How does lung POCUS findings help the initial evaluation of COVID-19 patients?

26th Nov 2020

With the knowledge of COVID-19’s appearance on lung ultrasound, as well as alternative lung disease diagnoses—let’s learn how to make an initial evaluation of a patient with suspected COVID-19 using point-of-care ultrasound (POCUS). 

 

Lung POCUS can help you confirm a COVID-19 diagnosis

First, let’s quickly review some of the presentations that definitely indicate the need for a lung point-of-care ultrasound (POCUS): 

  1. Undifferentiated hypoxia 
  2. Dyspnea 
  3. Shock
  4. Unstable for transfer   

Multi-component image of man with blue face, man with oxygen mask, female with crossed-out blood sign, and a female patient in intensive care all pointing to a doctor with an ultrasound.

Figure 1. Point-of-care ultrasound (POCUS) for patients with absolute indications for lung POCUS can help clinicians confirm a preliminary diagnosis of COVID-19. 

With these indications, if you see lung ultrasound findings typical of COVID-19 (e.g., B-lines, irregular pleura, small consolidations, and involvement of both lungs) with a moderate or higher pre-test probability, you can be fairly confident in a preliminary diagnosis of COVID-19.

We are still learning about COVID-19, as well as the sensitivity of our tests, including lung ultrasound. 

The best data so far shows that some patients—who are sick enough to be hospitalized—will still have a normal lung ultrasound. So, you can’t totally exclude COVID-19 even if the lung ultrasound looks fine, especially if your pre-test probability is now very low. One study from China reported that 10% of their cohort had a normal lung ultrasound at the time of hospitalization and diagnosis!

We don’t know the exact sensitivity and specificity of lung ultrasound, but it appears that sensitivity improves with worsening disease and more lung ultrasound findings.

 

Lung POCUS can help you make decisions about patient care

Now, let’s revisit some of the relative indications for a lung ultrasound scan: 

  1. Your patient is clinically COVID-19 positive, but disposition isn’t certain.
  2. Your patient is clinically COVID-19 positive, but no other testing is available or planned. 
  3. You are experiencing a large volume of patients where the emergency room is full of possible COVID-19 cases and the staff cannot keep up!

Multi-component image of man with uncertain dispositions, a women with no RT-PCR testing, and a clinician in personal protective equipment surrounded by sick patients all pointing to a doctor with an ultrasound machine.

Figure 2.  Point-of-care ultrasound (POCUS) for patients with relative indications for lung POCUS can help clinicians make appropriate treatment decisions based on the findings.  

Let’s first address the population where you’re uncertain about disposition. Should the patient be sent home, or do they require admission? If they require hospitalization, should they be on the floor or do they need a bed in the intensive care unit? 

For patients with uncertain dispositions, a scan that shows findings typical of COVID-19 might push you to be more conservative. Or, consider observing for a bit longer before making a decision, since we know that these patients can deteriorate quickly.

For the other two populations, if you see findings typical of COVID-19, then you’ve provided more support for your diagnosis and impression! Remember that in these populations, a normal lung ultrasound does not exclude COVID-19. It will support your decision to send the patient home with return precautions if they are otherwise appropriate for discharge.

 

Limitations of diagnosing COVID-19 with lung POCUS 

We still don’t know enough about the performance of lung ultrasound in mild COVID-19 disease—especially early on in the disease.

If patients are presenting early with non-respiratory symptoms and are young or at a low risk for poor outcomes, we might not expect that there would be pulmonary involvement, especially without dyspnea or cough.

The research surrounding COVID-19, including diagnostic tests such as lung point-of-care ultrasound (POCUS), is evolving rapidly. Lung POCUS can help you make safe and informed decisions for your patients. However, it is important to respect its limits and use it as one part of your evaluation and treatment plan. Medmastery note.

Clickable call to action, "Start learning for free", with direct link to sign up for a free Medmastery trial account.

Recommended reading

  • Dargent, A, Chatelain, E, Kreitmann, L, et al. 2020. Lung ultrasound score to monitor COVID-19 pneumonia progression in patients with ARDS. PLoS One15: e0236312. PMID: 32692769
  • Kim, DJ, Jelic, T, Woo, MY, et al. 2020. Just the facts: Recommendations on point-of-care ultrasound use and machine infection control during the coronavirus disease 2019 pandemic. CJEM22: 445–449. PMID: 32268930
  • Long, B, Brady, WJ, Koyfman, A, et al. 2020. Cardiovascular complications in COVID-19. Am J Emerg Med38: 1504–1507. PMID: 32317203
  • Mongodi, S, Orlando, A, Arisi, E, et al. 2020. Lung ultrasound in patients with acute respiratory failure reduces conventional imaging and health care provider exposure to COVID-19. Ultrasound Med Biol46: 2090–2093. PMID: 32451194
  • Pare, JR, Camelo, I, Mayo, KC, et al. 2020. Point-of-care lung ultrasound is more sensitive than chest radiograph for evaluation of COVID-19. West J Emerg Med21: 771–778. PMID: 32726240
  • Soldati, G, Smargiassi, A, Inchingolo, R, et al. 2020. Is there a role for lung ultrasound during the COVID-19 pandemic? J Ultrasound Med39: 1459–1462. PMID: 32198775
  • Soldati, G, Smargiassi, A, Inchingolo, R, et al. 2020. Proposal for international standardization of the use of lung ultrasound for patients with COVID-19: A simple, quantitative, reproducible method. J Ultrasound Med39: 1413–1419. PMID: 32227492
  • Volpicelli, G, Lamorte, A, and Villén, T. 2020. What’s new in lung ultrasound during the COVID-19 pandemic. Intensive Care Med46: 1445–1448. PMID: 32367169
  • Volpicelli, G and Gargani, L. 2020. Sonographic signs and patterns of COVID-19 pneumonia. Ultrasound J12: 22. PMID: 32318891
  • Xing, C, Li, Q, Du, H, et al. 2020. Lung ultrasound findings in patients with COVID-19 pneumonia. Crit Care24: 174. PMID: 32345353