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Blog

What is Corona Virus?

September 17, 2020 1:37 pm

At a highly technical level Viruses are considered non-living materials. Viruses can not replicate and reproduce by themselves. Therfore, they need to attach themselves and penetrate a living organism to allow multiplication. Double Stranded Viruses include smallpox, Chickenpox and Herpes simplex. Single Strand Sositive Sense Virus in varies groups include HIV, and  Corona Virus. Specifically, Corona virus is a Single Strand, Enveloped Helical Virus. The classifications of the viruses are based on their shape and the mechanism of attachment to the host cell. There are differnt classification of virusrs described. Viruses have cuased more death in the human history than any other diseases. However with vaccination, and public health policies we have been able to eliminate certain deadly viruses.

Covid-19 Mutation – Please physically distance and Wear Masks

August 18, 2020 1:16 pm

Introduction:

There is evidence emerging of Covid-19 mutation. This may explain the difference between the severity and intesity of the disease presented in the those geographical locations where the disease  first.

Scientists from The Scripps Research Institute, Jupiter, Florida have identified changes in the Spike protein. This protein is used to bind the virus to host membranes. As we now know Florida is one of the few hot spots of the Covid-19 pandemic.

This has significant implications for the long term strategy needed to control transmission and manage resurrgence.

Until there is effective vaccination or effective treatment available for everyone, prevention by wearing face mask is the most efficient form to avoid transmistion.

Prevention:

The facts are that the most consistent effective preventive measures are wearing face masks and physical distancing.

There are those who may feel invincible and think that you will 1. either not get the disease or even if you get it it will 2-not affect your health.  Lets first remind ourselves that wearing a mask is more to prevent passing the virus that getting it. We should all assume that someone that we come in contact with may already have it. Would you like them to breath the virus toward you ? This then brings the second issue: We do not know what the long term health effect of the virus is for those who develop significant symptoms and those who are asymtphomatic.

The unkown:

Let’s look at other viral infections that provide either no or minimal disease condition at the time of initial exposure only to result in long term health conditions that may result in death. These include hepatitis and HIV exposures and infections. Admitedly  Coronavirus is a differnt family of virus. I am not suggesting that this will behave like other family of the viruses. We just do not have enough information to know what happens to those exposed to the virus (regardless of being asymptotic or not). Could the virus become dormant and over time result in organ injury (lung) like in the case  of hepatitis (liver). Or make a home in our body and have recurrent debilitating infections and symptoms as it is seen with Varicella-zoster virus (VZV) which causes chickenpox and the time of the initial infection and makes residence in our body to reappear later on as herpes zoster (shingles). Will we need a new strain of vaccine every year similar to the flu vaccine?

That is the crux.  We do not know because the COVID virus is new and we do not know the long term effects.

Vitamin D and COVID 19

June 13, 2020 4:40 pm

There has been extensive discussion on the importance of Vitamin D published over the last few years in regards to bone health, immune health and Calcium physiology. The importance of vitmain D and bone structure has been discussed extensively. It is also important in the absorption of Calcium. It further plays role in immune modulation.

What is new is the possible correlation of Vitamin D and COVID 19. Recently it is been shown that low vitamin D may increase the risk of a poor outcome with Covid-19 exposure and infection.

There are different standard recommendation for the Vitamin D levels.

In our practice we aim to maintain a Vitamin D level of 0ver 60 in post weight loss surgical patients.

There are a number of theories as to how the Vitamin D deficiency may play a role in this. An emerging observation is that low Vitamin D may cause abnormal and excessive blood clot formation. Mohammad et. al. in 2019 published a study on the association of low vitamin D and “…Pathogenesis of Thrombosis”

This pathologic blood clot formation in COVID-19 patients may explain the extensive lung injury and  multi system organ failure in some patient. It is also one of the reason that some COVID-19 patients have loss limbs or appendages.

Please follow all supplement recommendations based on your laboratory studies and all COVID-19 recommendations. We would recommend frequent hand washing, surface cleaning, social distancing, and wearing face masks as the most basic precautions and increase precautions based on your health status.

Vitamin D and Covid -19

May 07, 2020 9:24 am

We are all aware of the many roles that Vitamin D plays in our bodies. This includes immune function in addition to all the regulatory roles that Vitamin D plays in several physiologic reactions. There may be a correlation of low Vitamin D and COVID-19 infection increasing death risk as looked at in research articles.

Covid -19 in a subset of patience causes significant lung injury. These patients require mechanical ventilation.

Previously reported publications have suggested a possible correlation between ace inhibitors and increased risk of pulmonary complications of Covid -19. Some researchers suspect that the Covid-19 may be able to enter lung cells by the ACE receptors.

Shown is the initial entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into cells, primarily type II pneumocytes, after binding to its functional receptor, angiotensin-converting enzyme 2 (ACE2). After endocytosis of the viral complex, surface ACE2 is further down-regulated, resulting in unopposed angiotensin II accumulation. Local activation of the renin–angiotensin–aldosterone system may mediate lung injury responses to viral insults. ACE denotes angiotensin-converting enzyme, and ARB angiotensin-receptor blocker. (N Engl J Med 2020; 382:1653-1659)

Vitamin D may positively implact the receptor ACE2. This study, report clear correlation between the high death rate with low vitamin D levels in Covid infected patients. There are limitation to this study that the attached abstract outlines.

Our take home message would be to please make sure you have updated labs and that you are all taking the recommended Vitamin D based on your surgical anatomy and laboratory values, not just an average non-bariatric person recommended dose.

https://www.dssurgery.com/wp-content/uploads/2020/05/manuscript.pdf

Copper Metabolims And Weight Loss Surgery

May 01, 2020 12:31 am

Written By: Osheen Abnous, Maria Vardapetyan, Eric Baghdasaryan

Copper is an essential element to all organisms, and it is a contributor in several enzymes vital to the function of hematopoietic, vascular, and skeletal tissues, as well as the structure and function of the nervous system. 

As a crucial metal, copper plays an important role in chemical reactions throughout the human body; this includes the central nervous system. Enzymes are substances that facilitate chemical reactions. There are many copper-dependent reactions in the human body.  In humans, the major site of absorption of dietary copper is still unclear.  Copper in humans is absorbed in the proximal small bowel, duodenum, and ileum. This is after it has passed the acidic environment of the stomach.

Copper deficiency can be caused by malnutrition, prematurity, parenteral or enteral feeding without copper supplementation, gastrectomy, and excessive zinc therapy. The common causes of copper deficiency have been zinc supplementation,  and changes to the PH (acidity) of the stomach. This can be the result of the alteration of the stomach anatomy, and by chronic acid suppression by proton pump inhibitors (antacids), and similar medications. Physicians need to be alert with patients who show signs of copper deficiency or are at a high risk of developing a copper deficiency. 

It is important to raise greater awareness about copper deficiency because there is a growing number of patients undergoing surgeries for obesity, as the occurrence of copper deficiency will increase in the future. 

Studies of patients who have had weight loss surgery in the past experience common symptoms such as pain involving the feet, gait abnormality (unusual walking), lower limb weakness, and recurrent falls. Common lab results include unusually low serum copper and serum ceruloplasmin levels. In some cases, elevated zinc levels are also present. Treatment includes cupric sulfate infusion until normal copper levels are reached, which then need to be maintained for the future. Vitamin B-12 deficiency has also been reported as a possible cause of myelopathy, which is a nervous system disorder that affects the spinal cord. As stated earlier, neurological damages are often irreversible and cause permanent damage to patients. Early diagnosis from physicians is crucial for patients who have undergone gastric bypass surgery, and the sooner they are diagnosed, the less permanent damage the patient will endure.

Case Discussions:

A 49-year-old woman had gastric bypass surgery for obesity 24 years age. She presetend with increasing lower limb stiffness and numbness. Additionally she reported tingling of the feet. As her pain continued to increase, she began using a walker, and her symptoms continued to worsen. After undergoing a neurological examination, results showed that the patient had increased lower limb tone and an absent perception of vibration at the toes and ankles. Laboratory results showed that the patient had copper levels barely detectable. This included serum copper and serum ceruloplasmin levels. In addition, the patient had reduced serum carotene (vitamin A) levels. 

The patient received cupric sulfate intravenously daily through an 8-week period. After each daily infusion of cupric sulfate, the patient reported to have slight decreases in numbness and an increased tingling sensation. After the 8-week period, lab results showed that serum copper levels were normal and are needed to be maintained. Her night blindness was corrected by vitamin A injections.

In another case, a 53-year-old woman had symptoms of abnormal gait (abnormal walking) and anemia (lack of healthy red blood cells), and was seen for evaluation. The patient complained of pain in the lower legs, which would worsen over time and move up towards her thighs. As her ability to walk continued to worsen, the patient resorted to using a wheelchair. Her medical history consisted of an RYGB surgery for obesity. The only significant supplementation she received was 1000 μg vitamin B12 subcutaneously for several years. She had absent positional and vibratory sensation in the lower extremities to the knee. In addition, touch sensation was decreased. Laboratory examination revealed an elevated serum zinc level, and extremely low serum copper and ceruloplasmin levels.  

For treatment, the patient received intravenous copper over a 6-day period, was discharged home, and then received weekly intravenous copper infusions thereafter. After a month of receiving intravenous copper, serum copper levels returned to normal. In addition, the patient’s pain in the lower leg improved, but vibratory sensation remained absent in the same area. Four months after being discharged from the hospital, the patient began walking with a cane.

Fat Soluble Vitamins

April 26, 2020 10:20 am

Written By: Maria Vardapetyan, Eric Baghdasaryan, Osheen Abnous

Vitamins are chemicals that facilitate many processes in the human body such as blood clot formation, good vision, fight infections etc. There are two classes of vitamins. Water soluble vitamins and fat soluble vitamins. Water soluble vitamins dissolve in water. This makes it possible for them to be absorbed through all mucous membranes. Fat soluble vitamins on the other hand do not dissolve or pass through mucous membranes. Fat-soluble vitamins are absorbed in the intestine along with fats in the diet. These vitamins have the ability to be stored in the fat tissues of the human body. Water-soluble vitamins are not stored in the body and have to be taken in daily with the food and dietary supplements. Solubility of a vitamin is not a function of its physical state. There are fat soluble vitamins that have a liquid form and almost all of the water soluble vitamins come in form of pills or powders.

In this article, we are going to focus on fat soluble vitamins. They are all complex molecules made of carbon, hydrogen, and oxygen in different arrangements (see figures 1, 2, 3 and 4). These fat soluble vitamins are vitamin A, D, E and K.

Vitamin A

Vitamin A has a major role in vision, immune function, cell growth, and maintenance of organs such as heart, kidneys, lungs, etc. It plays a pivotal role in the health of our eyes, specifically the retina1. Rhodopsin protein, a major protein that has the leading role in the process of vision, is found in the retina where it allows us to perceive light. This protein requires vitamin A to function properly. Without vitamin A, rhodopsin cannot sense light and thus cannot initiate the process by which vision occurs.

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Figure 1: Chemical structure of Vitamin A molecule

 

Vitamin D

Vitamin D regulates different chemical reactions that are associated with bones, muscles, and the immune system. The simplified way it does this regulation is it helps absorb calcium from dietary nutrients which in turn strengthens the bones, helps neurons exchange signals to move muscles and helps the immune system to fight against viruses and bacteria2. 

pastedGraphic_1.pngFigure 2: Chemical structure of Vitamin D molecule

Vitamin E

Vitamin E acts as an antioxidant. Antioxidants are naturally occurring chemicals that neutralize toxic byproducts of many chemical reactions in the human body. When food is consumed and digested, the human body converts it into energy. As a result of metabolism free radicals (toxic byproducts) are formed and are neutralized with the help of vitamin E. In addition, free radicals are also in the environment. Furthermore, vitamin E stimulates the immune system to fight against bacteria and viruses3.

pastedGraphic_2.pngFigure 3: Chemical structure of Vitamin E molecule

Vitamin K

Vitamin K can be obtained from food and dietary supplements. There are two forms of vitamin K: phylloquinone (Vitamin K1), which is found in spinach, kale and other greens and menaquinone-4 (Vitamin K2), which is found in animal products. Vitamin K1 is involved in blood clotting, and Vitamin K2 is involved in bone tissue building. Vitamin K1 is the main Vitamin K in human diet (75-90% of all vitamin K consumed), however, it is poorly absorbed in the body4,5. 

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Figure 4: Chemical structures of Vitamin K1 and K2 molecules

Absorption of fat soluble vitamins

Polarity describes the inherent charge(positive or negative) or lack of charge for any given substance or molecule.  Molecules that are charged are referred to as “polar”, while those that lack charge are “nonpolar”. When discussing solubility, it is important to remember the phrase “like dissolves like”. That means polar (charged) substances like to interact with a polar environment like water, since water contains a slight negative charge. Hence, charged substances are water-soluble. Nonpolar substances on the other hand readily interact with nonpolar environments such as fat, which contains no charge. Therefore, molecules that lack a charge such as vitamins A, D, E, and K are referred to as fat soluble. 

 

Due to their water fearing nature, these fat soluble vitamins cannot simply be absorbed directly into the bloodstream (which is mostly water) like the sugars and amino acids in our diet. As their name suggests, these fat soluble vitamins like to be embedded in fatty droplets, which facilitate their absorption in the following way. Fat soluble vitamins group together with other fat molecules to form fatty droplets, effectively reducing the amount of interaction with the watery environment of the intestines. Therefore, without an adequate amount of fat in your diet, your body is unable to effectively absorb these fat-soluble vitamins. This may be true in an intact anatomy, however, post weight loss surgical patients can not increase their fat soluble vitamin levels by increasing their fat intake. This is due to the fact that a high fat diet causes excessive bowel movement which in turn washes away any vitamins taken by mouth. DS limits fat absorption (thus the great weight loss) which can cause vitamin A and D deficiency that can not be easily corrected with oral supplementation.

As mentioned before, fat soluble vitamins are hydrophobic and nonpolar, which means they are also fat loving or lipophilic. Excess fat soluble vitamins can be stored in the liver and fat tissue. Therefore, these vitamins do not need to be eaten every single day since stores of these vitamins can sustain a person for some time. It may take several weeks or months for our body to deplete these stores of fat soluble vitamins which is why it generally takes a longer amount of time for fat soluble vitamin deficiencies to manifest themselves. The ability to store these fat soluble vitamins in tissues can also lead to vitamin toxicity – marked by an excess of vitamin stores in our body. 

Clinical manifestations of A, D, E, K deficiency

Vitamin Clinical Deficiency manifestations
Vitamin A Vision Problems

Night blindness 

Dryness of the eye

Vitamin D Softening and weakening of the bones

Decreased bone formation 

Bone shape distortion

Bowed legs (generally in children)

Hypocalcemia 

Vitamin E Damage to red blood cells 

Tissue/organ damage due to inability to supply enough blood

Vision problems

Nervous tissue malfunction

Vitamin K1  Excessive bruising

Increased bleeding time

Small blood clots under nails

Increased bleeding in mucous membrane

Vitamin K2  Weak bones

Increased plaque deposits along gumline

Arterial calcification

 

 

References

  1. Office of Dietary Supplements – Vitamin A. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#. Accessed April 26, 2020.
  1. Office of Dietary Supplements – Vitamin D. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-Consumer/. Accessed April 26, 2020.
  1. Office of Dietary Supplements – Vitamin E. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminE-Consumer/. Accessed April 26, 2020.
  1. Vitamin K. The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/vitamin-k/. Published July 2, 2019. Accessed April 26, 2020.
  1. Beulens JWJ, Booth SL, van den Heuvel EGHM, Stoecklin E, Baka A, Vermeer C. The role of menaquinones (vitamin K₂) in human health. The British journal of nutrition. https://www.ncbi.nlm.nih.gov/pubmed/23590754. Published October 2013. Accessed April 26, 2020.

Biofilm

April 26, 2020 9:44 am

Written By: Eric Baghdasaryan, Maria Vardapetyan, Osheen Abnous

Biofilm are tiny microorganism-filled communities found throughout the human gastrointestinal tract and oral cavity. These communities adhere to both biological and non-biological surfaces within the human body. They provide their inhabitants with many competitive advantages that help these bacterial communities withstand biological, chemical, and physical stresses1. Within these communities, microorganisms collaborate with one another to increase the likelihood of growth and multiplication despite the harsh conditions of the human gut. Not all bacteria within these biofilms are harmful, but those that are go on to cause infections and other severe health problems for the host. 

Biofilm formation

Studies have shown that approximately 60-80% of bacterial infections in the human body are associated with biofilm formation. Such findings have compelled researchers to investigate the complex factors responsible for biofilm formation.

Biofilm formation

Figure 1: Biofilm adhesion, formation, and maturation. whiteley.com.au/biofilms

It was shown that bacteria anchor themselves to the mocosa surface. They collectively form a protective layer made of polysaccharides, proteins, and extracellular DNA. This forms the biofilm matrix. This biofilm matrix acts as a shield against antimicrobials, toxins, and antibodies. From here, biofilm associated bacteria go on to cause chronic infections characterized by persistent inflammation and tissue damage, initiating in the gut and adjacent regions of the gastrointestinal tract. Furthermore, some biofilm associated bacteria have shown the ability to disperse from this mature biofilm to colonize new niches, underscoring the association between local infections and systemic diseases such as atherosclerosis and rheumatoid arthritis2 caused by the buildup of biofilm dispersed bacteria and subsequent inflammation in the coronary vasculature and joint capsules, respectively. In fact, BADAS syndrome (bowel associated dermatosis-arthritis syndrome) is a condition where patients present themselves with small bumps on their inner skin (mainly along the vasculature) caused by the buildup of circulating microtoxins (very small clusters of bacteria). This may lead to chronic bacteremia in the bloodstream. Also, the over circulation of host immune complexes presents many problems for the patients, such as the development of arthritis and the accompanying joint pain, caused by the build up of white blood cells in host joint capsules. Patients often link the lumps to a dermatological condition, when in reality the condition is caused by a bacterial overgrowth originating in the gut and bowel. Clinicians now believe it is very likely these bacteria are biofilm-associated and a proper early diagnosis of the biofilm origin is critical to the prevention of BADAS and similar pathologies3. 

The formation of biofilms has been studied on foreign substances such as intravenous catheters, orthopedic implants, and other biomaterials that have shown device-associated infections. However, it is commonly accepted that the majority of chronic bacterial infections involve biofilm formation on natural surfaces. The pathogenic bacterial overgrowth, forming the biofilms, have been linked to major diseases of the gastrointestinal tract including Inflammatory bowel disease and colo-rectal cancer4.

In addition to the gastrointestinal tract, biofilms can also be formed in the oral cavity. Over 700 bacterial species reside in the oral cavity. These contribute to the outgrowth of oral biofilms (otherwise known as dental plaque, see figure 2). These oral biofilms are responsible for major oral diseases such as tooth decay, gingivitis, and periodontitis. Moreover, those with periodontal infections have significantly increased risk of cardiovascular diseases, including atherosclerosis, myocardial infarction, and stroke2. The inflammation caused by oral biofilm may also be a contributing cause of conditions such as diabetes and rheumatoid arthritis1. Therefore, the control of oral biofilm growth before the development of oral infections is critical for the prevention of these system conditions.  

Dental biofilm

Figure 2: Oral Biofilm Formation.

https://phys.org/news/2018-10-scientists-infection-causing-biofilms.html

This symbiotic (mutually beneficial) relationship between gut microbiota (bacteria living in our gut) and the host begins at birth and is crucial to our overall fitness and health. However, certain external and internal factors modify the gut microbiota. This causes the formation of a pathogenic biofilm, which leads to detrimental health conditions. The same bacteria that was once helping us by maintaining a healthy gastrointestinal tract, is now triggering disease conditions4. 

Due to bacteria’s ability to translocate, migrate, and colonize new surfaces or niches, biofilm associated infections in the gut have been linked to systemic infections in other organs, including the joints, the skin, the eyes, the vasculature, the lungs, and even the central nervous system. It is assumed that the formation of a thick mucosal biofilm might be used as a diagnostic biomarker for the onset of systemic diseases. The outgrowth of a biofilm is widely viewed as the tipping point between two alternative states: a healthy and diseased gut1. 

Biofilm formation

Figure 3. Biofilm matrix – a protective layer.  Trends in Microbiology.

The biggest clinical challenge with biofilm-associated infections is their high resistance to antibiotic therapy. The effective therapeutic concentration of certain antibiotics to fight off bacteria within a biofilm (amount of the antibiotics needed in order to have positive therapeutic effects) is about 100-1000-fold higher than if the same bacteria were not associated with a biofilm2. The extracellular matrix, scaffold that keeps the bacteria anchored in place, prevents the penetration of host immune cells into the biofilm, thus contributing to the increased survival of the bacterial species living within the biofilm. Bacteria living within a biofilm also undergo an increased number of mutations, leading to the generation of more antibiotic-resistant phenotypes of bacteria. Finally, studies have shown that minimal concentrations of antibiotics may actually facilitate and stimulate biofilm formation, which can be extremely problematic in clinical treatment2. Therefore, to decrease the risk of biofilm induction, physicians should begin with very high doses of chemotherapeutics (antibiotics) from the very beginning of diagnosed infection. Looking ahead, there is clearly a need for novel biofilm-targeted therapies that are specifically made to prevent biofilm formation as well as eliminate the biofilm completely once it has already matured. Researchers have identified several drug candidates – DNase, lactoferrin, chlorhexidine, and taurolidine2 – that they believe have the potential to effectively penetrate and destroy components of the biofilm matrix. Further research is needed to determine their efficacy. 

 

References

  1. Tytgat HLP, Nobrega FL, van der Oost J, de Vos WM. Bowel Biofilms: Tipping Points between a Healthy and Compromised Gut? Trends in Microbiology. January 2019;27(1): 17-25. doi:10.1016/j.tim.2018.08.009.
  1. Marcinkiewicz J, Strus M, Pasich E. Antibiotic Resistance: a “dark side” of biofilm-associated chronic infections. Polskie Archiwum Medycyny Wewnetrznej (Polish Archive of Internal Medicine). 2013;123(6):309-312. 
  1. Dicken CH. Bowel Associated Dermatosis-Arthritis Syndrome: Bowel Bypass Syndrome Without Bowel Bypass. Mayo Clinic Proceedings. January 1984;59(1):43-46. doi:10.1016/S0025-6196(12)60341-3
  1. Buret AG, Motta JP, Allain T, Ferraz J, Wallace JL. Pathobiont release from dysbiotic gut microbiota biofilms in intestinal inflammatory diseases: a role for iron? Journal of Biomedical Science. January 2019;26(1) doi:10.1186/s12929-018-0495-4

Why Oxygenation in Covid-19 is a major problem

April 21, 2020 7:27 am

Covid-19 is a respiratory virus. The majority of patient may experience no or minimal symptoms. But small subset of those infected will unfortunately progress to have significant pulmonary dysfunction. Some will even require mechanical ventilation. Oxygenation in COVID 19 patients with severe symptoms is altered. This is the due to the changes caused by the virus.

Normal Physiology

Oxygen (O2) is exchanged with Carbon Dioxide(CO2) in the lungs. The CO2 is exhaled and the O2 is taken up by the blood. This high O2 continuing blood is then pumped to every single organ. With complete distribution network of capillary vessels, every cell then gets access to the O2 rich blood. Hemoglobin is the carrier that transports the O2.

The O2 is removed and dissociated from the Hgb  depends on a number of variables.  Each red cell Hgb has four binding site for the oxygen. The  affinity and strength of each one of those four units for oxygen changes based on a number variables. These are CO2, Acidity (PH), DPG and temperature.

Model of 2,3 DPG

Oxygen Dissociation Curve

The oxygen dissociation curve has a long “S” shape. On the low end of oxygen in the blood most of the Hgb site are occupied. As the oxygent level increase there is little change to the saturation.


Normally the relationship of the blood in the lungs (horizontal axis) and the amount of the O2 in the red cell (vertical axis) is following the red line. When the amout of oxygen insired is 25mmhg  the blood saturation is at 50% (A). The blood saturation is nearly 100% when room air is inhaled (C). Room air has PO2 of  75mmHg.  Note that there is very little change in blood saturation (SaO2) by increasing the PO2 from 75 to 100 mmHg (the red line is horizontal between 75-100).

Another way to look at this: If you increase the PO2 from 25 to 50 (doubling)  the Saturation goes from 50 (A) to nearly 85(B). Whereas increaseing the PO2 from 50 to 100 (doubling) only mober the Saturation from 85(B) to 100(C). This shows the efficiancy of system to be able to deliver the most amout of oxygen to the tissue even with the low level of oxygen present in the lungs.

As the Green and the Blue lines demosntrate the balance can change by changes in CO2, Acidity (PH), DPG and temperature.

COVID-19

When it comes to COVID-19 illness there may be a number of factors in play. Most patients with pre-existing conditions already have changes that may shift the curve to the right (high fever and high Co2). Furthermore, obesity, asthma and other conditions may decrease the ability to clear the lungs of secretions and mucus may contribute to decreased oxygenation. Additionally, there is significant inflammation associated with the chemicals released in COVID-19 (cytokines). These can cause devastating changes to the ability to exchange oxygen in the lungs.

Oxygenation in COVID-19 severely symptomatic patient can deprive oxygen from organ. This can  progress to organ failure.  One of the most common organ systems to fail is the kidneys which may require dialysis.