Category Archives: Ultrasound

Vascular Access In Children: Solve the Puzzle

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Dr. Rawan Alrashed (@rawalrashed)

PEM Physician

PoCUS Fellow

Reviewed and edited by: Dr. David Lewis

 

Background

Pediatric vascular access is one of the challenging skills in the medical field especially during an emergency, different guidelines have been established to facilitate the choice of the proper IV access one of which is the miniMAGIC that was published in 2020.1 Choosing the right access is crucial for success taking in consideration the urgency of access, patient safety, infused fluid characteristic  to determine the right one especially with a peripheral IV catheter failure rate of 77% in the first attempt.2 Difficult intravenous Access score (DIVA) is one of the tool that can be used to evaluate the feasibility of a peripheral IV and accordingly, the best next step for IV line insertion where Subjects with a DIVA score of 4 or more were more than 50% likely to have failed intravenous placement on first attempt.3

 

Figure-1: DIVA score.4

Types of vascular access

  • Peripheral IV catheters (PIVCS)
  • Intraosseous Access
  • Central Venous Catheters (CVCs) (Non-tunneled) 
  • US guided Access
  • Umbilical Catheter
  • Surgical cutdown

 

Figure 2: Vascular Access Locations.5

Consideration in pediatrics4

  • Pain management is a critical step for the success of IV cannulation

Multiple choices are available starting from non-pharmacological distraction technique and non-nutritive sucking to the utilization of local anesthetic such as EMLA and LMX as well the needle-free lidocaine jet-injection

  • Enhancing visualization of vein by using tourniquet, transilluminator with any available light source.
  • Ultrasound guided peripheral IV access is the recommended current practice in difficult access.
  • Ultrasound guided central IV access is the standard of care currently in comparison to anatomical landmark in critical care setting.

Indication of IV access

Patient resuscitation.

Delivering fluids, medication, Blood sampling.

Hemodynamics monitoring as well arterial blood gas.

Contraindications

Infection at the insertion site.

Thrombosis of the vein.

Bleeding diathesis in central line is a relative contraindication.

In IO Access, fracture on the same bone as well pathological disorder predisposing to fractures is a contraindication.

Peripheral IV catheter (PIVC)

Different veins can be used for PIVC starting with dorsal veins of the hand, then the feet and then proceeding to other choices including scalp vein in infants, external jugular vein, antecubital and the great saphenous vein as in Figure-2.5

Technique:5

  1. Prepare instruments: cleansing solution, tourniquet, catheter needle, connecting tube, flush, dressing, gauze, and stabilizer tape.
  2. Size of catheter as in the table: utilize the smallest gauge and shortest catheter as possible with exception in resuscitation where larger bore gauge is preferable or in case of midline cannulation where longer catheter is preferable.
  3. Apply tourniquet proximal to the site of insertion to enhance visualization
  4. Identify proper vein by visualization, palpation and utilizing the transilluminator or infrared light
  5. Clean the skin as per the facility protocol
  6. Hold the needle between the thumb and forefinger with the dominant hand and stretch the skin with the other hand
  7. Enter with an angle of 10-30 degree then if blood seen shallow your angle to advance 1-2 mm then advance the catheter and once in pull your needle or retract it.
  8. Flush to confirm patency and no swelling at the site then stabilize your catheter

 

 Neonate  Infant   Children Length
PIV 24-26G 22G 20G 2-6cm
Midline Access 22G 22G 20G 15-30cm

 

Table-1: Size of PIV catheter.

 

US guided peripheral vascular access

A recent RCT by Vinograd et.al. evaluated 167 children showed 85% success rate of first attempt with US guidance compared to 45% with traditional methods. Also US guidance resulted in shorter cannulation time, less redirection and fewer attempts.6 

Important consideration in US- guided PIV

  • The diameter and depth of the vein have been found determinate factors for success of cannulation in adult studies where very superficial (< 0.3 cm) and very deep (> 1.5 cm) veins are difficult to cannulate.7
  • The suggested veins are the cephalic vein in the forearm or the saphenous vein at the medial malleolus, while the antecubital vein might be an easy approach but the risk of brachial artery cannulation and the elbow bending make it less favorable. 7

Technique 7

  • Use a linear probe with 5-15 MHz ( Alternatively a hockey stick or MicroConvex might be useful)
  • Identify the vein and assess patency by being compressible and non pulsatile, for further confirmation utilize color or pulse wave doppler with augmentation to identify low status flow.

Longer catheter are preferable when using ultrasound guided insertion especially with a vein deeper then 0.5 cm to minimize the risk of dislodgment and infiltration (suggested to be longer than 2 cm). In a pilot study by Paladini, long catheter > 6 cm were associated with lower risk of failure in pediatric patients more than 10 years comparable to the short one <6 cm.8

  • Static or dynamic guidance are acceptable with preference of the latter. 
  • Two approach technique available with best outcome observed with out-of-plane in PIVC.

 

Out-of-plane (Short-Axis):
  • Consider using the middle point on the ultrasound machine to enhance alignment
  • The US wave perpendicular at right angle to the vessel.
  • The needle is inserted close to the probe at 20-30o angle then advance with meet and greet technique or dynamic needle tip positioning technique as in video

 

 

Pitfalls:

  • The needle shaft might be misidentified as the needle tip thus the importance of advancing the probe then the needle to maintain visualization of the tip only.  Also sweeping in the same plane can help to follow the needle proximal and distal to confirm the tip from the shaft.
  • Risk of posterior wall penetration and failure of cannulation.

 

In-Plane (Long-Axis):
  • The US beam is parallel to the vessel.
  • The whole needle shaft is visualized during insertion and advancement to the vein.
  • To facilitate visualization of needle “Ski left” technique can be used.

 

 

Pitfalls:

  • Maintaining the transducer static without any movement is difficult in small children as any movement would lead to loss of needle visualization, thus insertion will not be accurate (side lobe artifact)

No evidence of preferable technique in pediatrics but in adults out-of-plane proven to be superior for PIVC insertion.

 

How to Use US for PIVC:

https://www.coreultrasound.com/ultrasound-guided-peripheral-iv-access/

 

Intraosseous Access

It’s considered the best alternative IV access in emergencies (peri-arrest and arrest condition) after 2 failed attempts of PIVC within 60-90 seconds, AHA recommends IO catheter as first line access in cardiac arrest. Still the outcome of out of hospital cardiac arrest and best access need more delineation.4,5

Technique4

  • IO access can be accomplished using a manual needle or battery powered device such as EZ-IO or even a regular large bore needle.
  • Place the knee in slight flexion with padding.
  • Clean the skin and consider analgesia according to the urgency of the situation.
  • Insert the needle at 900 over the skin.
  • Remove the stylet and aspirate then infuse saline.
  • Confirmation of proper insertion by the needle standing still even if no backflow seen with lack of extravasation during fluid infusion.

Figure-2 (on green)  shows the possible site for IO insertion where the commonest one is the proximal tibial shaft about 1-2 cm from the tibial tuberosity avoiding the growth plate.

Complication4

  • IO needle is a temporary access that can not last for more than 24 hours
  • Longer use can predispose the child to complication including infection, thrombosis, fat embolism
  • Other complications of insertion include through-and-through penetration of the bone, physeal plate injury, pressure necrosis of the skin, compartment syndrome, osteomyelitis, subcutaneous abscess

 

Confirmation of IO by POCUS2

  • Use linear probe distal to the insertion site
  • Apply color doppler and observe for saline flush site
  • If above the bony cortical site or lateral or deep may indicate misplacement

 

Figure-3: POCUS confirmation of IO site.

 

 

Central IV Catheter (CIVC)

This an alternative longer duration route that can be utilized as an emergency line but less favorable compared to the IO during initial resuscitation. It is still considered a good choice in ill patients with difficulty of PIVC and failure of US guided peripheral access as well IO when fluid, high concentrated electrolytes and vasopressors are needed.4

The common site for insertion of non-tunneled CVC in pediatric is the internal jugular in critical care setting with higher success rate compared to femoral vein9 , but the femoral vein might be the first choice in PEM as it’s easily accessible and don’t interfere with resuscitation measures.10

Technique10

Always prepare your equipment and check them, also get consent when possible before attempting a central line

 

Age(years) weight (kg) Catheter gauge French gauge length (cm)
<1y 4-8 24 3 5-12
<1y 5-10 22 3-3.5 5-12
1-3y 10-15 20 4 5-15
3-8y 15-30 18-20 4-5 5-25
>8y 30-70 16-20 5-8 5-30

Table-2: CVC sizes.4

Anatomical Landmark5

Internal Jugular vein:

  • Under aseptic technique with proper draping, put the patient in Trendelenburg position and turn the head slightly to the other side.
  • Use the medial head of the sternocleidomastoid muscle or between the tow head at the level of the thyroid cartilage just lateral to the carotid artery guide your needle on a 45o  toward the ipsilateral nipple while aspirating during insertion until you feel loss of resistance and have a backflow.
  • follow with the guidewire into your needle and then dilator
  • Complete by  inserting the catheter line and fixing it.

Subclavian vein:

Directly below the clavicle at the junction of the lateral one third with the medial two third directing the needle toward the sternal notch

Femoral vein:

1-2 cm below the inguinal ligament medial to the femoral artery, guide the needle toward the umbilicus

 

US Guided CVC

The use of ultrasound guided insertion is considered the standard of care for central line insertion. Ultrasound use reduces the number of attempts and procedure duration, increases the successful insertion rate, and reduces complications compared to the skin surface anatomic landmarks technique.9

This can facilitate visualization, increase the success rate with 95% first attempt success rate of ultrasound-guided venous punctures compared to 34% of the anatomical landmark and decrease the rate of complication that would occur with the anatomical landmark.11

 

  • Always start by identifying the land mark on US before starting the procedure (vein is compressible and less pulsatile than the adjacent artery)
  • Probe position according to the site of insertion.  
  • Prepare the patient under aseptic technique as well the probe with sterile sheet and the ultrasound counsel unless you have assistance.
  • Infiltrate local anesthesia to the skin puncture site.
  • Utilize sterile gel on the outside of the sterile sheet or alternatively sterile water or saline
  • Use an out of plane technique to guide the needle into the vein (higher success rate).
  • Start by inserting the needle at 45 degree angle from the probe and the same distance away as the vein from the skin
  • Follow the dynamic needle tip positioning technique (meet &greet) to keep visualizing the needle tip while guiding it toward the vein
  • If confusing the needle tip with the shaft try to slide the probe proximal and distal until confirmation
  • Use the same steps in aspirating while inserting until having a backflow and confirming the needle is inside the vein lumen
  • Complete the steps as before and confirm the position of the guidewire by ultrasound.
  • Insert the central catheter and fix it with sutures and transparent dressing.

 

Internal jugular vein:

Subclavian vein

Femoral vein

 

Complication12

Confirm proper placement by US as well X-Ray

R/O complication as pneumothorax, hemothorax or hematoma, mis-displacement

Artery puncture, air embolism, thoracic duct injury, arrhythmia are possible complications.

 

Umbilical Catheter

  • Can be used in neonate up to 7 days old.
  • Apply tourniquet to umbilical stump then cut the upper dried part.
  • Identify the vein which is single and thin walled while arteries are two and thick wall.
  • Stent the vessel with a forceps then insert the catheter up to 3-4 cm until blood return (Do NOT advance further as the risk of complication and adverse events are high)

 

Venous Cutdown

It is uncommon access in pediatric patients with the availability of IO needle, if needed the classic site is the saphenous vein which is 2 cm superior and anterior to the medial malleolus.

 

 

Resources:

  1. Ullman AJ, Bernstein SJ, Brown E, et al. The Michigan Appropriateness Guide for Intravenous Catheters in Pediatrics: miniMAGIC. Pediatrics. 2020;145(Suppl 3):S269-S284. doi:10.1542/peds.2019-3474I.
  2. Delacruz N, Malia L, Dessie A. Point-of-Care Ultrasound for the Evaluation and Management of Febrile Infants. Pediatr Emerg Care. 2021;37(12):e886-e892. doi:10.1097/PEC.0000000000002300.
  3. Yen K, Riegert A, Gorelick MH. Derivation of the DIVA score: a clinical prediction rule for the identification of children with difficult intravenous access. Pediatr Emerg Care. 2008;24(3):143-147. doi:10.1097/PEC.0b013e3181666f32.
  4. Whitney R, Langhan M. Vascular Access in Pediatric Patients in the Emergency Department: Types of Access, Indications, and Complications. Pediatr Emerg Med Pract. 2017;14(6):1-20.
  5. Naik VM, Mantha SSP, Rayani BK. Vascular access in children. Indian J Anaesth. 2019;63(9):737-745. doi:10.4103/ija.IJA_489_19.
  6. Vinograd AM, Chen AE, Woodford AL, et al. Ultrasonographic guidance to improve first-attempt success in children with predicted difficult intravenous access in the emergency department: a randomized controlled trial. Ann Emerg Med. 2019;74:19–27.
  7. Nakayama Y, Takeshita J, Nakajima Y, Shime N. Ultrasound-guided peripheral vascular catheterization in pediatric patients: a narrative review. Crit Care. 2020;24(1):592. Published 2020 Sep 30. doi:10.1186/s13054-020-03305-7.
  8. Paladini A, Chiaretti A, Sellasie KW, Pittiruti M, Vento G. Ultrasound-guided placement of long peripheral cannulas in children over the age of 10 years admitted to the emergency department: a pilot study. BMJ Paediatr Open. 2018;2(1):e000244. Published 2018 Mar 28. doi:10.1136/bmjpo-2017-000244.
  9. Pellegrini S, Rodríguez R, Lenz M, et al. Experience with ultrasound use in central venous catheterization (jugular-femoral) in pediatric patients in an intensive care unit. Arch Argent Pediatr. 2022;120(3):167-173. doi:10.5546/aap.2022.eng.167.
  10. Skippen P, Kissoon N. Ultrasound guidance for central vascular access in the pediatric emergency department. Pediatr Emerg Care. 2007;23(3):203-207. doi:10.1097/PEC.0b013e3180467780.
  11. De Souza TH, Brandão MB, Santos TM, Pereira RM, Nogueira RJ. Ultrasound guidance for internal jugular vein cannulation in PICU: a randomised controlled trial. Arch Dis Child. 2018; 103(10):952-6.
  12. Georgeades C, Rothstein AE, Plunk MR, Arendonk KV. Iatrogenic vascular trauma and complications of vascular access in children. Semin Pediatr Surg. 2021;30(6):151122. doi:10.1016/j.sempedsurg.2021.151122

 

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CanPoCUS May 2022

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CanPoCUS May 2022

New to Point of Care Ultrasound (PoCUS)? Been scanning for a while but wanted some formal, hands on training? Join us for the CanPoCUS Core Course in Saint John, NB this upcoming May 2022. 

This introductory PoCUS course has been designed for doctors, nurse practitioners, physician assistants who work in acute care e.g Emergency Medicine, Family Medicine, Internal Medicine, Critical Care, Surgery.

It provides the core knowledge and hands-on training required to confidently add PoCUS to your practice.

Our course fills up quickly – what are you waiting for? Register today 

 

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Scrotal Pain – Scrotal PoCUS in a nutshell

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Rawan Alrashed (@rawalrashed)

PEM Physician

PoCUS Fellow

Background

Acute Scrotal pain represent 0.5% of Emergency department visit, less than 25% of those are due to testicular torsion (1). Clinical history and physical examination don’t consist a definitive tool to diagnose the problem especially when presentation of different causes of scrotal pain can overlap. Testicular torsion doesn’t always present with the typical acute onset of pain as gradual onset was found in 25% of presentation which is described for the epididymo-orichitis (2-3). Scrotal pathology is divided into the 4 following groups: torsion, trauma, infection, and tumors, often described as the scrotum’s “4 T’s (4).

 

Review on how to approach Acute scrotal pain can be found on this post:

The Acute Scrotum

Anatomy

The testicles originate in the posterior abdominal wall in embryonic life then migrates to the scrotum, in case of failure of migration presentation of acute scrotum can be along the abdomen, inguinal canal.

 

       

 

Figure-1 Anatomy on Transverse and Longitudinal plane (Radiology Key)(5) 

 

The testicle is enveloped by a fibrous capsule called the tunica albuginea, which projects into the testis to form the mediastinum testis. The tunica vaginalis is a two-layered membrane that covers the tunica albuginea. Multiple testicular seminiferous tubules run toward the mediastinum and coalesce into a network of channels called the rete testis. These channels pass through the mediastinum and tunica albuginea to form the epididymal head, body, and tail ducts, which continue as the vas deferens. The spermatic cord contains the vas deferens, testicular vessels, pampiniform venous plexus, and nerve (6).

PoCUS Technique

  • Patient should be in supine position.
  • Use a towel under the scrotum for elevation and support and a second towel to cover and retract the penis of the scrotum.
  • Use a linear high-frequency (>7MHz) transducer with broad bandwidth.
  • Scan in transverse and sagittal planes.
  • Assess the size and texture of each testicle and look to the surroundings including the epididymis and tunica vaginalis for fluids.
  • Use comparison by visualizing both testicle in transverse plane.
  • Use Color and spectral Doppler imaging for the assessment of blood flow.
  • Images of the inguinal canal and spermatic cord can be obtained in the upright position during Valsalva maneuver to evaluate for inguinal hernias and varicoceles, respectively.

N.B. Doppler settings should be optimized to maximize detection of low-velocity flow. Color Doppler gain should be adjusted to eliminate artifacts. This can be done by adjusting the scale of flow on the normal testis then use it to visualize the abnormal one. (6)

 

Video on how to do the scan (7):

 

Normal Findings

Figure 2- Ultrasound Anatomy: a- Transverse view, b- sagittal view (6)

 

  • Scrotal wall is heterogeneous and the wall thickness ranges from 2 to 8mm.
  • The normal adult testicle is oval and measures approximately 5×3×2 cm, with a homogeneous echotexture and diffuse intermediate level echogenicity.
  • The tunica albuginea appears as a thin hyperechoic rim encasing the testicle, which invaginates in the central testicle as a hyperechoic band corresponding to the mediastinum testis.
  • The tunica vaginalis can be identified as a thin hyperechoic line, but this structure is not routinely visualized in the absence of hydrocele.
  • The epididymis is best visualized on longitudinal views and appears isoechoic to slightly hypoechoic relative to the adjacent testis.
  • The spermatic cord has a straight course from the external inguinal ring along the posterior border of the testicle, with a normal transverse diameter of less than 5mm. (6)

 

– Comparing testicular echogenicity bilaterally (Q-path)

– Comparing bilateral Testicular blood supply and notice the low flow scale (Q-path)

 

 

 

 

 

 

 

 

PATHOLOGY

1.VASCULAR 

 

Testicular Torsion (Torsion of the spermatic cord)

Testicular Torsion is a clinical diagnosis mainly affecting children with two age peaks at 1 year and adolescence (6). TWIST score can help in risk stratifying  the patients which was developed by urologist and validated in pediatric age group in emergency setting (8).

REMEMBER

Time is testicle, So once suspected involve surgical specialty for De-torsion. As the salvage rate is as high as 80%-100%  if it was repaired within 6 hours of symptom onset then drops to 20% after 12 hours (9).

If diagnosis couldn’t be made clinically, Scrotal ultrasound can help with the use of color and spectral doppler to rule in this diagnosis.

 

Findings:

It will depend on the timing of presentation

Early (within 6 hours):

  • Abnormal position.
  • Normal echogenicity could be seen early.
  • Twisting of the spermatic cord (most specific) (“whirlpool sign”)
  • Reduced venous flow.
  • Later testicular enlargement within the 6 hours due to tissue edema.
  • Scrotal wall thickening, and secondary hydrocele may also be observed. (6,9)

After 6 hours Reduced arterial blood supply with high resistance flow pattern compared to normal flow.

Late(After 24 h):

  • Testicular heterogeneity, hypo-echogenicity due to infarction and hemorrhage (at this stage salvageability is less likely (10).

 

Normal right testis (Q-path)

Abnormal echogenicity of left testis (Q-path)

Absence of color flow on this image (Q-path)

 

 

 

 

 

 

 

Whirlpool sign (11)

 

 

Important to keep in mind:

-In case of Partial torsion, the previous findings might not fully manifest and the scan could be falsely negative, still the abnormal spermatic cord can be seen as well on spectral doppler the arterial flow will be either absent or reversed diastolic flow.

-In Case of Torsion- De-torsion, rebound reperfusion with hyperemia may make the diagnosis difficult and confusing, so regular monitoring and re-scan could help in reaching the diagnosis (6,9).

 

Video explaining the findings on PoCUS and spectral doppler wave :

 

 

Torsion of testicular appendage

It’s the commonest presentation of pediatric testicular pain. This appendage is usually pedunculated and is present in more than 80% of children. It is located at the superior aspect of the testis in the groove between the testicle and the epidydimal head.

Findings:

  • Appendages are more readily apparent in the presence of a hydrocele.
  • Enlarged, rounded, extra-testicular masses, with mixed hyperechoic and heterogeneous echotexture depending on the degree of ischemia.
  • Absent flow on color Doppler, and hyperemia of the surrounding structures. (6)

 

normal appearing testicular appendix with hydrocele (11)

Hyperechoic torsion appendage (11)

Absent blood supply inside the appendage with hyperemia around it (11)

 

 

 

 

 

 

 

2. INFECTIOUS

 

Epididymitis and epididymo‑orchitis

Always try to scan the Epididymis from head to tail (some infection may be limited to the  tail) then compare the findings to the unaffected site.

Findings: 

  • Heterogenous echogenicity.
  • Enlargement in size.
  • Increase in color flow doppler.
  • Secondary findings includes Hydrocele and scrotal wall thickening.

The primary infection might get complicated and develop Abscess or Pyocele or end up with infarction and reversal arterial diastolic flow (6,9).

Enlarged epididymis (Q-path)

Increase flow on color doppler (Q-path)

 

 

 

 

 

 

 

 

 

Fournier gangrene

It’s a polymicrobial necrotizing fasciitis of the perineal, perianal, or genital areas. This diagnosis is clinical though the characteristic crepitus could only be found in 19-64% of cases. It’s critical that if this diagnosis is suspected, treatment should not be delayed for imaging confirmation. The modality of choice for diagnosis is CT scan (12).

Findings on US:

  • Diffuse subcutaneous tissue thickening.
  • Perifascial fluid accumulation.
  • Bright echogenic foci with dirty shadowing and reverberation artifacts corresponding to the underlying soft tissue gas. (12)

 

Thickening of scrotal wall with hydrocele and air reverberation artifact (13)

 

3. TRAUMA

The American Urological Association recommends surgical exploration in case of testicular trauma to delineate the extent of injury and should be within 72 hours as the rate of salvage up to 90% of blunt testicular rupture cases; But when surgery is delayed beyond this time point, the orchiectomy rate is 45%. (6,9)

 

Testicular Rupture: 

  • A tear in the tunica albuginea that results in extrusion of testicular contents.
  • Radiology US sensitivity 100% Specificity 93.5%.
  • Images will show heterogeneous testicle, contour abnormality, and disruption of the tunica albuginea.
  • Color Doppler imaging demonstrates focal or diffuse loss of vascularity.

Testes look heterogenous with irregular wall and abnormal blood supply (11)

Complete loss of the testicle contour (13)

 

 

 

 

 

 

 

 

 

 

 

 

Testicular fracture 

Disruption of the testicular parenchyma with preserved testicular shape and integrity of the hyperechoic tunica albuginea. The fracture plane appears as an avascular linear hypoechoic band extending across the parenchyma.

It’s critical to identify blood flow on color doppler to determine salvageability(9,10).

 

Scrotal hematoma

Depend on the chronicity of the evolving blood products; hematoceles and focal testicular, epididymal, and scrotal wall hematomas are acutely hyperechoic with decreasing echogenicity and increasing complexity (septa, loculations, and fluid levels) as they evolve to subacute and chronic phases. Hematomas have no internal flow on color and power Doppler images(9,10).

 

4. OTHERS

 

Testicular tumors:

  • Well-defined, hypoechoic or heterogeneous echogenicity intra-testicular lesion.
  • Might also see calcifications, micro-lithiasis, and necrosis.
  • Low level echoes with increased blood flow on color Doppler.(9)

 

multiple hypoechoic area with micro-lithiasis (11)

 

Varicocele:

  • Normal diameter of the pampiniform plexus veins range from 0.5 to 1.5 mm, the diameter of the main draining vein measuring up to 2 mm.
  • When this diameter increases, the collection of tortuous elongated veins seen posterior to testes.
  • Primary varicocele is almost always (98%) left sided due to venous drainage into the renal vein, contrary to direct drainage of the right vein into the inferior vena cava.
  • Secondary varicoceles are bilateral in up to 70%.

Dilated vein (worm like appearance) (14)

 

augmented vascularity with Valsalva (14)

 

 

 

 

 

 

 

 

 

The Evidence

  • Color and power Doppler ultrasonography reported sensitivity ranges between 86% and 98%, specificity up to 100%, and accuracy up to 97% by radiologist(9).
  • Friedman et.al. reported an agreement rate of  70% accuracy of all performed acute scrotum point-of-care ultrasound with final diagnosis(15).
  • Testicular torsion showed a sensitivity of 100% and Specificity of 99.1% with 73 minutes difference between the emergency physician and the radiologist acquiring the results(15).
  • For the other applications, still the evidence to be established but Blaivas et al. in a sample of 36 patients found the accuracy of emergency physician diagnosis compared to radiological studies was 95% sensitive and 94% specific(16).

 

Limitation and pitfalls

  • Normal variant
  • Overlapping of pathological findings might interfere with diagnosis, so clinical correlation is needed.
  • PoCUS in the emergency department is mainly a Rule In NOT out, So if no testicular torsion is identified it doesn’t mean that it’s ruled out.
  • Absence of scrotal pathology might signify an abdominal one especially if you identified undescended testes.

 

Bottom line:

  • Presentation of scrotal pathology could overlap greatly, and PoCUS can aid in delineating the diagnosis.
  • Most critical for emergency physician is to identify testicular torsion as time here is your enemy so PoCUS can assist in Ruling in this diagnosis with accuracy reaching 100%.

 

References

  1. Blaivas M, Sierzenski P, Lambert M. Emergency evaluation of patients presenting with acute scrotum using bedside ultrasonography. Acad Emerg Med. 2001;8(1):90-93.
  2. Cos LR, Rabinowitz R. Trauma-induced testicular torsion in children. J Trauma. 1982; 22:244–6.
  3. Melekos MD, Asbach HW, Markou SA. Etiology of acute scrotum in 100 boys with regard to age distribution. J Urol.1988; 139:1023–5.
  4. Wittenberg AF, Tobias T, Rzeszotarski M, et al. Sonography of the acute scrotum: The four T’s of testicular imaging. Curr Probl Diagn Radiol 2006;35:12-21.
  5. Testicular Ultrasound | Radiology Key.
  6. Sweet DE, Feldman MK, Remer EM. Imaging of the acute scrotum: keys to a rapid diagnosis of acute scrotal disorders. Abdom Radiol (NY). 2020;45(7):2063-2081.
  7. Badar Bin Bilal Shaf, 2018, Testicular Evaluation using Bedside Ultrasonography. (Testicular Evaluation using Bedside Ultrasonography: Practice Essentials, Indications, Positioning (medscape.com)
  8. Frohlich LC, Paydar-Darian N, Cilento BG Jr, Lee LK. Prospective Validation of Clinical Score for Males Presenting With an Acute Scrotum. Acad Emerg Med. 2017;24(12):1474-1482.
  9. Cokkinos DD, Antypa E, Tserotas P, et al. Emergency ultrasound of the scrotum: a review of the commonest pathologic conditions. Curr Probl Diagn Radiol. 2011;40(1):1-14.
  10. Rebik K, Wagner JM, Middleton W. Scrotal Ultrasound. Radiol Clin North Am. 2019;57(3):635-648.
  11. Radiopedia (Radiopaedia.org, the wiki-based collaborative Radiology resource).
  12. Levenson RB, Singh AK, Novelline RA (2008) Fournier gangrene: role of imaging. Radiographics 28:519-528.
  13. The Pocus Atlas (TPA (thepocusatlas.com)
  14. Liftl (Ultrasound Case 105 • LITFL • POCUS Top 100).
  15. Friedman N, Pancer Z, Savic R, et al. Accuracy of point-of-care ultrasound by pediatric emergency physicians for testicular torsion. J Pediatr Urol. 2019;15(6):608.e1-608.e6.
  16. Blaivas M, Sierzenski P, Lambert M. Emergency evaluation of patients presenting with acute scrotum using bedside ultrasonography. Acad Emerg Med. 2001;8(1):90-93.
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DVT PoCUS: When?, Where?, How? and What to do next?

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Dr. Kyle Traboulsee

EM Physician, PoCUS Fellow

Reviewed by Dr. David Lewis

Copyedited by Dr. Rawan Alrashed 

 

Background

Lower extremity deep vein thrombosis (DVT) is a common, and potentially life-threatening vascular condition, with an annual incidence of 1 per 1000 adults. If left untreated, it may progress to pulmonary embolism, which is associated with a higher mortality. Therefore, accurate and timely diagnosis and treatment are incredibly important. (1,2,3)

An initial approach to the diagnosis of DVT involves risk stratification, often with the clinical risk score “Well’s score”, in conjunction with D-dimer assays. Based on the associated pre-test probability of the above risk stratification, further imaging may be required.

Although the gold standard for the diagnosis of DVT has traditionally been contrast venography, Duplex ultrasonography has become the standard of care due (in large part) to its lack of radiation and intravenous contrast, as well as widespread availability. This elective scan evaluates from groin to ankle and can take upwards of 1 hour depending on the difficulty of the individual exam. Studies have shown that a simplified ultrasound technique, limited to proximal segments of the femoral and popliteal veins using compression alone has a high sensitivity and specificity for proximal DVT detection. (2,4)

Point of care ultrasound (POCUS) has been increasingly used by emergency room physicians to assess for proximal lower extremity DVTs, with studies finding comparable diagnostic accuracy to radiology or vascular lab-performed duplex ultrasonography for detection of proximal DVT. (2)

 

Anatomy

 

Figure 1: Veins of the lower extremity (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The venous anatomy of the lower limb is relatively simple. The most proximal vein of interest is the Common Femoral Vein (CFV), which gives off the great saphenous vein (a superficial branch). Distal to this, the Common Femoral Vein should bifurcate into the Deep Femoral Vein, and Femoral Vein.

 

       N.B: the Femoral Vein also known as the Superficial Femoral Vein, but because it is still considered a deep vein with respect to the diagnosis of deep vein thrombosis, it is usually referred to as simply the Femoral Vein.

 

As the femoral Vein travels distally, it enters the adductor canal, passing posterior to the knee, and becomes the popliteal vein. The popliteal vein gives rise to three deep veins at the level of the calf: the perineal vein, anterior tibial vein, and posterior tibial vein. (5)

 

DVT POCUS protocols

There are multiple POCUS protocols with respect to lower extremity DVT evaluation, ranging from a 2-point ultrasound scan to a whole leg protocol. The more commonly studied, and utilized, protocols in the emergency department are referred to as the 2-point compression study and 3-point compression study. (1,2,5)

(It should be noted that the “points” are regions being scanned, opposed to distinct, singular points).

 

Figure 2: DVT protocols (5)

 

 

2-point compression study

This study evaluates the:

  • common femoral vein
  • popliteal vein

The common femoral vein is evaluated from the inguinal ligament until it becomes the femoral vein, including the junction of the common femoral vein and greater saphenous vein (CFV-GSV). Ensure this scan includes at least 1-2cm above and below the CFV-GSV junction. (2)

The popliteal vein is assessed from the popliteal fossa until it trifurcates. (2)

 

3-point compression study

This technique evaluates the:

  • Common femoral vein
  • Femoral vein
  • Popliteal vein.

Like the “2-point” examination, the common femoral vein is evaluated from the inguinal ligament until it becomes the femoral vein (including the CFV-GSV junction). The femoral vein is then further evaluated at least 2 cm distal to the bifurcation of the femoral vein and deep femoral vein. Some variations on the 3-point protocol may suggest continued evaluation of the femoral vein distally as it transitions to the popliteal vein. (2,4,5)

 

PoCUS Technique (3-point compression technique)

The linear array is the probe of choice for this scan.

 

 Femoral Veins

 

  1. Position the patient by raising the head of the stretcher 30 degrees and placing the patient in reverse Trendelenburg (if able). This allows distension of the lower limb veins. Slightly flex the knee and externally rotate the hip. (4,5)
  2. Place the probe along the inguinal ligament in the transverse plane midway between the pubic symphysis and anterior superior iliac spine and identify the common femoral vein (CFV). The common femoral artery and vein should be side by side, with the artery lateral to the vein.
  3. Ensure that you are at the most proximal part by sliding the probe proximally towards the abdomen until the CFV become in the far field obscured by bowel gases (most proximal point) then slide the probe distally and  Apply firm pressure with the probe until the vein collapses completely, or the artery begins to collapse without full collapse of the vein (which could indicate a DVT). (4,5)

 

Fig 3: Common femoral vein (5)

CFA: Common femoral artery
CFV: Common femoral Vein (5)

CFV compression (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

4. After that slowly slide the probe distally, stopping every centimeter (or every width of the probe head), to compress the vein, ensuring it flattens completely. The end point of the scan is 1-2 cm distal to the bifurcation of the common femoral vein into the deep femoral vein and femoral vein. (4,5)

a. Within the first 1-2 cm, the great saphenous vein will branch off from the common femoral vein, usually medially and near field. Monitor the compressibility of both the common femoral vein, as well as the first 1-2 cm of the great saphenous vein.

 

Fig. 4: Branching of great saphenous vein (5)

CFA: common femoral artery
CFV: common femoral vein
SV: Great Saphenous Vein (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b. The common femoral vein should bifurcate into the deep femoral vein, and femoral vein 1-2 cm distal to the CFV-GSV junction.  Ensure compressibility is assessed at least 1-2 cm distal to the bifurcation if the common femoral vein. Consider continuing to scan distally until the femoral vein becomes the popliteal vein or are no longer able to assess.

 

Fig.5: Femoral vein (5)

FA: Femoral Artery
FV: Femoral Vein (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Popliteal vein

  1. If the posterior aspect of the knee (popliteal fossa) can be easily accessed in the patient’s current position (i.e., hip externally rotated, knee slightly flexed), no further positioning changes are needed. Other options include having the patient turn to a lateral decubitus position, with the leg of interest above the other, or, have the patient sit on the side of the stretcher, with their legs dangling. (4,5)
  2. Place the probe into the posterior crease of the knee (popliteal fossa), in a transverse plane and scan 2 cm above and below to locate the popliteal vein. If the structure is not immediately identified, slide the probe slightly medially and laterally to attempt to locate it. The vein should be near field, and directly over, the popliteal artery. Once located, assess compressibility of the vessel (4,5)

 

Fig. 6: Popliteal Vein (5)

PA: Popliteal Artery
PV: Popliteal Vein (5)

Popliteal Vein compression (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

Continue scanning distally (assessing compressibility along the way), until the popliteal vein trifurcates into the anterior tibial, posterior tibial, and peroneal vein. This marks the end of the examination. (4,5)

 

Fig.7: Popliteal Vein trifurcation (5)

PA: Popliteal artery
V: Popliteal Vein Trifurcation (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

Doppler flow augmentation

If the veins are difficult to identify or compress, color doppler can be applied. With the probe held stationary over the vessel in question, gently squeeze the calf distal to the probe. This should augment blood flow into the vein of interest and appear (briefly) as a brighter signal. If there is no increase in blood flow seen, a DVT could be present. (3,5)

Of note, normal venous flow will also change with the respiratory cycle. As the intrabdominal pressure increases with inspiration, venous return from the lower extremities will decrease, while with expiration, flow increases. This can be appreciated with spectral doppler. (3)

 

Positive Scan

Failure to completely collapse the vein (with enough pressure to partially compress the adjacent artery), at any level, is highly suggestive for the presence of a clot.

Depending on the chronicity of the clot, it may appear echogenic enough to directly visualize under ultrasound, but this is not always the case. (3,4,5)

 

Direct clot visualization (5)

Non-compressible popliteal vein (own image)

Doppler flow around a DVT, popliteal vein (own image)

 

The Evidence

A meta-analysis published in 2019, looked at 16 articles utilizing either 2-point compression or 3-point compression and found comparable sensitivities and specificities for proximal DVT, with no statistically significant difference (1):

 

2-point compression technique

Sensitivity 91%

Specificity 98%

 

3-point compression technique

Sensitivity 90%

Specificity 95%

 

Although there was no statistically significant difference between tests, many clinicians still recommend performing the 3-point compression, to include visualization of the femoral vein.

Other studies have quoted sensitivities ranging from 93% to as high as 100% (3).

It’s important to note that compression ultrasound alone is not accurate at picking up below-knee DVT. It is rare for below-knee DVT to progress to pulmonary embolism without first extending to an above-knee DVT. Therefore, although proximal DVT is of more clinical significance in the emergency department, a negative proximal PoCUS DVT scan should be followed by a repeat scan in 5-7 days to ensure a below-knee DVT was not missed. (3)

 

Pitfalls (false positives and negatives)

False negatives

  • Small, non-occlusive DVTs may near completely compress under applied probe pressure. Ensure complete vein occlusion when applying pressure during scan.
  • Excessive probe pressure. If enough pressure is applied to compress the adjacent artery, then a DVT may also be compressed.
  • A pelvic vein DVT may be missed either due to starting the scan to distally or being unable to compress the vein due to its location. Further imaging may be required if high clinical suspicion including venography, MRI, or extended ultrasound to include the iliac vessels and IVC (3,4).

 

False positives

  • Lymph nodes can appear as non-compressible vessels. If in doubt, rotating the probe in a longitudinal orientation will reveal the spherical nature of the lymph node.
  • Superficial thrombophlebitis. These non-compressible superficial veins may be mistaken for deep veins. The major difference is superficial veins should not accompany arteries.
  • Recanalized DVT. Old thrombi that have recanalized may not compress appropriately under probe pressure, but flow should be apparent on color doppler imaging. (3,4,5)

 

Approach to DVT Diagnosis/exclusion

One in three patients with untreated DVTs will progress to clinically significant pulmonary emboli, thus diagnosis and treatment of DVT is vitally important.

Although a positive scan is very helpful, a negative scan does not rule out a thrombus, specifically a below-knee DVT, which can propagate to an above-knee DVT, and eventually a PE given time.

Multiple diagnostic approaches have been described, incorporating the DVT PoCUS scan, well established risk stratification tools (Such as Well’s criteria), and repeat imaging. Below is one such approach, adapted from Mazzolai 2017. (5,6)

 

DVT diagnostic algorithm (5)

 

Bottom Line

DVT PoCUS is a (relatively) simple scan, that can be performed quickly and used to assess for proximal DVT. Its utility is well recognized, and it is considered one of the core ultrasound applications for emergency medicine physicians by the American College of Emergency Physicians.

When assessing for DVT, the PoCUS scan should be incorporated into a diagnostic algorithm along with other risk stratification tools, and due to its low sensitivity for below-knee DVT, repeat imaging in the context of a negative scan may be warranted.

 

References

  1. Lee, J. H., Lee, S. H., & Yun, S. J. (2019). Comparison of 2-point and 3-point point-of-care ultrasound techniques for deep vein thrombosis at the Emergency Department. Medicine, 98(22).
  2. Varrias, D., Palaiodimos, L., Balasubramanian, P., Barrera, C. A., Nauka, P., Melainis, A. A., Zamora, C., Zavras, P., Napolitano, M., Gulani, P., Ntaios, G., Faillace, R. T., & Galen, B. (2021). The use of point-of-care ultrasound (Pocus) in the diagnosis of deep vein thrombosis. Journal of Clinical Medicine, 10(17), 3903.
  3. Atkinson, P., Bowra, J., Harris, T., Jarman, B., & Lewis, D. (2019). Point-of-care ultrasound for Emergency Medicine and Resuscitation. Oxford University Press
  4. Socransky, S., & Wiss, R. (2016). Essentials of point-of-care ultrasound: The ede book. The EDE 2 Course, Inc.
  5. Dinh, V. (n.d.). DVT Ultrasound made easy: Step-by-step guide. POCUS 101. Retrieved November 26, 2021, from https://www.pocus101.com/dvt-ultrasound-made-easy-step-by-step-guide/.
  6. Mazzolai, L., Aboyans, V., Ageno, W., Agnelli, G., Alatri, A., Bauersachs, R., Brekelmans, M. P., Büller, H. R., Elias, A., Farge, D., Konstantinides, S., Palareti, G., Prandoni, P., Righini, M., Torbicki, A., Vlachopoulos, C., & Brodmann, M. (2017). Diagnosis and management of acute deep vein thrombosis: A joint consensus document from the European Society of cardiology working groups of aorta and peripheral vascular diseases and pulmonary circulation and right ventricular function. European Heart Journal, 39(47), 4208–4218.
  7. Deep vein thrombosis (DVT). ACEP Symbol. (n.d.). Retrieved November 29, 2021, from https://www.acep.org/sonoguide/basic/dvt/.

 

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Managing alcohol withdrawal

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EM Reflections Sept 2021 – Managing alcohol withdrawal

Authored and Copyedited by Dr. Mandy Peach

Big thanks to Dr. Paul Page for leading this month’s discussions.

All cases are imaginary but highlight important learning points.

 

Case

A 72 yo male presents to the emergency department with left sided CP after sustaining a fall 3 days ago. He states he hasn’t slept and is having a hard time breathing due to the pain – “ I think I cracked a rib”. On further history surrounding the fall he divulges that he was quite intoxicated at the time of injury and that he does fall quite often when drinking. He drinks 8-10 beers per day, sometimes more, and has done so for many years. He denies any complications of his drinking other than frequent injuries and has never been admitted or attended a rehabilitation facility.

Financially there have been increasing constraints and currently he is unable to obtain alcohol. His last drink was 2 days ago. He states he feels uneasy and slightly nauseous with a mild headache, but he feels it is related to the chest pain.

His PMH is non-contributory – he has no family doctor and has no regular care. He has smoked 1-2ppd for “as long as I can remember”.

His vital signs: 142/76, HR 112, RR 20, O2 93% on RA, T 36.7. He appears diaphoretic, mildly uncomfortable and taking shallow breaths.

Physical exam for signs of trauma reveals no significant injury except for a small area of bruising and tenderness at the L 10th rib with air entry heard bilaterally. As the trauma was 2 days ago, and he is satting 93% on RA on a background of suspected COPD, you feel it is unlikely he has any complication of his fall. Imaging is unlikely to change your management – he needs analgesia.

You instead focus on his alcohol use as you suspect that is what is contributing most to his symptoms.

What are symptoms/signs of alcohol withdrawal? How soon do you anticipate symptoms?1,2

A spectrum – early withdrawal -> seizures -> alcoholic hallucinosis -> delirium tremens (DT).

Symptoms Signs
Abdominal pain Tachycardia
Nausea/vomiting Elevated BP
Headache Tremor – The tremor is key to diagnosis. It is an intention tremor – when resting it is not visible. Ask the patient to extend their arms/hands and it becomes apparent. This is a persistent tremor and it does not fatigue
Anxiety Tongue Tremor – more sensitive finding. See video
Hallucinations – clear cognition with hallucinations *High risk deterioration to DT Seizures – occur at 12-48 hours and are typically preceded by tremor

 

 

Tongue tremor1

Symptoms from alcohol withdrawal can start as early as 6-8 hours after the last drink, as the alcohol levels decline.

Symptoms typically peak at 72 hours and are gone by day 5-7.

Delirium Tremens can be anytime from day 3-12 after abstinence.

You examine your patient for signs of withdrawal. From the vitals he is tachycardiac. On exam he appears diaphoretic and he complains of a few symptoms. You ask him to extend his arms and he does have an intention tremor that doesn’t fatigue.

You confirm he is in alcohol withdrawal – this is a clinical diagnosis.

Are there any investigations that should be done for acute alcoholic withdrawal?

It depends on the patient presentation and the level of severity.

Mild cases – lab work/imaging rarely contributory. But there are situations where it is warranted.

  • Severe symptoms with potential DTs – really this could be a patient with acute delirium of any etiology. So screen for :
    • electrolyte abnormalities
    • alcoholic ketoacidosis
    • infection
    • toxidromes
    • thyrotoxicosis
    • neuroleptic malignant syndrome
    • serotonin syndrome
    • hypertensive crisis
    • acute pain
    • ECG – chronic alcohol use leads to hypomagnesemia and electrolyte abnormalities, increasing risk of long QT.
    • CT head – These patients are high risk for falls during both intoxication and withdrawal. Combine this with fragile intracranial bridging veins and potential coagulopathy if underlying liver disease and their risk of ICH goes up substantially.

 

  • Unclear history? Maybe the patient is not in DTs but actually is acutely intoxicated. An alcohol level can be ordered, but keep in mind that patients experiencing withdrawal will have symptoms at varying levels. Chronic users may have withdrawal symptoms at a level that is intoxicating to someone who rarely drinks. Add a urine tox screen if concern for co-ingestants as above.

 

So, if alcohol levels aren’t helpful how do I differentiate between an acute alcoholic intoxication vs severe withdrawal with DTs?1

Giving benzodiazepines to a patient who is acutely intoxicated can lead to decreased LOC.

Before considering treatment look for the withdrawal tremor – if it isn’t present they are likely intoxicated.

 

The CIWA-Ar protocol is one method to monitor withdrawal symptoms and quantify the severity to ensure the patient receives appropriate treatment.

https://insight.qld.edu.au/shop/clinical-institute-withdrawal-assessment-of-alcohol-scale-revised-ciwa-ar-insight-2019

This is a 10 item scale and is done hourly. If a patient scores > 10 they are treated, if  back to back scores are < 10 they can be discharged.

Is there a faster tool that can be used in the ED to quantify alcohol withdrawal?1

SHOT protocol is a 4-item scale. It is done every 1-2 hours. It is not validated, but has been shown to correlate well with CIWA score. It is shorter and easier to administer. Patient can be discharged if back to back scores are 0-1.

You decide to calculate your patient’s SHOT score3.

You calculate the patient’s SHOT score to be 6

  • Sweating: He has beads of sweat on his forehead (2)
  • Hallucinations: He has no hallucinations (0)
  • Orientation: He knows where he is, but gets the month wrong (1)
  • Tremor: he has a moderate intention tremor (3)

Any score over 2 requires medical intervention

Your patient requires intervention.

What medication do you choose to treat alcohol withdrawal?

Longer acting benzodiazepines are preferred as they have a more predictable course and are less likely to result in withdrawal or seizures 1,2,4.

Lorazepam Diazepam
Onset of action Slower Faster
Half-life 8-12 hours 100 hours
Duration of action 12 hours 5 days
Risk withdrawal Higher Lower
Sedation risk Less risk of oversedation

Use if liver dysfunction as less systemic accumulation

 Oversedation risk if liver dysfunction, elderly, low albumin, methadone or high dose opiods

Use oral doses if mild withdrawal and the patient can tolerate.

You order oral diazepam for the patient when a trauma team activation is heard overhead – it is a multiple vehicle MVC. Currently the department is critically understaffed, and all available staff are sent to trauma while one nurse manages the acute patients.

A couple of hours have passed and you finally get back to reassess your withdrawal patient. He has since had a CT head that showed the expected atrophy but no hemorrhage. You review his lab values and other than some mild electrolyte abnormalities there are no glaring values or signs of co-ingestants. You hear raised voices in the department and go to assess. Your patient now appears to the hallucinating and is severely agitated. He is not responding to verbal de escalation. A code white is called. The patient is restrained and a glucose is immediately checked to r/o hypoglycemia – it is 5.8. IV access is still intact.

Your patient is likely experiencing DTs and is in severe withdrawal.

What medication do you want to avoid in this agitated patient withdrawing from alcohol1?

Haldol – antipsychotics can prolong QT interval in patients already at risk of long QT. It can also lower seizure threshold.

How do you manage severe alcohol withdrawal 5?

Lots of benzos via IV with the goal of having a calm, cooperative patient.

Start with diazepam 10 mg IV and reassess in 5 minutes, if not suffice then re-dose another 10mg. If still no success than increase the dose increase by 10mg and repeat that pattern, reassessing every 5 mins.

What if the patient doesn’t respond to these treatments?

Once approaching 200mg total – these patients are benzo resistant and will likely require intubation (*keeping in mind you’ve considered other etiologies)5.The same is true for refractory seizures that have not responded to escalating benzodiazepine doses.

Before proceeding to intubation you can consider phenobarbital as adjunct, but there is no evidence that phenobarbital alone is superior to benzos in treating withdrawal. The side effect profile is also higher if using an anticonvulsant instead of a benzodiazepine 2.

If you intubate the patient, consider the following adjuncts6:

Of these – phenobarbital, propofol and dexmedetomidine have been shown to decrease benzodiazepine requirements in severe withdrawal, but none are proven to shorten duration of illness of length of stay in ICU.

If using demedetomidine you must have another adjunct as it does not protect against withdrawal seizures.

The following is a summary1

 

You administer escalating benzodiazepine doses to your patient and eventually he settles. You are charting and preparing to admit the patient when the nurse lets you know the patient is now on 2L of oxygen despite having a normal respiratory rate and end tidal. His GCS is 13 – he opens his eyes to speech, is responding to questions but seems confused still and is moving spontaneously to command.

You go to reassess. You confirm the GCS and don’t feel that it is contributing. You remember the low oxygen saturation on initial vitals you thought was secondary to underlying COPD. You auscultate the lungs and now notice decreased air entry to the L side. In the setting of recent trauma you are concerned your patient had a pneumothorax that worsened.

Would PoCUS have been of benefit in initial assessment of the patient?

It depends on the thoroughness of the scan.

There is evidence that a single view of the anterior chest in the midclavicular line, 3rd intercostal space, is comparable to a 4-zone lung scan for finding a clinically significant pneumothorax in the setting of blunt trauma. In this study clinically significant means those pneumothoraces that required thoracostomy7.

So, using this single view approach smaller pneumothoraces can be missed. But they are less likely to require a chest tube up front.

Could this patient have had a small traumatic pneumothorax that worsened in the setting of his agitation? Could he have had a secondary spontaneous pneumothorax in the setting of COPD?

Without imaging of some sort before hand it is difficult to know with certainty. Keep in mind that CXR has a sensitivity of 20-48% for pneumothorax 6. A thorough PoCUS exam has a higher sensitivity and equivocal specificity for pneumothorax in the setting of blunt trauma6. Gold standard? CT of course.

Regardless, have a low threshold to image elderly people in the setting of trauma.

You place a probe in the 3rd IC space anteriorly and see the following

There is lack of lung slide or comet tails/B lines suspicious for pneumothorax.

What can complicate interpretation of a lung scan for pneumothorax? What is the most specific sign of pneumothorax?

In certain patient populations (ie. critically ill ICU patients, ARDS, pneumonia, fibrosis, pleurodesis, cardiopulmonary arrest) the typical findings of lack of lung sliding and B lines are not reliable.

Absence of lung sliding does not diagnosis pneumothorax (spec 78-91%) in these patients.

Definite sign? Lung point, or the area where the visceral pleural begins to separate from the parietal pleural – it is 100% specific.

You confirm a pneumothorax and place a chest tube without complication. You now CT the patient looking for further injury. The CT confirms multiple L sided rib fractures with a small hemothorax and reinflation of the pneumothorax. There is also stable, but acute, thoracic spine fractures.

The patient is admitted to the ICU for severe alcohol withdrawal in the setting of trauma.

What extra treatments do you consider before handing over to the ICU staff1,2?

Fluids – often these patients are hypovolemic and hypoglycemic. Consider glucose containing fluids.

High dose Thiamine – thiamine deficit patients can develop Wernicke’s encephalopathy. Glucose and thiamine compete for the same co-factor so theoretically giving glucose in a thiamine deficient patient could precipitate Wernicke’s. However, there is no evidence that a single glucose dose will cause this. So, give glucose at the same time or after thiamine, but if critically low glucose don’t wait to administer.

Magnesium – required for thiamine related kinetics and is often low in this population. Check and replace when giving thiamine2.

 

The patient did well and upon discharge he was provided resources and support for seeking treatment. He completed the detox while admitted.

What about patients being discharged from the emergency department with mild alcohol withdrawal? How are they managed 1?

Key is avoiding prescription for benzodiazepine as an outpatient. This has a risk of oversedation, dependence and drug seeking behaviour. Giving diazepam in the ED can prevent seizures due to it’s long half life.

Take home points:

  1. Alcohol withdrawal is a clinical diagnosis – recognize the symptoms and signs.
  2. Persistent intention tremor is a sensitive sign of withdrawal.
  3. Consider other causes in the acutely delirious patient.
  4. These patients are high risk for injury – have a low threshold to image if suspicion of trauma
  5. Quantify the severity for treatment – consider using the SHOT protocol. Diazepam > Lorazepam in the patient with no underlying liver dysfunction.
  6. High, escalating IV benzos for refractory agitation/seizure
  7. Avoid benzodiazepine prescriptions as an outpatient.

 

References and further reading

  1. Helman, A, Borgundvaag, B, Gray, S. Alcohol Withdrawal and Delirium Tremens: Diagnosis and Management.Emergency Medicine Cases. October, 2016. https://emergencymedicinecases.com/alcohol-withdrawal-delirium-tremens/. Accessed [Oct 31, 2021].
  2. Fabian, C. Alcohol: Beyond the “Breakfast Plan”. EM Ottawa. December 2015. https://emottawablog.com/2015/12/alcohol-beyond-the-breakfast-plan/. Accessed [Oct 31, 2021].
  3. Gray S, Borgundvaag B, Sirvastava A, Randall I, Kahan M. Feasibility and reliability of the SHOT: A short scale for measuring pretreatment severity of alcohol withdrawal in the emergency department. Acad Emerg Med. 2010;17(10):1048-54
  4. Hoffman R, Weinhouse G. Management of moderate and severe alcohol withdrawal syndromes. UpToDate. September 2021. https://www.uptodate.com/contents/management-of-moderate-and-severe-alcohol-withdrawalsyndromes?search=alcohol%20withdrawal&sectionRank=1&usage_type=default&anchor=H17&source=machineLearning&selectedTitle=1~150&display_rank=1#H17. Accessed [Oct 31, 2021]
  5. Justin Morgenstern. Management of Delirium Tremens, First10EM, 2016. Available at:

https://doi.org/10.51684/FIRS.1898

  1. Darrel Hughes, “Benzodiazepine-Refractory Alcohol Withdrawal”, REBEL EM blog, April 28, 2016. Available at: https://rebelem.com/benzodiazepine-refractory-alcohol-withdrawal/.
  2. Michael Prats, MD. Comparison of Four Views Versus Single View for Pneumothorax. Ultrasound G.E.L. Podcast Blog. Published on November 7, 2016. Accessed on November 1, 2021. Available at https://www.ultrasoundgel.org/6.
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Alternative Rib Fracture Management in the ED

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Alternative Rib Fracture Management in the ED – A Medical Student Clinical Pearl

Victoria Mercer, Clinical Clerk 3, DMNB

Reviewed and Copyedited by Dr. Mandy Peach

Rib fractures are a frequent presentation in the ED, occuring in approximately 10% of all injured patients with the primary causes being blunt chest trauma and MVAs(1,2).  The mainstay of treatment for rib fractures is analgesic control(1). When pain cannot be adequately managed, the patient is at a heightened risk of hypoventilation due to decreased thoracic mobility and secretion clearance, predisposing the patient to significant atelectasis(1,2).

Historically the pain from rib fractures has been managed with acetaminophen or NSAIDS and if these do not sufficiently alleviate the pain, opioids are used(1,3). Unfortunately, these methods often do not provide adequate pain control or in the case of opioids, come with a myriad of side effects such as nausea, vomiting, constipation, respiratory depression and the potential for dependency and abuse (1,4).

An alternative to traditional methods include regional techniques such as paravertebral or epidural nerve blocks. These interventions have been shown to effectively control pain in rib fractures(3,4). The downside to these interventions include being technically challenging and time consuming with significant complication risks and contraindications such as coagulation disorders (1,3).

The solution? A serratus anterior block 

An ultrasound guided blockade of the lateral cutaneous branches of the thoracic intercostal nerves was first described by Blanco et al. in 2013 for patients following breast surgery to manage their postoperative pain(5). This procedure has been adopted by many emergency departments for its convenience and practicality compared to epidural or paravertebral nerve blocks(3).

Serratus anterior blocks are less invasive and considerably more practical in the ED setting, providing paresthesia to the ipsilateral hemithorax for 12-36 hours (6).

The only absolute contraindications are patient refusal, allergy to local anesthetic and local infection(1).

Complications of a serratus anterior block include pneumothorax, vascular puncture, nerve damage, failure/inadequate block, local anesthetic toxicity and infection(1).

Serratus anterior blocks are only effective for the anterior two-thirds of the chest wall (3).

 

Figure 1. Ultrasound image of serratus anterior muscle and surrounding tissues with superficial or deep needle guides. Image from Thiruvenkatarajan V, Cruz Eng H, Adhikary SD. An update on regional analgesia for rib fractures. Current Opinion in Anaesthesiology. 2018;31(5):601–607.

How do you do it?

The procedure is usually performed with the patient laying supine however the patient could also lay in a lateral decubitus position (1,3). Using a high frequency linear ultrasound probe (6-13MHz), identify the serratus anterior and latissimus dorsi muscles over the fifth rib in the mid-axillary line(1,3). Using an in-plane approach, insert the needle either superficial or deep to the serratus anterior and confirm correct needle placement by visualizing anaesthetic spread via ultrasound(1,3). According to May et al., superficial spreading tends to have a longer lasting analgesic effect(1). Place and secure a catheter to infuse the remainder of the bolus(1,3). Thiruvenkatarajan et al. recommend a bolus of 40ml of 0.25% levobupivacaine and a 50mm 18G Tuohy catheter needle(3).

See this excellent review by Dr. David Lewis on identifying rib fractures and their complications using ultrasound (start 3:08) as well as a review of the block and procedure (start 8:00)

Rib Fractures and Serratus Anterior Plane Block

References

  1.         May L, Hillermann C, Patil S. Rib fracture management. BJA Education. 2016 Jan 1;16(1):26–32.
  2.         Malekpour M, Hashmi A, Dove J, Torres D, Wild J. Analgesic choice in management of rib fractures: Paravertebral block or epidural analgesia? Anesthesia and Analgesia. 2017 Jun 1;124(6):1906–11.
  3.         Thiruvenkatarajan V, Cruz Eng H, Adhikary S das. An update on regional analgesia for rib fractures. Vol. 31, Current opinion in anaesthesiology. 2018. p. 601–7.
  4.         Tekşen Ş, Öksüz G, Öksüz H, Sayan M, Arslan M, Urfalıoğlu A, et al. Analgesic efficacy of the serratus anterior plane block in rib fractures pain: A randomized controlled trial. American Journal of Emergency Medicine. 2021 Mar 1;41:16–20.
  5.         Blanco R, Parras T, McDonnell JG, Prats-Galino A. Serratus plane block: A novel ultrasound-guided thoracic wall nerve block. Anaesthesia. 2013 Nov;68(11):1107–13.
  6.         Mayes J, Davison E, Panahi P, Patten D, Eljelani F, Womack J, et al. An anatomical evaluation of the serratus anterior plane block. Anaesthesia [Internet]. 2016 Sep 1 [cited 2021 Apr 18];71(9):1064–9. Available from: http://doi.wiley.com/10.1111/anae.13549

 

 

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