Role of Ultrasound in Covid-19 and the 4 parameters of recovery from pandemic

— By Dr KK Aggarwal, President Confederation of Medical Associations of Asia and Oceania

337: What is The National Convalescent Plasma Project

Fact: The project has launched a website for patients who have recovered from COVID-19 and want to donate plasma, and for healthcare providers who are considering this treatment for their patients.

Additionally, doctors will use the site to input data on how their patients respond to the plasma treatment. The hope is that we can move this potentially life-saving therapy to controlled clinical trials and then to wider use if effectiveness is demonstrated as quickly as possible.

338: Peripheral lymphocytes are the key

According to a study published in The Journal of Infectious Diseases, peripheral lymphocyte subset alteration was associated with the clinical characteristics and treatment efficacy of COVID-19.

Fan Wang, MD, Zhongnan Hospital of Wuhan University, Wuhan, China, and colleagues measured levels of peripheral lymphocyte subsets in 60 patients hospitalised with COVID-19, and found that total lymphocytes, CD4+ T cells, CD8+ T cells, B cells, and natural killer (NK) cells decreased in patients with COVID-19, but severe cases had lower levels than milder cases.

After treatment, 37 (67%) patients reached clinical response, with an increase of CD8+ T cells and B cells; however, no significant change of any subset was detected in patients who did not respond to treatment. In multivariate analysis, post-treatment decrease of CD8+ T cells and B cells and increase of CD4+/CD8+ ratio were indicated as independent predictors for COVID-19 severity and treatment efficacy.

339: Role of ultrasound in Covid 19

Lastly, a study published in Echocardiography showed how lung ultrasound can be used as a bedside tool for identification of lung involvement, along with pulmonary severity, in patients with suspected or documented COVID‐19, thus reducing the use of chest x-rays and CTs. A scan of the 3 different areas of the thorax — anterior, lateral, and posterior — and then superior and inferior segments are performed.

The authors noted that an experienced sonographer can do this examination within 5 minutes. For those who are not experienced, a brief training and about 25 supervised exams seem to be sufficient to achieve a basic ability to perform the lung ultrasound.

340: What is an empirical estimate of the serial interval

It is the time from illness onset in a primary case (infector) to illness onset in a secondary case (infectee).

NEJM: Early data suggest that SARS-CoV-2 infection is more likely to be transmitted than MERS-CoV infection because of a higher estimated reproductive number (2.2 vs. 0.9) and a shorter estimated serial interval distribution (7.5 days vs. 12.6 days). The mean interval (±SD) from symptom onset to diagnosis was 4.3±4.1 days.

341: What are the 4 benchmarks for return to normalcy

1. Hospitals must be able to safely treat all patients requiring hospitalization, without resorting to crisis standards of care. That means having adequate beds, ventilators and staff.

2. Authorities must be able test at least everyone who has symptoms, and to get reliable results in a timely manner.

3. Health agencies must be able to monitor confirmed cases, trace contacts of the infected, and have at-risk people go into isolation or quarantine.

4. There must be a sustained reduction in cases for at least 14 days. Because it can take up to two weeks for symptoms to emerge, any infections that have already happened can take that long to appear.

342: Pets can infect you

No. Nadia, a tiger at the Bronx Zoo in New York, tested positive for the virus. Your cat will probably not infect you, but experts say to take the same precautions around pets as you would around people.

337: When to start oxygen

Society of Critical Care Medicine (SCCM) Surviving Sepsis Campaign guideline on management of critically ill adults with coronavirus disease 2019 (COVID-19) recommendations on ventilatory support.
Consider supplemental oxygen in patients with peripheral oxygen saturation (SPO2) < 92% (SCCM Weak recommendation, Low-quality evidence)

Start supplemental oxygen in patients with SPO2 < 90% (SCCM Strong recommendation, Moderate-quality evidence)

SPO2 should be maintained no higher than 96% in adults with acute hypoxemic respiratory failure on oxygen (SCCM Strong recommendation, Moderate-quality evidence)

Consider high-flow nasal cannula (HFNC) in patients with acute hypoxemic respiratory failure despite conventional oxygen therapy (SCCM Weak recommendation, Low-quality evidence)

HFNC preferred over non-invasive positive pressure ventilation (NIPPV) (SCCM Weak recommendation, Low-quality evidence)

Trial of NIPPV with close monitoring and frequent assessment for worsening respiratory failure may be considered if HFNC is not available and there is no urgent indication for endotracheal intubation (SCCM Weak recommendation, Very low-quality evidence)

No recommendation can be made regarding helmet NIPPV compared to mask NIPPV; helmet NIPPV may be an option, but safety and efficacy are unknown in patients with COVID-19

Patients receiving HFNC or NIPPV should be closely monitored for worsening of respiratory status, with early intubation if worsening occurs (SCCM Best practice statement)

((The writer is President, CMAAO, HCFI and Past national President IMA))