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Pediatric Emergency Medicine POCUS

Created in 2020 by series editor, Dr. Margaret Lin-Martore, this series focuses on point-of-care ultrasonography (POCUS) for pediatric emergency medicine (PEM).

 

PEM POCUS Series: Pediatric Ultrasound-Guided Fascia Iliaca Block

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric fascia iliac block. 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. List indications of performing a pediatric point-of-care ultrasound fascia iliaca nerve block (POCUS-FINB)
  2. List the limitations of POCUS-FINB
  3. Describe the technique for performing POCUS fascia iliaca nerve block 
  4. Identify anatomical landmarks accurately on POCUS
  5. Calculate the maximum safe weight-based local anesthetic dose
  6. Recognize the signs and symptoms of local anesthetic systemic toxicity (LAST) and describe the appropriate management 

Case Introduction: Child with thigh pain

Sarah is a 3-year-old girl who comes into the emergency department complaining of acute thigh pain that started 30 minutes ago. She was playing on a trampoline when she accidentally fell off. She had immediate pain to the left thigh and she’s been unable to walk since the fall. Parents carried her in to the emergency department for further evaluation.

On arrival, her vital signs are:

Vital SignFinding
Temperature97.5 F
Heart Rate130 bpm
Blood Pressure97/50
Respiratory Rate22
Oxygen Saturation (room air)100%

 
She is in distress secondary to pain. She has a normal HEENT, neck, cardiac, respiratory, abdominal, and back examination. She points to her left anterior thigh when you ask her where her pain is. She has limited range of motion with flexion and extension of her left hip and complains of pain with any manipulation. Her leg is externally rotated and slightly shortened when compared to the opposite leg. She cries when you palpate any part of her leg, but is able to range her knee, ankle, and foot fully. She has 2+ dorsalis pedis and posterior tibialis pulses with intact sensation to light touch throughout. 
 
Given her pain with range of motion at her hip and tenderness to palpation to the femur, you obtain a thigh radiograph, which shows a femoral shaft fracture. The orthopedic team is notified about the patient in order to discuss pain control and possible next steps. You ask your self several questions to help you best care for this child. 
  1. What can we do for pain control in this patient? Are there opioid-sparing options?
  2. Can nerve blockade be utilized in this case?
  3. What local anesthetic is appropriate, and what is a safe dose?
  4. What safety precautions need to be considered for performing a regional block?
You consult with the orthopedic team and discuss performing a Point-of-Care Ultrasound-Guided Fascia Iliaca Nerve Block (POCUS-FINB).

The fascia iliaca nerve block anesthetizes the femoral nerve (FN), lateral femoral cutaneous (LFC) nerve, and obturator nerve (ON), as demonstrated in the lower leg nerve anatomy drawing below.

 

anatomy leg

Figure 1. Thigh and lower leg sensory nerve anatomy. The expected distribution of a fascia iliaca block (via infrainguinal approach described here) includes the FN – Femoral Nerve, often but not always the LFC – Lateral Femoral Cutaneous Nerve, and unreliably the ON – Obturator Nerve.  (Illustration by Dr. Muki Kangwa)

 

The fascia iliaca block thus can assist with pain control for:

  1. Femoral neck and femoral shaft fractures
  2. Patella injuries 
  3. Anterior thigh wound care

Clinicians should keep in mind relative contraindications to this procedure particularly in nonverbal or peri-verbal patients. See the exclusion criteria from the UCSF Benioff Children’s Hospital Oakland institutional protocol:

  1. Young, preverbal patients <2 years old (lower age cutoff may range from 2-5 years dependent on orthopedic consultant)
  2. Concern for acute compartment syndrome of the thigh
    • Tense or firm compartment on palpation
    • Expanding hematoma of the thigh
    • Pain out of proportion to injury
    • Neurologic deficit in femoral distribution
    • Mechanism: crush injury or open fracture
  3. Any child with an American Society of Anesthesia score of >2
  4. Neurologic deficits in the femoral distribution (specifically loss of touch sensation to the anterior thigh)
  5. Signs of vascular injury, coagulopathy, hemodynamic instability, and/or suspected multi-organ system trauma  
  6. Patients at high risk for local anesthetic toxicity (e.g., cardiac/hepatic dysfunction, metabolic/mitochondrial disease, infants <6 months)

Using ultrasonography to perform a fascia iliaca nerve block helps to identify key anatomical landmarks for appropriate administration of local anesthetic. The point-of-care ultrasound-guided fascia iliaca nerve block (POCUS-FINB) allows us to identify the area of interest, which is underneath the fascia iliaca fascial plane. Note that this plane is just deep to femoral artery and vein, in contrast to the fascia lata plane, which is superior to the femoral artery and vein (Figure 2). The area is best visualized distal to the inguinal canal and proximal to the bifurcation of the femoral artery.  

 

fascia iliaca anatomy

Figure 2. Relevant anatomy for the fascia iliaca block for the right groin, demonstrating the location of the fascia iliaca and fascia lata planes (illustration by Dr. Muki Kangwa)

fascia iliaca equipment supplies

Figure 3. Key supplies needed for the ultrasound-guided fascia iliaca block

 

  1. Sterile gel 
  2. Chlorhexidine/alcohol wipes 
  3. Sterile ultrasound probe cover (or equivalent such as Tegaderm dressing, sterile glove, or condom)
  4. 22-gauge spinal/block needle (50-80 mm) with attached tubing primed with sterile saline
  5. Local anesthetic
    • Superficial: 1% lidocaine (buffered, if available) for skin wheal via 30G needle, or LMX, or EMLA cream 
    • Block: Long-acting local anesthetic
  6. 10-20 cc syringes (depending on child’s weight)
  7. Sterile saline flushes 
  8. Tegaderm dressing to label block after completion

Local Anesthetic (LA) Dosing for Fascia Iliaca Block

Table 1. Local anesthetic medications, their pharmacokinetics, and weight-based maximum dosages [1, 2]

A long-acting local anesthetic (e.g., ropivacaine or bupivacaine)  is preferred for this block. Ropivacaine is the preferred anesthetic, because it is thought to be less lipophilic than bupivacaine and, as such, less cardiotoxic and neurotoxic. Minimizing the risk of local anesthetic toxicity is particularly relevant to fascial plane blocks, which remain far from the neurovascular bundle and thus require higher volumes of local anesthetic. This higher volume allows for bathing of the nerve via anesthetic tracking along the fascial plane. Table 1 above illustrates the pharmacokinetics and weight-based dosing maximums for the various local anesthetics.

Table 2 provides guidance on the fascia iliaca block volumes with the medication diluted in 0.9% normal saline to increase the volume. The suggested volumes of local anesthetic and saline depend on the type and concentration of local anesthetic also well as the patient’s ideal body weight, which impacts both the relative size of the potential space in the fascial plane as well as the maximum safe dose.

long anesthetic fascia iliaca dosing table

Table 2. Suggested Fascia Iliaca Block Total Volumes with Local Anesthetic + 0.9% Normal Saline [1, 3, 4]

Notes: Use ~½ maximum dose. Use ideal body weight for obese patients. Volumes shown represent local anesthetic (LA) volume. Hydrodissect/dilute with additional 1-10 ml saline to achieve target total block volume.
 

1. Consult with orthopedist to discuss appropriateness of block.

2. Perform and document a neurovascular and compartment exam prior to and after block.

  • Sensation
    • Anterior thigh (femoral)
    • Medial shin/calf (saphenous/femoral)
    • Lateral foot (sural)
    • Plantar surface of foot/heel (tibial)
    • Dorsal surface of foot (superficial peroneal)
    • 1st webspace (deep peroneal)
  • Motor
    • Great toe extension (extensor hallucis longus)
    • Great toe flexion (flexor hallucis longus)
    • Foot dorsiflexion (tibialis anterior)
    • Foot plantar flexion (gastrocnemius/soleus)
  • Vascular
    • Dorsalis pedis
    • Posterior tibial
    • Capillary refill

3. Ensure informed consent with patient and family.

  • In addition to discussion of risks/benefits/alternatives, consider the relative need for pre-traction/pre-op pain control vs. post-op pain control. Depending on the dose of local anesthetic and timing of operation, a subsequent intra-operative block may or may not be possible.

4. Position the patient supine with hip and knee in extension.

5. Anticipate the child’s anxiety during the procedure.

  • Pro-tip: Depending on the age of the child, the presence of a guardian can be helpful in keeping the child calm and cooperative while undergoing the procedure.
  • It may be helpful to have a dedicated person to hold the limb of interest during the procedure.
  • Involve a childlife specialist, if available.
  • Offering the child a toy, book, or phone/tablet for distraction during the procedure can also help ease anxiety. 
  • Intranasal or intravenous midazolam may be needed for anxiolysis.

6. Select a linear high frequency ultrasound transducer with a wide footprint.

Figure 4. Ultrasound linear transducer with wide footprint and appropriate ultrasound musculoskeletal setting

 

7. Apply a single-use probe cover.

8. Ensure proper ergonomics and positioning.

  • Adjust the height of the bed.
  • Stand on the side of the affected leg.
  • Position the ultrasound machine on the opposite side of the bed such that the ultrasound screen is directly in line of sight with the affected leg us without rotating one’s head.

Figure 5. Appropriate patient, proceduralist, and ultrasound positioning with POCUS machine across from the affected leg

 

9. Place the transducer parallel to the inguinal canal.

  • Perform a survey scan to identify landmarks starting from the inguinal canal (Figure 6).
  • Aim the probe marker towards the patient’s right. This ensures that the screen image directionally matches the body part being scanned.

Figure 6. Linear ultrasound probe placement parallel to the inguinal ligament with probe marker (red dot) aimed towards the patient’s right (illustration by Dr. Muki Kangwa)

10. Ensure immediate intralipid availability

  • Key step: Before starting your procedure, confirm availability of intralipid, the antidote for local anesthetic toxicity.
    • Dose: 1.5 ml/kg bolus over 1 minute
  • Place patient on cardiac monitor.
  • Review the weight-based maximum safe dose of local anesthetic, based on patient’s ideal body weight if they are overweight.
  • Local anesthetic maximum dose calculator (MDCalc)

11. Perform ultrasound survey scan and identify the anatomical landmarks (Figure 7)

  • Muscles: Iliopsoas, sartorius
  • Neurovascular bundle: Femoral nerve, artery, and vein (most medial)
  • Fascia: Fascia lata and fascia iliaca

Figure 7. POCUS image of left hip demonstrating the normal anatomy of the femoral artery (FA), femoral vein (FV), fascia iliaca, fascia lata, femoral nerve, and iliopsoas muscle (left is medial and right is lateral)

 

12. Anesthetize your needle insertion point (adjacent to the lateral edge of the ultrasound probe).

  • Use with 1% buffered lidocaine, if available.
  • Alternatively, apply topical lidocaine, such as LMX or EMLA on the desired area at least 30 minutes prior to the start of the procedure.

13. Prime the needle and tubing with normal saline.

  • The normal saline in the tubing and needle will hydro-dissect the fascial planes prior to injecting the local anesthetic. This helps mitigate the risk for potential local anesthetic toxicity. Furthermore, it ensures appropriate fascial spread prior to injection of the anesthetic, allowing for better visualization of the anatomy and a safe window for anesthetic injection.
  • An alternative practice is to prime the needle and tubing with the diluted local anesthetic.

14. Insert the block/spinal needle.

  • Visualize the length of the needle in-plane and the needle tip at all times.
  • Warning: The needle shaft can easily be confused for the needle tip if the probe is not adequately oriented in parallel with the needle along the entire length. Make subtle rotations in the probe to ensure that the true needle tip is visualized.

15. Identify the femoral nerve.

  • Be sure to remain lateral the the femoral nerve (~2 cm). It is NOT necessary to be directly adjacent to the nerve, which increases the risk of nerve injury.
  • Use the ‘fanning’ technique to elicit anisotropy and identify the femoral nerve. The nerve is DEEP the fascial plane and lateral to the femoral artery. A common mistake is to misidentify the adipose tissue, which lies SUPERFICIAL to the fascial plane and is immediately lateral to the femoral artery, as the femoral nerve (Figure 8). 

Figure 8. POCUS image of the left hip during a fascia iliac block procedure. The adipose tissue (pink) can be confused for the femoral nerve (yellow) which lies below the fascia iliaca (red). The local anesthetic (hypoechoic) is hydrodissecting between the vascular bundle and femoral nerve. FA=femoral artery.

 

16. Puncture the needle through the fascia iliaca.

  • Keep your neurovascular bundle in the corner of your screen as you advance your needle in order to visualize your saline and local anesthetic as you hydro-dissect the nerve from the fascia.
  • Be aware of the patient’s comfort throughout the procedure.

17. Practice key safe injection techniques.

  • Ensure excellent, real-time needle and needle tip visualization on ultrasound.
  • Aspirate and look for blood once the needle is below the fascia iliaca to confirm that you will not inject into the vasculature.
  • Hydrodissect the fascial plane with 2-5 mL of normal saline. You will visualize the saline migrating medially towards the neurovascular bundle. Make adjustments in depth to find the correct plane.
  • Inject small aliquots (2-5 mL at a time) of local anesthetic. Aspirate between each aliquot to check for blood, allowing time (circulation cycle) between aliquots to monitor the patient for signs of local anesthetic systemic toxicity.

Video 1. POCUS clip of a traditional femoral nerve block block showing hydrodissection. The needle is seen directly below the bright fascia iliaca with anechoic (black) saline injected into the fascial plane. Note that in this clip, the needle tip is directly adjacent to the nerve as in a traditional femoral nerve block, rather than more laterally as in a fascia iliaca block. 

 

Video 2. POCUS clip showing a fascia iliaca block hydrodissection. In comparison to Video 1, this clip shows the needle directly below the bright fascia iliaca with anechoic (black) saline injected into the fascial plane. Note the difference in the needle positioning in comparison to the nerve. This is the correct positioning of your needle, more lateral to the neurovascular bundle compared to the needle positioning in video 1. Video courtesy of Dr. Arun Nagdev (highlandultrasound.com) 

 

Video 3. POCUS clip showing a fascia iliaca block hydrodissection. The pulsatile femoral artery can be seen medially, and the femoral nerve can be seen being displaced downwards below the fascial plane.

 

18. Instill the appropriate volume of long-acting anesthetic.

  • Once the needle is appropriately positioned deep to the fascia iliaca plane, carefully and incrementally instill the weight-based volume of either ropivacaine or bupivacaine, utilizing the safe injection techniques described in step 17.

19. Label your block and document in the medical record.

  • Label the block location with a Tegaderm dressing noting time and date of procedure.
  • Document the procedure in real-time, including type and dose of local anesthetic, to ensure accurate and timely communication with multidisciplinary care team (e.g., anesthesia, in order to avoid cumulative local anesthetic overdose).

20. Monitor the patient post-procedure.

  • Maintain the patient on a cardiac monitor to watch for local anesthetic systemic toxicity for 30 minutes post-block.
  • Re-evaluate the patient for efficacy of the block.

There are many errors that can make defining the relevant sono-anatomy difficult, but there are 2 common errors that are easily corrected by small changes in probe placement.

1.  Error: Probe placement distal to femoral artery bifurcation

Problem: In order to get the view needed for a successful block, the operator must image the vasculature at the level of the common femoral artery, prior to its bifurcation. When distal to the common femoral artery, the structures that are seen are usually the superficial and deep femoral arteries (Figure 9 and Video 4). At this level, the femoral nerve and the fascia iliaca can be difficult to visualize.

Solution: Slide the probe cephalad and position it just inferior to the inguinal ligament. The common femoral artery is well-visualized at this level.

Figure 9. Arterial anatomy of the thigh, adapted from Wikimedia Commons (left); POCUS image of the femoral artery bifurcation. which is too distal for fascia iliaca block (right)

 

Video 4. POCUS clip showing a femoral artery bifurcation, which is too distal for the fascia iliaca block

 

2. Error: Incorrect probe angle

Problem: If the probe is not perpendicular to the common femoral artery, the artery will be visualized, but the fascia iliaca and iliopsoas muscle can be difficult to locate.

Solution: Keep the probe parallel to the inguinal ligament, which aligns it perpendicularly to the common femoral artery (Figure 10).

 

Figure 10. Proper ultrasound probe positioning means placing the probe parallel to the inguinal canal and perpendicular to common femoral artery. Grey: probe with probe marker to patients right, Purple: inguinal canal, Red: femoral artery (illustration by Dr. Muki Kangwa)

  1. Quadriceps muscle spasms: These are usually secondary to anesthetic injection directly into the femoral nerve.
  2. Delayed recognition of compartment syndrome: This is less common in the thigh compartment compared to the lower leg.
    • Fractures account for approximately 75% of cases of acute extremity compartment syndrome. The risk increases with increasing severity of the fracture (e.g., comminuted fractures). The tibia is involved most often, with acute compartment syndrome developing in approximately 1-10% of such fractures.
  3. Local anesthetic systemic toxicity (LAST) is a rare event resulting from dose-dependent blockade of the sodium channels in the cardiovascular and central nervous system.
    • Risk of LAST can be mitigated by:
      • Calculating the maximum safe dose for the anesthetic and patient’s weight
      • Real-time cardiac monitoring
      • Continuous needle visualization to ensure proper placement of anesthetic
      • Aspirating prior to each injection
      • Hydrodissection of fascial plane with saline prior to anesthetic
      • Injection of small aliquots and monitoring for signs/symptoms during circulation cycle
      • Monitoring of the patient for 30 minutes as per American Society of Regional Anesthesia and Pain Management recommendations.
    • Mild-moderate LAST toxicity
      • Oral numbness and tingling
      • Metallic taste
      • Tinnitus
      • Nausea and dizziness
    • Severe LAST toxicity
      • Tremors
      • Convulsions
      • Bradycardia and other cardiac arrhythmias
      • Respiratory depression
      • Hypotension
      • Cardiac arrest
    • Treatment
      • Lipid emulsion (20%) – 1.5 mL/kg followed by continuous infusion at 0.25 mL/kg/min
      • For more local anesthetic systemic toxicity resources, visit asra.com

Nerve blockade is being performed widely by many emergency medicine physicians, and is now becoming standard of care in an attempt to reduce the amount of opiates used particularly in the elderly with femoral fractures. However, ultrasound guided nerve blockade it is not a core skill found in most pediatric emergency medicine curricula, and the lack of educational training presents a barrier to implementation within Pediatric Emergency Medicine. Prior studies of fascia iliaca nerve blockade have shown great success and improved pain control. A few of these studies are summarized below.

 

YearAuthorsTitleStudy TypeFindings
2007Wathen JE et al.Randomized Controlled Trial Comparing a Fascia Iliaca Compartment Nerve Block to a Traditional Systemic Analgesic for Femur Fractures in a Pediatric Emergency Department (PMID 17210208)Randomized controlled trialFascia iliaca compartment block performed by pediatric emergency medicine attendings and fellows for children ages 15 months to 18 years with a femur fracture can result in lower pain scores, longer duration of analgesia, and higher staff satisfaction in comparison with traditional analgesia.
2012Frenkel O et al.Ultrasound-guided Femoral Nerve Block for Pain Control in an Infant with a Femur Fracture due to Non-accidental Trauma (PMID 22307191)Case reportCase report of a 3-month-old female with a subtrochanteric femoral neck fracture due to non-accidental trauma requiring multiple doses of IV pain medication. An ultrasound-guided femoral nerve block was performed using 2 mL of 0.25% bupivacaine for placement into a Pavlik harness. The patient only required 1 dose of analgesia in 18 hours following the femoral nerve block.
2014Turner AL et al.Impact of Ultrasound-guided Femoral Nerve Blocks in the Pediatric Emergency Department (PMID 24651214)Retrospective cohort studyIn a pre- and post-implementation retrospective cohort study of children with femur fractures in a pediatric ED, an ultrasound-guided femoral nerve block was associated with a 3-times longer duration of initial analgesia (6 hr vs 2 hr), lower total morphine dose, and fewer nursing interventions in comparison with systemic analgesia alone.
2014Neubrand T et al.Fascia Iliaca Compartment Nerve Block Versus Systemic Pain Control for Acute Femur Fractures in the Pediatric Emergency Department (PMID 24977991)Retrospective chart studyRetrospective chart review of children receiving systemic analgesia (control) vs fascia iliaca nerve block evaluating effectiveness and adverse effects. Outcomes included total doses of systemic medications received and comparison of pre- and post-intervention pain scores. Effectiveness, as measured by pain scores and total doses of systemic analgesia, was improved in the fascia iliaca nerve block group versus the control. There was no difference in adverse events between the groups.
2022Heffler MA et al.Ultrasound-Guided Regional Anesthesia of the Femoral
Nerve in the Pediatric Emergency Department (PMID 35245015)		Multicenter retrospective case seriesUltrasound-guided regional anesthesia of the femoral nerve (fascia iliaca compartment block, n=70; femoral nerve block, n=15) was performed by residents, fellows, and attendings with varying degrees of formal POCUS training for pediatric patients aged 50 days to 15 years at 6 pediatric emergency departments across North America. There were no reported complications across a heterogenous patient population at these 6 tertiary care centers, supporting the safety and generalizability of these techniques.
Table 4. Published studies supporting effectiveness of POCUS fascia iliaca nerve block in pediatric patients.

Full Video of Fascia Iliaca Nerve Block 

Video 5. POCUS clip of the complete fascia iliaca block procedure. The clip starts with an initial anatomy scan, followed by needle visualization, and lastly hydrodissection.

 

    Case Resolution

    Given that the patient remains in significant painful distress despite non-opioid analgesia, you decide to incorporate POCUS-FINB to your evaluation and treatment.

    The patient is evaluated by the on-call orthopedic team member and is found to have no evidence of neurovascular compromise or signs and symptoms of compartment syndrome. You confirm the availability of lipid emulsion (intralipid) in the emergency department and calculate the maximum safe dose of your anesthetic.

    • The patient weighs 20 kg.
    • The MAXIMUM safe dose of 0.2% ropivacaine (3 mg/kg) equals 60 mg, or 30 mL.
    • Looking at your institutional guidelines and Table 2 you decide to use 12 mL, which is well underneath this maximum dose.
    • You add 3 mL of saline to increase the overall fluid volume to reach the weight-based target goal of 15 mL volume for the fascia iliaca procedure.
     

    Tables 1 and 2 (cropped from original tables): Local anesthetic medications and their pharmacokinetics, weight-based maximum doses, and suggested total volumes (anesthetic + 0.9% normal saline) for fascia iliaca block

     

    The patient undergoes a safe and effective fascia iliaca nerve block with her pain score improving from a 10 to a 2. The orthopedic team is able to place the patient into traction prior to transfer to the operating room.

    Orthopedic Clinic Follow-Up

    At her orthopedic follow-up visit 4 weeks later, she’s doing well with minimal pain. Her follow up x-ray demonstrates appropriate healing with new bone formation. 

     

    Learn More…

    References

    1. Suresh S, Polaner DM, Coté CJ. 42 – Regional Anesthesia. In: Coté CJ, Lerman J, Anderson BJ, eds. A Practice of Anesthesia for Infants and Children (Sixth Edition). Elsevier; 2019:941-987.e9.
    2. Gadsen J. Local Anesthetics: Clinical Pharmacology and Rational Selection. The New York School of Regional Anesthesia website, October 2013.
    3. Dalens B. Lower extremity nerve blocks in pediatric patients. Techniques in Regional Anesthesia and Pain Management. January 2003 2003;7(1):32-47.
    4. Karmakar MK, Kwok WH. 43 – Ultrasound-Guided Regional Anesthesia. In: Coté CJ, Lerman J, Anderson BJ, eds. A Practice of Anesthesia for Infants and Children (Sixth Edition). Elsevier; 2019:988-1022.e4.

     

    Additional Reading

    1. Black KJ, Bevan CA, Murphy NG, et al. Nerve blocks for initial pain management of femoral fractures in children. Cochrane Database Syst Rev. 2013(12):CD009587.
    2. Bretholz A, Doan Q, Cheng A, et al. A presurvey and postsurvey of a web- and simulation-based course of ultrasound-guided nerve blocks for pediatric emergency medicine. Pediatr Emerg Care. 2012;28(6):506-9. PMID 22653464
    3. Chenkin J, Lee S, Huynh T, et al. Procedures can be learned on the Web: a randomized study of ultrasound-guided vascular access training. Acad Emerg Med. 2008;15(10):949-954. PMID 18778380
    4. Coté, Charles J., et al. “Chapter 42: Regional Anesthesia.” A Practice of Anesthesia for Infants and Children, Elsevier, Philadelphia, PA, 2019.
    5. Frenkel O, Mansour K, Fischer JW. Ultrasound-guided femoral nerve block for pain control in an infant with a femur fracture due to nonaccidental trauma. Pediatr Emerg Care. 2012 Feb;28(2):183-4. PMID 22307191
    6. Heffler MA, Brant JA, Singh A, et al. Ultrasound-Guided Regional Anesthesia of the Femoral Nerve in the Pediatric Emergency Department [published online ahead of print, 2022 Jan 10]. Pediatr Emerg Care. PMID 35245015
    7. Lam-Antoniades M, Ratnapalan S, Tait G. Electronic continuing education in the health professions: an update on evidence from RCTs. J Contin Educ Health Prof. 2009;29(1):44-51. PMID 19288566
    8. Lin-Martore M, Olvera MP, Kornblith AE, et al. Evaluating a Web‐based Point‐of‐care Ultrasound Curriculum for the Diagnosis of Intussusception. Academic Education and Training. 2020 Sep 23;5(3):e10526. PMID 34041433
    9. Marin JR, Lewiss RE, American Academy of Pediatrics CoPEM, et al. Point-of-care ultrasonography by pediatric emergency physicians. Policy statement. Ann Emerg Med. 2015;65(4):472-478. PMID 25805037
    10. Neubrand TL, Roswell K, Deakyne S, Kocher K, Wathen J. Fascia iliaca compartment nerve block versus systemic pain control for acute femur fractures in the pediatric emergency department. Pediatr Emerg Care. 2014 Jul;30(7):469-73. PMID 24977991
    11. Thigh Arteries Schema. Wikimedia Commons, 23 July 2010. Accessed 17 Dec. 2021.
    12. Turner AL, Stevenson MD, Cross KP. Impact of ultrasound-guided femoral nerve blocks in the pediatric emergency department. Pediatr Emerg Care 2014 Apr;30(4):227-9. PMID 24651214
    13. Vieira RL, Hsu D, Nagler J, et al. Pediatric emergency medicine fellow training in ultrasound: consensus educational guidelines. Acad Emerg Med. 2013;20(3):300-6. PMID 23517263
    14. Wathen JE, Gao D, Merritt G, et al. A randomized controlled trial comparing a fascia iliaca compartment nerve block to a traditional systemic analgesic for femur fractures in a pediatric emergency department. Ann Emerg Med. 2007. ;50(2):162-171.e1. PMID 17210208
    By |2026-03-04T15:33:37-08:00Apr 6, 2022|Orthopedic, Pediatrics, PEM POCUS, Ultrasound|
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    PEM POCUS Series: Pediatric Ocular Ultrasound for Optic Nerve Evaluation

    Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric ocular ultrasonography for optic nerve evaluation. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

     

    Take the ALiEMU PEM POCUS: Pediatric Ocular Ultrasound Quiz – test your skills

    PATIENT CASE: Child with a Headache

    Madeline is a 15-year-old female presenting to the Emergency Department with chief complaint of a headache for 1 week. She has been struggling with headaches for more than a year. The headache has been intermittent and tends to develop close to the end of the day, but it does improve with sleep. She denies photophobia, but has been complaining of blurry vision over the last week for which she is scheduled to see an ophthalmologist. Her medications include ibuprofen as needed for the headache and a daily medication for her acne.

    Vital Signs

    Vital SignFinding
    Temperature97°F
    Heart rate78 bpm
    Blood pressure130/85
    Respiratory rate14
    Oxygen saturation (room air)100%
    Weight200 lbs (90.1 kg)

    Exam

    Overall she is well appearing. She has a normal cardiac, respiratory, abdominal, and neurological examination including the cranial nerves.

    On ocular examination, she has normal extra-ocular movements and a pupillary examination.

    • Visual acuity: Right eye 20/30, left eye 20/25
    • No visual field deficits
    • You attempt to evaluate her optic discs with an ophthalmoscope. Although not confident, you believe she has blurring of the optic disc margins bilaterally.

    Given your examination findings, you request an ophthalmology evaluation and consider head imaging. While waiting, you decide to perform an ocular point of care ultrasound (POCUS) examination.

    Why perform an ocular POCUS?

    Ocular POCUS can be performed for various complaints, and it can provide valuable information. This especially is true in cases where the physical examination is difficult to perform such as from lack of patient cooperation, sensitivity to light, or pain. In resource-limited settings and when access to advanced diagnostic imaging or an ophthalmologist could be delayed or unavailable, ocular POCUS can be easily performed and provide information within minutes. 

    Indications to performing ocular POCUS include:

    • Visual changes
    • Acute loss of vision
    • Ocular trauma
    • Non-traumatic eye pain
    • Evaluation for increased intracranial pressure (ICP)

    IMPORTANT NOTE: Ocular POCUS should not be performed when there is a concern for globe rupture to avoid applying pressure on the eye and exacerbating loss of intraocular contents. 

    Figure 1: Hockey stick linear transducer that can be used for ocular point of care ultrasonography
    Figure 2. Linear transducer to use for ocular point of care ultrasonography

    Step-By-Step Technique

    • The examination can be performed with the patient in the supine position or with the head of the bed slightly elevated
    • A high frequency linear transducer (Figures 1 & 2) should be used, preferably with a smaller footprint
    • A copious amount of gel should be applied to a closed eye
      • Different types of gel could be used such as the regular water-soluble ultrasound gel, sterile gel/surgical lube, and commercially available ocular-specific ultrasound gel. All these are safe, easy to clean, and do not irritate the eye.

    Pro Tip: A tegaderm placed over a closed eye could be used to keep the gel from going into the eye. A tegaderm placed over a closed eye could be used to keep the gel from going into the eye depending on the patient’s preference.

    • Ultrasound Setup: Ideally use the ocular preset. The ocular setting lowers both mechanical and thermal indices, thus decreasing the amount of ocular exposure to the energy released from the transducer. Set the depth at 4-5 cm. This will allow imaging of the globe and the orbit behind the eyeball.

    Pro Tip: If your POCUS machine does not have an ocular preset, a musculoskeletal or small parts preset could be used after turning down the dynamic range and mechanical index. Figure 3 is an example of how this could be done on a Mindray TE7 ultrasound machine.

    Figure 3: To change the mechanical index (highlighted in the left upper corner), press on image, then slide the A.power down. Note as you are reducing the A.power, the mechanical index decreases. A mechanical index around 26% is sufficient.
    ocular ultrasound transducer probe over eye
    • Provider Positioning: Anchoring is important when performing an ocular examination to avoid applying pressure on the eyeball. Place 2 or 3 fingers on the patient’s forehead, nasal bridge, or temple (Figure 4, left). Please note: Applying high pressure to the eye can induce the oculocardiac reflex leading to bradycardia. It can also stimulate nausea and vomiting.
    • Ultrasound Views: The ocular POCUS exam can be performed in transverse and sagittal orientations (Figure 5).
      • Transverse: place the transducer on the closed eyelids with the marker towards the patient’s right. Fan the probe until you identify the optic nerve.
      • Sagittal: with the transducer in transverse, turn it 90 degrees until the marker is pointing to the forehead. Tilt Fan the probe until you identify the optic nerve.
    Figure 5: Transducer positioning while performing ocular POCUS in the sagittal (left) and transverse (right) orientation

    Pro Tip: If the optic nerve cannot be seen, ask the patient to move the eye from one side to another. The optic nerve will move in the opposite direction (opposite to the patient gaze).

    Normal Anatomy

    Figure 6: A transverse ocular POCUS showing the hypoechoic eyelid anterior, the anechoic anterior chamber, hyperechoic iris, the hypoechoic lens with hyperechoic anterior and posterior edges, anechoic posterior chamber, and a hyperechoic retina. The optic nerve is appreciated posterior to the retina as a hypoechoic structure that may run vertically or at an angle.
    Video 1: Normal ocular POCUS with a view of a straight optic nerve
    Video 2: Another ocular POCUS showing a normal optic nerve and disc

    Assessment of the Optic Disc

    The optic disc is where the optic nerve enters the eyeball. On POCUS, it normally appears smooth and in-line with the retina. Sometimes a small elevation is noted at the optic disc. This is called Optic Disc Elevation (ODE). It can be measured from the base of the optic disc to its peak at the widest area. It normally measures < 1 mm (figure 7). If the ODE is > 1 mm, this indicates papilledema and increased ICP. Of note, normal ranges are still an active area of study, see table in Ocular POCUS: Facts and Literature Review section for more information.

    Figure 7: Look at the optic disc. Is it elevated? When measured, it was 0.08 cm (0.8 mm).

    Assessment of the optic nerve sheath diameter (ONSD)

    • The optic nerve is covered with the optic nerve sheath that is made up of the 3 layers of meninges surrounding the brain (dura mater, arachnoid mater, and pia mater). Pressure in the subarachnoid space is transmitted to the optic nerve sheath. ONSD (which is the hyperechoic membrane covering the hypoechoic optic nerve) can be measured 3 mm behind the retina (Figures 8 & 9 below). This measurement should done from the outer wall of the optic nerve sheath (hyperechoic sheath) to the outer wall of the sheath on the other side.
      • Do not include the shadow outside the ONSD in the measurement.
      • Identify the trajectory of the optic nerve because this measurement has to be done perpendicular to the nerve’s axis. 
    • Although definitive ONSD normal ranges are still an active area of research, a rough guide for a normal ONSD measurement is:
      • Infants less than 1 year: ONSD <4 mm
      • Children older than 1 year: ONSD <4.5 mm
    Figure 8: Identification of the optic nerve, sheath, and disc
    Figure 9: Measuring the ONSD 0.3 cm (3 mm) behind retina results in an ONSD of 0.385 cm (3.85 mm)
    • Use color doppler to identify the central retinal vessels that run in the middle of the optic nerve. This will help identify the axis/direction of the optic nerve. However, care should be taken to limited duration of color doppler use (Figure 10).

    Pro Tip: ONSD normative values are not well established in pediatrics. Multiple studies attempted to set normal cutoffs for ONSD in various age groups. While measurement more than 5 mm in adults is considered abnormal, a value of 4 mm for infants and 4.5 mm in older children is used as the cut off [1]. The are different cutoffs that are used in the literature with variable sensitivity and specificity. See literature review section. ONSD is also highly operator dependent. An inappropriate technique in measuring the ONSD can lead to under- or over-estimation of the diameter. 

    Ocular POCUS: Abnormal Ultrasound Findings


    Optic Disc Elevation (ODE)

    When ODE is >1 mm, it suggests papilledema, which is concerning for an increased ICP. The following figures and videos below illustrate abnormal ODE measurements. Note that normal ODE ranges are an active area of study.

    Optic Nerve Sheath Diameter (ONSD)

    Assessment of the optic nerve can provide information about intracranial pressure. Increased ICP is suggested when you see an enlarged ONSD.

    Figure 11: Optic disc elevation can be seen as bulging of the hyperechoic optic disc into the posterior chamber, measured as 1.56 mm (normal is >1 mm elevation)
    Video 2: Ocular ultrasound with bulging optic disc, concerning for papilledema
    Figure 12: Ocular ultrasound label showing the elevated optic disc from Video 2

     

    Video 3: Ocular POCUS showing elevated ODE and abnormal ONSD measurements for a 6-year-old patient
    Figure 13: Labeled measurement of the optic disc elevation (ODE) from Video 3.
    Figure 14: The optic nerve sheath diameter (ONSD) is 4.5 mm in Video 3, as measured 3 mm posterior to the retina. This is at the upper limit of normal for the age range.

    Pseudopapilledema is a mimicker

    Pro Tip: Pseudopapilledema (anomalous elevation of one or both optic discs without edema of the optic nerve) is a mimicker of papilledema and can be caused by a number of conditions including:

    • Optic nerve head drusen: Calcified deposits in the optic disc appear hyperechoic with posterior shadowing, and cause swelling (Video 4, Figure 15)
    • Congenital anomalies
    • Vitreopapillary traction
    • Systemic disease

    In these mimic cases, the POCUS ODE is typically <1 mm, whileas true papilledema is ≥1 mm. If the findings are equivocal, providers should perform additional evaluation for papilledema and elevated ICP.

    Video 4: Optic disc drusen
    Figure 15: Optic disc drusen with hyperechoic calcium deposits of the optic disc with posterior shadowing. The ODE measurement is <1 mm.

    Ocular POCUS: Facts and Literature Review

    Ocular POCUS has been used in the Emergency Department for detection of various ocular conditions, including increased ICP. The American Academy of Pediatrics (AAP) supported its use for ocular evaluation in its policy statement [2].

    Optic Disc Elevation (ODE)

    ODE has been reported as a method for detection of increased ICP with decent accuracy. There has been multiple attempts to assess the quantitative measurement of ODE and its correlation with increased ICP (table 1). This is an area of ongoing research with early studies limited by small sample sizes.

    StudySensitivitySpecificityComments
    Teismann et al 2013 [3]At 0.6 mm cut off: 82%
    (95% CI 48-98%)

    At 1 mm cut off: 73%
    (95% CI 39-94%)    		At 0.6 mm cut off: 76% (95% CI 50-93%)

    At 1 mm cut off: 100% (95% CI 81-100%)    		Sample size: 14 adults

    These measurements were compared to ophthalmology-performed fundus exam. Only 6 of 14 patients had papilledema.
    Tessaro et al 2021 [4]At 0.66 mm cut off (for mean of ODE of both eyes): 96%
    (95% CI 79–100%)     		93% (95% CI 79–100%)Sample size: 40 children (mean age 11.4 years)

    26/40 patients had increased ICP.
    Table 1: Literature about optic disc elevation measurements using ultrasonography

    Optic Nerve Sheath Diameter (ONSD)

    Normal values for ONSD have been established in adults [5]. It is still a controversial topic in children. The current standard is that an ONSD >4 mm in infants and 4.5 mm in children older than 1 year is considered abnormal, based on pediatric study of 102 healthy children [1]. There have been multiple studies to assess the sensitivity and specificity of this exam (table 2). 

    StudyAbnormal ONSD ifSensitivitySpecificityComments
    Blaivas et al 2003 [5]>5 mm100%95%Sample size: 34 adults

    This is an adult study comparing ONSD on POCUS with CT results.
    Le et al 2009 [6]>4 mm for infants

    >4.5 mm for children >1 year old    		83% (95% CI 60-94%)38% (95% CI 23-54%)Sample size: 64 children

    24/64 patients had confirmed ICP based on CT, MRI, or direct ICP monitoring.
    Marchese et al 2018 [7]>4.5 mm90% (95% CI 67–98%)57% (95% CI 43–70%)Sample size: 76 children

    20/76 patients had concern for optic nerve swelling on ophthalmology exam. The test characteristics of ONSD changed with increasing or decreasing cutoffs or adding ODE as another marker for increased ICP.
    Table 2: Studies assessing correlation of optic nerve sheath diameter (ONSD) measurements with increased intracranial pressure (ICP)

    Case Resolution

    You perform an ocular POCUS exam with a linear probe. The following image was obtained. What do you see?

    Figure 16. Ocular ultrasound of patient case

    ED Course

    This patient’s POCUS showed optic disc swelling with optic disc elevation and an enlarged optic nerve sheath diameter suggesting elevated ICP. The brain MRI was normal without signs of hydrocephalus. Ophthalmology evaluation confirmed the presence of papilledema. After consulting with neurology, an ultrasound-assisted lumbar puncture (LP) was performed. The patient’s opening pressure was 35 mm H2O. CSF was removed until a goal pressure of 25 mm H2O was achieved. The patient was diagnosed with idiopathic intracranial hypertension (formerly known as pseudotumor cerebri). The patient symptoms were resolved after the LP. She was admitted for further evaluation and management.

    Hospital Course

    The patient was evaluated by neurology while on the inpatient unit. She was started on acetazolamide and discharged home. After multiple follow-up visits at the neurology clinic, her symptoms continue to be well-controlled.

    Learn More…

    References

    1. Ballantyne J, Hollman AS, Hamilton R, et al. Transorbital optic nerve sheath ultrasonography in normal children. Clin Radiol. 1999 Nov;54(11):740-2. PMID: 10580764.
    2. Marin JR, Lewiss RE; American Academy of Pediatrics, Committee on Pediatric Emergency Medicine; Society for Academic Emergency Medicine, Academy of Emergency Ultrasound; American College of Emergency Physicians, Pediatric Emergency Medicine Committee; World Interactive Network Focused on Critical Ultrasound. Point-of-care ultrasonography by pediatric emergency medicine physicians. Pediatrics. 2015 Apr;135(4):e1113-22. PMID: 25825532.
    3. Teismann N, Lenaghan P, Nolan R, Stein J, Green A. Point-of-care ocular ultrasound to detect optic disc swelling. Acad Emerg Med. 2013 Sep;20(9):920-5. PMID: 24050798.
    4. Tessaro MO, Friedman N, Al-Sani F, Gauthey M, Maguire B, Davis A. Pediatric point-of-care ultrasound of optic disc elevation for increased intracranial pressure: A pilot study. Am J Emerg Med. 2021 May 21;49:18-23. PMID: 34051397.
    5. Blaivas M, Theodoro D, Sierzenski PR. Elevated intracranial pressure detected by bedside emergency ultrasonography of the optic nerve sheath. Acad Emerg Med. 2003 Apr;10(4):376-81. PMID: 12670853.
    6. Le A, Hoehn ME, Smith ME, et al. Bedside sonographic measurement of optic nerve sheath diameter as a predictor of increased intracranial pressure in children. Ann Emerg Med. 2009 Jun;53(6):785-91. PMID: 19167786.
    7. Marchese RF, Mistry RD, Binenbaum G, et al. Identification of Optic Nerve Swelling Using Point-of-Care Ocular Ultrasound in Children. Pediatr Emerg Care. 2018 Aug;34(8):531-536. PMID: 28146012.
    By |2021-06-23T12:54:16-07:00Jun 17, 2021|Pediatrics, PEM POCUS|
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    PEM POCUS Series: Pediatric Peripheral IV Access

    PEM POCUS peripheral IV ultrasound badge

    Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric peripheral IV placement. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

    Take the ALiEMU PEM POCUS: Peripheral IV Quiz – test your skills

    PATIENT CASE: Child with Sickle Cell Pain

    Abigail is a 10-year-old girl with known sickle cell disease, who presents with severe atraumatic pain in her hips and back. She is afebrile, but tachycardic and tachypneic with 10/10 pain. Nurses have made several attempts but have been unsuccessful in establishing a peripheral IV(PIV) for giving IV fluids and medications. They now ask you to obtain access. You decide to perform an ultrasound-guided PIV placement. 

    Exam

    Vital SignFinding
    Temperature37.6C
    Heart rate135 bpm
    Blood pressure135/90
    Respiratory rate23
    Oxygen saturation (room air)99%
    • General: Well-developed, appears in significant distress due to pain.
    • Cardiovascular: Tachycardic with regular rhythm, good distal pulses, and capillary refill
    • Pulmonary: Tachypneic without retractions; good aeration without wheezes, rales, crackles.
    • Abdomen: Soft, normal bowel sounds
    • Neurologic: Alert and oriented x3 with GCS 15; no focal deficits on cranial and sensorimotor exam

    What are some potential challenges in peripheral IV placement?

    • Dehydration: Veins may collapse as a result of dehydration, making them harder to identify and cannulate.
    • Vein mobility: Veins are more mobile than arteries. Particularly mobile veins can “roll” or move during cannulation attempts.
    • Overlying soft tissue: Large body habitus can interfere with visualization of veins.
    • Vein size: Some patients, especially infants, have small veins.
    • Repeated venipuncture: Some patients with chronic conditions, such as sickle cell disease, often require frequent venipuncture. Repeated venipuncture can cause veins to change morphologically over time, making them difficult to identify and cannulate.

    How can POCUS be helpful in obtaining IV access?

    • Direct visualization and guidance: Real-time visualization of IV catheter/needle in real-time as it approaches and cannulates the vessel.
    • Surrounding anatomy: Visualization of surrounding structures (e.g., nerves, arteries, other veins) which may not be apparent on visual examination.
    • Differentiating vein from artery: Distinguishing between different types of vessels.

    Ultrasound-Guided Peripheral IV Access: Normal Findings

    1. Differentiating Veins from Arteries

    Veins and arteries can be difficult to distinguish. Below is a table to help differentiate using ultrasonography. 

    CharacteristicVeinsArteries
    DiameterTypically larger than arteries (is dependent on fluid status)Relatively fixed in size, round in shape
    Wall ThicknessThinThick
    CompressibilityEasyMore difficult
    Color Doppler FlowNon-pulsatilePulsatile
    Vessel ValvesPresent (but not always visible)Absent
    Table 1. Anatomical and ultrasonography differences between veins and arteries
    • Compressibility: Typically, veins are easily compressed, while arteries with their thick walls are more difficult to compress.  
    Video 1: Ultrasound clip of a vein being compressed
    • Color Doppler Flow: Color Doppler can be used to differentiate pulsatile from non-pulsatile flow. Red and blue colors do NOT correlate with venous or arterial blood flow. Instead, the colors represent the direction of flow. A helpful acronym is BART – “Blue Away, Red Towards.”
    Video 2: Ultrasound clip of a vein (red) with non-pulsatile flow and artery (blue) with pulsatile flow

    2. Identifying Nerves

    Nerves can be confused with blood vessels when looking on ultrasound. The following are ways to identify a nerve.

    • Honeycomb appearance: Classically nerves appear in cross-section with small hypoechoic (dark) areas separated by hyperechoic (bright) septae.
    Video 3: Ultrasound clip of nerve (left) and artery (right). The nerve has a honeycomb appearance with several hypoechoic (dark) areas separated by hyperechoic (bright) septae whereas the artery is more uniformly hypoechoic. There is also a needle entering from the left of the screen. See below labeled still image of same anatomical structures below.
    peripheral IV ultrasound nerve artery
    Figure 1: Ultrasound still image with labeled nerve and artery. See Videos 3 and 4 for ultrasound videos of same structures with and without doppler flow. 
    •  No Color Doppler flow: While Color Doppler can be used to assess for pulsatile and non-pulsatile flow of arteries and nerves, respectively, nerves should not demonstrate any flow. 
    Video 4: Ultrasound clip of nerve (left) and artery (right) with color Doppler. This is a clip of the same location on the same patient in Video 3 and Figure 1. The nerve (center of yellow box) shows no flow under color Doppler. In contrast, the artery (partially captured at right of yellow box) demonstrates pulsatile flow. 
    • Anisotropy: This ultrasound artifact is exhibited by nerves (as well as tendons and ligaments), whereby the nerve changes brightness depending on the angle of ultrasound beam.
    Video 5: Ultrasound clip of nerve exhibiting anisotropy. The brightness of the nerve (in center, labeled in Figure 2 below) changes with the angle of the probe.

    PEM POCUS peripheral IV anisotropy ultrasound
    Figure 2: Still image from Video 5 above with nerve highlighted in yellow. 

    Fun fact: Certain gemstones like tiger’s eye and figured woods like flamed maple exhibit chatoyance which is analogous to anisotropy, but occurs under visible light, rather than ultrasound beams like anisotropy.

    gemstone anisotropy
    Figure 3: Image of Tiger’s eye gemstone. These gemstones exhibit chatoyance, a characteristic of light reflection which is analogous to “anisotropy” under ultrasound. (Image: Benjamint444 [CC BY-SA])

    3. Needle Artifact

    Needles exhibit ultrasound artifacts which can help with identification.

    • Ring down artifact:  This resonance artifact describes when ultrasound beams encounter trapped gas and create a spotlight effect.  See additional information on Radiopaedia.org.
    • Reverberation artifact:  This artifact describes when ultrasound beams reflect back and forth between two strong parallel reflectors and the machine interprets additional objects deeper than the actual object.  See additional information on Radiopaedia.org.
    Video 6: Ultrasound clip of needle in water bath with both ring down and reverberation artifacts. The tip of the needle appears to have a spotlight beam shining down,  this is an example of ring down artifact from trapped air at the needle tip. This video also demonstrates reverberation artifact where there appears to be a deeper hyperechoic (bright) needle at the bottom left of the video seen best at the beginning of the clip.

    TECHNIQUE

    Vein Selection: Upper Extremity

    Typically, pediatric patients receive a peripheral IV in the upper extremity in one of 2 locations: 

    1. Antecubital fossa (Figure 4):
      • Access superficial veins, which includes the basilic, cephalic, and median cubital veins. 
      • Tip: Beware of tortuously curved paths of veins, branch points, and nearby nerves.
    arm anatomy vein
    Figure 4: Diagram of venous anatomy of the arm focused on antecubital fossa. The antecubital fossa area (the inside of the elbow) is shown in the blue box. Adapted from image By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. [CC BY 3.0]
    1. Upper arm near medial bicipital groove (Figure 5):
      • Access the deep brachial vein or more proximal aspect of the basilic vein.
    upper arm vein anatomy
    Figure 5: Diagram of venous anatomy of the upper extremity. By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. [CC BY 3.0]

    Vein Selection: Lower Extremity

    If unable obtain upper extremity access, the lower extremity can also be accessed. This is more typically performed in infants and young children. 

    • Lower medial leg (Figures 6, 7): This site allows for access to thegreat saphenous vein. 
    leg vascular anatomy
    Figure 6: Diagram of veins of the leg. Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014“. WikiJournal of Medicine 1 (2). [CC BY 3.0]
    Figure 7: Diagram of veins of the lower leg. Adapted from image by Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). [CC BY 3.0]

    Set up for success

    • Prior to starting the procedure, set up the room for optimal visualization. 
    • Place ultrasound system monitor in direct line of site with the angiocatheter.
    ultrasound set up position peripheral IV
    Figure 8: Ultrasound machine positioning such that the probe, patient, and screen are in one line of sight.
    • Apply tourniquet around the extremity.
    • Use the high-frequency linear transducer (Figure 9) to identify potential veins before the procedure to map out the course, depth, and size of veins. Initial scanning can be done without sterile precautions. 
      • The best vein: The ideal vein is large, superficial, not near other anatomic structures, and relatively straight.
      • Depth: Set an appropriate depth on the ultrasound monitor such that the target vein is centered on the screen.
    ultrasound linear probe
    Figure 9: A high-frequency linear probe
    • Tip: Pre-scan multiple areas on both arms (or legs) to find the optimal site for ultrasound-guided peripheral IV placement. 
    • Cleaning and probe covers
      • Clean off any non-sterile gel from the patient’s skin.
      • Prepare the skin with chlorhexidine or an alcohol swab.
      • Use a single-use probe cover.
        • Consider a Tegaderm patch, sterile glove, condom, or sterile probe cover.
        • For further discussion of the relevant literature around probe covers, see this ALiEM post.
      • Use sterile ultrasound gel between the skin and the covered probe.
    linear ultrasound probe cover glove
    Figure 10: Sterile glove as a makeshift probe cover. Here the entire probe fits into a single finger of a sterile glove. For another method of using a sterile glove as a probe cover see this Trick of the Trade.

    Probe Positioning

    • Proper orientation and terminology
      • In this procedure, there are 3 objects to coordinate in space. All of these relationships should be in a perpendicular or parallel orientation (not oblique). 
        • The vein
        • The probe
        • The needle 
      • The needle should always be parallel with (i.e., directly overlying) the vein. This leaves two other positional relationships: probe/vein and probe/needle. 
        • Probe/vein: The probe is either transverse or longitudinal relative to the vein (Figure 11).
        • Probe/needle:The needle is either out of plane (i.e., perpendicular) or in plane (i.e., parallel) relative to the length of probe. When using the transverse orientation, the needle is typically also perpendicular, or out of plane, with the length of the probe. Conversely, when using longitudinal orientation, the needle will be parallel, or in plane, with the probe.
    ultrasound short and long axis linear probe
    Figure 11: Labeled axes of linear ultrasound probe

    POCUS-Guided IV Cannulation Technique

    There are 2 approaches in using POCUS for cannulating peripheral veins based on if the operator is using the transverse or longitudinal orientation.

    1. Transverse orientation: This view is particularly helpful for keeping adjacent structures in view and requires less precision to keep the vein in view. It is important to keep in mind the distance the needle must travel to successfully enter the vein, which will depend on the angle of the needle and the depth of the vein. Videos 7 and 8 show the transverse orientation ultrasound views. Note that in this view, once the needle passes into the plane of the ultrasound beam,  it can be difficult to distinguish the tip of the needle from the shaft. 
    Video 7: Ultrasound clip of a phantom model vein in transverse orientation with vein cannulation at end of clip. The needle can be identified based on the ring down artifact as it passes into the plane of the ultrasound beam.

    Video 8: Ultrasound clip of a patient’s vein in transverse orientation with vein cannulation. The vessel is in the top center of the screen. The needle is the bright white (hyperechoic) dot entering it, seen out of plane.
    • Transverse technique (out of plane) with dynamic needle tip visualization: The shaft of the needle can appear indistinguishable from the tip of needle in the transverse or out-of-plane approach. The dynamic needle tip visualization technique allows the operator to continuously identify the location of the tip of the needle. 
      • As soon as the skin is entered, slide the probe closer towards the tip of the needle. 
      • Advance the probe just beyond the tip of the needle. As soon as the needle is no longer in view (i.e., just beyond the tip), it is clear where tip of the needle is. 
      • Hold the probe steady just beyond the needle tip, and advance the needle forward, returning it into the field of view. 
      • Advanced the probe just beyond the tip of the needle again.
      • Repeat the previous steps until the needle is visualized entering the vein.
        • Tip: Make small movements and attempt to keep the vein in the center of the screen. For beginners with this technique, it is recommended to alternate moving either the probe or the needle, one at a time.
    Video 9: Ultrasound clip of a phantom model in transverse orientation with vein cannulation using dynamic needle tip visualization. The operator alternates moving the probe just beyond the tip of the needle and advancing the needle toward the vessel until cannulation. 

    Video 10: Demonstration of the dynamic needle tip visualization technique, showing alternating movements of the probe and needle
    1. Longitudinal orientation: Conceptually, this orientation is more straightforward (probe, vein and needle are all parallel), but the precision involved requires a steady hand and a stationary patient. The needle must stay parallel to the probe within the slice thickness of the ultrasound beam. This value will vary depending on the machine and the probe, but is on the order of millimeters. Video 12 demonstrates the importance of maintaining the vein and needle parallel to the ultrasound beam or else the vein and/or needle disappears from view.
    Video 11: Ultrasound clip with needle in and out of view using the longitudinal orientation technique. Being slightly out-of-plane makes it difficult to visualize the needle and needle tip. Of note, this needle has a guidewire extended past the needle tip which is curved slightly upward from the length of the needle.
    • Longitudinal (in plane) technique
      • Align the probe parallel to the vein. Ideally, the vein should be the same depth and thickness across the screen. 
      • Introduce the needle in-plane (parallel) to the probe marker at a shallow angle. Depending on the depth and size of the vein, this may be close to parallel with the skin.
      • Maintain visualization of the needle tip as it enters the vessel.
      • Tip: If it is unclear where the needle tip is, first stop moving the needle and assess if the probe has drifted or rotated. While keeping the needle still, make corrections with the probe until the needle and needle tip is once again visualized in plane. 

    Video 12: Ultrasound clip of needle cannulating vessel in longitudinal view using in-plane technique

    After Cannulation

    After the needle tip is visualized entering the vein and a flash of blood appears in the hub of the needle, advance the needle forward an additional 1-2 mm before threading the catheter. Why? The catheter does not extend fully to the tip of the needle. Thus the needle must be advanced past the initial flash of blood to ensure that the catheter has also penetrated the vein. If there is resistance when threading the angiocatheter into the vein, reassess the needle tip position using the ultrasound and confirm the needle is still positioned intravascularly. 

    Peripheral IV catheter with needle
    Figure 12: Typical angiocatheter for peripheral IV access. The first few millimeters of the needle tip extend beyond the catheter.

    After successful threading, retract the needle, attach pre-primed IV tubing, and flush and lock the tubing. Secure the catheter in place.

    LITERATURE REVIEW

    There have been many studies evaluating ultrasound-guided peripheral IVs in patients, and below are several key articles involving pediatric patients. Overall, ultrasound-guidance appears to be helpful in pediatric patients with difficult access, but the exact technique involved and the experience of the operator likely have an effect. 

    YearAuthorsTitleMajor Findings
    2009Doniger et al. [1]Randomized controlled trial of ultrasound-guided peripheral intravenous catheter placement versus traditional techniques in difficult-access pediatric patientsUltrasound-guided peripheral IV placement in difficult-access patients took less time, was more often successful, and required fewer needle re-directions.
    2010Oakley and Wong [2]Ultrasound-assisted peripheral vascular access in a paediatric EDUltrasound-guidance was associated with slightly increased success rates in peripheral IV placement. This effect was more pronounced in cases with difficult-access patient.
    2018Otani et al. [3]Ultrasound-guided peripheral intravenous access placement for children in the emergency department In contrast to many other publications on ultrasound-guided peripheral IV procedures, the authors report a LOWER success rate for patients that had one failed IV attempt, as compared to the conventional method. An important potential confounder was that this study used a “dual-operator” method, in which one clinician operates the ultrasound, and the other places the IV. 
    2018Desai et al. [4]Longevity and complication rates of ultrasound guided versus traditional peripheral intravenous catheters in a pediatric emergency departmentUltrasound-guided peripheral IVs had a longer catheter survival time compared with traditionally-placed peripheral IVs. Complications from the peripheral IVs were similar between the two groups. 
    Table: Key literature on pediatric cases studying ultrasound-guided peripheral IV access

    References [click to expand] +

    1. Doniger SJ, Ishimine P, Fox JC, Kanegaye JT. Randomized Controlled Trial of Ultrasound-Guided Peripheral Intravenous Catheter Placement Versus Traditional Techniques in Difficult-Access Pediatric Patients. Pediatr Emerg Care. 2009;25(3):154-9. doi:10.1097/pec.0b013e31819a8946.
    2. Oakley E, Wong A-M. Ultrasound-assisted peripheral vascular access in a paediatric ED. Emerg Med Australas. 2010;22(2):166-70. doi:10.1111/j.1742-6723.2010.01281.x.
    3. Otani T, Morikawa Y, Hayakawa I, et al. Ultrasound-guided peripheral intravenous access placement for children in the emergency department. Eur JPediatr. 2018;177(10):1443-49. doi:10.1007/s00431-018-3201-3.
    4. Desai K, Vinograd AM, Abbadessa MKF, Chen AE. Longevity and Complication Rates of Ultrasound Guided Versus Traditional Peripheral Intravenous Catheters in a Pediatric Emergency Department. J Assoc Vascular Access. 2018;23(3):149-54. doi:10.1016/j.java.2018.06.002.

    CASE RESOLUTION

    Using POCUS, you begin by visualizing Abigail’s veins at the antecubital fossa and are able to identify the basilic and cephalic veins. Tracing the basilic vein proximally, you note that it is relatively large and straight; however, you see a honeycomb-like structure nearby it, which displays anisotropy and appears to be a nerve. You opt instead to follow the cephalic vein. There do not appear to be any nerves or other vessels nearby. You clean her skin appropriately and apply a sterile glove over the probe, and apply sterile gel. After these preparations, you re-identify the vessel in the transverse plane, use dynamic needle tip visualization with an out-of-plane approach, and successfully guide the tip of the needle into the vein. 

    Video 13: Ultrasound clip of a vein in transverse orientation being successfully cannulated.

    After visualizing the tip of the needle in the vein, you slightly advance the needle another 2 mm and then thread the catheter. You are able to obtain bloodwork. After flushing the catheter and cleaning the surrounding skin, you secure the catheter. Abigail is now able to get pain medications and fluids.

    She soon feels much improved after 3 hours. Her laboratory results are similar to her baseline values. She is able to return home with ongoing management as an outpatient basis with close follow-up. 

    Take the ALiEMU PEM POCUS: Peripheral IV Quiz – test your skills

    The PEM POCUS series was created by the UCSF Division of Pediatric Emergency Medicine to help advance pediatric care by the thoughtful use of bedside ultrasonography.

    Read other PEM POCUS tutorials. Learn more about bedside ultrasonography on the ALiEM Ultrasound for the Win series.

    By |2021-05-27T10:14:48-07:00May 24, 2021|PEM POCUS, Ultrasound|
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    PEM POCUS Series: Hip Effusion

    Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric hip effusion. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

    Take the ALiEMU PEM POCUS: Hip Effusion Quiz – test your skills

    PATIENT CASE: Child with a Limp

    Sarah is a 4-year-old girl who comes into the emergency department complaining of a limp for the last day. She had an upper respiratory infection which started a week ago for which she had been taking acetaminophen and ibuprofen with her last dose of either being 2 days ago. Those symptoms have improved. Yesterday, she started complaining of diffuse right leg pain primarily at her hip, thigh, and knee. Today, her parents noted she was walking with a limp.

    On arrival, her vital signs are:

    Vital SignFinding
    Temperature100.1F
    Heart rate100 bpm
    Blood pressure97/50
    Respiratory rate19
    Oxygen saturation (room air)100%

    She is well appearing and walks with an antalgic gait favoring the left leg. She has a normal HEENT, neck, cardiac, respiratory, abdominal, and back examination. She points to her right anterior thigh when you ask her where her pain is. She has limited range of motion with internal and external rotation of her right hip and complains of pain. She cries when you palpate any part of her leg, but is able to range her knee, ankle, and foot fully. She has 2+ dorsalis pedis and posterior tibialis pulses and intact sensation to light touch throughout. 

    Given her pain with range of motion at her hip, you order a hip radiograph, but while waiting for it, decide to perform a hip point of care ultrasound (POCUS) examination.

    PEDIATRIC HIP EFFUSION: Ultrasound Technique

    It can be difficult for children to locate the exact area of pain and often hip pain can present with referred knee and thigh pain. A thorough physical examination along with hip POCUS can help localize the area of discomfort. When we use POCUS to evaluate the hip, we are primarily looking for a joint effusion in the synovial space. This is best visualized anterior to the femoral neck.  

    hip anatomy hip effusion
    Figure 2. Hip anatomy with target landmark being the femoral neck (red arrow) 

    Technique

    1. The patient should be positioned supine.
      • Depending on the age of the child, the child can be positioned supine in the guardian’s lap while undergoing the examination. 
      • Offering the child a toy, book, or phone/tablet for distraction during the examination can also help ease anxiety.
    2. Use a linear high frequency transducer with a wide footprint.
    3. Place the transducer along the anterior hip.
      • Use the greater trochanter as a lateral landmark and place the probe on top of the femoral head and neck (Figure 3)
    4. Aim the probe marker towards the patient’s umbilicus.
    hip effusion ultrasound
    Figure 3. Linear transducer at the hip with probe marker (red dot) aimed towards the patient’s umbilicus
    1. Identify the anatomical landmarks on ultrasound (figure 4) 
      • Hip muscles: Sartorius, quadriceps, and iliopsoas
      • Bones: Femoral head, femoral neck
    2. The area of interest in looking for a hip effusion is the synovial space anterior to the femoral neck and NOT anterior to the femoral head. This area is also referred to as the anterior synovial recess.
    Figure 4. Ultrasound image showing the normal landmarks for a pediatric hip without an effusion and the location of the femoral head (X) and synovial space (circle) with the linear transducer positioned overlying and longitudinal to the femoral neck
    • Tips:
      • It is often helpful to ultrasound the unaffected side as a comparison.
      • Be aware of the patient’s comfort throughout the examination.

    ABNORMAL ULTRASOUND FINDINGS

    A hip effusion will appear anechoic (black) in the synovial space anterior to the femoral neck (anterior synovial recess). Measure the distance between the anterior surface of the femoral neck and the posterior surface of the iliopsoas muscle. Examples are illustrated in figures 5 and 6.

    hip effusion PEM POCUS ultrasound

    There have been different methods used to assess if an effusion is present including:​1,2​

    • Measured effusion is >0.5 cm 
    • Measured effusion with >0.2 cm difference compared to the contralateral hip
    • Gestalt view with the anterior synovial recess areas appearing asymmetric compared to the other hip

    Limitations of the Hip POCUS

    Note that hip POCUS does not tell you the cause of an effusion but rather only whether an effusion is present or not. Effusions can result from infectious, inflammatory, and traumatic etiologies, and thus it is important to take into account the context of the patient’s presentation. 

    References

    1. Vieira R, Levy J. Bedside ultrasonography to identify hip effusions in pediatric patients. Ann Emerg Med. 2010;55(3):284-289. PMID 19695738
    2. Cruz C, Vieira R, Mannix R, Monuteaux M, Levy J. Point-of-care hip ultrasound in a pediatric emergency department. Am J Emerg Med. 2018;36(7):1174-7. PMID 29223689 

    FACTS and LITERATURE REVIEW

    There have been multiple case reports of hip POCUS identifying hip effusions in children with fractures, septic joints, and in the work up of children with limps.​1–3​ There are limited studies examining the accuracy of hip POCUS compared to radiology-performed ultrasound in children (table 1).

    StudyNSensitivitySpecificityComments
    Vieira et al., Ann Emerg Med, 2010​4​2885%93%If the pediatric emergency physician had a high confidence in ultrasound accuracy, the sensitivity increased to 90% and specificity to 100%
    Cruz et al., Am J Emerg Med, 2018​5​51685%98%For each additional hip POCUS performed, the odds of an accurate scan increased by 2.4%. 
    Table 1. Published studies comparing pediatric hip POCUS to radiology-performed ultrasound

     

    References [click to expand] +

    1. Deanehan J, Gallagher R, Vieira R, Levy J. Bedside hip ultrasonography in the pediatric emergency department: a tool to guide management in patients presenting with limp. Pediatr Emerg Care. 2014;30(4):285-287. PMID 24694889
    2. Garrison J, Nguyen M, Marin J. Emergency Department Point-of-Care Hip Ultrasound and Its Role in the Diagnosis of Septic Hip Arthritis: A Case Report. Pediatr Emerg Care. 2016;32(8):555-557. PMID 27490732
    3. Tsung J, Blaivas M. Emergency department diagnosis of pediatric hip effusion and guided arthrocentesis using point-of-care ultrasound. J Emerg Med. 2008;35(4):393-399. PMID 18403170 
    4. Vieira R, Levy J. Bedside ultrasonography to identify hip effusions in pediatric patients. Ann Emerg Med. 2010;55(3):284-289. PMID 19695738
    5. Cruz C, Vieira R, Mannix R, Monuteaux M, Levy J. Point-of-care hip ultrasound in a pediatric emergency department. Am J Emerg Med. 2018;36(7):1174-1177. PMID 29223689 

    CASE RESOLUTION

    The patient’s hip plain film radiographs are unremarkable. You decide to incorporate hip POCUS to your evaluation. You place a linear, high-frequency transducer and visualize the patient’s bilateral hips. You observe the following:

    Right Hip (Affected Side) POCUS Video and Key View

    Though the child complained of hip, knee, and thigh pain, your POCUS evaluation identifies a right hip effusion which helps you narrow the location of her pain.

    Video 1. A hip POCUS of the case patient’s right hip (affected side)

     

    PEM POCUS hip effusion
    Figure 7. Right (affected side) hip POCUS with a hip effusion measuring 0.77 cm

    Left Hip (Normal Side) POCUS Video and Key View

    Video 2. A hip POCUS of the case patient’s left hip (unaffected side) for comparison

     

    PEM POCUS hip no effusion normal
    Figure 8. Left (unaffected side) hip POCUS with no effusion

    ED Course

    The patient’s labs result, and she has reassuring labs, which include a serum WBC 8.3 x109/L and ESR 34 mm/hr. The patient receives ibuprofen during her visit and within 1 hour is able to walk without a significant limp and states she feels better. The patient’s family notes they have spent the last few weeks of summer in a Lyme-endemic region, and so you send off Lyme titers.

    Given the resolution of limp, lack of fever, and reassuring lab values, you do not believe the patient has a septic joint. Her effusion is more likely the result of a transient tenosynovitis. You recommend close pediatrician follow-up.

    Pediatrician Clinic Follow-Up

    At her pediatrician clinic visit 1 week later, her Lyme titers return negative, and the patient continues to be limp-free.  

     

    Take the ALiEMU PEM POCUS: Hip Effusion Quiz – test your skills

    The PEM POCUS series was created by the UCSF Division of Pediatric Emergency Medicine to help advance pediatric care by the thoughtful use of bedside ultrasonography.

    Read other PEM POCUS tutorials. Learn more about bedside ultrasonography on the ALiEM Ultrasound for the Win series.

    By |2021-07-21T18:55:01-07:00May 17, 2021|Orthopedic, PEM POCUS, Ultrasound|
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    PEM POCUS Series: Intussusception

    Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric intussusception. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

     

    Take the ALiEMU PEM POCUS: Intussusception Quiz – test your skills

    PATIENT CASE

    Johnny is a 2-year-old boy who comes into the emergency department for abdominal pain for the last day. His parents are concerned that he has been having intermittent abdominal pain and has seemed very tired all day. Parents deny bloody stool.

    On arrival, his vital signs are:

    Vital SignFinding
    Temperature36.9C
    Heart rate110 bpm
    Blood pressure97/50
    Respiratory rate22
    Oxygen saturation (room air)99%

    He is tired appearing, and his abdominal exam is soft but diffusely tender. Given his intermittent abdominal pain, you decide to perform an intussusception point of care ultrasound (POCUS) exam.

    ULTRASOUND TECHNIQUE

    Intussusception is when one part of the bowel telescopes, or gets stuck, in another part of the bowel. Typically intussusception refers to ileocolic intussusception where the ileum becomes stuck in the colon. To perform the ultrasound, start in the right lower quadrant and trace the colon. See below for a step-by-step technique.

    intussusception
    Overview of sequential ultrasound transducer positioning on the anterior abdomen to assess for intussusception

    Technique

    • The patient should be positioned supine.
    • To aid in comforting the child, the child can be positioned supine in the parent’s lap while undergoing the scan. Having the parent or another provider offer a toy, book, or phone/tablet to distract the child during the scan can also help ease anxiety.
    • Begin in the right lower quadrant (RLQ), using a high frequency linear probe with the probe marker to patient’s right.
    • First, identify the anatomical landmarks in the RLQ (see ultrasound images below):
      • Psoas muscle (green) laterally
      • Right iliac vessels (blue)
      • Abdominal muscles (red)
      • Bladder (yellow) medially

    Ultrasound image: Anterior Abdomen (RLQ) View

    intussusception RLQ ultrasound

    Ultrasound Image: Anterior Abdomen RLQ (More Medial) View

    PEM POCUS intussusception RLQ More Medial
    • Perform graded compression, with slow steady pressure to displace bowel gas
    • Follow the colon from the RLQ to right upper quadrant (RUQ) until the liver (purple) and gallbladder are identified

    Ultrasound Image: Anterior Abdomen (RUQ) View

    PEM POCUS intussusception RUQ
    • Rotate the probe marker to patient’s head and scan the entire length of the transverse colon.
    • Rotate the probe marker back to patient’s right and scan the entire length of the descending colon, making sure to scan all four quadrants.
    • Save representative video clips and still images of each quadrant.
    • If an intussusception is found, measure its diameter in transverse view and note in which quadrant(s) it is found.
    • At the end of scan, if you have found an intussusception, re-image the abdomen to make sure it was not transient.
    • The provider should maintain awareness of the patient’s comfort throughout the scan.

    INTUSSUSCEPTION CLASSIC FINDINGS

    Normal (no intussusception)

    Normal: There is no target or sandwich sign, but rather just folded normal bowel. (To replay, press circular arrow in bottom left corner)

    Abnormal findings

    • Look for findings of a sandwich sign (or pseudo-kidney sign) in the longitudinal view and target sign (or donut sign) in the transverse view.
    • If visualized, measure the diameter of the intussusception in short axis (transverse) and note which in which quadrant(s) it is located.

    Sandwich

    Anterior abdomen ultrasound: Intussusception – Presence of a sandwich sign (long axis view) and target sign (short axis view)

    Target Sign

    Intussusception diameter ultrasound
    Measurement: The diameter of an intussusception (i.e., target sign) in transverse view involves measuring the distance from outer wall to outer wall.

    Additional Anterior Abdominal Ultrasound Videos

    Pro Tip
    It can be difficult to distinguish intussusception of the small bowel-small bowel (i.e., when the ileum or part of the small bowel telescopes into itself) versus ileocolic (i.e., when the ileum becomes telescopes into the colon). The former often does not require a procedure for reduction, while the latter typically does. If the target sign diameter is <2 cm and transient, a small bowel-small bowel intussusception should be suspected. The length of the intussusception, or how many quadrants are involved, can also be measured for an idea of how much bowel is involved.

    Small bowel-small bowel intussusception

    Small bowel-small bowel intussusception – Note the small size of the target lesion. Because the ultrasound video scans to a depth of 3.3 cm (see bottom right side of the screen), the target sign appears to be approximately only 1 cm in diameter.

     

    Small bowel-small bowel intussusception – There is a target sign, but it is small (<2 cm) with a small fat (white) core.

     

    Ileo-colic intussusception

    Ileo-colic intussusception with classic target sign – Note the lymph nodes (black) inside the mesenteric fat (white) in the center of the target.

    FACTS and LITERATURE REVIEW

    Mimickers of Intussusception

    There are additional pathologies that can be mistaken for intussusception such as an intussuscepted appendix, appendicitis surrounded by abscess, and Meckel’s diverticulum, which are beyond the scope of this course. Any concerning finding for intussusception should be followed by a confirmatory study by the radiology department.

    Benefits of intussusception POCUS scans

    Although few studies have looked at point of care ultrasonography (POCUS) for intussusception, the existing studies have shown excellent test characteristics and a decreased length of stay with using POCUS.

    Two studies assessed the test characteristics of the intussusception POCUS.

    PublicationStudy MethodologySensitivitySpecificity
    Riera et al. (2012)​1​This journal publication was a prospective study of 82 patients who underwent POCUS by pediatric emergency medicine (PEM) providers. The gold standard was a comprehensive radiology ultrasound.85%97%
    Trigylidas et al. (2017) ​2​This abstract reported a retrospective study of 105 intussusception POCUS scans by PEM providers. The gold standard was either a direct radiology over-read of the POCUS scans or a radiology department ultrasound.96.2%92.6%
    Lin-Martore et al. (2020)6This systematic review and meta analysis included 1,303 patients and 6 studies.94.9%99.1%
    Bergmann et al. (2021)7This prospective study of 256 children across 17 sites (35 sonologists) compared POCUS and radiology performed ultrasound using a gold standard of clinically important intussusception which was defined as an intussusception that required radiographic or surgical reduction during or within 7 days of the incident ED visit.96.6%98%

    In terms of ED length of stay (LOS), Kim et al. (2017) reported that after the introduction of an intussusception POCUS scanning protocol, the LOS decreased by >200 minutes.​3​

    Differentiating small bowel-small bowel from ileocolic intussusception

    In general, true ileocolic intussusceptions are:

    • Found on the right side of the abdomen
    • >2 cm in diameter
    • Have mesenteric fat (which is white) and lymph nodes in the center
    • Do not self resolve

    There have been studies looking at distinguishing small bowel-small bowel from ileocolic intussusception. These, however, have been radiology-based and not POCUS studies, making generalizability to the ED setting challenging. Thus, if there is a concern for an intussusception, a radiology ultrasound should be ordered.

    One small study with 27 patients by Wiersma et al. (2006) found that small bowel-small bowel intussusceptions had a smaller mean diameter and length compared to ileocolic intussusceptions.​4​

    Type of intussusception# of patients and scansMean diameter (range)Mean length (range)Location
    Small bowel-small bowel10 patients, 11 scans1.5 cm (1.1-2.5 cm)2.5 cm (1.5-6 cm)Distributed throughout the abdomen (6 paraumbilical, 2 RUQ, 2 RLQ, 1 LLQ)
    Ileocolic14 patients, 16 scans3.7 cm (3-5.5 cm)8.2 cm (5-12.5 cm)All on right side of abdomen

    Lioubashevsky et al 2013​5​ had a larger sample size (174 patients) with similar findings. The authors also measured the ratio of the inner fat core to the intussusception outer wall and identified the presence or absence of lymph nodes within the lesion.

    Type of Intussusception# of patientsMean diameter (range)Mean length (range)Ratio of fat core to the intussusception outer wall% of patients with lymph nodes in the lesion
    Small bowel-small bowel57 patients1.4 cm 
    (1.1-2.5 cm)    		2.5 cm 
    (1.5-6 cm)    		<114%
    Ileocolic143 patients2.6 cm 
    (1.3-4 cm)    		8.2 cm 
    (5-12.5 cm)    		>189.5%

    References [click to expand] +

    1. Riera A, Hsiao A, Langhan M, Goodman T, Chen L. Diagnosis of intussusception by physician novice sonographers in the emergency department. Ann Emerg Med. 2012;60(3):264-268. PMID 22424652
    2. Trigylidas TE, Kelly JC, Hegenbarth MA, Kennedy C, Patel L, O’Rourke K. 395 Pediatric Emergency Medicine-Performed Point-of-Care Ultrasound (POCUS) for the Diagnosis of Intussusception. Annals of Emergency Medicine. October 2017:S155. DOI
    3. Kim J, Lee J, Kwon J, Cho H, Lee J, Ryu J. Point-of-Care Ultrasound Could Streamline the Emergency Department Workflow of Clinically Nonspecific Intussusception. Pediatr Emerg Care. September 2017. PMID 28926507
    4. Wiersma F, Allema J, Holscher H. Ileoileal intussusception in children: ultrasonographic differentiation from ileocolic intussusception. Pediatr Radiol. 2006;36(11):1177-1181. PMID 17019589
    5. Lioubashevsky N, Hiller N, Rozovsky K, Segev L, Simanovsky N. Ileocolic versus small-bowel intussusception in children: can US enable reliable differentiation? Radiology. 2013;269(1):266-271. PMID 23801771
    6. Lin-Martore M, Kornblith AE, Kohn MA, Gottlieb M. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception in Children Presenting to the Emergency Department: A Systematic Review and Meta-analysis. West J Emerg Med. 2020 Jul 2;21(4):1008-1016. doi: 10.5811/westjem.2020.4.46241. PMID: 32726276.
    7. Bergmann KR, Arroyo AC, Tessaro MO, et al; P2Network. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception: A Multicenter, Noninferiority Study of Paired Diagnostic Tests. Ann Emerg Med. 2021 Jul 2:S0196-0644(21)00340-1. doi: 10.1016/j.annemergmed.2021.04.033. Epub ahead of print. PMID: 34226072.

    Case Resolution

    You place a linear, high-frequency probe on the right side of the patient’s abdomen. You perform a bedside ultrasound scan, viewing transversely and longitudinally through the upper and lower abdomen. You observe the following:

    What is the diagnosis?

    This is an intussusception!

    The intussusceptum (red) is the part of the bowel that has telescoped into the intussuscipiens (blue). When ileum becomes trapped in the colon, this can lead to ischemia and necrosis over time. This is what causes the classic “currant jelly stools”, which are bloody stools.

    Tip: The classic triad of colicky abdominal pain, palpable mass and bloody stool are present in less than 50% of patients, and intussusception should be suspected for patients with vomiting, abdominal pain, and/or lethargy.​1​

    Hospital course

    Johnny underwent an air enema reduction in the Radiology department, which successfully reduced the ileocolic intussusception.

    Reference

    1. Daneman A, Alton D. Intussusception. Issues and controversies related to diagnosis and reduction. Radiol Clin North Am. 1996;34(4):743-756. PMID 8677307.
    Take the ALiEMU PEM POCUS: Intussusception Quiz – test your skills

    The PEM POCUS series was created by the UCSF Division of Pediatric Emergency Medicine to help advance pediatric care by the thoughtful use of bedside ultrasonography.

    Learn more about bedside ultrasonography on the ALiEM Ultrasound for the Win series

    By |2021-10-21T16:59:09-07:00May 10, 2021|Gastrointestinal, PEM POCUS, Ultrasound|
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