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CMAAO Corona Facts and Myth Buster 41

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Dr KK Aggarwal    08 April 2020

Extended Wear vs Reuse of masks

The CDC recommendations on optimizing the use of N95s are categorized into conventional, contingency, and crisis. Many hospitals in the contingency and crisis stages are currently implementing policies of extended use or limited reuse.

What are the strategies for mask conservation

There are reports of nurses getting one mask per day, per week, or even every 2 weeks. Some nurses have to wear surgical masks over their N95 respirators to make them last longer.

The CDC guidance  pointed to studies showing that the virus causing COVID-19 can live on plastic, stainless steel, and cardboard surfaces for up to 72 hours.

The agency thus suggested a passive decontamination strategy. This involves issuing five respirators to each healthcare worker caring for COVID-19 patients. The worker wears each mask in the same order and places it in a paper bag at the end of the day. If done appropriately, there is a minimum of 5 days between each respirators repeat use.

Unused respirators that have crossed the expiration dates on their labels can be used, states the CDC. However, if a respirator is compromised or if a seal check fails, it has to be discarded and replaced.

What is decontamination

While there is no CDC-approved method for decontamination, the agency has stated that ultraviolet germicidal irradiation (UVGI), vaporous hydrogen peroxide (VHP), and moist heat seem to be the most promising as methods for decontaminating respirators.

The FDA issued guidance on March 29 stating that in time of this public health emergency, the agency does not intend to object to the distribution and use of sterilizers, disinfectant devices, and air purifiers that are intended to be effective at killing SARS-CoV-2.

Is Ultraviolet Light effective

It is important to ensure that light must reach every part of the mask and absorption levels have to be monitored.

UV radiation doesnt seem to harm the respirators capacity for filtration.

What about vaporous hydrogen peroxide

Decontaminate N95 respirators for reuse using a VHP procedure with 2.5 hours of exposure to concentrated gases and a maximum of 20 decontamination cycles per respirator.

VHP decontamination has shown minimal effect on filtration efficacy and has demonstrated 99.9999% efficiency in killing bacterial spores and similar efficacy against bacteriophage viruses.

The elastic bands; however, can degrade after about 30 cycles.

What about heat

Moist heat, as a method of decontamination, has been studied at 60°C and 80% relative humidity.

Yi Cui, PhD, of Stanford University, and colleagues have experimental data to suggest that use of dry heat around 75°C for 30 minutes can also potentially decontaminate N95 respirators and maintain filtration efficiency over several cycles.

But the process requires more research before it can be confirmed.

The CDC guidance noted that decontamination with an autoclave, 70% isopropyl alcohol, microwave irradiation, and soap and water led to significant filter degradation.

What Not to Do 

  • Do not bake a respirator in a home oven; it could expose the wearer and others to the virus.
  • Do not use tanning lamps or nail dryers as a source of UV radiation. These lamps use UVA radiation that have a longer wavelength and do less damage to pathogens.
  • Do not go on randomly redistributing decontaminated respirators; clinicians should write their names on their masks and hospitals should have a system to ensure they are returned to the appropriate owner.
  • Masks are disinfected but not cleaned.

What are homemade substitutes

As a last resort, homemade masks are better than nothing. Theyre more effective at keeping the germ in than keeping the germ out.

Homemade masks can be given to outsiders visiting patients or confirmed COVID-19 patients who are being sent home. The masks are cleaned, and could be used by clinicians, in future, to make their own N95s last longer.

[CDC Guidance; Medpage Today]

CMAAO Corona Facts and Myth Buster 40

Can COVID-19 cause encephalitis

Fact: Experts from Henry Ford Health System in Detroit, Michigan, reported the first presumptive case of acute necrotizing hemorrhagic encephalopathy associated with COVID-19. [published online March 31 in Radiology.] 

Acute necrotizing encephalopathy (ANE) is a rare complication of viral infections; however, till now, it had not been reported as a result of COVID-19 infection. ANE has been linked with intracranial cytokine storms. A report published in the Lancet suggested that a subgroup of patients with severe COVID-19 might go on to develop a cytokine storm syndrome.

What is the latest in azithromycin and hydroxychloroquine combination

On March 20, a controversial study, led by Didier Raoult, MD, PhD, on the combination of hydroxychloroquine and azithromycin in patients with COVID-19, was published. The latest results from the same Marseille team, involving 80 patients, were reported on March 27.

A significant reduction in the viral load (83% patients had negative results on quantitative polymerase chain reaction testing at day 7, and 93% had negative results on day 8) was reported. There was a clinical improvement compared to the natural progression. Investigators reported one death, and three intensive care unit tranfers.

What about false negative in RT-PCR

Fact: In many patients, it takes three to four swabs to get a positive RT-PCR. The Chinese ophthalmologist, Li Wenliang, who had sounded the alarm about coronavirus, had several negative tests. However, he died from the infection. A Chinese study reported that the sensitivity of RT-PCR (the proportion of the infected who test positive) was around 70%.

When to give prone ventilation

Fact: It is suggested to perform prone ventilation in patients with refractory hypoxemia and COVID-19 pneumonia (i.e. acute respiratory distress syndrome [ARDS])

When to use ECMO

Fact: Consider extracorporeal membrane oxygenation (ECMO) in patients with refractory hypoxemia, COVID-19 pneumonia (i.e. ARDS), who have failed prone ventilation.

Is the lung involvement like high altitude sickness

Fact: Several patients have low oxygen, but their lungs don’t look that bad. In an editorial published in the journal Intensive Care Medicine, Luciano Gattinoni, MD, a guest professor of anesthesia and intensive care at the University of Gottingen in Germany, who is also one of the world’s experts in mechanical ventilation, stated that more than half the patients he and his colleagues have treated in Northern Italy have had this symptom. While they appear to be able to breathe just fine, their oxygen is very low.

Gattinoni stated that about 30% of COVID-19 patients who come to the hospital have more classic symptoms of ARDS. Their lungs are cloudy on imaging scans, and they’re stiff and inflamed, indicating that they aren’t working well. Patients have low levels of oxygen in their blood, and they struggle to breathe. They resemble patients with severe pneumonia caused by a virus. Doctors are more used to seeing this type of lung trouble with respiratory diseases like influenza and SARS.

Patients with more classic ARDS-type COVID-19 often require mechanical ventilation right away.

Patients with respiratory failure who can still breathe fine, but have very low oxygen, may improve on oxygen alone, or on oxygen given through a lower pressure setting on a ventilator.

Gattinoni believes that the problem for these patients may not be swelling and stiffening of the lung tissue. Instead, it may lie in the intricate web of blood vessels in the lungs.

When lungs become damaged, the vessels that carry blood through the lungs constrict, so blood can be shunted away from the damaged area to an area that’s still working properly. This protects the body from a fall in oxygen.

Some COVID-19 patients are unable to do this anymore. Blood is therefore still flowing to damaged parts of the lungs. People feel they’re taking good breaths, but their blood oxygen is dropping.

This problem with the blood vessels is similar to the condition called high-altitude pulmonary edema, or HAPE.

These patients with more normal-looking lungs, but low blood oxygen, may be particularly susceptible to ventilator-associated lung injury, where pressure from the air being forced into the lungs damages the thin air sacs that exchange oxygen with the blood. [WebMD]

Do not get admitted unless you need oxygen: if you have the infection you will infect others or you will come back with an infection

  1. The Wockhardt Hospital in Mumbai is now a containment zoneafter 26 nurses and three doctors tested positive for COVID-19 over a week.
  2. New admissions have been stopped and the Outpatient Department (OPD) has been closed at the Jaslok Hospital after at least one of its staff tested positive for coronavirus.
  3. Four COVID-19 cases among healthcare workers, one doctor and three nurses, were confirmed by Delhi State Cancer Institute last week. The OPD has been closed and around 45 cancer patients are being shifted to a private hospital.
  4. At Sir Ganga Ram Hospital, 108 staff members were advised quarantine after two patients who had visited the hospital were confirmed as COVID-19 positive cases.
  5. At least a dozen staff at All India Institute of Medical Sciences (AIIMS) were advised to self-quarantine after a doctor tested positive.
  6. Two doctors at Safdarjung Hospital were confirmed positive for COVID-19 and at least 50 healthcare workers have been advised to self-quarantine.
  7. Nearly 92 staff members, which includes several doctors, of the DY Patil Hospital, Pune have been quarantined after an accident victim, being treated at the facility, tested positive for coronavirus.
  8. More than 50 healthcare workers have tested positive for COVID-19 elsewhere across the country.
  9. Over 150 doctors and nurses have died combating coronavirus across the world.
  10. In Spain, where healthcare workers had released videos of using garbage bags as protective clothing, more than 15,000 are sick or under self-isolation. Thousands more are unable to perform their duties across Europe and the US due to the virus. Of the 8,098 cases during the SARS outbreak in 2002, health workers accounted for 1,707 (21%) cases.

Call on global ban on wildlife markets

Fact: The United Nations biodiversity chief, Elizabeth Maruma Mrema, has called for a global ban on wildlife markets, like the one in Wuhan, China, believed to be the origin of the new coronavirus that has caused the pandemic. Mrema said wet markets where animals such as civets, wolf pups and pangolins are kept in cages could incubate future diseases. While China has issued temporary bans on such markets, experts call for a global ban as they fear that Beijing will relax the restrictions once the crisis has passed. SARS and H1N1 viruses, too, crossed over to the human population from such markets.

What is the Indian pattern of cases

Fact: Senior citizens account for a disproportionate share of fatalities in India, suggests ministry data. 

Those above 60 years of age made up just 19% of coronavirus cases but accounted for 63% of the fatalities. Those who are 40 to 60 years old accounted for 30% of the fatalities, while only 7% of the fatalities were in those younger than 40.

As many as 86% of the fatalities had conditions such as diabetes, hypertension, heart and kidney disease. Of the total number of people infected so far, 76% were males and 24% females; men also accounted for more deaths at 73%. 

Can COVID-19 mutate

Fact: Based on current data, SARS-CoV-2 seems to mutates much more slowly than the seasonal flu. SARS-CoV-2 seems to have a mutation rate of <25 mutations per year, while the seasonal flu has been reported to have a mutation rate of almost 50 mutations per year.

The SARS-CoV-2 genome is almost twice as large as the seasonal flu genome. The seasonal flu seems to mutate about four times as fast as SARS-CoV-2. The significantly slower mutation rate of SARS-CoV-2 raises hopes for the potential development of effective long-lasting vaccines against the virus.

If endotracheal intubation is required, who should do it

Fact: It should be performed by a healthcare worker most experienced in airway management in order to minimize the number of attempts and risk of transmission (SCCM Best practice statement)

Video-guided laryngoscopy or direct laryngoscopy

Fact: Video-guided laryngoscopy 

HCQS and diabetes

Yes. Hydroxychloroquine is approved for treatment of complicated diabetes.

What is the main feature of X-rays in COVID-19

Fact: All subpleural ground glass appearances or opacities are more in lower zones

Dr K K Aggarwal,

President Confederation of Medical Associations of Asia and Oceania

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