INFOGRAPHIC: DISEASE & CHRONIC INFLAMMATION
Tag Archives: Infographics
Covid-19 Review: Airborne Transmission Of Viruses
In a very good article, the Journal ‘Science’ has collated a lot of basic science regarding aerosol transmissions in viral infection generally, and Covid-19 in particular.
Early in the epidemic, I thought that large droplet transmission, which fell to the floor, and was transmitted by fomites and hand autoinoculation into the respiratory membranes, was more important. The main thesis of the article is that it is not large droplets, but aerosol particles that mainly transmit.
The secondary assertion is that aerosols can be up to 100 µm microns in diameter and still be transmitted by inhalation. they also stated that particle size of equal or less than 5 µm contain more virus particles than all the larger particles put together in spite of the greater mass of the larger particles . Normal speaking creates about 1000 aerosol particles per minute, And normal breathing about 7200 aerosol particles per liter of exhaled air. Coughing is more sporadic and tends to produce the larger droplets which don’t stay airborne as long, but I wouldn’t count on it.
There is a tremendous difference between individuals as to the number of particles they generate. It’s estimated that 10 to 20% of individuals account for 80 to 90% of the virus.
Slide number two deals with viral load and infectivity which is a function of the pH value, electrical charge, and other characteristics of the virus. An important point is that even though there is lots of viral RNA, that doesn’t mean that the virus is infective. Once again there’s a tremendous difference between the infective viable virus content of the aerosols from infected patient to patient. He stated that in one room with two Covid patients, they were 6 to 74 TCID/50 per liter, which means you’re almost certain to be infected if you don’t have a mask that filters out the virus, or some kind of purification in the room.
Slide Three was very interesting to me. The persistence in hours graphed against the aerosol particles size. 100 µm particles stay in the air only about five seconds, 5 µm particles stay in the air for 30 minutes, and one micrometer particles will stay in the air for 12 hours or more.
The fourth slide talks about factors affecting the distribution of indoor aerosols. There may be certain parts of the room where the particles congregate , depending on the ventilation type, whether natural, mechanical or filtered, flow patterns within the room, and indoor filtration and killing devices such as ultraviolet light.
Mention is made of the CO2 level in the room as a measure of air circulation. There is a higher CO2 in the air with lots of people and poor ventilation. The recommendation is that 7-8 ppm is about the highest acceptable level, and the possibility of using a portable HEPA filter would not be a bad idea for people frequenting indoor restaurants. Of course, outdoor air with its breezes, dispersion, less humidity, higher ultraviolet and usually Greater dispersion of people is preferable to indoor contact.
Some other interesting points are that children produce less aerosol particles because they have a smaller number of bronchi. I thought the bacteria were less likely to be aerosol transmitted than viruses, but they state that the R0 of tuberculosis can be as high as 4.3, vs. 7-8 for covid. The typical tuberculosis bacillus is relatively large, and yet is only 2 µm in length, well within the size of an aerosol particle.
–Dr. C
COVID-19 INFOGRAPHIC: U.S. VACCINATION RATES & STATES HOSPITALIZATIONS (AUG 9)
Highly Vaccinated States Keep Worst Covid-19 Outcomes in Check as Delta Spreads, WSJ Analysis Shows
SCIENCE: CLEANING INDOOR AIR WILL IMPROVE HUMAN HEALTH AND COGNITION
COMMENTARY:
Joseph Allen, the “air investigator”, was apparently on board early in the COVID-19 epidemic, stressing the importance of suspended air particulates, less than 2 microns in size, causing transmission of the disease.
His article in Science: “clean indoor air will improve human health and cognition” is well worth reading, or at least inspecting the info graphic. As a practicing allergist, I was aware that inside dust mite particles and mold spores made allergies worse. We had a service where we would go into homes and sample the air. An excess of certain Indoor mold spores, compared with those outside, would indicate a “problem home”. We would then try to find the water leakage source that produced the molds.
I also had a patient who could not tolerate a new house, with its carpets and other artificial materials. The only place where she felt better was in an old seaside house 100 miles south of San Francisco. I thought there were some psychological factors, but who knows? Volatile organic compounds, VOCs, probably affect some people more severely.
Beginning shortly after the energy crisis in the 80s, the “sick building syndrome”, characterized by headache and fatigue in certain buildings, was on the news. The eventual solution was to create better ventilation, with a reduction of CO2 and VOCs in those buildings. In addition, federal agencies began banning certain artificial fabrics that out-gassed VOCs.
There was eventually less talk about sick building syndrome, except for the occasional air system which was contaminated with Legionella bacteria.
The present article stresses accumulation of CO2 and VOCs In the stale air in the individual home or office as a cause of diminished attention and productivity.
CO2 monitors still cost about $200, and so I think I am going to just try to increase the ventilation in my office, where I get sleepy in the afternoon, by opening the windows and sliding doors. I wonder about the indoor CO2 in Scandinavian winters, where depression is increased.
—Dr. C.
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Tachycardia: Types, Causes & Symptoms (Mayo Clinic)
Tachycardia is the medical term for a heart rate over 100 beats per minute. There are many heart rhythm disorders (arrhythmias) that can cause tachycardia.
Types of tachycardia
There are many different types of tachycardia. They’re grouped according to the part of the heart responsible for the fast heart rate and cause of the abnormally fast heartbeat. Common types of tachycardia include:
- Atrial fibrillation. Atrial fibrillation is a rapid heart rate caused by chaotic, irregular electrical impulses in the upper chambers of the heart (atria). These signals result in rapid, uncoordinated, weak contractions of the atria.Atrial fibrillation may be temporary, but some episodes won’t end unless treated. Atrial fibrillation is the most common type of tachycardia.
- Atrial flutter. In atrial flutter, the heart’s atria beat very fast but at a regular rate. The fast rate results in weak contractions of the atria. Atrial flutter is caused by irregular circuitry within the atria.Episodes of atrial flutter may go away themselves or may require treatment. People who have atrial flutter also often have atrial fibrillation at other times.
- Supraventricular tachycardia (SVT). Supraventricular tachycardia is an abnormally fast heartbeat that starts somewhere above the lower chambers of the heart (ventricles). It’s caused by abnormal circuitry in the heart that is usually present at birth and creates a loop of overlapping signals.
- Ventricular tachycardia. Ventricular tachycardia is a rapid heart rate that starts with abnormal electrical signals in the lower chambers of the heart (ventricles). The rapid heart rate doesn’t allow the ventricles to fill and contract efficiently to pump enough blood to the body.Ventricular tachycardia episodes may be brief and last only a couple of seconds without causing harm. But episodes lasting more than a few seconds can become a life-threatening medical emergency.
- Ventricular fibrillation. Ventricular fibrillation occurs when rapid, chaotic electrical impulses cause the lower heart chambers (ventricles) to quiver instead of pumping necessary blood to the body. This can be deadly if the heart isn’t restored to a normal rhythm within minutes with an electric shock to the heart (defibrillation).Ventricular fibrillation may occur during or after a heart attack. Most people who have ventricular fibrillation have an underlying heart disease or have experienced serious trauma, such as being struck by lightning.
INFOGRAPHIC: WHAT IS CARDIAC REHABILITATION?
Telemdicine: Growth Rate Peaked During April 2020, Then Stabilized In 2021
A year ago, we estimated that up to $250 billion of US healthcare spend could potentially be shifted to virtual or virtually enabled care. Approaching this potential level of virtual health is not a foregone conclusion. It would likely require sustained consumer and clinician adoption and accelerated redesign of care pathways to incorporate virtual modalities.
- Telehealth utilization has stabilized at levels 38X higher than before the pandemic. After an initial spike to more than 32 percent of office and outpatient visits occurring via telehealth in April 2020, utilization levels have largely stabilized, ranging from 13 to 17 percent across all specialties.2 This utilization reflects more than two-thirds of what we anticipated as visits that could be virtualized.3
- Similarly, consumer and provider attitudes toward telehealth have improved since the pre-COVID-19 era. Perceptions and usage have dropped slightly since the peak in spring 2020. Some barriers—such as perceptions of technology security—remain to be addressed to sustain consumer and provider virtual health adoption, and models are likely to evolve to optimize hybrid virtual and in-person care delivery.
- Some regulatory changes that facilitated expanded use of telehealth have been made permanent, for example, the Centers for Medicare & Medicaid Services’ expansion of reimbursable telehealth codes for the 2021 physician fee schedule. But uncertainty still exists as to the fate of other services that may lose their waiver status when the public health emergency ends.
- Investment in virtual care and digital health more broadly has skyrocketed, fueling further innovation, with 3X the level of venture capitalist digital health investment in 2020 than it had in 2017.4
- Virtual healthcare models and business models are evolving and proliferating, moving from purely “virtual urgent care” to a range of services enabling longitudinal virtual care, integration of telehealth with other virtual health solutions, and hybrid virtual/in-person care models, with the potential to improve consumer experience/convenience, access, outcomes, and affordability.
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ESOPHAGEAL CANCER: SYMPTOMS & DIAGNOSIS
Doctors Without Waiting Rooms 