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
Acclimation, Altitude Science, Athletic Training, Exposure, Health, High Altitude, High Altitude Training & Fitness, Hyperbaric Therapy, Medicine, Mountaineering

Pressure as Prevention: Can Hyperbaric Oxygen Help You Beat Altitude?

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Pictured above is the highest hyperbaric chamber in the world at the Bolivian Naval Station at Lake Titicaca.

If you’ve ever climbed high enough to feel short of breath, dizzy, or just “off,” you’ve likely experienced the effects of high altitude on the human body. Once you get above about 2,500 meters (8,200 feet), the air gets “thinner”—not because oxygen disappears, but because there’s less pressure pushing oxygen into your body. This particular problem is termed hypobaric hypoxia, and it can turn a beautiful mountain adventure into a medical problem quickly.

Why Altitude Hits So Hard

At elevation, your body is forced to adapt fast—and sometimes it isn’t able to keep up. That’s when altitude illness can develop, ranging from mild to life-threatening ailments:

  • Acute Mountain Sickness (AMS): headache, nausea, fatigue
  • High-Altitude Pulmonary Edema (HAPE): fluid in the lungs, causing shortness of breath
  • High-Altitude Cerebral Edema (HACE): brain swelling, confusion, and potentially coma

These aren’t separate diseases so much as a continuum of worsening hypoxia. Most severe cases can start as mild symptoms and can later progress to more severe presentations. The quicker you can recognize the more subtle symptoms, the better you may be in avoding severe illness. 

What’s Happening Inside the Body?

When oxygen levels drop, the body goes into survival mode:

  • Blood vessels in the lungs constrict → raising pressure (risk of HAPE)
  • Blood vessels in the brain become leaky → swelling (risk of HACE)
  • Inflammatory and hormonal systems ramp up → causing AMS symptoms

In short: your body is trying to compensate in response to the change in environment, but sometimes those compensations backfire.

Enter Hyperbaric Oxygen Therapy (HBOT)…

Now imagine flipping the script. Instead of struggling in thin air, what if you could flood your body with oxygen under pressure? That’s exactly what Hyperbaric Oxygen Therapy (HBOT) does. Inside a pressurized chamber, you breathe 100% oxygen, dramatically increasing how much oxygen dissolves into your blood. In a way you have artificially placed yourself in a lower altitude. 

How HBOT Helps at Altitude

HBOT essentially acts like a “simulated descent”—one of the most important treatments for altitude illness.

It can:

  • Boost oxygen levels in your blood and tissues
  • Improve brain function in hypoxic states
  • Reduce inflammation and oxidative stress
  • Potentially stabilize the blood–brain barrier

In wilderness medicine and EMS settings, portable hyperbaric chambers are already used when immediate descent isn’t possible. They can be lifesaving.

But there’s a catch: The benefits are temporary. Once the pressure is removed, symptoms can return if the person is still at altitude where their symptoms first started.

A New Idea: Can HBOT Be Used Before You Climb?

Here’s where things get interesting. Researchers are now exploring whether HBOT could be used not just as treatment—but as preparation.

The concept: preconditioning

The idea is that repeated exposure to hyperbaric oxygen before ascent might “train” the body to handle low-oxygen environments better—similar to acclimatization.

Potential effects include:

  • Activation of hypoxia-response pathways (like HIF)
  • Improved mitochondrial efficiency (better energy use)
  • Increased antioxidant defenses
  • Enhanced microcirculation

In theory, this could mean: fewer symptoms, better performance, and lower risk of severe altitude illness

What Does the Evidence Say?

Early research is promising, but not definitive.

Some studies suggest:

  • Reduced incidence and severity of AMS
  • Better oxygen saturation at altitude
  • Possible protection against brain and lung edema

But there are still big unknowns:

  • What pressure and duration work best?
  • How long before ascent should HBOT be done?
  • Who benefits most—athletes, mountaineers, or everyone?

For now, HBOT preconditioning is an exciting idea—not standard practice.

What About Athletes and High Performers?

Altitude is a major challenge for:

  • Endurance athletes
  • Military personnel
  • Search and rescue teams
  • Mountaineers

Performance drops quickly due to:

  • Lower VO₂ max
  • Faster fatigue
  • Impaired decision-making

HBOT might help by:

  • Improving oxygen efficiency
  • Preserving cognitive function
  • Delaying fatigue

But again—this is still being studied, and access to HBOT can be limited and expensive.

How Does HBOT Compare to Proven Strategies?

Right now, the gold standard hasn’t changed:

  • Gradual ascent → still the most effective prevention
  • Acetazolamide → helps your body acclimate faster
  • Dexamethasone → used in higher-risk situations

HBOT (for prevention) is still catching up in terms of evidence.

Is HBOT Risk-Free?

Not entirely. While generally safe, it can cause: ear or lung barotrauma (due to pressure-related injury), oxygen toxicity (rare but serious), and can lead to increased oxidative stress with overuse. These risks matter more when using HBOT proactively rather than as a rescue therapy.

Where This Is Headed

HBOT sits at a fascinating intersection of performance, medicine, and physiology.

Future research is looking to focus on finding optimal preconditioning protocols like treatment duration and number of set times. Some other areas also include identifying which patient populations would benefit most from this form of treatment and combining HBOT with other strategies like hypoxic training.

Bottom Line…

Hyperbaric oxygen therapy is already a powerful tool for treating severe altitude illness, especially when descent from altitude isn’t immediately possible.

As a preventive strategy, it shows real promise, but it’s not ready to replace the fundamentals.

For now, your best defense at altitude is still:

  • Climb gradually
  • Know the symptoms and have a buddy!
  • Use proven medications when appropriate (like Acetazolamide)

HBOT may one day become part of the toolkit—but for now, it’s a high-potential frontier, not a first-line solution.

References 

Centers for Disease Control and Prevention. (2023). High-altitude travel and altitude illness. https://www.cdc.gov/travel/page/high-altitude-travel

National Center for Biotechnology Information. (2023). High-altitude illness. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK430716/

National Center for Biotechnology Information. (2023). Hyperbaric oxygen therapy. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK459172/

PubMed Central. (2020). Hyperbaric oxygen therapy: Mechanisms and clinical applications. https://www.ncbi.nlm.nih.gov/pmc/articles/PMCPubMed Central. (2018). Pathophysiology, prevention, and treatment of high-altitude illness. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC

Wilderness Medical Society. (2019). Wilderness Medical Society clinical practice guidelines for the prevention and treatment of acute altitude illness. Wilderness & Environmental Medicine, 30(4), S3–S18. https://doi.org/10.1016/j.wem.2019.04.006

Hackett, Peter H., & Roach, Robert C.. (2001). High-altitude illness. New England Journal of Medicine, 345(2), 107–114. https://doi.org/10.1056/NEJM200107123450206

Bärtsch, Peter, & Swenson, Erik R.. (2013). Acute high-altitude illnesses. New England Journal of Medicine, 368(24), 2294–2302. https://doi.org/10.1056/NEJMra1214870

Moon, Richard E.. (2019). Hyperbaric oxygen therapy indications. Undersea & Hyperbaric Medicine, 46(3), 425–430.

Milledge, James S., West, John B., & Schoene, Robert B.. (2013). High altitude medicine and physiology (5th ed.). CRC Press.

Dylan Raulie was born and raised in Colorado Springs, Colorado and went out of state for his undergraduate years at Creighton University in Omaha, Nebraska, trading mountains for cornfields and altitude for attitude … from the wind. He got a Bachelor’s of Science in Emergency Medical Services majoring in sirens, stress, and 2 a.m. calls. After studying and learning about what could go wrong with future patients, he would often times avoid trying to become one on his interscholastic rugby team. He worked as a 911 paramedic in Colorado Springs. Between brutal call volumes, lack of sufficient ambulances on the streets, and extreme variety in patient presentations, no day was the same.  He later earned his Master’s in Biomedical Sciences at Rocky Vista University where he developed into being a better student and lifelong learner, which directly influenced his approach as a medical student. On his days off, he is a part-time grappler (in BJJ), but a full-time adventurer, always in motion—physically and mentally.

Avalanche Safety, Backcountry, Backpacking, Exposure, High Altitude, Huts, Mountaineering, Resources

THE WAY OUT

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A TRUE STORY OF SURVIVAL IN THE HEART OF THE ROCKIES

This book by long time Colorado high country resident, writer and hut master Devon O’Neil is essential reading (or listening) for everyone who loves nature, mountains, rivers, adventure, or snow. Skillfully written to weave in  stories of tragedies and near-misses, he includes details about avalanches, frostbite, hypothermia, river raft catastrophes, mountain bike crashes and moose attacks- something for everyone!

We are including a review of this book on highaltitudehealth.com because the true story it describes is a scenario not unlike many others that have occurred (and always has the potential to play out) at so many backcountry high altitude excursions. At a recent author event with Devon at Next Page Books in Frisco, CO, the author even noted that part of the appeal and thrill of these experiences are the risks inherent in the activity, which includes, not least of all, changeability of weather and conditions in high altitude environments.

Two bright headlamps shine in darkness over snowy trail.
Headlamps of hut trip members searching for late arrivals

The main story involves a group of families from Salida, Colorado who embark on a trip to Uncle Bud’s Hut at 11,000 ft. Fathers and their teens come from a variety of backgrounds but all with some expertise in medicine, rescue, and extreme sports. When a snowstorm comes in and two of them are separated and missing the rescue team is also broad, experienced, and personally committed to finding their friends. All the family members affected by this event are skillfully and sympathetically portrayed.  Colorado readers will relate to the locations, relationships and situations.  O’Neil includes a thoughtful discussion of the risks we take in our sports and recreation and how it can affect us and our families in the years to come.

This narrative contains crucial information for staying safe as described in our blog posts about climbing fourteeners and hut trips, such as wearing layers of wear clothing that wick moisture, carrying adequate nutrition and water, using communication devices with backup power sources, strategizing fire starting materials, and avoiding dangerous wildlife.

In spite of the dangerous events described in this particular account, Devon also noted personally that his aim was not to diminish the importance of embracing the adventure of being in the outdoors in the face of risk. It is in the risks, after all, that we find so much of the thrill of every outdoor adventure.

I expect someday this book will be a movie, bringing Into Thin Air (the book by Jon Krakauer that was a hit movie) to our backyards..

Windows shine light on late sleepers in their sleeping bags at hut

Backcountry, Backpacking, Exposure, Health, High Altitude, Huts, Mountaineering, Summit Huts

Lightning Strikes in Colorado

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My love for hiking developed during my childhood explorations of the breathtaking landscapes of the Sierra Nevada. As I ventured into the rugged mountains and hiked along scenic trails, I couldn’t help but feel a deep connection with nature. However, my passion for hiking was not without its moments of caution. On several occasions, I witnessed the awe-inspiring yet intimidating power of lightning storms dancing across the vast mountain skies. These encounters instilled in me a profound curiosity about the risks associated with lightning strikes in high-altitude regions.

When I moved to Colorado for PA school, my awareness of the dangers posed by lightning strikes grew even stronger. The dramatic topography and frequent thunderstorms in Colorado amplify the risk for individuals exploring high-altitude areas. It was during my last clinical rotation at a burn unit that I had the opportunity to care for several patients who had been struck by lightning. Witnessing the effects firsthand fueled my determination to educate the public about the actionable steps they can take to stay safe during lightning storms.

Lightning strikes

​Lightning possesses an immense amount of energy, with a voltage of over 10 million volts (in comparison, most car batteries measure 12.6 V).1 Additionally, a lightning bolt reaches incredibly high temperatures, reportedly up to 30,000 Kelvin (53540.33 F).1 Lightning injuries occur in different ways, including as direct strikes, side splash, contact injuries, or ground current. 

Direct strikes are uncommon, accounting for only 5% of cases, and happen when a person is directly struck by lightning.2

Contact injuries occur when a person touches an object that is struck by lightning. 2

Side splash injuries occur when the current jumps or “splashes” from a nearby object and then follows the path of least resistance to reach the individual. These injuries make up about 1/3 of all lightning related injuries. 2

Ground current is the most prevalent cause of injury, accounting for half of all cases, and occurs when lightning strikes an object or the ground near a person and subsequently travels through the ground to reach the individual. 2

In Colorado, an average of 500,000 lightning flashes hit the ground each year. Based on data since 1980, lightning causes 2 fatalities and 12 injuries per year throughout the state.3According to data since 1980, lightning causes an average of 2 fatalities and 12 injuries annually throughout the state. 3 Colorado ranked third in the United States for the number of lightning fatalities between 2005 and 2014, as depicted in Figure 1.

Fig. 1. Lightning fatalities by state. 3

The high number of injuries attributed to lightning in Colorado can be influenced by several factors. One of these factors is the easy access to high elevation terrain, such as 14ers (mountains with a peak elevation of at least 14,000 feet). This accessibility allows inexperienced outdoor enthusiasts to venture into potentially dangerous situations due to their lack of knowledge and preparation.

For instance, individuals who are not familiar with summer weather patterns may embark on a hike above the tree line late in the day, underestimating the risk of a storm forming. This lack of understanding puts them in an exposed and perilous position should adverse weather conditions arise.

Even with thorough preparation and extensive knowledge of weather patterns, it is still possible to find oneself in a situation where you have to weather a storm. Given that a significant proportion of Colorado’s hiking trails are located above the tree line, where appropriate shelter is sparse, hikers are more susceptible to lightning strikes in these exposed areas. 

Pathophysiology of Lightning Strike Injuries

The overall ratio of lightning injuries to deaths is 10:1 and there is a 90% chance of sequelae in survivors.4 The primary mechanism of injury in lightning strikes is the passage of electrical current through the body. The high voltage and current can cause tissue damage through several mechanisms, including thermal injury, electrical burns, and mechanical disruption of tissues. The severity of the injury depends on factors such as the voltage and current of the lightning bolt, the duration of contact, and the pathway the current takes through the body.

Lightning strikes can cause various types of injuries, with cardiac and respiratory arrest being the most common fatal complications.5 The path of least resistance determines the flow of electricity through different organs in the body, with nerves being the most conductive, followed by blood, muscles, skin, fat, and bone. 5 When lightning strikes, the electrical surge can induce cardiac arrest and cessation of breathing by affecting the medullary respiratory center. As a result, most patients initially present with asystole and may progress to different types of arrhythmias, commonly ventricular fibrillation. 5

Interestingly, there have been case reports documenting successful resuscitation of lightning strike victims who were initially apneic and pulseless for as long as 15 to 30 minutes. 5This has led to the recommendation that in the immediate aftermath of a lightning strike, individuals who appear to be dead should be prioritized for treatment.

Superficial skin burns are experienced by around 90% of lightning strike victims, but deep burns are less common, occurring in less than 5% of cases. A characteristic skin manifestation of a lightning strike is the Lichtenberg figure, which is considered pathognomonic. Neurological symptoms can also occur, including keraunoparalysis, which is a transient paralysis affecting the lower limbs more than the upper limbs. This paralysis is often accompanied by sensory loss, paleness, vasoconstriction, and hypertension, and is thought to result from overstimulation of the autonomic nervous system, leading to vascular spasm. In most cases, this paralysis resolves within several hours, but in some instances, it may last up to 24 hours or cause permanent neurological damage. 5

Additionally, it is common for lightning strike victims to have a perforated tympanic membrane (eardrum) or develop cataracts immediately following the incident. These injuries to the ear and eyes are associated with the intense energy of the lightning discharge. 6

What can hikers do to stay safe?

Preparation

Monitor weather forecasts: Stay updated on weather conditions before engaging in outdoor activities, especially in areas prone to thunderstorms. Pay attention to thunderstorm warnings or watches issued by local authorities. Having a mobile or handheld NOAA Weather Radio All-Hazards (NWR) can also be helpful as it can transmit life-saving weather information at a moment’s notice. 

In Colorado most thunderstorms develop after 11 am, so it is best to plan your trip so that you are descending by late morning.7 Fig. 2 shows number of lightning fatalities by time of day in Colorado between 1980 and 2020. The vast majority take place after the 11 am threshold.

Fig. 2  Lightning fatalities in Colorado by time of day3

What to Do If Caught in a Storm

If you can hear thunder, you are close enough to be struck by lightning. Lightning can strike up to 25 miles away from the storm. 7 Once you hear thunder, if possible quickly move to a sturdy shelter (substantial building with electricity or plumbing or an enclosed, metal-topped vehicle with windows up). Avoid small shelters, such as picnic pavilions, tents, or sheds. Stay sheltered until at least 30 minutes after you hear the last clap of thunder.

Fig 3. Areas to avoid when sheltering from lightning.

If you are outdoors and cannot reach a suitable shelter, avoid open areas, hilltops, and high places that are more exposed to lightning strikes. Seek lower ground and stay away from tall objects, such as trees, poles, or metal structures. Bodies of water, including lakes, rivers, pools, and even wet ground, are conductive and increase the risk of a lightning strike. Move away from these areas during thunderstorms. Separate group members by at least 20 ft as lightning can jump up to 15 feet between objects.

​If a strike is eminent (static electricity causes hair or skin to stand on end, a smell of ozone is detected, a crackling sound is heard nearby), the current recommendation is to assume “lightning position”, pictured in Fig. 4.

Fig. 4. Lightning position8

To potentially reduce the risk of ground current injury from an imminent lightning strike, another strategy is to insulate oneself from the ground. This can be done by sitting on a pack or a rolled foam sleeping pad. However, it’s important to note that this and the lightning position should be considered a strategy of last resort and not relied upon as the primary means of prevention. Maintaining this position for an extended period can be challenging, and it’s crucial to prioritize seeking proper shelter and following established lightning safety guidelines to minimize the overall risk of injury. 5

Case Study

25 YO F presents to the Burn Unit as a transfer from Cheyenne Regional Medical Center s/p lighting strike. Patient (pt) was caught in a thunderstorm on a hike and sheltered under a tall tree. Suddenly, she felt like she was being lifted up into the air and then dropped. Pt had a brief (<5 sec) loss of consciousness (LOC). When she woke up, she was completely numb and couldn’t move any of her extremities. Witness (friend) states the lightning splashed from the tree to the pt. Pt denies hitting her head with the fall. She denies taking blood thinners. She has no past medical history (PMHx) or past surgical history (PSHx).

Physical exam 

Neuro: AOX4, No CN deficit on exam, LE paralysis resolved, LE paresthesia improving but still present

HEENT: L ruptured tympanic membrane, hearing loss on L side

CV: RRR

MSK: Soft compartments diffusely

Skin: Lichtenberg figures on bilateral LE 

Fig. 6. Lichtenberg figure on LLE

V/S: BP: 128/92, HR: 96, RR:18, SPO2: 98%, Temp 98.1F. 

CBC, CMP, troponin were all WNL. Serum hCG negative. CK mildly elevated (222) 

EKG showed NSR.

CXR, CT brain, and c-spine neg for acute injury

She was admitted to the UC Health burn center for observation with tele. Her lab work and vitals remained stable throughout her hospitalization. She was evaluated by the trauma team with a negative trauma work up. The day of discharge, she was tolerating a regular diet, ambulating and sating well on room air. She was deemed appropriate for discharge home without patient audiology and ophthalmology follow up. 

References

1. US Department of Commerce N. Understanding lightning science. National Weather Service. April 16, 2018. Accessed July 8, 2023. https://www.weather.gov/safety/lightning-science-overview. 

2. Cooper MA, Holle RL. Mechanisms of lightning injury should affect lightning safety messages. 21st International Lightning Detection Conference. April 19-20, 2010; Orlando, FL. 

3. US Department of Commerce N. Colorado Lightning statistics as compared to other states. National Weather Service. March 4, 2020. Accessed July 7, 2023.https://www.weather.gov/pub/Colorado_ltg_ranking. 

4. US Department of Commerce N. How dangerous is lightning? National Weather Service. March 12, 2019. Accessed July 8, 2023. https://www.weather.gov/safety/lightning-odds. 

5. Chris Davis, MD; Anna Engeln, MD; Eric L. Johnson, MD; Scott E. McIntosh, MD, MPH; Ken Zafren, MD; Arthur A. Islas, MD, MPH; Christopher McStay, MD; William R. Smith, MD; Tracy Cushing, MD, MPH. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Lightning Injuries: 2014 Update. WILDERNESS & ENVIRONMENTAL MEDICINE. 2014; 25, S86–S95 

6. Flaherty G, Daly J. When lightning strikes: reducing the risk of injury to high-altitude trekkers during thunderstorms. Academic.oup.com. Accessed July 8, 2023. https://academic.oup.com/jtm/article/23/1/tav007/2635599. 

7. NWS Colorado Offices – Boulder G. Colorado Lightning Awareness Week june 19-25, 2022. ArcGIS StoryMaps. June 25, 2022. Accessed July 8, 2023. https://storymaps.arcgis.com/stories/11d021f1b800429a869ead2dc32c0f96. 

8. McKay B and K. How to survive A lightning strike: An illustrated guide. The Art of Manliness. April 25, 2022. Accessed July 8, 2023. https://www.artofmanliness.com/skills/outdoor-survival/how-to-survive-a-lightning-strike-an-illustrated-guide/. 

A woman with long, light brown hair over her shoulders wearing a blue, sleeveless shirt with red details smiles with blue eyes.

Sophia Ruef is a Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up on the central coast of California and earned her Bachelor of Science degree inBiology with a concentration in anatomy and physiology from Cal Poly San Luis Obispo. She worked as an EMT and a tech in the Bay Area after her undergraduate education. In her free time, she enjoys hiking, backpacking, canyoneering, and spending time with family and friends.

Accessibility, Acclimation, Altitude Science, Athletic Training, Genetics, Health, High Altitude

Peak Performance: Coach wants a Blood Test

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Iron Deficiency without Anemia in Individuals Living at Altitude 

Madeline Larson, PA-S2

People living at high altitude typically have higher hemoglobin levels compared to those at sea level. This physiological adaptation occurs due to the lower oxygen availability at high elevations which stimulates the production of erythropoietin, a hormone that prompts the bone marrow to produce more red blood cells made famous by the Lance Armstrong blood-doping scandal. Hemoglobin, the protein in red blood cells that carries oxygen, thus increases to enhance the blood’s oxygen-carrying capacity. This adaptation helps individuals efficiently transport oxygen to tissues despite the reduced atmospheric pressure. Over time, this increased hemoglobin level helps maintain adequate oxygen delivery to vital organs, supporting overall health and physical performance in the challenging high-altitude environment.

Despite this natural adaptation of increased hemoglobin levels, people living at high altitude are still susceptible to anemia. Chronic exposure to lower oxygen levels can sometimes lead to a condition where the body’s capacity to produce red blood cells is insufficient to meet increased demands. This can be due to various factors, including inadequate dietary iron, vitamin deficiencies, or underlying health conditions that impair red blood cell production or lifespan. Additionally, individuals who move to high altitudes without sufficient acclimatization may experience a temporary drop in hemoglobin levels until their bodies adjust. Addressing anemia in such environments often involves a combination of dietary adjustments, supplementation, and medical interventions to ensure that the red blood cell count remains adequate to maintain optimal oxygen transport and overall health.

In people living at high altitudes, the threshold for diagnosing anemia is often adjusted to account for the lower oxygen levels in the environment. At high altitudes, the normal range for hemoglobin and hematocrit levels can be higher due to the body’s adaptation to reduced oxygen levels.

For example:

  • Hemoglobin Threshold: At sea level, anemia is commonly defined as a hemoglobin level below 13.0 grams per deciliter (g/dL) in men and 12.0 g/dL in women. In high-altitude areas, these thresholds might be higher. For instance, at elevations above 2,500 meters (8,200 feet), a hemoglobin level of around 14.0 g/dL in men and 13.0 g/dL in women might be considered the lower limit of normal.
  • Hematocrit Threshold: Similarly, normal hematocrit levels are adjusted. At sea level, anemia is typically diagnosed with hematocrit levels below 39% in men and 36% in women. At high altitudes, these values might be adjusted to about 42% for men and 40% for women.

These adjustments are necessary because high-altitude residents tend to have higher hemoglobin and hematocrit levels as a physiological response to lower oxygen availability. If someone at high altitude presents with symptoms of anemia but has hemoglobin or hematocrit levels within the high-altitude normal range, further evaluation might be needed to assess their overall health and adapt to the specific altitude.

Understanding Iron Deficiency Without Anemia: What You Need to Know

Iron is an essential mineral that plays a crucial role in various bodily functions, most notably in the production of hemoglobin, which is vital for oxygen transport in the blood. While many people are familiar with iron deficiency anemia, where low iron levels lead to a reduced number of red blood cells, there is another, often overlooked, condition: iron deficiency without anemia. Understanding this condition is important for addressing health issues that can arise even in the absence of anemia. 

What is Iron Deficiency Without Anemia?

Iron deficiency without anemia occurs when the body’s iron levels are insufficient, but the quantity of red blood cells and their capacity to carry oxygen remain within normal ranges. Essentially, it’s a state where iron stores are low, but the body has not yet progressed to a point where anemia develops. This can make it a bit tricky to diagnose since standard blood tests for anemia might not immediately show abnormalities.

Symptoms and Effects

The symptoms of iron deficiency without anemia can be subtle and may vary from person to person. Common signs include:

  • Fatigue and Weakness: Even without anemia, low iron can lead to feelings of tiredness and decreased energy levels. Coaches notice that some competitive athletes benefit from addressing iron deficiency without anemia.
  • Frequent Headaches: Iron is involved in various enzymatic processes in the body, and a deficiency might contribute to headaches or migraines.
  • Cold Hands and Feet: Poor circulation or lower iron levels can result in feeling unusually cold.
  • Brittle Nails and Hair: Iron deficiency can affect the health and strength of nails and hair.
  • Restless Legs Syndrome: Some people with low iron levels experience uncomfortable sensations in their legs, particularly at night.

Causes of Iron Deficiency Without Anemia

Several factors can contribute to iron deficiency without leading to anemia:

  • Dietary Intake: Inadequate consumption of iron-rich foods, such as red meat, legumes, and fortified cereals, can lead to low iron levels.
  • Increased Iron Requirements: Certain life stages and conditions, such as pregnancy, heavy menstrual periods, or intense physical activity, can increase iron needs.
  • Absorption Issues: Conditions like celiac disease or inflammatory bowel disease can impair iron absorption.
  • Chronic Inflammation: Chronic illnesses or inflammatory conditions can affect iron metabolism and utilization, even if anemia does not develop.

Diagnosis and Testing

Diagnosing iron deficiency without anemia typically involves a combination of tests and assessments:

  • Serum Ferritin Levels: Ferritin is a protein that stores iron in the body. Low levels can indicate depleted iron stores, even if anemia is not present.
  • Serum Iron and Transferrin Saturation: These tests measure the amount of circulating iron and how well it is being transported in the blood.
  • Complete Blood Count (CBC): While a normal CBC might not show anemia, it can help rule out other conditions.

Treatment and Management

Addressing iron deficiency without anemia often involves dietary and lifestyle changes:

  • Iron-Rich Diet: Incorporate foods high in iron, such as lean meats, leafy green vegetables, nuts, and seeds. Iron from animal sources (heme iron) is generally more easily absorbed than plant-based iron (non-heme iron).
  • Vitamin C Intake: Consuming vitamin C-rich foods like oranges, strawberries, and bell peppers can enhance the absorption of non-heme iron.
  • Iron Supplements: In some cases, a healthcare provider may recommend iron supplements. It’s important to follow dosing instructions carefully, as excessive iron intake can have adverse effects.
  • Address Underlying Causes: If an underlying condition is contributing to iron deficiency, treating that condition is crucial for resolving the deficiency.

Conclusion

While long-term adaptation to high altitude allows individuals to increase their iron available for erythropoiesis due to higher demand, those who have not adapted or are vulnerable due to exercise or pregnancy, are at risk of depleting their iron stores. Iron deficiency without anemia is a condition that requires attention to prevent potential health issues and improve overall well-being. 

Resources & References:

Alkhaldy HY, Hadi RA, Alghamdi KA, Alqahtani SM, Al Jabbar ISH, Al Ghamdi IS, Bakheet OSE, Saleh RAM, Shehata SF, Aziz S. The pattern of iron deficiency with and without anemia among medical college girl students in high altitude southern Saudi Arabia. J Family Med Prim Care. 2020 Sep 30;9(9):5018-5025. doi: 10.4103/jfmpc.jfmpc_730_20. PMID: 33209838; PMCID: PMC7652112.

Kaylee Sarna, Gary M Brittenham, Cynthia M Beall, Detecting anaemia at high altitude, Evolution, Medicine, and Public Health, Volume 2020, Issue 1, 2020, Pages 68–69, https://doi.org/10.1093/emph/eoaa011

Martina U. Muckenthaler, Heimo Mairbäurl, and Max Gassmann. Iron metabolism in high-altitude residents. 2020 Jan 9: https://journals.physiology.org/doi/pdf/10.1152/japplphysiol.00019.2020

Acclimation, Altitude Science, Child Growth & Development, Diabetes, Doc Talk, Health, High Altitude, Wildlife

Ducks, Mice and Sea Turtles Teach Us About High Altitude

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You may be surprised to learn that the University of California San Diego has been on the forefront of high altitude and hypoxia research since 1968. I recently attended the 9th Annual Center for Physiologic Genomics of Low Oxygen Summit (CPGLO) led by Tatum Simonson PhD where I gave a short presentation on Growth At Altitude. I met Dr John West who joined the university in 1968 after a Mount Everest research expedition with Sir Edmund Hillary in 1960.  He also consulted for NASA serving on the advisory committee for Spacelab. He studied medicine and physiology at the University of Adelaide.

Dr. Chris and Dr. John West

The featured speaker was Isha Jain PhD from the University of San Francisco.  Her research on mice shows how chronic hypoxia can mitigate and possibly cure some conditions, such as the devasting condition of mitochondrial disease.  Colleen Julian PhD, from the University of Colorado, gave a talk on “Surviving Birth at Altitude: Genetic and Physiologic Insights”.        

Other short presentations included a scientist from Florida who spoke of studying waterfowl who migrate at very high altitude as well as diving deep into the water to fish, thus adapted to two very different low oxygen environments.    Among the poster presentations were a study on the effects of hypoxia on mitochondrial function in fibroblasts from loggerhead sea turtles  presented by B. Gabriela Arango from the University of California Berkeley and a study on sleep apnea in self-identified Latinos.

Gabriela Arango from University of California Berkeley with her sea turtle research poster.

Acknowledging that chronic hypoxia may increase the risk of depression and suicide, the benefits include decreased incidence of obesity and diabetes and lower cholesterol/LDL with decreased or unchanged hypertension.   These scientists study animals to help us understand the effects of our environment on our health. At conferences like this, we discuss how what I see as a clinician  could be related to their study on the cellular and genomic levels.      

                            

Dr Chris and Gabriela meeting again- they both presented research at the Hypoxia 2025 conference in Lake Louise, Canada
Gabriela Arango and Dr. Chris were excited to meet again after both presented at the Hypoxia 2025 conference in Lake Louise, Canada in February
High Altitude, Medicine

Trauma Related High-Altitude Pulmonary Edema

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HAPE Poster

This poster was presented at the American Thoracic Society International Conference in San Diego in May of 2018.  As yet unrecognized and unpublished, Trauma HAPE joins other presentations that have been suggested by altitude providers but have not been studied yet including Highlander HAPE, Post Anesthesia HAPE and Reverse HAPE,  where life threatening hypoxia develops after return from altitude.   The blog highaltitudehealth.com functions to raise awareness among other healthcare providers practicing at any altitude about the potential health complications associated with rapid changes in elevation.

Acclimation, Altitude Science, Athletic Training, Health, High Altitude, High Altitude Training & Fitness

KYRGYZSTAN VS SUMMIT COUNTY, COLORADO: EXERCISE AT ALTITUDE

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How does the low oxygen environment at altitude affect our ability to exercise?  What is the risk for developing harmful changes in the heart and lungs? Does sleep apnea contribute to these risks? Can supplemental oxygen reverse or reduce these risks and increase our exercise ability at altitude?

An audience of conference participants sit observing a slide in a presentation reading "Cardiac function and PH in 97 Kyrgyz Highlander and 76 Lowlander (50% women).

These important questions have been studied by an international research team conducting tests on residents of the Tien Shan mountain range in Kyrgyzstan, 2500-3500 m (8,200 to 11,482 feet). Dr. Silvia Ulrich presented some of their findings at the Hypoxia 2025 conference in Lake Louise in the Canadian Rocky Mountains this past winter. Using an exercise bike they measured ECG, pulmonary gas exchange and oxygen saturation in healthy highlanders. Participants’ average age was 48 years, 46 % were women, and their average oxygen saturation (SpO2) at rest was 88%. Normal occupations include nomadic herdsmen, hunters and soldiers who usually travel by car or horse, with no prior experience cycling or running. An echocardiogram was performed to assess pulmonary artery pressures (PAP) and right heart function.

Arterial blood gas analysis at baseline showed a normal pH, low oxygen, mildly decreased carbon dioxide and bicarbonate, and higher hemoglobin concentrations. Bicarbonate values were 22-26 moles/L. In Summit county, in the Rocky Mountains of Colorado, with residents living between 2500 to 3300 m bicarbonate values are 17-20 moles/L.

Results showed their peak oxygen uptake, and peak work rate was reduced by one quarter compared to predicted values for lowlanders. Oxygen saturation decreased during exercise. “Exercise limitation was related to an exercise -induced worsening of hypoxemia, high ventilation equivalents for oxygen uptake and carbon dioxide output, a reduced external work efficiency and a lower peak heart rate than predicted for age.” (1) In other words, they had to breathe harder to maintain their oxygen and carbon dioxide at normal values and use more effort for the same musculoskeletal output. Their heart rate did not increase as much as a person from lower altitude doing the same work.

There is little research on exercise capacity in long-term residents at altitude.  Most studies focus on athletes or comparing healthy acclimatized men to recent arrivals. The hypoxic environment is a known risk for pulmonary hypertension, which can lead to exercise intolerance and fatigue that is reversible with descent or oxygen use when diagnosed in a timely manner. Sleep apnea with the accompanying hypoxic episodes adds to this risk. Summit County residents show improvement in both systemic and pulmonary hypertension with supplemental oxygen during sleep, according to local health care providers.

Kyrgyzstan residents studied showed a strong correlation between  the incidence of sleep apnea with hypoxia (time below 90% SpO2), and abnormal pulmonary artery pressures. Echocardiograms compared 97 highlanders with 76 lowlanders who were asymptomatic. Between 6% and 35% had increased PAP depending on which definition is used. 

A slide at a conference presentation on the effect of high-dose SOT on pulmonary artery pressures and cardiac output in highlanders at risk for PH at 3250 meters.

The research team also evaluated their response to supplemental oxygen at altitude and 760m elevation using the six minute walk test. Although the test subjects reported less shortness of breath and had higher measured oxygen levels they were not able to walk further. Supplemental oxygen did reduce pulmonary artery pressures in those at risk when tested at 3,200 m.

A slide from a presentation on an experiment where oxygen levels in residents of high altitude in Kyrgyzstan are measured during a 6-minute walk.

This research was conducted by a crew of scientists who brought all the equipment with them to a basic medical clinic in a village.

Summit County cardiologist Warren Johnson was impressed by the numbers of people with elevated pressures in their lungs. “It could be as high as 30 per cent of adults,” he told local physicians. Symptoms are subtle: decreased exercise tolerance, mild shortness of breath, trouble sleeping, high red blood cell counts. Most people just think they are out of condition or aging.

A study in Spiti Valley India of residents living at 9000-13000 ft found an incidence of three per cent with PH.  Dr Johnson suspects this is a highly adapted population with centuries of mountain living.

Diagnosing this condition early with Echocardiogram can prevent serious disability.  Treatment is as simple as sleeping on oxygen. These measurements and much more are performed on a daily basis at the St. Anthony Summit Hospital, a 34-bed hospital serving five counties in Colorado, located at 2800 m. A parallel study to establish baseline normal values for the healthy population and identify the risk for pulmonary hypertension in asymptomatic mountain residents would be valuable for health care providers who are frequently asked to counsel residents on the risk of living at altitude.

References

Forrer A, Scheiwiller PM, Mademilov M, Lichtblau M, Sheraliev U, Marazhapov NH, Saxer S, Bader P, Appenzeller P, Aydaralieva S, Muratbekova A, Sooronbaev TM, Ulrich S, Bloch KE, Furian M. Exercise Performance in Central Asian Highlanders: A Cross-Sectional Study. High Alt Med Biol. 2021 Dec;22(4):386-394. doi: 10.1089/ham.2020.0211. Epub 2021 Aug 24. PMID: 34432548.

Lichtblau M, Saxer S, Furian M, Mayer L, Bader PR, Scheiwiller PM, Mademilov M, Sheraliev U, Tanner FC, Sooronbaev TM, Bloch KE, Ulrich S. Cardiac function and pulmonary hypertension in Central Asian highlanders at 3250 m. Eur Respir J. 2020 Aug 20;56(2):1902474. doi: 10.1183/13993003.02474-2019. PMID: 32430419.

Altitude Science, COVID-19, Doc Talk, Health, High Altitude, Medicine, Pandemic

COVID-19 and Altitude: A discussion about the research with Dr. Isain Zapata

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Early in the pandemic, researchers were eager to learn more about the COVID-19 virus and how it takes shape in different communities. One area of particular interest for some of those researchers was the relationship between COVID-19 and high altitude, as altitude has been shown to impact other chronic diseases like COPD1, lung cancer2, and cardiovascular disease3. However, many of the early studies that were conducted resulted in nonspecific findings or trends in data that could be better explained by different variables than solely altitude. 

For example, one of the preliminary studies conducted in Colombia analyzed positive cases, deaths, and case fatality rates in 70 different municipalities ranging from 1 to 3180m above sea level. What these researchers found was that there was a negative correlation between altitude and COVID-19 case fatality rates4, meaning there were less COVID-19 deaths at higher altitude when compared to those at low altitude. One thing that is mentioned by the researchers is that population density plays an important role in the transmission of this virus4. The researchers concluded that this negative correlation seen between altitude and COVID-19 fatalities could be better explained by the differences in population in the varying locations4. 

Another early study conducted in 2020 looked at around 4 months of data in the U.S and around 2 months of data in Mexico and found that U.S. communities living at >2000m elevation had higher mortality rates than those at <1500m5. In Mexico, individuals <65 years old, the risk of death due to COVID-19 was 36% for those living at >2000m when compared to those living at <1500m5.

We discussed some of these findings with Dr. Isain Zapata, who is one of the authors of the article “Revisiting the COVID-19 fatality rate and altitude associated through a comprehensive analysis”. Which was a study conducted by a group of researchers at Rocky Vista University that further investigated the relationship between altitude and COVID-19 fatalities. Dr. Zapata said that some of their motivation to look further into this relationship was due to the lack of consistency in the conclusions formed by many of the studies conducted early in the pandemic. He hypothesized that there could be a few reasons for these inconsistencies, one being that there is a large discrepancy over what level of elevation is considered “high altitude” and another being that many of the studies published early on were specific to a certain location. Lastly, these studies were solely looking at data from the first few months of the pandemic, when COVID-19 infections were just beginning to take form. 

In their study, this group of researchers looked at COVID-19 fatality data from March 2020 to March 2021 in the mountain region of the western United States, including Montana, Idaho, Wyoming, Nevada, Utah, Colorado, Arizona, and New Mexico. Within each state, they looked at the data specific to each county and then subdivided them into census blocks6. Then determined the weighted average of the block’s altitude and adjusted for population density6. 

They found that in Colorado, Idaho, and Wyoming, communities living at higher altitude had lower COVID-19 fatality rates6. This trend was also observed when they performed a meta-analysis of all of the data from the U.S. Mountain region6. However, when looking at Arizona, Montana, Nevada, and Utah individually, there was not a significant relationship observed between high altitude and COVID-19 mortality6. One of the points discussed by the researchers is that in these states, the discrepancy may be based on the population density6. In Arizona and Nevada, the majority of the population in that state live at lower altitudes6. The researchers also discuss that the size of the state and the number of counties in each state may also play a role in these trends6. 

They also found that in Arizona, Colorado, Idaho, and Wyoming, areas with higher median incomes were associated with lower COVID-19 fatality rates6. 

The researchers observed that in New Mexico, there was a reverse altitude effect, in which, there was higher mortality rates at higher altitudes6. There was also a higher associated risk across the whole mountain region for the Native American population6. One observation that was pointed out in the discussion section of this article, is that New Mexico has one of the highest Native American populations6. In addition, Native Americans have been shown to have higher incidence of developing chronic diseases that are associated with worse COVID-19 fatality rates6. 

So, what does this all of this mean? Overall, in the U.S. western Mountain region, there were fewer Covid-19 deaths for communities living at higher altitude when compared to those living at lower altitude6. This same trend was observed when just looking at the data for Colorado6. 

Another point that was discussed by the researchers is that these implications can likely be explained by both protective physiologic changes that occur at altitude as well as demographic trends6. The demographic trend may be hypothesized to be a result of people who choose to live in areas of higher altitude as they are often seeking more active lifestyles. The results of this study leave room for more research to be conducted on how our bodies physiology changes in order to adapt to life at higher altitudes.  

  1. Andreas Horner et al., “Altitude and COPD Prevalence: Analysis of the Prepocol-Platino-Bold-Epi-Scan Study,” Respiratory Research 18, no. 1 (August 23, 2017), https://doi.org/10.1186/s12931-017-0643-5.
  2. Kamen P. Simeonov and Daniel S. Himmelstein, Lung Cancer Incidence Decreases with Elevation: Evidence for Oxygen as an Inhaled Carcinogen, November 12, 2014, https://doi.org/10.7287/peerj.preprints.587v2.
  3. Martin Burtscher, “Effects of Living at Higher Altitudes on Mortality: A Narrative Review,” Aging and Disease, 2014, https://doi.org/10.14336/ad.2014.0500274.
  4. Eder Cano-Pérez et al., “Negative Correlation between Altitude and Covid-19 Pandemic in Colombia: A Preliminary Report,” The American Journal of Tropical Medicine and Hygiene 103, no. 6 (December 2, 2020): 2347–49, https://doi.org/10.4269/ajtmh.20-1027.
  5. Orison O. Woolcott and Richard N. Bergman, “Mortality Attributed to Covid-19 in High-Altitude Populations,” High Altitude Medicine &amp; Biology 21, no. 4 (December 1, 2020): 409–16, https://doi.org/10.1089/ham.2020.0098.
  6. Carson Bridgman et al., “Revisiting the Covid-19 Fatality Rate and Altitude Association through a Comprehensive Analysis,” Scientific Reports 12, no. 1 (October 27, 2022), https://doi.org/10.1038/s41598-022-21787-z. 
Acclimation, Acetazolamide, Altitude Science, Child Growth & Development, Diamox, Doc Talk, Health, High Altitude, Medicine, Sleep at Altitude

Sharing at the Chateau: 23rd International Hypoxia Symposium in Lake Louise

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I attended the 23rd International Hypoxia Symposium in Lake Louise, Canada to present some of the research on altitude I’ve been conducting in Colorado. The conference has been going on since 1979, and for the past 26  years the organizers have been Robert Roach and Peter Hackett, world-renowned medical researchers from Colorado. Meeting most of the famous altitude researchers from all over the world was an inspiration.  Personal talks and sharing information were equally important to imbibing the latest knowledge about hypoxia and hemoglobin.

A slide is projected onto a screen over the heads of conference participant, depicting statistics showing infant birthweight in mammals decreasing over increasing elevations.
From Jay Storz’s presentation at the 2025 International Hypoxia Symposia in Lake Louise, Canada

Antarctic Icefish: Life Without Hemoglobin, was presented by Kristen O’Brien, expanding the concept of oxygen distribution in living beings and introducing us to varieties of fish we have never heard of. Her talk was followed by our “Mice and Men” guy, Jay Storz (and colleague Graham Scott), who along with Jon Velotta mentioned in our blogpost on the show “This Podcast Will Kill You” collect the large eared deer mice from peaks such as Blue Sky Mountain to study adaptation to hypoxia in their labs. The talk recognized for first prize was on Altitude Headaches, including a discussion of migraines, by Andrew Charles.

Every evening there was a banquet and speaker.  Astronaut Jessica Meir spent 210 days aboard the space station.  She shared a wide range of challenges such as exercising without gravity, choosing a compatible crew, getting boxes of treats from home, and effects of prolonged weightlessness on your eyes and muscles.

A slide projected onto a conference room screen before participants depicts results for six minute walks on and off oxygen.
Silvia Ulrich presented on Pulmonary Circulation of Central Asian Highlanders at the 2025 International Hypoxia Symposium at Lake Louise, Canada.

The research I would like to see duplicated in Summit County was from Kyrgyzstan, where Silvia Ulrich studied the hearts and lungs of the permanent residents at 9000 feet using the six minute walk as one of her tools.  They did not score higher when studied at sea level! She ran tests for pulmonary hypertension, which could be important here.

Of course, there was a talk on Sleep Disordered Breathing (sleep apnea) by Esther Schwarz, something we pay a great deal of attention to in our own clinic in Frisco, Colorado and have several research projects on the improvement we see with supplemental oxygen. The role of mitochondria in cellular function in hypoxia was presented by Dr. Christian Arias-Reyes, a researcher at Seattle Children’s Hospital who is originally from La Páz, Bolivia.  I met him at the Chronic Hypoxia conference in 2019 when he was a graduate student in Quebec and again in La Páz at this year’s conference. 

A line of people pose in front of a cafe with signs and plants hanging above a stone-tiled street lined with buildings
Altitude experts Dr. Zubieta Calleja, Dr. Christian Arias-Reyes, Dr. Michele Samaja and Dr. Christine Ebert-Santos with colleagues of the Hypoxia Symposia in front of a pizzeria in Coroico, Bolivia.

A deep dive into how our neurons react to hypoxia in the brain by releasing nitric oxide to dilate blood vessels and preserve circulation reenforced the counseling I do here in my clinic to parents whose children have breath holding spells or babies with dips in their oxygen on home monitors. Along with all the millions of children and adults living at 12,000 feet in Bolivia, we can witness that hypoxia does not cause brain damage. (Not to be confused with anoxia, a complete lack of oxygen.)

Lastly, Nobel prize winner and fellow pediatrician Gregg Semenza spoke on research to find a blocking compound against HIF- hypoxia inducible factor, as a cure for some cancers. Gregg’s work was described in our blog on the Nobel prize being awarded to scientists working on hypoxia. HIF deserves its own blogpost! More about cancer and hypoxia at altitude from the Chronic Hypoxia Conference in La Páz.

I was selected to give my presentation, “Colorado Kids Are Smaller” to both conferences. I have been working on this for 20 years. You can read more on our blog where it is titled “Mountain Kids Are Smaller”.  My goal is to get a unique growth chart for children under age two at altitude, to save parents and providers anxiety and money trying to get our kids to “be the same” as those at sea level.

The most useful tidbit of information came on the bus ride back to Calgary. Dr Heimo Mairbaurl, PhD shared that a quarter dose of acetazolamide was sufficient for his acute mountain sickness symptom prevention, 62 mg for a guy over 6 feet tall. Although there was a study on a new possible preventive treatment, prochlorperazine, done on Mount Blue Sky last fall, I still swear by the old drug formerly known as “Diamox”.

Acclimation, Altitude Science, Child Growth & Development, Doc Talk, Genetics, Health, High Altitude

The Frisco Score: A New Tool for Diagnosing HAPE

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by Madison Palmiero, PA-S

While HAPE may be a run-of-the-mill diagnosis for providers with years of experience practicing at altitude, it can be less straightforward for those who are unfamiliar with the condition. There are currently three recognized categories of HAPE. Classic HAPE (C-HAPE)  occurs when someone who resides at low altitude travels to high altitude and develops pulmonary edema. Re-entry HAPE (R-HAPE) occurs when high altitude residents travel to low altitude, then return to high altitude. High-altitude resident pulmonary edema (HARPE) occurs in high altitude residents without a change in altitude. HARPE is often brought on by an upper respiratory tract infection. 

HAPE and pneumonia can have similar presentations including shortness of breath, cough, fatigue, and malaise. Patients with either condition may have decreased oxygen saturation levels and abnormal findings on chest radiography. In response to this phenomena, Dr. Chris Ebert-Santos of Ebert Family Clinic in Frisco, Colorado (9000′) and Sean Finnegan, PA-C set out to develop a scoring system to differentiate the two diagnoses. If providers could easily differentiate between pneumonia and HAPE, this would shorten the time from presentation to diagnosis and would avoid unnecessary antibiotic use.

Dr. Chris and Sean Finnegan, PA-C summarized their research findings into a scoring system named the “Frisco Score”. They analyzed data from St. Anthony Summit Medical Center and associated clinics at or above ~2,760 meters above sea level from January 1, 2018 to May 30, 2023. The study looked at patients under the age of 19 who presented with hypoxemia or other respiratory concerns and had a chest x-ray performed and oxygen saturation measured. The final case review consisted of 138 total patients with 77 diagnosed with HAPE, 38 diagnosed with pneumonia, and 23 diagnosed with concomitant HAPE and pneumonia. Variables found to have no significance included gender, age, heart rate, and temperature. Variables with significance included respiratory rate, number of days ill, oxygen saturation, and chest x-ray findings. These significant variables were used to develop the Frisco Score. They do include a disclaimer that these findings are preliminary results on a small data set. Thus, as of yet, the Frisco Score should not be used on its own to make a diagnosis, but rather should be used as a clinical tool in differentiating conditions with similar presentations. 

Oxygen saturation varied greatly between patients with HAPE and those with pneumonia. Patients diagnosed with HAPE had an average oxygen saturation of 74% and those with pneumonia had an average of 92%. 

Patients who were diagnosed with HAPE had a higher average respiratory rate compared to those diagnosed with pneumonia.

 In patients diagnosed with HAPE, the duration of illness, or number of days ill, was shorter than those diagnosed with pneumonia. 

In comparison of chest x-rays, patients with HAPE were more likely to have diffuse findings and patients with pneumonia were more likely to have focal findings. 

Overall, there were no variables associated with a concomitant diagnosis of pneumonia and HAPE.

The asphalt road in the foreground leads past a sign for Common Spirit St. Anthony Summit Hospital just before the shelter over the entrance to a building labeled "ambulance" with deep green conifer forests stretching halfway up tall grey rocky mountains in the backgroundl.

In summary, patients diagnosed with HAPE had decreased oxygen saturation, increased respiratory rate, and diffuse findings on chest x-ray; while patients diagnosed with pneumonia had a longer duration of illness and focal findings on chest x-ray. The Frisco Score takes these variables into account to help differentiate a diagnosis of HAPE in children. Dr. Chris and Sean Finnegan, PA-C are currently presenting their findings at the 8th World Congress on Mountain and Wilderness Medicine in Snowbird, Utah. They hope that in the near future, the Frisco Score will be used to facilitate the diagnosis of HAPE by providers in high altitude communities state-wide.

References

1. Ebert-Santos, C. (2017). High-Altitude Pulmonary Edema in Mountain Community Residents. High Altitude Medicine & Biology, 18 (3), 278-284. https://doi.org/10.1089/ham.2016.0100

2. Ebert-Santos, C., Finnegan, S. (2024). Differentiating Pneumonia & HAPE in Children.