All posts by Dr. Chris

Pediatrician trained at University of Michigan Medical School, University of Hawaii and University of Chicago for residencies. Spent 20 years at the Commonwealth Health Center in Saipan, CNMI, before establishing Ebert Children's later Ebert Family Clinic in Frisco, CO in 2000. Published in the Journal of High Altitude Medicine and Biology

A conversation with Dr. Chris on neonatal oxygen levels at elevations 9000’ and above

My name is Austin Ethridge, I am a physician assistant student from Red Rocks Community College PA program who has been fortunate enough to have completed my pediatric rotation with Dr. Chris in Frisco, Colorado, this month. Dr. Chris has extensive experience providing care to the pediatric residents of Summit County, having established her practice here in 2000, following 20 years as a pediatrician on Saipan, in the Northern Mariana Islands, southeast of Japan. She has a unique perspective on high altitude health, having transitioned from sea level to the 8000′ and above elevations unique to Summit County. Since moving here, she has been advocating for more in-depth medical research regarding the needs specific to these high-altitude communities. We are here in her office today at the Ebert Family Clinic to discuss neonatal oxygen use in Summit County.

Dr. Chris, based on your experience, why do neonates need oxygen at a higher elevation? Is it because they need to acclimate?

Yes, that’s basically it, and smaller lung size at birth.

Yes, that’s what I read. Basically, the maternal physiology compensates for the higher altitude. When the infant is born, their lung size and physiology need to catch up to the altitude.

Based on your practice, when do you place neonates on oxygen?

Usually at 89% or below, but you see, that’s just it. Many parents ask why their children need to be on oxygen when neither themselves nor their siblings were on oxygen. One of the primary reasons that this has become more of an issue is the less invasive methods of measuring oxygen saturation in the blood. Before the 1990s, the only time to measure oxygen saturation in a newborn was if a concern for illness or pulmonary problems existed, which was completed by obtaining an arterial blood gas, a very invasive procedure. Do you know at what oxygen saturation level we begin to detect cyanosis in neonates?

Around75%, which means before the pulse oximeter used today, we had no idea if the infant’s oxygen saturation was in the 80s! Now that we have the pulse oximeter, we have access to so much more information. And this is why it is essential to determine the normal oxygen levels for these infants at higher elevations.

Does this include cyanosis or blue discoloration of the hands and feet, or is it just central as in the face and chest?

The blue discoloration of legs and arms do not count; this is very common and not concerning, only the discoloration of the trunk and face.

Yes, based on the articles that I have been reading while I have been here, there are not many studies that reflect normal oxygen saturation in neonates at a higher elevation. Most of the articles that I did find determined that newborn oxygen saturation is lower at elevations of around 6000’, with average values within the range of 89-96% SpO2 compared to greater than 97% at sea level. However, there could be a significant difference between 9000’-10000’ feet and the 6000’ in these studies.1-3

That is exactly right, and that is why I want to do a study here in Summit County to determine the average oxygen saturation at these altitudes.

On average, how many newborns do you place on oxygen in Summit County?

About 40% of newborns are placed on oxygen due to low oxygen levels at birth, and I would say that less than 5% will still need oxygen after their two-week visit; however, this rate may be higher in those that live at elevations of 10,000′ or greater. In general, studies have observed that the lowest oxygen levels tend to occur around the 4th day of life and then improve from this point onward. What is the main complication that we are worried about in infants that have low oxygen levels?

Pulmonary hypertension. At birth, when the fetal circulation is shunted back through the lungs, the pulmonary pressure decreases to allow this to happen. If the oxygen levels are too low, the vessels in the lungs may not dilate enough, and this could lead to elevated pulmonary pressures. I read an interesting study that found increased pulmonary pressures in Tibet children as measured by ECHO cardiogram until the age of 14. These pressures were noted to increase with increasing elevation but to decrease with increasing age. Generally, by the age of 14, the pulmonary pressures had normalized; the authors considered this to be a normal physiological response. However, it is worth noting that these children in the study came from generations of individuals that have always lived at these altitudes.4-5

That is correct. That is the difference between adaptation and acclimatization. Many of the children that live up here are acclimatized, meaning that their bodies have adapted on a physiological level, but their genetics remain the same. However, adaptation is observed in many families that have lived at high elevations for generations; in these instances, the changes have occurred at the genetic level.

That makes sense; so the data from some of those studies may not directly apply to the population here.

That is correct. Are we worried about brain damage in this setting of low blood oxygen levels?

No, I do not think so.

We are not! In fact, as an example of this: when I was in Saipan, there was a child that had a cyanotic, congenital heart defect that was unable to be repaired for social reasons. This child always appeared blue, and his oxygen saturation would have been very low. He did just fine in terms of development and progress in academics. There were no signs of developmental delay or any other neurological problems at all.

Are there any resources you recommend for parents whose newborn may need to be on oxygen?

Yes, I have a handout that I provide to all families whose infants are on oxygen. 

Are there any red flags or signs that the newborns’ oxygen may not be high enough when they are sent home? Is there anything parents should look out for? I know that you mentioned the oxygen level needs to be as low as 75% before there are any signs of concerning central cyanosis.

No, there really are no clinical signs. A company called Owlet produces a sock for the newborn’s foot that monitors oxygen saturation. I am not sure how accurate this is, but if the parents really want to do something to monitor the oxygen level, this could be a way to do so. It is pretty expensive. On an aside, we are currently in communication with this company regarding future opportunities to conduct research using their product with regards to newborn oxygen saturation at higher elevations, so stay tuned for more developments on this topic.

Are there any risks to starting the infant on oxygen?

No, not at the level that these newborns are sent home on. In premature infants, there is a risk associated with oxygen therapy for eye and lung disease. However, these premature infants are placed on very high flow rates and positive pressures. The damage is actually caused by the pressures of the oxygen being too high. This is not the case for the newborns that we place on oxygen.

Are there any risks to infants or children growing up at high altitude?

Yes, there is some evidence of a very slight increased risk of pulmonary hypertension, but this is very rare.

Thank you so much for taking the time to discuss this, Dr. Chris!

References

  1. Ravert P, Detwiler TL, Dickinson JK. Mean oxygen saturation in well neonates at altitudes between 4498 and 8150 feet. Adv Neonatal Care. 2011 Dec;11(6):412-7. doi: 10.1097/ANC.0b013e3182389348. Erratum in: Adv Neonatal Care. 2012 Feb;12(1):27. PMID: 22123474.
  2. Morgan MC, Maina B, Waiyego M, Mutinda C, Aluvaala J, Maina M, English M. Oxygen saturation ranges for healthy newborns within 24 hours at 1800 m. Arch Dis Child Fetal Neonatal Ed. 2017 May;102(3):F266-F268. doi: 10.1136/archdischild-2016-311813. Epub 2017 Feb 2. PMID: 28154110; PMCID: PMC5474098.
  3. Bakr AF & Habib HS, Normal Values of Pulse Oximetry in Natewborns at High Altitude. Journal of Tropical Pediatrics 2005; 51(3) 170-173.
  4. Qi HY, Ma RY, Jiang LX, et al. Anatomical and hemodynamic evaluations of the heart and pulmonary arterial pressure in healthy children residing at high altitude in China. Int J Cardiol Heart Vasc. 2014;7:158-164. Published 2014 Nov 12. doi:10.1016/j.ijcha.2014.10.015
  5. Remien K, Majmundar SH. Physiology, Fetal Circulation. [Updated 2020 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539710/
  6. Thilo EH, Park-Moore B, Berman ER, Carson BS. Oxygen Saturation by Pulse Oximetry in Healthy Infants at an Altitude of 1610 m (5280 ft): What Is Normal? Am J Dis Child. 1991;145(10):1137–1140. doi:10.1001/archpedi.1991.02160100069025

Austin Ethridge is a second-year physician assistant student at the Red Rocks Community College Physician Assistant Program. Originally from the Colorado front range, Austin attended the University of Northern Colorado where he obtained both a bachelors and masters degree in chemistry prior to attending PA school. In his free time, Austin enjoys spending time with his friends and family, reading, and cycling.

COVID in Colorado Update: Reasons high altitude residents may be less susceptible

Last week we were privileged to have a Zoom discussion with two high altitude experts from the Instituto Pulmonar Y Patologia de la Altura (IPPA) founded in La Paz,  Bolivia in 1970. Dr Gustavo Zubieta-Calleja and Dr. Natalia Zubieta-DeUrioste answered our questions about their recently published article, Does the Pathogenesis of SAR-CoV-2 Virus Decrease at High Altitude?. They and the seven  coauthors presented data comparing COVID cases in high altitude areas of China, Bolivia and Ecuador showing a marked reduction in numbers compared to low altitude areas in the same countries, with dramatic, colorful topographic maps.

Drs. Zubieta-Calleja and Zubieta-DeUrioste and their colleagues theorized four reasons why altitudes above 2500 m could reduce the severity of the corona virus. (Note: Frisco, CO is at 2800 m, Vail 2500 m). As described in their previous paper published in March, the intense UV radiation at altitude as well as the dry environment likely reduce the viability of the virus in the air and on surfaces.

Dr. Zubieta-Calleja on a Zoom chat with Dr. Chris explaining a chart comparing UV exposure in La Paz, Bolivia (top line) and Copenhagen, Denmark (bottom line).
Dr. Chris with Dr. Gustavo Zubieta-Calleja and other altitude experts from the Hypoxia Conference in La Paz on the Camino Chacaltaya, which reaches an elevation of 17,785’/5421 m.

The low barometric pressure causes air particles to be spaced more widely, which would also decrease the viral particles inspired with each breath, reducing the severity and frequency of infections.

Furthermore, residents accustomed to chronic hypoxia may express reduced levels of angiotensin converting enzyme 2 (ACE2) in their lungs and other tissues. This enzyme has been found to be the entry path for the corona virus into cells where it replicates. Finally, the normal adaptation and acclimatization of populations with prolonged residence above 2500 meters may reduce the severity of the disease in individuals, and reduce mortality. This includes increased ventilation, improved arterial oxygen transport, and higher tissue oxygenation mediated by increased red blood cells produced under the influence of erythropoietin, which could be explored as a possible therapy.

Dr. Zubieta-Calleja with statistics reflecting the number of COVID-19 infections at different elevations in Bolivia. Note the most infections occur at a lower elevation.

As we stated in our interview quoted in the Summit Daily News March 17th, none of these factors can be relied upon to protect every individual. Therefore it is important to continue frequent hand washing, wearing masks, social distancing, and avoid touching your face.

COVID in the Mountains: What are the Risky Situations to Avoid as We Start Leaving Our Homes?

We are on the back slope of the epidemic, according to University of Massachusetts Dartmouth Professor of Biology Erin S. Bromage, Ph.D. He explains what to expect and where not to go in an article this week which was cited in the New York Times: The Risks-Know Them-Avoid Them. The bad news is that the back slope can have as many deaths as the upslope.

The good news is that you don’t get COVID outdoors, as long as you are not standing close to someone who might have the virus for a period of time, perhaps over ten minutes. Bromage reviews a series of epidemiologic studies tracing the spread of the disease in situations including standing outside talking to someone (one case), church choir practice (45 of 60 infected, 2 died), indoor sports, specifically a curling tournament in Canada where 24 of 72 attendees became ill, birthday parties and funerals (high rate of infection and many deaths related to hugging, kissing and sharing food), grocery stores (safe for shoppers but employees get infected), and restaurants (50% infection rate after sharing a meal with nine at the table). He also reported details about the spread of disease at meat packing plants, a call center and a medical conference.

The risk of infection increases with exposure to a larger number of virus particles over a longer period of time in a smaller space with poor air flow. This is why shopping and outdoor activities are not likely to be dangerous. Breathing releases a small number of virus, between 50-5000 droplets per breath. Talking expels more and  singing is definitely a means of spreading virus. A single cough releases 3000 droplets traveling 50 miles per hour, mostly falling rapidly to the ground. In contrast a sneeze may release 30,000 droplets at 200 MPH, many of which are smaller and stay in the air longer.

Dr. Bromage writes that 44% of infections come from people who have no symptoms at the time.  The virus can be shed up to five days before a person becomes ill. Most people contract COVID from a family member who brings it home. Children are three times less likely to become ill but three times more likely to spread the virus.

I wondered if the lower barometric pressure at altitude could cause viral particles to be less compact. I called Peter Hackett, MD of the Hypoxia Institute in Telluride and he agreed that theoretically the less dense air would not carry as many particles. We also discussed antibody tests, which are still experimental, not recommended and difficult to interpret. The population screened in Telluride showed a 0.5% positive rate, but when a disease has a low prevalence there are more false positives. They did blood tests on some 5,000 people early in the outbreak. They were not able to repeat the serology due to staffing problems at the lab where many technicians contracted the illness.

My advice is to wear masks anytime you are out of the house, except if you are biking, hiking, running where the viral particles will be dissipated rapidly. Wearing a mask during these activities is still a kind gesture  to reduce the anxiety of others. Continue with frequent hand washing, avoid touching your face, practice social distancing, and when the churches reopen we should hum instead of sing.

COVID-19 Update: Accordion Theory and Preparing for Next Steps

Today, I am going to share news gleaned from meetings and publications that address the importance of preventive care, returning to daycare, pulse oximetry as a screening tool for COVID, and the Accordion Theory.

Every Thursday the Children’s Hospital of Colorado presents a panel of experts with updates and answers to questions.

“Your offices are the safest place in the country,” they proclaimed. With social distancing many parents and patients are delaying routine care which has led to the largest drop in vaccination rates in 50 years. This could result in outbreaks of measles, whooping cough, pneumococcal and other infections. With the loss of revenue, small clinics may go out of business, and large clinics and hospitals are laying off workers by the hundreds. If there is a large outbreak of preventable disease, on top of a resurgence of COVID, there could be a devastating shortage of providers to care for the victims. Now is the time to call your clinic and set up appointments for check ups and vaccines. If you don’t feel safe yet you can do a Telehealth visit initially and schedule the vaccines and hands-on portion of the exam in a month.

Another reason not to delay preventive care is the increase in stress, isolation, and anxiety which can cause serious depression. We had a tragic teen suicide in the county this month. Students from middle school through college should be seen annually for mental and physical health screening as well as vaccines. One mother told me that the depression screening done at our office “saved my daughter’s life.”

More daycares are opening soon. Parents are asking me whether to send their child back. These facilities follow strict public health guidelines to prevent infection. Children are not likely to be affected by COVID. Any child with symptoms should be tested. Enrollment should be diminished due to parents preferring to keep their child at home.  However, if there is a high risk family member, I advise not to return to daycare yet.

School age children should be limited to playing with friends and family members who have been part of their social circle during the last two months. To borrow a slogan from the AIDS campaign, “KNOW YOUR NETWORK”.  This is not the time to expand friendships. There will be no team sports this summer. Children should play outside and not share toys or balls.

An emergency physician in New York, Richard Levitan, published an editorial in the NY Times on April 20 advocating the use of pulse oximeters to screen for COVID. Citing the many patients with low oxygen levels and abnormal x-rays who did not complain of trouble breathing, the delay in obtaining results and inaccuracy of the COVID testing, he sees the simple pulse oximeter as a source of immediate information as to who needs medical attention. I’ve been speaking and writing about this for weeks.

Finally, one of the panelists at Children’s mentioned the accordion phenomenon. As we reduce social distancing restrictions and open commerce and travel, there will inevitably be more cases of COVID. It is likely that restrictions will be imposed again, and this may occur in cycles during the next year(s). We may be able to decrease future shutdowns by wearing masks and gloves when we go out, using hand sanitizer, soap and water, not touching our face, covering our coughs and sneezes, and limiting exposure to large groups of people. I hope all these will be permanent behavior changes except the masks and the large groups (I love the Lake Dillon Amphitheater and the BBQ challenge).

Take care, stay engaged, and have another safe week!

COVID-19: Where Are We At Now?

A panel of experts at the University of Colorado School of Medicine had some good news this morning: we may have passed our peak here in Colorado.

Of the 8,675 cases there are 374 deaths. Less than 2% of those with the illness are under age 18, compared to the population of 22% children. This week there are only 4 children admitted to Children’s hospital with COVID-19, two in the ICU. There is a leveling-off of patients presenting to the hospitals and less ICU admissions.

So social distancing has flattened the curve and no hospitals were overextended or lacked ventilators. The initial R naught (the number of people infected from one individual) of each infected person spreading to 4 is now down to 1.5. A study from Singapore showed that 7% of cases came from presymptomatic persons. The infection can be transmitted 2 to 3 days before symptoms show. Of 121 healthcare workers exposed 35% developed symptoms but only 2.5% tested positive.

Our own experience with testing has been equally frustrating. The virus can be present for weeks but usually rapidly declines after 7 days. The PCR test (polymerase chain reaction test – the standard nasal swab being conducted to test for Corona virus) is said to be 75% accurate in detecting viral RNA. Even patients we’ve tested during the first 4 days of typical symptoms have been negative. Other viruses identified at Children’s Hospital in the last month include rhinovirus, adenovirus, enterovirus and human metapneumovirus, which can all cause fevers and respiratory illnesses.

However, many people we are treating have the unusual symptoms and course that seems unique to COVID. Not all have fever. They experience chills, fatigue, sore throat, then improve. A day later they are having chest tightness, trouble breathing, making it difficult to talk or walk, and upper abdominal pain. They feel worse at night and better in the morning. Symptoms can last for weeks. Lung specialists describe several different effects the virus can have. ARDS (adult respiratory distress syndrome) is a diffuse loss of protective protein that causes the air sacs to collapse. The pulmonary disease in the second week is described as a cytokine storm, where the immune system overreacts and damages the lungs.

Testing is less accurate when the prevalence of a disease is low. In Colorado 1.4% have been affected, in comparison with Wuhan where 5-10% were. Experts and individuals are waiting for antibody testing to see if they are immune and if so for how long. Immunity in similar infections has been shown to last anywhere between 3 weeks and 3 months, as opposed to diseases like measles and chickenpox which confer lifelong immunity.

Pediatricians are seeing few patients in the office these days, which raises the concern for a future epidemic of preventable diseases from a delay in vaccinations. Most clinics, like Ebert Family Clinic, are only seeing healthy patients or those with noninfectious complaints such as eczema and lacerations. Anyone with respiratory symptoms or fever is seen by Telehealth. This is effective because COVID, like most illnesses in the community, is usually mild and self-limited. Antibiotics are rarely indicated. A recent study showed that of several hundred children diagnosed with community-acquired pneumonia, those given antibiotics had the same outcomes at those who were not treated, with 4% of each group needing hospitalization for worsening symptoms.

Telehealth does not allow for auscultation of the heart and lungs (listening with a stethoscope), but the vital signs including oxygen saturation, heart rate and temperature along with the patient’s history usually give the provider enough information to make treatment and testing decisions. A face-to-face video interaction is ideal, protecting the patient and provider from exposure to infection. The expanded use of Telehealth is one of the good outcomes of this pandemic, especially in states like Colorado with far flung rural populations.

 The University of Colorado is doing 3000 telehealth visits daily. Specialists at Children’s are ramping up their services online while accepting the sickest patients in the state for inpatient care. They have the largest number of doctors in Colorado, many of whom are in research and can transfer to frontline and ICU duties. The University does 500 million dollars of sponsored research every year, with over 1000 studies. Many of these are on hold now, but with the capacity to initiate new trials within a week and laboratories adjacent to clinical care sites, CU has been tapped for many COVID-related studies. They are testing several antiviral drugs, including the new product from Gilead laboratories Remdesivir. There are also studies on disease modifying treatments such as steroids to prevent future problems caused by the infection. Other trials focus on sample collecting and processing. Some studies may show results within weeks but others take months or years to determine effect.

The University was one of the first centers to use convalescent plasma to treat COVID. The hope is that antibodies from previously-infected and recovered individuals can be lifesaving for severe cases, although the best timing of such treatment, originally used one hundred years ago in the influenza epidemic, is not yet determined. Plasma donations can be arranged by visiting the UC Health website. Since most people will not need hospitalization, instructions for home care can be found on the CDC website.

Vaccine development will proceed over the next 12 months. Until then, lifting of current social restrictions will depend upon having adequate and accurate testing to find cases early enough to quarantine patients and public health workers to trace contacts. Antibody testing must be done and repeated over months and years to determine susceptibility. Continued use of masks in public and the prohibition of large gatherings may continue for a year.

COVID VS HAPE: Experts Analyze Effect on Lungs

Dr. Chris with Dr. Eric Swenson from the University of Washington

An article published yesterday, April 13, 2020 in the Journal of High Altitude Medicine and Biology clarifies misconceptions in the media comparing high altitude pulmonary edema (HAPE)and COVID lung injury. The six authors include two critical care pulmonologists from the University of Washington: Andrew Luk MD and Eric Swenson MD, as well as Peter Hackett MD of the Hypoxia Institute in Telluride and the University of Colorado Altitude Research Center. Dr. Swenson is the editor of the journal and has given presentations in Summit County on altitude. Both Dr. Hackett and Dr. Swenson personally communicated with Dr. Chris yesterday.

Dr. Chris with Dr. Peter Hackett of the Hypoxia Institute in Telluride, CO

Severe viral pneumonia, as seen in COVID-19, can cause Adult Respiratory Distress Syndrome (ARDS) leading to respiratory failure and the need for ventilator support. As with HAPE, this is a form of non-cardiogenic pulmonary edema, where the air sacs in the lung fill with fluid due to conditions not related to heart failure, the most common cause of pulmonary edema. Other causes include bacterial pneumonia, near-drowning, nervous system conditions, re-expansion, and negative pressure edema. Radiographic findings are similar in all these cases with diffuse bilateral densities in the lungs. All these patients have severe hypoxia.

At altitude, hypoxia can lead to uneven pulmonary vascular constriction, (hypoxic pulmonary vasoconstriction or HPV). In the areas with the highest pressure, fluid leaks from capillaries into the alveoli. With COVID, alveolar inflammation reduces the protein surfactant that maintains expansion of the alveoli. The alveolar collapse causes hypoxemia, low blood oxygen. Severe viral and bacterial infections also cause inflammation in other organs, such as the liver, kidneys, and brain, which is not seen with HAPE.

Medications used to treat HAPE are not likely to be useful in treating COVID pneumonia and may have harmful effects such as increasing perfusion to damaged areas of the lung that are not oxygenated.

Both these conditions likely have large numbers of patients with mild symptoms who recover without seeing a medical provider. However, both HAPE and COVID can cause a sudden, rapid deterioration with severe hypoxia and death.

ACCESS TO A PULSE OXIMETER TO TRACK OXYGEN SATURATION IS VITAL.

Oxygen levels below 90% merit medical attention. Pulse oximeters can be purchased online, at drug stores, or at Ebert Family Clinic.

Doc Talk with Cardiologist Dr. Pete Lemis

Dr. Peter Lemis is a cardiologist in Summit County, CO. He sat down with us in December to share his experience treating heart patients in the mountains.

Summit County cardiologist Dr. Pete Lemis

I graduated medical school in ‘77, practiced internal medicine in New Rochelle, New York, the first county just north of the Bronx. Then I went to New Hampshire for three years. I was reading the New England Journal and saw an unexpected cardiology opening at Henry Ford Hospital in Detroit. Next I was in Pittsburg for 26 years practicing cardiology. Decided I wanted to retire to Colorado, so I built a vacation home here only to discover I didn’t have to wait to retire to move here, so I came five years ago. 

What is it about high altitude and the heart that makes it healthy for heart patients?

Summit is the fifth highest county in the US with the highest population of those counties. The 21 highest are all in Colorado. Lower air pressure means that although there is 21% oxygen in the atmosphere, there are fewer oxygen molecules. So every breath we take is giving us less oxygen, unless we breathe faster and deeper to make up for it, a natural tendency for people. They don’t even think about it. Some people have hypoxia without shortness of breath. Every once in a while, I’ll see a patient who moved to altitude for work or something, and they’re hypoxic. It is probably genetic that some people have a decreased central respiratory drive. 

These patients with low oxygen often are ordered to have an echocardiogram. When they first come up here, they usually won’t have pulmonary hypertension. For some, the decreased central respiratory drive develops not when they first move here, but years after they move here. They become more and more hypoxic without having the feeling of shortness of breath. They have the same physiological response that people with hypoxia get. Their pulmonary vessels are still being constricted, which is reversible if diagnosed and treated with oxygen supplementation during the first few years of high altitude living. If not treated they are likely to get scarring of their pulmonary vessels. The length of time for this to develop is different for different people, and is unpredictable.

For example, I had somebody just this week who’s been here about 2 years who has a resting oxygen saturation of about 82% at 60 years old. 

We can’t tell who is susceptible to this problem. There are likely some genetic factors involved. Dr. Johnson, who recruited me for my job in Summit County, has been here since 2008. He warned me about the issue of high altitude and hypoxia. Most doctors who are unfamiliar with life at high altitude think you adapt and that’s it. Dr. Johnson said to me, “wait three months and test yourself and your wife with an overnight oximetry to see if there’s hypoxia.” Based on that test I started using nocturnal oxygen and I sleep better when I use it. My wife doesn’t need it. Neither does her mother, who is 90 years old. Neither do my sons.

Awake, we’re able to maintain our oxygen levels, but at night when asleep most people who are here in Summit County have low oxygen. Hence my advice is to get a nocturnal pulse oximetry test. Low oxygen for several hours every night over the years can lead to pulmonary hypertension due to the narrowing of the pulmonary arteries. Then there is the question of what is normal: most high altitude studies were done in La Paz with indigenous, adapted populations as opposed to people living in the mountains of Colorado who have been here years or decades. (See what Dr. Chris has written on her collaboration with physicians and scientists in La Paz, Bolivia.)

We asked Dr. Lemis about arrhythmias at altitude. There are two categories-atrial (from the top chamber) and ventricular (from the bottom chamber).

Studies have shown that cardiac arrhythmias are increased initially, but people become acclimated after about 3 – 5 days and the risk returns to baseline. I don’t think these studies have been conducted over enough time. Hypoxia leads to an increase in arrhythmias. I see a lot of atrial fibrillation  and atrial flutter up here; plus, I send three to four patients a month for an electrical procedure to ablate some of the cardiac conduction pathways to get rid of their arrhythmias. Many patients experience relief from atrial arrhythmias when put on nocturnal oxygen.

JB is a 70 year old who has lived at high altitude for 14 years. He experienced atrial fibrillation several times after returning to Summit County from a trip to sea level. He wore a heart monitor for over a month to see how his heart was beating. He felt the atrial fibrillation was related to dehydration and has prevented further episodes, never needing a pacemaker or other treatment. Jim uses a device that monitors his oxygen and heart rate continually while he sleeps, downloading a written report in the morning.

Why do so many people who live up here have bradycardia?

I think because many are athletes. Athletes often have an efficient heart; I see just as many people who have tachycardia because they have low oxygen. Low oxygen causes higher levels of epinephrine. This stimulates their adrenal gland, which can increase their blood pressure. Many people have high blood pressure at high altitude because they have low oxygen. One of my criteria for testing someone for low oxygen at night is if they have high blood pressure.

Many people have central apnea during sleep at altitude caused by the brain’s blunted response to high CO2 and low O2. Similar to obstructive sleep apnea, this central sleep apnea can increase the risk of heart problems. Many people with obstructive sleep apnea here at high altitude need to have oxygen put into their CPAP machine so they get oxygen, rather than just air with continuous positive airway pressure.

There is less fatal ischemic heart disease up here. People tend to be healthier, more athletic. They’ve moved here for an active lifestyle. There’s less cigarette smoking, more exercise, generally better diet (not always), but people up here still have heart attacks. My impression is more of them survive their heart attacks because of their increased physical activity and healthy lifestyle. They have better collateral flow with more capillaries in the heart. They’re protected to some degree. The corollary to this is the fact that when visitors come here and have heart disease, I don’t think that their cardiologist back at low altitude understands high altitude risks and therefore are unable to provide appropriate medical advice. The same amount of exertion here is much harder on the heart, much more stressful to the heart, than it would be at low altitude. There’s something called a double product when you do an exercise test, related to blood pressure and heart rates. You get the same double product causing the same stress on the heart here as at low altitude, but it takes much less exertion to get to a specific double product. 

People who are accustomed to a certain work load at home come up here and try to do the same amount of exertion. If they have coronary artery disease, suddenly there is a middle aged guy with coronary disease having a cardiac ischemic event, perhaps even sudden cardiac death. 

Another important point is that people with known heart disease who live at low altitude, if they’re unstable at all, they shouldn’t be up here within three to six weeks of a heart attack. They should be able to pass a stress test at low altitude before coming to high altitude to visit.

Valvular heart disease patients who have not been treated with surgery, who don’t already live up here, shouldn’t come up here from lower altitude. People with heart failure can come up here if the failure is compensated.

For people who have trouble acclimating to high altitude in the short term, Diamox is quite useful. Using oxygen at night helps you acclimate as well. Diamox makes your blood a little acidotic which increases your respiratory drive.

Avoid alcohol when you first come to high altitude. Unfortunately people on vacation don’t do that. Alcohol is a respiratory suppressant. At high altitude the hypoxia and cold promotes diuresis, so people tend to get dehydrated. Anti-inflammatory drugs are useful in treating the acute altitude sickness for some people. During the first two or three days, try not to push your physical activity to the limits. Try to get a good amount of sleep.

I would say that I have way fewer heart failure patients [up here]. Because patients who develop advanced heart failure really do not do well here, so they tend to move away to lower altitude before that happens. I have younger patients as compared with my former Pittsburgh practice. I also have way fewer patients with COPD. Anything that causes chronic respiratory difficulties you will find a lot less of that up here. Plus, I’m working in an environment where there are less consultants. 

Back in Pittsburg, two thirds of my practice was taking care of patients in the hospital, so I would deal with patients who would come in with a heart attack, with a heart failure exacerbation, or other acute cardiac problem. Here in Summit County, those severely ill patients get transferred down to Denver, so I provide more in-office preventive or post-illness follow-up than I do care in the hospital. My patients who need advanced procedures (e.g. heart catheters, ablation for arrhythmias), I generally send them down to our sister hospital (St. Anthony in Lakewood). 

The cardiac surgeon who will do the bypass surgery usually knows that the patient returning to the mountains will have to be on oxygen for two weeks after surgery.


Gone, Gaper, Gone:COVID-19 April 3, 2020

April 1 is traditionally celebrated in Colorado’s mountain resort communities as “Gaper Day.” Locals dress in their finest 70’s and 80’s outdoor fashions and commemorate the tourists who stop in the middle of the mountain to stare at the beauty that surrounds us. This year travel is discouraged, so the tourists are gone. Here are some local updates on the pandemic to reinforce these directives from Governor Jared Polis.

One day this week, several residents were intubated and transferred to intensive care in Denver. Physicians at St. Anthony Summit Medical Center have access to an ICU and ventilators, but patients with severe respiratory symptoms and hypoxia have a better chance at lower altitude. Let’s hope the day doesn’t come when the Denver hospitals are full, leaving us no choice but to provide this care locally in our low-oxygen environment.

As of April 3, 29 people in have been hospitalized with COVID illnesses, ranging in ages from 20’s to 60’s. There have been 43 confirmed cases in Summit County, according to the Summit Daily News.   It’s here, it’s real, it’s dangerous to all.

Follow the footprints of the fox.

EVERYONE LIVING AT ALTITUDE SHOULD HAVE ACCESS TO A PULSE OXIMETER. You can buy this simple instrument at the pharmacies or call Ebert Family Clinic. You don’t need to go to the hospital if you are breathing normally and your oxygen is above 88%. You can call your doctor or the Ebert Family Clinic for a Telehealth assessment and advice. Our nurse practitioner Tara Taylor will be available 7 days a week between 9 am and 5 pm and Dr. Chris will answer calls and texts for parents and children 24/7. We all know to keep washing our hands: the Corona virus hates soap. Don’t touch your face.

And now I’m going to endorse recommendations from New York and other hard-hit locations: wear a mask and gloves when you go shopping. A bandana, ski mask, surgical mask, anything that reduces the spray of droplets from your mouth and the chance you will inhale these from others.  We are all wearing gloves to keep our hands warm this time of year anyways.

For your mental and physical health, get outside every day. Walk around your neighborhood. Exercise stimulates the immune system. Sunlight helps prevent depression. Look up at the mountains. Gaze at the stars. Let us all be gapers.

First tracks on the track.

A Sea-Level Dweller Climbs Cotopaxi

During the winter of 2018, the Little Rock Climbing Center Alpine team ventured south to Ecuador for a mountaineering expedition. However, poor weather and high avalanche risk thwarted our summit attempts of Cayambe (18,996’, 5789 m) and Cotopaxi (19,347’, 5896 m). This winter (2019), we returned to Ecuador to attempt to summit Cotopaxi again, with a new and improved acclimatization plan and high hopes for better weather. Little Rock, AR sits at a mere 335 ft (102 m) above sea level … but we are lucky to have Pinnacle Mountain, with 750’ (228 m) of elevation gain to train on. A small mountain is better than no mountain!  My training plan entailed hiking Pinnacle Mtn 2-3 times during the week, and then hiking or mountain biking on the weekend for approximately 3 months. I also rock climbed at the climbing gym 2 days a week, but Cotopaxi is not a technical climb, so that was mostly for fun.  I took a week-long trip out to Colorado in September to reassess how my body reacts to high altitude.  During this week we rock climbed in Boulder Canyon, Idaho Falls, and climbed the first and second Flat Irons, as well as hiked up to Sky Pond at Rocky Mountain National Park, hiked Mt. Bierstadt, and hiked out to Crystal Mill with Dr. Chris. I chose not to run too much this year for training because I have a meniscal tear in my left knee that gets aggravated on long runs. 

We arrived in Quito, the capitol of Ecuador on December 30. Quito sits at 9,350’ (2849 m), so we took our first day pretty easy, and walked from our hotel to the older part of town with historic churches and cathedrals. Walking up the many flights of stairs in the Basilica del Voto Nacional got my heart pumping and legs and lungs burning! New Year’s Eve in the La Mariscal area of Quito was quite entertaining and a little rowdy, with fireworks, burning of effigies, and jumping over the fires. Our first day hike was up Rucu Pichincha (15,413’, 4697 m), a stratovolcano right in Quito! The TeleferiQo (a gondola) brings you up to 12,943’ (3945 m) where you begin the hike. The hike up Rucu Pichincha starts out mellow, on smooth trail with short steep, punchy climbs. Once you near the top, the steepness increases and the last few hundred feet involve very easy scrambling on sharp volcanic rock. The winter in Ecuador is typically the rainy season, so scattered showers and electrical storms are very common. However, we lucked out with perfect weather on Rucu Pichincha, and fantastic views of the big mountains – Cotopaxi, Antisana, and Chimborazo. The next day we drove to the base of the Ilinizas, and just missed the horse that was supposed to carry our packs up to the refugio. It was about a 3,000’ (914 m) climb up to Refugio Nuevos Horizontes, in relentless wind and dense fog. About half way up to the refugio, a lone figure emerged out of the fog. The horse that was supposed to carry out gear was carefully making his way down the mountain, such a surreal sight! We spent the night sharing bunk beds, packed like sardines in the tiny refugio (15, 696’, 4784 m). The next morning, the wind hadn’t let up, and the fog was still suffocatingly thick. A few groups had attempted an early morning ascent of Iliniza Norte, but said it was too icy and windy to summit. Our mountain guide, Alejo, suggested we traverse around the backside of Iliniza Norte to avoid the worst of the wind, and his advice was on point. The wind was whipping so hard at the summit (16,818’, 5126 m), we spent less than 5 minutes on top before beginning our decent back to the car. The wind was so strong on our descent (upwards of 60mph!), it knocked me off my feet several times. Next time I will use my hiking poles when it is so windy! We spent the next day resting and recuperating at Los Mortinos Hacienda, a cozy B&B at the edge of Cotopaxi National Park where we watched llamas graze, went horseback riding, and dined on fresh trout from a nearby river. 

The next day we drove up to the Cotopaxi parking lot, and slogged up the soft, ashy trail for an hour or so before reaching Refugio Jose Rivas (15,744’, 4798 m) at the base of Cotopaxi. At the refugio we ate some dinner, hydrated, and then tried to rest as much as possible. Alejo woke us up at 10pm and by 11pm we were on our way up the volcano. The skies were finally clear and calm after days of clouds and windy weather, all of the stars were out and we watched an impressive lightning storm down in Quito. We began the trek in mountaineering boots as the glacier starts about two hours uphill. While I felt fine the day before hiking up to the refugio, I had a pretty decent headache when we woke up. My right foot kept falling asleep in my mountaineering boot, and I was starting to overheat because I had too many layers on. This was the first time on the trip that I felt bad, and doubts about a successful summit started to creep in my mind. Alejo asked if I wanted to turn around, but even though I didn’t feel good, I didn’t feel bad enough to turn around. After about two hours of hiking, we reached the glacier and donned our crampons. And then I started to finally feel GOOD! As long as I kept switching my stepping technique, alternating between duck-footing, side-stepping, and French technique, my right foot wouldn’t fall asleep. The higher we climbed, the better I felt! About an hour away from the summit is when it really began to get steep. Alejo said it would be really steep, then a little easier, and then really steep again. We trudged on. And it got steep — really, REALLY steep. Just keep moving. Step up, rest, step up again, rest. Repeat. The mountain seemed to keep going up and up and up. But then around 8am we were at the top of Cotopaxi! I had seen photos of the summit, but seeing smoke coming out of the crater with my own eyes was mind-blowing. We ACTUALLY made it! We waited for Ian and his guide to summit, and then spent the better part of an hour taking photos and enjoying what Alejo said was the nicest weather he’d ever experienced at the summit. 

Ian brought along an Accumed Pulse Oximeter, so being the science nerd that I am, I measured my oxygen saturation percentage at various elevations over the course of the trip. While the percentage of oxygen in the air is the same, the fall in atmospheric pressure at high altitude decreases the driving pressure for gas exchange in the lungs, leading to lower oxygen saturation levels.  I measured my oxygen saturation level on my right index finger after being seated for approximately 5 minutes. The Accumed Pulse Oximeter is a small battery-powered device that measures the ratio of red light and infra-red light that is absorbed through the finger to calculate oxygen saturation levels.

Here is a table of my oxygen saturation levels at various elevations throughout the trip:

Day Location Elevation  (ft/m) O2 saturation (%)
1 Quito 9,350/2849 80
2 Summit of Rucu Pichincha 15,413/4697 75
3 Refugio Nuevos Horizontes 15, 696/4784 74
7 Summit of Cotopaxi 19,347/5896 57

Before reading too much into this very limited data set, there are a number of limitations with these observations I would like to point out. First, sample size is very limited, and I only took one reading at each elevation.  Second, pocket pulse oximeters are not very accurate below oxygen saturation levels of 70%, and ambient light interference (as we experienced at the summits of Rucu Pichincha and Cotopaxi) can interfere with accuracy. Also, the literature suggests that pulse oximetry utility is limited in diagnosis of acute mountain sickness, and that measuring oxygen saturation after light exercise compared to rest may be more predictive of acute mountain sickness. I believe that I did not experience altitude sickness at any point during this trip. I had a mild headache after sleeping above 15,000’ (4572 m), but that resolved once we started hiking up the mountain. We stayed at the summit of Cotopaxi for approximately 1 hr, and while I had a slight headache and was day-dreaming (more than usual), I felt pretty good overall and had no problems on the descent. Pulse oximetry is painless and non-invasive, and can be a useful tool in evaluating respiratory and other complaints at high altitude, but care should be taken to minimize erroneous measurements to avoid misinterpreting the data.

Keshari Thakali, PhD is an Assistant Professor in the Department of Pediatrics at the University of Arkansas for Medical Sciences in Little Rock, AR. She is a cardiovascular pharmacologist by training and her research laboratory studies how maternal obesity during pregnancy programs cardiovascular disease in offspring. When not at work, you can find her mountain biking, rock climbing, hiking or paddling somewhere in The Natural State. She has a long-term career goal of merging her interests in mountaineering with studying cardiovascular adaptations at high altitude, and would appreciate any tips on how to accomplish this!

La Paz: Healthy Living At 12,000 feet

Dr Gustavo Zubieta-Calleja explains how lessons learned in La Paz can make space exploration easier

I just returned from the “Chronic Hypoxia” conference in La Paz, Bolivia at 12,000 feet elevation (3,640 m). The sponsor and organizers were Drs. Gustavo Zubieta-Calleja and his daughter Natalia Zubieta De Urioste who run the Institute of High Altitude Pulmonology and Pathology there. Presenters and attendees came from 16 countries covering topics ranging from molecular biology to genetics.
Dr. Zubieta previously published a scientific analysis of centenarians living at various altitudes. He compared Santa Cruz, Bolivia, at sea level, with La Paz/El Alto, each with populations of over three million, and found there are eight times more people over 100 years old at high altitude. (BLDE University Journal of Health Sciences, see blog post 1/5/18) Since his father Gustavo Zubieto Castillo founded the institute in 1970, they have been advocates of the health promoting effects of a low oxygen environment.
A presentation on “BioSpaceForming” even identifies chronic hypoxia as a “fundamental tool”, that “gives humans and other species an advantage on earth and beyond.” Dr Zubieta explained that the space station is engineered to have the barometric pressure (760 mmHg) and oxygen content of sea level. When the astronauts change into their space suits to work outside the ship they experience a pressure drop of over 200 mm Hg in a laborious process of donning the suit. Seeing that millions of inhabitants are healthy at 486 mm HG in Bolivia, he advocates that maintaining lower pressures and lower oxygen levels in the space station would be economical and promote the health of the astronauts. Several altitude scientists see this as a future that “uncouples biology and physics.