Today we're focused on POCUS! Here's what you need to know about point-of-care ultrasound in COVID-19.  

 

Potential advantages to POCUS in COVID

• Lack of ionizing radiation
• Superiority to CXR for common diagnoses1
• PPE conservation: performed by treating physician2
• Potential to reduce transmission by minimizing transport and healthcare worker contacts3
• Replace the use of the stethoscope?2

 

Safety and Infection Control

• Development of infection-control procedures (IPC) before using POCUS is imperative for these patients. This will vary by centre/machine, but considerations include:4
  • Equipment
    • Dedicated COVID-19 machine
    • Minimizing equipment brought into the room
    • Using sterile probe covers and single-use gel packets
    • Handheld devices may be ideal if available due to ease of cleaning3
  • Cleaning and disinfecting
    • Disinfect all machine surfaces with an appropriate product – see ipac-canada.org for choice of products
    • PRACTICE your IPC including incorporation donning and doffing of PPE before performing on patients!
  • Scanning personnel
    • Minimize scanners at the bedside

 

Scanning protocols

• Standard LUS: curvilinear or phased probe1
  • Linear to focus on the pleura
• How many zones to scan? More zones will be more sensitive
  • Some groups recommend 8 per side5
• Contrast-enhanced lung ultrasound?? See below

 

POCUS findings in COVID

• There are NO pathognomonic findings
• Findings may include6
  • "Inflammatory" B-lines: Patchy/asymmetrical B-lines with irregular pleura and subpleural consolidations
    • This pattern can be seen in ANY inflammatory/infectious cause of B-lines: Atypical pneumonia, other viral pneumonias, pulmonary hemorrhage, interstitial lung disease, etc.
  • Subpleural consolidations: could these actually be representative of peripheral pulmonary infarcts due to PE?
    • One group found PE in 3 of 3 ICU patients who had evidence of subpleural consolidations on POCUS7
    • Contrast-enhanced ultrasound (CEUS): a couple fascinating case reports demonstrating that subpleural consolidations were avascular and actually represented microinfarcts8,9
  • Bilateral dense consolidations
    • With development to acute respiratory distress syndrome (ARDS)
  • Cardiac findings10
    • May include pre-existing cardiac disease, LV involvement from COVID myocarditis, RV failure (due to PE, ARDS, mechanical ventilation)

 

Potential pitfalls11

• Cannot distinguish between other causes of "infectious/inflammatory" B-lines
• Cannot distinguish acute vs chronic changes (eg ILD)
• Will miss pathology that doesn't reach the pleura
• Limited scanning protocols (ie 3 zones per hemithorax) may miss early/localized disease

 

When to use POCUS

• Employ POCUS in confirmed or suspected COVID-19 patients if it will change management4
  • No educational scans; and no novice scans. Have an experienced operator scanning.
  • No scans in patients who are already have a confirmed diagnosis, in whom POCUS results won't change management
• Times to consider POCUS use
  • To look for other diagnoses
  • To look for compatible signs of COVID is suspected patients in whom PCR testing is imperfect*
  • To minimize use of other radiologic studies, especially CT scans
  • To monitor critically ill patients, especially those in shock or profound respiratory failure

 

From SoMe

An EM physician diagnosed with COVID-19 who shared the progression of his self-scanned POCUS clips throughout his disease course: https://twitter.com/yaletung

 

 

Sources

1. Volpicelli G, Elbarbary M, Blaivas M et al. International recommendations for evidence-based point of care lung ultrasound. Intensive Care Med, (2012) 38:577–591. doi:10.1007/s00134-012-2513-4
2. Buonseno D, Pata D, Chiaretti A. COVID-19 outbreak: less stethoscope, more ultrasound. Lancet Resp Med, Apr 2020. doi:10.1016/ S2213-2600(20)30120-X
3. Kiamanesh O, Harper L, Wiskar K et al. Lung Ultrasound for Cardiologists in the Time of COVID-19. Can J Cardiol, May 2020. doi: 10.1016/j.cjca.2020.05.008
4. Ma I, Somayaji R, Rennert-May E et al. Canadian Internal Medicine Ultrasound (CIMUS) Recommendations Regarding Internal Medicine Point-of-Care Ultrasound (POCUS) use during Coronavirus (COVID-19) Pandemic. Can J Gen Internal Med, Apr 2020. doi:10.22374/cjgim.v15i2.438
5. Soldati G, Smargiassi A, Inchingolo R et al. Is There a Role for Lung Ultrasound During the COVID‐19 Pandemic? J Ultrasound Med, Mar 2020. doi:10.1002/jum.15284
6. Peng QY, Wang XT, Zhang LN et al. Findings of lung ultrasonography of novel corona virus pneumonia during the 2019 – 2020 epidemic. Intensive Care Med, Mar 2020. doi:10.1007/s00134-020-05996-6
7. Zotzmann V, Lang C, Bamberg F et al. Are subpleural consolidations indicators for segmental pulmonary embolism in COVID-19? Intensive Care Med, Apr 2020. doi:10.1007/s00134-020-06044-z
8. Tee A, Wong A, Yusuff T et al. Contrast-enhanced ultrasound (CEUS) of the lung reveals multiple areas of microthrombi in a COVID-19 patient. Intensive Care Med, May 2020. doi:10.1007/s00134-020-06085-4
9. Soldati G, Giannasi G, Smarigiassi A et al. Contrast‐Enhanced Ultrasound in Patients With COVID‐19. J Ultrasound Med, May 2020. doi:10.1002/jum.15338
10. Johri A, Galen B, Kirpatrick J et al. ASE Statement on Point-of-Care Ultrasound (POCUS) During the 2019 Novel Coronavirus Pandemic. Apr 2020. https://www.asecho.org/wp-content/uploads/2020/04/POCUS-COVID_FINAL2_web.pdf.
11. Cheung JC, Lam KN. POCUS in COVID-19: pearls and pitfalls. Lancet Resp Med, Apr 2020. doi:10.1016/S2213-2600(20)30166-1