, Scheeren TWL, Teboul J-L. Ultrasound-guided central venous catheter placement: A Structured Review and recommendations for Clinical Practice – Critical Care. BioMed Central. Published August 28, 2017. Accessed September 21, 2022.
  5. Life/form Central Venous Cannulation Simulator. Universal Medical. . Accessed September 21, 2022.
  6. Blue Phantom internal jugular Central Line Ultrasound manikin. 3012495 – Blue Phantom – BPP-060 – Ultrasound Trainers. Accessed September 21, 2022.
By |2022-09-26T01:52:50-07:00Sep 30, 2022|IDEA series, Medical Education, Ultrasound|
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SAEM Clinical Images Series: Breast Swelling

A female in her 50s with a past medical history of coronary artery disease, pacemaker placement, hypertension, and ESRD presented to the emergency department with the chief complaint of missed dialysis, breast engorgement, and an increase in vascularity in her chest and abdomen. The patient reported an increase in breast swelling and increased vascularity in her belly over the past three months. Additionally, she woke up short of breath on the morning of presentation and reported dyspnea at rest. She denied chest pain, diaphoresis, breast pain, fever, rash, trauma to the breasts, or drainage.

 

Vitals: T 36.9°C; HR 105; BP 109/74; RR 20; O2 sat 97% on nasal canula @ 3L

Neck: JVD

Lungs: Bilateral crackles

Chest and abdomen: Increased vascularity

Breast: Bilateral breast swelling and redness

Lower extremity: Bilateral pitting edema and varicose veins

Basic metabolic panel (BMP): K 6.9; Cr 9.53

Brain natriuretic peptide (BNP): >35,000

Troponin I: 0.1

DDX: Inflammatory carcinoma, mastitis, superior vena cava syndrome, portal hypertension, pulmonary hypertension, pulmonary embolism.

Superior vena cava (SVC) syndrome results from any condition that leads to obstruction of blood flow through the SVC. Our case was caused by complete occlusion from a thrombus and the patient presented with bilateral breast swelling, skin changes (peau d’orange), and an increase in vascularity in the abdomen and chest (caput medusa). Breast tissue largely drains into the axillary veins, and more proximally into the subclavian veins. Due to occlusion of the SVC, a complete backup of venous flow occurs, resulting in all of the noted collateral hypervascularity.  Often SVC occlusion is caused by malignancy obstructing the superior vena cava or invading the vein.

The CTA demonstrates occlusion of the superior vena cava. There are multiple varices in the chest wall and the imaged upper abdominal wall. There is also diffuse subcutaneous edema with diffuse soft tissue swelling and skin thickening of the bilateral breasts.

Take-Home Points

  • Consider superior vena cava occlusion in patients undergoing hemodialysis who present with the above physical exam findings.
  • Consider occult malignancy as the source or cause of thrombosis.
  • Be sure to fully expose your patient when appropriate and keep your differential broad.

  • Corduff N, Rozen WM, Taylor GI. The superficial venous drainage of the breast: a clinical study and implications for breast reduction surgery. J Plast Reconstr Aesthet Surg. 2010 May;63(5):809-13. doi: 10.1016/j.bjps.2009.02.055. Epub 2009 Apr 3. PMID: 19345164.
  • Friedman T, Quencer KB, Kishore SA, Winokur RS, Madoff DC. Malignant Venous Obstruction: Superior Vena Cava Syndrome and Beyond. Semin Intervent Radiol. 2017 Dec;34(4):398-408. doi: 10.1055/s-0037-1608863. Epub 2017 Dec 14. PMID: 29249864; PMCID: PMC5730434.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2022-08-28T22:47:29-07:00Aug 29, 2022|Heme-Oncology, Radiology, SAEM Clinical Images|
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SAEM Clinical Images Series: Found Down

found down

A 67-year-old caucasian male experiencing homelessness was “found down” in a parking lot. EMS reported that he had a GCS of 6 with a systolic blood pressure in the 80’s, finger stick glucose of 100, and no response to intranasal naloxone. He was intubated in the field and arrived to the emergency department unresponsive with a BP of 95/60, HR 125, T 38°C, and O2 Sat 100%. Hemodynamic stabilization was achieved with central venous access, and laboratory and imaging studies for the evaluation of altered mental status ensued.

 

General: Disheveled male

HEENT: Normocephalic; PERRLA 3-2 mm; dried blood in nares

Skin: Warm; dry; no visible signs of trauma

Cardiovascular: Tachycardic with no murmurs, rubs, or gallops

Respiratory: Bilateral breath sounds on ventilator; diffuse rales

Gastrointestinal: Soft; non-distended; bowel sounds present

Musculoskeletal: No deformities

Neurologic: Unresponsive; GCS 3

COVID-19 rapid antigen: Detected

Complete Blood Count (CBC): WBC 17 k; Hemoglobin 15; Platelets 185

Comprehensive Metabolic Panel (CMP): Na 133; K 4.6; Cl 91; CO2 21; BUN 18; Cr 2.2; Ca 8.4; Alb 2.1; Tbili 0.4; Alk phos 112; AST 242; ALT 68

ABG on FiO2 100%: 6.99/>95/405/23/100%

Lactate: 16.4

Ammonia: 90

CK total: 716

Trop I HS: 809

PT: 14

INR: 1.05

PTT: 45

Urinalysis: Unremarkable

EtOH, Acetaminophen, Salicylate: Negative

UDS: Negative

Chest Radiograph: Diffuse ground-glass opacities

Air embolism to the right ventricle and pulmonary artery. As little as 20 mL or less of air rapidly infused may cause obstruction, ischemia, and hemodynamic collapse.

Risk factors include central venous catheterization, lung trauma, ventilator usage, hemodialysis, surgery (esp. coronary, neurosurgery), childbirth, and scuba diving barotrauma.

Take-Home Points

  • In the appropriate clinical scenario, especially those involving respiratory, cardiac, and neurologic findings where invasive procedures were utilized, the diagnosis of venous air embolism should be entertained.
  • Immediate management of an air embolism involves administration of 100% oxygen by nonrebreather mask (NRM) or ventilator and placement of the patient in the left lateral decubitus (Durant maneuver) and Trendelenburg positions. Hyperbaric oxygen therapy has also been used if there is no clinical improvement.
  • The purpose of the Durant maneuver and Trendelenburg position is to trap air along the lateral right ventricular wall, preventing right ventricular outflow obstruction and embolization into the pulmonary circulation.

  • Gordy S, Rowell S. Vascular air embolism. International Journal of Critical Illness and Injury Science. 2013;3(1):73. doi:10.4103/2229-5151.109428 Malik N, Claus PL, Illman JE, Kligerman SJ, Moynagh MR, Levin DL, Woodrum DA, Arani A, Arunachalam SP, Araoz PA. Air embolism: diagnosis and management. Future Cardiol. 2017 Jul;13(4):365-378. doi: 10.2217/fca-2017-0015. Epub 2017 Jun 23. PMID: 28644058.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2021 SAEM Annual Meeting | Copyrighted by SAEM 2021 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2022-07-19T14:49:13-07:00Aug 8, 2022|Cardiovascular, Critical Care/ Resus, Pulmonary, Radiology, SAEM Clinical Images|
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