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Already an extreme sport, mountaineering at high altitudes adds exponential risk! Know before you go!

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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.

Acclimation, Altitude Science, Athletic Training, Backpacking, Exposure, Health, High Altitude, High Altitude Training & Fitness, Mountaineering

Mountain People Can Still Get Mountain Sickness: HL-HAPE, a Fourth Type of High Altitude Pulmonary Edema

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There are three types of High Altitude Pulmonary Edema (HAPE) recognized in visitors and people living at high altitudes. These include classic HAPE (C-HAPE), which involves an individual that lives at low altitude traveling to high altitude. Re-entry HAPE (RE-HAPE)  is seen in an individual that lives at high altitude who travels to low altitude and then returns to high altitude, and high-altitude resident pulmonary edema (HARPE) which occurs in an individual that lives at high altitude and does not change altitude (Ebert-Santos, Wiley). While these have been extensively studied and are subtypes that people are warned of, a fourth unexpected type of HAPE has been recently described by pediatric pulmonologist Santiago Ucros in Bogota, Columbia at the Universidad de los Andes. (Ucros)

Highlanders HAPE (HL-HAPE) occurs in people that live at high altitude who then travel to higher altitudes. Though most people who live at high altitudes for long periods of time assume they are immune to HAPE, the recognition of HL-HAPE shows this is not the case. One man had a run-in with HL-HAPE during his long-awaited trip to Mt. Kilimanjaro. 

A man wearing a neck gator under a grey baseball cap and dressed in cold-weather jacket and pants sits on a rock next to a tall giant groundsel plant with cushions of dead leaves puffing up heads of light-green leaves before the sloping of the mountain down into a valley with a white cloud floating above it.

A resident of Summit County, Colorado, Jonathan Huffman set out to climb Mt. Kilimanjaro with his wife Katie when he was 37 years old. He is originally from Texas, but has been living in Breckenridge, Colorado, elevation 9,600 ft, for 15 years. In preparation for the climb, he spent the summer hiking multiple fourteen thousand foot peaks in Colorado, trail running at 9,000-12,000 ft, and mountain biking. 

Two people stand smiling toward the camera with an arm around each other, dressed warmly in long pants, thick jackets and hats, one holding a water bottle, standing on an open field of high alpine shrubs with Mt. Kilimanjaro illuminated in the pink light of the sun, streaked with long, narrow clouds in the background

The elevation of Mt. Kilimanjaro is 19,341 feet and the summit generally takes each group anywhere from 5 to 9 days, depending on the route taken. In September, Jonathan and Katie traveled to Tanzania where they spent two days adjusting to jet lag and preparing for their climb. They had chosen to follow the Lemosho Route which is 42 miles long with an elevation gain of 16,000 to 17,000 feet. 

On the first day, Jonathan and his party started at the Lemosho trailhead (7,742 feet) and hiked up 9,498 feet to the first camp. He noticed that his throat felt dry and he found himself having to clear it often. He attributed this symptom to the dusty environment. 

On the second day, he felt as though his body was fighting the dust, which had found its way into his eyes, sinuses, and throat. He also felt extremely fatigued and stated that every action felt more difficult. Though he could tell his body was struggling to adapt, Jonathan continued to push forward with full force. He made it to the second camp at 11,500 feet. 

A group of orange and white panelled tents sit in the shade of a rocky mountain peak streaked with snow, illuminated in sun above the camp against a cloudless blue sky.

“Day three, we went from 11,500 feet to 13,800 feet,” Jonathan recounts. “After we arrived to this camp, our guides offered to allow us to take a break then hike even higher. This was [an] optional acclimatization test … but I actually skipped it. I was so tired when I got to camp on this day, I decided to just nap in the tent until dinner time.”

On the fourth day, Jonathan’s group hiked up an overpass to Lava Tower located at 15,190 feet. This was also an altitude test, and he passed. He stated that this was the highest he had ever climbed, but that he was beginning to feel more like his normal self. The group stopped for lunch at the tower, but he did not have much of an appetite. He ate the food anyways at the insistence of the guides. 

A sea of clouds illuminated in blues and soft pinks stretches out behind several tents pitched over a shaded, rocky mountain slope in the foreground.

“Then after lunch, we descended down to Barranco Camp [from 15,190 feet to 13,044 feet] and this is where I realized I had HAPE.”

As they were nearing the camp, he felt fluid building in his lungs that was easy to cough up. By the evening, however, he felt as though he was drowning and was unable to lay down. While the guides encouraged him to immediately hike down, he did not want to hike in the dark. He spent the night propped up on duffle bags or sitting in a kitchen chair, with his oxygen reaching as low as 67% at one point. 

Two people sit in the dark of a tent, one with an oxygen mask on and a red head lamp illuminating tin food containers and medical supplies in the foreground as he is administered oxygen.

In the morning, he received 30 minutes of oxygen treatment before beginning his 8-hour descent. His symptoms improved when he reached 6,500 feet. He was picked up in a rescue vehicle and received further treatment at a hospital in Moshi. While he made a full recovery, he stated that he still felt the effects of HAPE while exercising in Colorado at times, up to months after the experience. While Jonathan was only about 2 days away from the summit, he knew that turning back was the best choice. He plans to re-attempt the climb in a few years. 

Jonathan’s story serves as an important reminder to those living at altitude that HAPE can affect anyone. Jonathan’s wife Katie along with everyone else in the group also experienced mild symptoms of altitude sickness including headaches. Research still needs to be conducted on the cause and prevention of this condition in all types. While this shouldn’t stop hikers and climbers from climbing mountains, they should be aware of the signs and symptoms of HAPE, when to seek treatment, and the best ways to prevent it from occurring. 

A map of the Lemosho route as listed on the Ultimate Kilimanjaro guide site can be found here.

A group of people in bright colored pants, jackets and backpacks make their way down a red dirt trail surrounded by tall green grasses and trees extending over a white SUV with a red cross symbol on it in the background down the road.
A man in a beige baseball cap takes a selfie with three men in hats and jackets behind him smiling toward the camera with a white jeep labelled with a red cross in the background behind them.
Acclimation, Alcohol at Altitude, Altitude Science, Athletic Training, Backcountry, Backpacking, Child Growth & Development, Exposure, Health, High Altitude, High Altitude Training & Fitness, Huts, Hyperbaric Therapy, Medicine, Mountaineering, Naturopathic Medicine, Sleep at Altitude, Summit Huts

HAFE: High-Altitude Flatus Expulsion

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Often, at high altitude we hear complaints of gas pain and increased flatus in our infant population. Parents often wonder, are we doing something wrong? Is my child reacting to breastmilk, or showing an intolerance to certain foods?  Actually there is another explanation for increased flatus and gas pain in the high-altitude region of Colorado. 

The term HAFE was coined by Dr. Paul Auerbach and Dr. York Miller and published in the Western Journal of Medicine in 1981. Their discovery began In the summer of 1980, when the two doctors were hiking in the San Juan Mountains of Colorado on a quest to summit three 14ers. During their ascent they noticed that something didn’t smell right! As the pair continued to emit noxious fumes, they began to put their scientific brains to work and discovered HAFE. The symptoms include an increase in frequency and volume of flatus, or in other terms an increase in toots! We all have familiarity in watching our bag of potato chips blow up when reaching altitude or our water bottle expanding as we head into the mountains. This reaction is due to a decrease in barometric pressure. Based on Boyle’s law, decreased barometric pressure causes the intestinal gas volume to expand, thus causing HAFE (Skinner & Rawal, 2019).

A graphic illustrating how Boyle's law works: the pressure of a gas increases as its volume decreases.

To my surprise, a gas bubble the size of a walnut in Denver, Colorado (5280 ft) would be the size of a grapefruit in the mountain region of Summit County, CO (8000+ ft)! Trapped gas is known to lead to discomfort and pain. The use of simethicone may have merit in mitigating the effects of HAFE. Simethicone works by changing the surface tension of gas bubbles, allowing easier elimination of gas. This medication, while benign, can be found over the counter and does not appear to be absorbed by the GI tract (Ingold, C. J., & Akhondi, H., 2022). 

While this phenomenon may not be as debilitating as high-altitude pulmonary edema (HAPE), it deserves recognition, as it can cause a significant inconvenience and discomfort to those it inflicts. As the Radiolab podcast explained in their episode The Flight Before Christmas , expelled gas in a plane or car when driving up to the mountains can be embarrassing. While HAFE can be inconvenient, it is a benign condition and a matter of pressure changes rather than a disease or pathological process. We would love to talk more about HAFE at Ebert Family Clinic if you have any questions or concerns!

A bald eagle flies over a misty settled into the valley against the blue-green pine forest of a mountain.
A bald eagle flies toward its nest atop a bare lodgepole pine.

As always, stay happy, safe, and healthy 😊

Taylor Hollingsworth is finishing her final semester as a family nurse practitioner (FNP) student at Georgetown University. Originally from the east coast, Taylor plans to start her FNP career in North Carolina close to family. She has a passion for pediatric and family wellness and has worked as a pediatric intensive care unit nurse for 6 years! In her free time, Taylor loves to hike, fly fish, run, and spend time with her fiancé Logan. 

References

Auerbach, P. & Miller, Y. (1981). High altitude flatus expulsion. The Western Journal of Medicine, 134(2), 173-174.

Chemistry Learner. (2023). Boyle’s Law. https://www.chemistrylearner.com/boyles-law.html

Ingold, C. J., & Akhondi, H. (2022). Simethicone. StatPearls Publishing. 

McKnight, T. (2023). The Flight Before Christmas [Audio podcast]. Radiolab. https://radiolab.org/episodes/flight-christmas

Skinner, R. B., & Rawal, A. R. (2019). EMS flight barotrauma. StatPearls Publishing. 

Acclimation, Altitude Science, Athletic Training, Backpacking, Exposure, Health, High Altitude, High Altitude Training & Fitness, Mountaineering

When Altitude gets High, does Stroke get higher?

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Does altitude increase or decrease risk of strokes? As one review put it, “Due to limited literature, lack of large series, and controlled studies, the understanding of stroke at high altitude is still sketchy and incomplete”. What is clear is that stroke at high altitude can often be misdiagnosed (or underdiagnosed), due to the similarity of initial presentation with high altitude cerebral edema (HACE). Both conditions present with imbalance or ataxia, and both can present with focal neurological deficits.  There are few large urban populations at high altitude (Addis Ababa in Ethiopia is 7,726 ft), so medical providers have fewer resources.  Without the ability to perform neuroimaging with a CT scan or MRI in a timely manner a diagnosis of HACE vs. stroke could be uncertain. HACE often causes global cerebral dysfunction, differentiating it from an early stroke before the onset of focal symptoms can and often does prove challenging. 

While the prevalence of strictly hemorrhagic and ischemic strokes at high altitude remains murky, it is known that exposure to high altitude can result in conditions such as TIA, cerebral venous thrombosis (CVT), seizures, and cranial nerve palsies. Most of the research that has been done on strokes is focused on “moderate” and “high” altitudes, as opposed to “very high” or “extremely high” altitudes. As such, there is very little research on populations living at 3500m or higher. There was at least one tangible piece of evidence indicating that the higher the elevation, the earlier the mean onset of stroke – Dhiman et al. (2018) found that at an elevation of 2,000m, the mean age of onset of stroke was 62 years. The age decreased to a mean of 57.9 years at 2,200m in another study (Mahajan et al. (2004)). Yet another study (Razdan et al. (1989)) found 10.9% of the patients in their sample suffered strokes aged < 40, though this was at an altitude of only 1,530m. Some reports suggest higher stroke prevalence at higher altitudes, and at a strikingly young age – between age 20 and age 45.

Student presentation on stroke at altitude at Colorado Medical Society meeting 2022

There have been mixed results on the effect that altitude has on strokes. One systematic review study found 10 studies displaying an increase in stroke prevalence with higher altitude, 5 other studies showing that altitude was actually protective against stroke, and 2 studies in which the results were ambiguous. This study and other sources alluded to the fact that poorer stroke outcomes at higher altitude may be due to polycythemia and increased viscosity of blood. Specifically, Ortiz-Prado et. al noted that “living in high-altitude regions (>2500m) increases the risk of developing thrombosis through hypoxia-driven polycythaemia which leads to a hypercoagulation unbalance”, which was associated with increased risk for stroke. Ortiz-Prado et. al noted that most of their info came from “very few cross-sectional analyses”. These analyses did find “a significant association between living in high-altitude regions and having a greater risk of developing stroke, especially among younger populations”. When the effects of altitude on stroke were broken down by race (Gerken, Huber, Barron, & Zapata, 2022) it was found to be protective in some populations (Whites, African Americans), but detrimental in other populations (Hispanics, Asian-Pacific, and American-Indian). Going back to the work of Ortiz-Prado et. al, altitude increased the risk of stroke at elevations above 3500m, when the time spent at this elevation was at least 28 days, and more so in younger persons (below the age of 45). At lower elevations, between 1500m and 3500m, increased / easier acclimatization and adaptation to hypoxia seemed to offer protective effects against the risk of stroke. Chronic exposure to hypoxia at high altitude triggers adaptive / compensatory mechanisms, such as higher pulmonary arterial flow and improved oxygen diffusing capacity. Ortiz-Prado et. al concluded that a window of ideal elevation seems to exist – below an altitude of 2000m the adaptive mechanisms do not seem to be sufficient to yield a protective effect – however, above 3500m, adaptive mechanisms may actually become maladaptive (excessive polycythemia & blood stasis), yielding a higher risk for stroke. A lack of any adaptation (i.e. in altitude naïve persons) was even more detrimental at such high altitudes, with the authors concluding that “above 3500–4000m, the risk of developing stroke increases, especially if the exposure is acute among non-adapted populations” (Ortiz-Prado et. al, 2022).

Strokes are more common in males compared to females, and this held true at altitudes of 3380m, 4000m, and 4572m. In addition to the standard vascular risk factors such as hypertension, smoking, and diabetes, the higher incidence of polycythemia in persons living at high altitude is thought to play a role. One study (Jha et al. (2002)) found that 75% of the patients in their sample who had suffered strokes had some form of polycythemia – this was at an altitude of 4270m. (Dr. Christine Ebert-Santos of Ebert Family Clinic in Frisco, Colorado at 2743m suspects everyone who lives at altitude has polyerythrocythemia as more accurately described by Dr. Gustavo Zubieta-Calleja of La Paz, Bolivia at 3625m.)

Only about 2% of the world’s population resides at what is considered “high altitude”. Given the current world population (over 8 billion, 5 million), that is still over 160,100,000 people. The sheer number of people that may be at increased risk of stroke is all the more reason for us to act, and act soon, to get more research done. This is further exemplified by the fact that “cerebrovascular events or stroke is the second leading cause of death worldwide, affecting more than 16 million people each year” (Ortiz-Prado et. al). Guidelines need to be implemented to assist in the diagnosis and treatment of stroke at high altitude, to help differentiate it from related conditions such as HACE, giving patients the standard of care that they need and deserve. While a fascinating topic, stroke seems to be delegated to the sidelines in the mountains, cast aside by culprits such as HAPE, HACE, altitude sickness, and hypoxia. More research, more resources, and more funding need to be funneled into understanding stroke at higher altitudes. Overall, it is clear living at or even exposure to higher altitudes can result in a multitude of neurological symptoms, and that a higher incidence of stroke may yet be one of them.

References

Maryam J. Syed, Ismail A. Khatri, Wasim Alamgir, and Mohammad Wasay. Stroke at Moderate and High Altitude. High Altitude Medicine & Biology.Mar 2022.1-7. http://doi.org.mwu.idm.oclc.org/10.1089/ham.2021.0043

Current World Population – https://www.worldometers.info/world-population/ 

Ortiz-Prado E, Cordovez SP, Vasconez E, Viscor G, Roderick P. Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review. BMJ Open. 2022;12(4):e051777. Published 2022 Apr 29. doi:10.1136/bmjopen-2021-051777

Gerken, Jacob (MS), Huber, Nathan (MS), Barron, Ileana (MD, MPH-S), Zapata, Isain (PhD). “Influence of Elevation of Stroke and Cardiovascular Outcomes”. Poster presented at a conference in Colorado, in 2022.

Links

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9058702/ https://www-liebertpub-com.mwu.idm.oclc.org/doi/full/10.1089/ham.2021.0043

Born in Salt Lake City, Utah, Piotr Poczwardowski has also lived in Upstate New York, Florida, and Colorado (where he spent the 13 years prior to moving to Glendale for PA school). While attending the University of Denver, he volunteered at a nearby hospital Emergency Department, and also participated in a study abroad program in Italy. After earning a degree in Psychology, he worked as both a Primary Care Medical Scribe and Neurology MA. His main hobbies include skiing, watching movies, hiking, swimming, playing video games, reading, and playing ping pong. Piotr has also volunteered at the Sky Ridge Medical Center Emergency Department and secured a job as a Primary Care Medical Scribe after graduating from the University of Denver in 2018. Piotr is now attending Midwestern University’s PA program in Glendale, AZ.

Acclimation, Altitude Science, Athletic Training, Child Growth & Development, Doc Talk, Exposure, Health, High Altitude, High Altitude Training & Fitness, Medicine, Mountaineering

Going Home to the Mountains Can Be Dangerous: Re-Entry HAPE (High Altitude Pulmonary Edema)

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Louie was excited to get out on the slopes after spending Thanksgiving with family in Vermont. He got tired early and felt his breathing was harder than usual, leaving early to go home and rest. As a competitive skier he thought that was strange. But he was getting over a cold. He could not have imagined that in 24 hours he would be in the emergency room, fighting for his life.

Louie experienced a dangerous condition, set off by altitude, and inflammation from his “cold”, that caused his lungs to fill with fluid.  His oxygen saturation was 54 % instead of the normal 92, he had been vomiting and feeling very weak and short of breath. His blood tests showed dehydration, hypoxemia and acute kidney injury. His chest x-ray looked like a snowstorm. He was transferred to Children’s Hospital in Denver and admitted to the intensive care unit.

The diagnosis of Re-entry HAPE was confirmed by echocardiogram showing increased pressures in his lungs. He improved rapidly with oxygen and low altitude.

Re-entry HAPE is not rare, affecting several Summit County children every year.  Many do not come to medical attention because after their first episode parents carefully monitor their oxygen and have a concentrator available in their home when they return from travel. 

Medical providers may not be aware of this risk, expecting that children living at altitude are acclimatized. (See blog entry on Acclimatization vs. Adaptation, April 17, 2019) Re-entry HAPE seems to occur mostly in children between the ages of 4 and 15. Inflammation, such as a viral respiratory infection, seems to play a role.  Trauma may also predispose a returning resident to Re-entry HAPE, as described in our blog post from February 5, 2018, Trauma related High Altitude Pulmonary Edema

Louie agreed to share his story on our blog to help educate medical personnel and families living in the mountains about this dangerous condition. Further research will help define who is at risk. 

Acclimation, Altitude Science, Backpacking, Exposure, Health, High Altitude, High Altitude Training & Fitness, Medicine, Mountaineering, Technology

High-Altitude Pulmonary Edema is not just for tourists

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HAPE can affect long term locals too. There is no specific test to diagnosis HAPE leading to delayed treatment or improper treatment, including death.

HAPE is defined as fluid accumulation in the lungs when an individual spends about 48 hours at elevations of 8,200 feet or higher. This can occur when 1) tourists who are not accumulated to high altitudes appropriately 2) locals who re-enter high altitude after being at lower elevation for a period of time or 3) long term residents who develop an illness.

What are the signs and symptoms you ask? Exhaustion, dyspnea on exertion, productive cough, tachypnea, tachycardia, low oxygen saturation levels, and crackles upon lung assessments are the most common to be seen. These are very generic symptoms and resemble many other diseases, such as pneumonia and asthma, leading to misdiagnosis and improper treatment.

How is HAPE treated?

The answer is simple, oxygen. The body is being deprived of oxygen and is unable to feed our cells. By giving oxygen (either through an artificial source or returning to lower elevation) and allowing the body to rest, the body is able to meet its demand for oxygen and symptoms resolve. If one receives oxygen and symptoms do not improve, there is most likely an underlying cause that is contributing to the symptoms unrelated to HAPE.

A pulse oximeter is the easiest way that one can monitor their oxygen levels at home. This device can be purchased over the counter, relatively inexpensive, and easy to use. By placing the pulse oximeter on one’s finger, the device will read the individual’s oxygen level which should be greater than 90% (when at altitude). The heart rate will also be recorded which tends to be between 60-100 beats per minute when at rest for adults.

References

A new mechanism to prevent pulmonary edema in severe infections. Lung Disease News. (n.d.). Retrieved September 2, 2022, from https://lungdiseasenews.com/2015/01/14/researchers-discover-a-new-mechanism-to-prevent-pulmonary-edema-in-severe-infections/

Bhattarai, A., Acharya, S., Yadav, J. K., & Wilkes, M. (2019). Delayed-onset high altitude pulmonary edema: A case report. Wilderness & Environmental Medicine, 30(1), 90–92. https://doi.org/10.1016/j.wem.2018.11.002

Fixler, K. (2017, October 12). Colorado doctor: Health effects of living in mountains unknown to medical establishment. SummitDaily.com. Retrieved September 2, 2022, from https://www.summitdaily.com/news/summit-county-doctor-makes-a-case-for-high-altitude-disorder-that-affects-even-the-acclimated/

Backcountry, Backpacking, Exposure, Health, High Altitude, High Altitude Training & Fitness, Huts, Medicine, Mountaineering, Naturopathic Medicine, Wildlife

Lost, Stranded, and Hungry in the Mountains of Western Colorado? A Mini Guide to Edible Plants

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From backpacking and camping to skiing and snowboarding, there are plenty of activities outdoors in the Colorado high country. If you find yourself wandering around and lost without food in the mountains, there are several wild plants that you can eat. 

However, before you consume the delectable greens, there are a few precautions to take.

Moose shopping
  • Do not eat any wild plants unless you can positively identify them. There are iOS and Android apps that you can download prior to your hike to help distinguish plants, such as PictureThis and NatureID. 
  • Be aware of environmental factors such as pollution or animal waste. Avoid popular wild animal gathering areas.
  • Make sure you’re not allergic to the plant by rubbing it against your skin and observing for a reaction. If so, do not eat the plant. Before ingesting a large quantity, eat a small amount and check for a reaction. 

It may be difficult to cook if you did not come prepared with a portable stove, pots, and water, which could limit ways to enjoy vegetation. Here is a list of edible plants, how to identify them, where can they be found, and which part you can eat.

Wild plants

Dandelions (Taraxacum officinale): yellow ray florets that spread outward from center with toothy, deep-notched, hairless basal leaves and hollow stems. They can be found everywhere and anywhere. Every part of the dandelion plant is edible including the leaves and roots.

Yellow-green hemispheres bud in a bunch from green stems with pine needle-like leaves.

Pineapple Weed/ Wild Chamomile (Matricaria discoidea): the flower heads are cone-shaped and yellowish-green and do not have petals. Often found near walking paths and roadsides, harvest away from disturbed, polluted areas. If you’re feeling anxious about being lost, pineapple weed promotes  relaxation and sleep and serves as a  digestive aid.

Fireweed (Epilobium angustifolium): vibrant fuchsia flowers. Grows in disturbed areas and near recent burn zones. Eat the leaves when they are young as  adult leaves can stupefy you. Young shoot tips and roots are also edible. 

Wild onions (Allium cernuum): look for pink, lavender to white flowers with a strong scent of onion. They grow in the subalpine terrain and are found on moist hillsides and meadows. Caution: do not confuse with death camas. If it doesn’t smell like an onion and has pink flowers, it is not likely an onion.

Cattails (Typha latifolia or Typha angustifolia): typically 5-10 feet tall. Mature flower stalks resemble the tail of a cat. Grow by creek, river, ponds, and lakes. This whole plant is edible, from the top to the roots. Select from pollution-free areas as it is known to absorb toxins in the surrounding water.

Wild berries:

Wild strawberries (Fragaria virginiana): they are tiny compared to  store-bought. Can be identified by their blue-green leaves; small cluster of white flowers with a yellow center; and slightly hairy, long and slender red stems.

Huckleberries (Vaccinium spp): They grow in the high mountain acidic soil and flourish in the forest grounds underneath small, oval-shaped, pointed leaves. They resemble blueberries and have a distinguishable “crown” structure at the bottom of the berry. They can be red, maroon, dark blue, powder-blue, or purple-blue to almost black, and they range from translucent to opaque.

Deep blue berries stand out against bright red and green, waxy leaves.

Oregon grapes (Mahonia aquifolium): powder-blue berries, resembling juniper berries or blueberries, with spiny leaves similar to hollies that may have reddish tints.

Fun fact: The roots and bark of the plant contain a compound called berberine. Berberine has antimicrobial, antiviral, antifungal, and antibiotic properties.

Mushrooms

Brown whole and halved mushrooms lie on a green table with ridged, sponge-looking caps.

True morels (Morchella spp.): cone-shaped top with lots of deep crevices resembling a sponge. They will be hollow inside. A false morel will have a similar appearance on the outside but will not be hollow on the inside and are toxic. Morels are commonly found at the edge of forested areas where ash, aspen, elm, and oak trees live. Dead trees (forest wildfires) and old apple orchards are prime spots for morels.

Short, stubby mushrooms with white stems and brown camps stand in a row growing over grass.

Porcini (Boletus edulis): brown-capped mushrooms with thick, white stalks. Found at  high elevations of 10,500 and 11,200 ft in  areas with monsoon rains and sustained summer heat.

There are many more edible plants, flowers, berries, and mushrooms in the mountains. These are just 10 that can be easily identifiable and common in the Western Colorado landscapes. I recommend trying out the apps listed above and reading “Wild Edible Plants of Colorado” by Charles W. Kane, which includes 58 plants from various regions, each with details of use and preparation. Hopefully this post made you feel more prepared for your next adventure. 

Resources:

Davis, E., 2022. Fall plant tour: Frisco, CO | Wild Food Girl. [online] Wildfoodgirl.com. Available at: <https://wildfoodgirl.com/2012/eleven-edible-wild-plants-from-frisco-trailhead/> [Accessed 10 July 2022].

McGuire, P., 2022. 8 Delicious Foods to Forage in Colorado | Wild Berries…. [online] Uncovercolorado.com. Available at: <https://www.uncovercolorado.com/foraging-for-food-in-colorado/> [Accessed 10 July2022].

Rmhp.org. 2022. Edible Plants On The Western Slope | RMHP Blog. [online] Available at: <https://www.rmhp.org/blog/2020/march/foraging-for-edible-plants> [Accessed 10 July 2022].

Lifescapecolorado.com. 2022. [online] Available at: <https://lifescapecolorado.com/2014/01/edible-plants-of-colorado/> [Accessed 10 July 2022].

Pfaf.org. 2022. Plant Search Result. [online] Available at: <https://pfaf.org/user/DatabaseSearhResult.aspx> [Accessed 10 July 2022].

Cindy Hinh is a second-year Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up in southern Louisiana and received her undergraduate degree in Biology from Louisiana State University. Prior to PA school, she was a medical scribe in the emergency department and an urgent care tech. In her free time, she enjoys baking, cooking, going on food adventures, hiking, and spending time with family and friends.

Acclimation, Altitude Science, Athletic Training, Backcountry, Health, High Altitude, High Altitude Training & Fitness, Huts, Hyperbaric Therapy, Mountaineering, Sleep at Altitude

Sleep at High Altitude

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Have you thought of what it would be like living in the mountains year-round? Medical professionals find it is important to look at what living at high elevations can do to the human body. One activity heavily affected is sleep. As mentioned in previous blog posts, visitors often have trouble falling asleep, staying asleep, and feeling rested in the morning. A recent study published in Physiological Reports measured the effects of sleeping patterns at high elevation. The participants experienced a simulated elevation inside a hyperbaric chamber. This mimicked sleeping at elevations of 3000 meters (9,842 feet) and 4050 meters (13,287 ft) for one night and then sleeping at sea level for several nights to establish a baseline for the research participants. Participants exercised for 3 hours in the hyperbaric chamber allowing researchers to observe how the lower oxygen concentrations affected their ability to perform strenuous tasks. The group that slept in a simulated 4050 meter environment had an increased heart rate that was 28% higher and an oxygen saturation 15% lower than the 3000 meter participants. When comparing sleep itself, the group at 4050 meters had 50% more awakening events throughout each night. This goes along with previous research on this blog that states that people who sleep at high altitude complain of insomnia and frequent awakening when first arriving at high elevation.

These numbers increase even more dramatically when compared to participants at sea level. Related symptoms reported during this study showed the incidence of acute mountain sickness occurred in 10% of the participants at a simulated 3000 meters, increasing to 90% at 4050 meters. As mentioned, the average heart rate increases and oxygen saturation decreases as the elevation increases. The baseline heart rate at sea level was 62 beats per minute, increasing to 80 at 3000 meters and 93 at 4050 meters. Ideally health care providers aim to oxygenate vital organs by keeping the oxygen saturation level between 92-100%. The lower the oxygen level the harder it is to keep organs properly profused. Age, health status, and place of residence are taken into consideration when examining study reports. Oxygen saturation at sea level was 98% decreasing to 92% at 3000 meters and 84% at 4050 meters.

As mentioned in a previous post by Dr. Neale Lange, sleeping at high altitudes can be hard due to the frequent awakenings and nocturnal hypoxia caused by the low oxygen levels at higher elevation. This study reiterates these findings with the results of the average oxygen saturation at 3000 meters being around 92%. Dr. Lange also found that sleep apnea was often more prominent and had more negative effects on the human body in environments that were lower in oxygen. This study agrees with that statement finding that people with sleep apnea had twice the hourly awakenings compared to those at higher elevation that did not have sleep apnea. Dr. Lange also pointed out that the contribution of hypobaric atmosphere to symptoms at altitude as opposed to pure hypoxemia is unknown. Frisco, Colorado is at an elevation of 2800 meters. Ongoing research at Ebert Family Clinic including residents and visitors along with laboratory studies such as this one can guide decisions about interventions and treatment to improve sleep and help us enjoy our time in the mountains.

References

  1. Figueiredo PS, Sils IV, Staab JE, Fulco CS, Muza SR, Beidleman BA. Acute mountain sickness and sleep disturbances differentially influence cognition and mood during rapid ascent to 3000 and 4050 m. Physiological Reports. 2022;10(3). doi:10.14814/phy2.15175
  2. Blog post: HOW DO YOU DEFINE A GOOD NIGHT’S SLEEP?:AN INTRODUCTION TO THE SLEEPIMAGE RING, AN INTERVIEW WITH DR. NEALE LANGE

Casey Weibel is a 2nd year student at Drexel University, born and raised in Pittsburgh, Pennsylvania. He went to Gannon University for his undergrad and got a degree in biology.  Before PA school, Casey was an EMT.  He enjoys hiking and kayaking and is a big sports fan. 

Backcountry, Backpacking, Exposure, High Altitude, High Altitude Training & Fitness, Mountaineering

After 21 Years of Hiking at Altitude I Had to Call Rescue

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Another Lesson on High Altitude Health and Safety

Wild animals, storms, avalanches, cold, high altitude pulmonary edema or cerebral edema, falls, fires and injuries are the most common dangers in the mountains. I’ve climbed 19 different mountains in Colorado over 14,000′, and some of them more than once, making for 28 successful ascents. But I called Summit County Search and Rescue Saturday for something I was not expecting: deep wet snow that trapped me less than 2 miles from the trailhead.

A colorful map of lines in red, green and white depicting trails through various mountain terrain.
Summit County trail map

It was a bright, warm day — I had even left my hand warmers at home. My plan was to hike from Miners Creek trailhead in Frisco to Gold Hill Trailhead north of Breckenridge which is about a 6- or 7-mile trip one way. I had hiked from both ends in previous weeks and saw the turn-off had snow and no tracks. I attached my snowshoes to my backpack with plans to turn up towards Gold Hill if there were tracks, and there were.

After 4 miles I was out of the forest on top with gorgeous 360˚ views of mountains. I no longer saw the trail markers or tracks so set out across the open space with my snowshoes sinking into the snow every 10 to 20 feet. The trail maps and GPS on my phone were sketchy, only showing I was very near the Colorado Trail. I turned down a logging road to get out of the wind thinking the snow would be packed. I could see several open areas that I thought would take me to the familiar trails to Gold Hill.

After an hour sinking into deep snow I noticed I had only one snowshoe. I backtracked 100 feet following the tracks to find it, dug at several spots where I had sunk the deepest but never found it. I went back towards the Colorado Trail but could not progress, having to dig my boot out of deep snow several times.  I tried to backtrack in my footsteps but couldn’t get far. I had now covered a mile in an hour and a half, my phone showing I was only 48 minutes from the Gold Hill trailhead.

So I called 911, thinking they could drive a snowmobile up to get me.  Bad news: the vehicle would just sink the same way I was. The 911 operator knew me and the Summit County Search & Rescue mission coordinator Mark Svenson was in touch several times as I waited from 3:17 until about 6 pm when the crew arrived with skis and extra snowshoes. My Blue Heeler Isa and I stayed within one foot of a small pine tree where we found firm footing after rolling through the deep, soft snow. Luckily the sun kept us warm until 5 pm, and I had food and water. My gloves and boots were soaked so my feet were very cold and I tried to keep Isa lying over my legs or feet.  I had a plastic rain shield extension that I could pull out and sit on in a pocket of the backpack that one of my students had gifted me.

The rescuers had water, snacks, dry socks, dry gloves, gators and snowshoes. They had packed down the trail but there were still times we post-holed on the way down. We arrived at the rescue vehicle as darkness fell. Special Operations Sheriff SJ Hamit waited with Mark and other SCSR staff to welcome us. One of the rescuers told me how happy he was that I was still smiling when they arrived!

Summit County Search & Rescue team, Sheriff Hamit on the left, Dr. Chris far right.

What did I learn? Stay out of deep, wet snow even if it means going back the long way. Bring extra socks and gloves. Buy gators.

I was not afraid because I knew they were coming before dark. I do feel exhilarated that I was able to do such a challenging hike without any pain or blisters, that my knees were strong enough to extract my feet from the deep snow so many times, and that Isa was with me to warn if any animals were near and announce when the rescuers arrived.

Christine Ebert-Santos, MD, MPS is the founding physician and president of Ebert Family Clinic in Frisco, Colorado, where she leads high altitude research in addition to running a full-time family practice. Isa is a two-year-old blue heeler and Dr. Chris’s familiar and guardian angel.

Acclimation, Altitude Science, Health, High Altitude, Medicine, Mountaineering

How to Stay Healthy During Your Holidays at High Altitude

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Acute Altitude Illness affects about 7.4% of travelers to mountain resort areas, including Frisco, Colorado which sits at an altitude of about 2800 meters. Dr. Kendrick Adnan, MD, MSPH is an emergency medicine physician associated with Vail Health. Dr. Adnan often sees visitors to Vail and other popular ski and vacation areas in Summit County that are experiencing Acute Altitude Illness. I sat down with Dr. Adnan, and we discussed the treatment of Acute Altitude Illness as well as signs, symptoms, risk factors, and prevention of Acute Altitude Illness.

What causes Acute Altitude Illness?

  • Acute Altitude Illness develops when the body responds to hypoxia, a low level of oxygen in the blood. Areas of high altitude have a lower concentration of oxygen in the air than lower altitudes, which makes your body work harder to put oxygen in your blood. Your body responds to the lower oxygen concentration by increasing how often and how deeply you breathe. This causes a decrease in carbon dioxide and increase in tpH in the blood. Your heart, lungs, blood vessels, and kidneys all respond to the low pH in your blood, which can cause the signs and symptoms of Acute Altitude Illness.
  • Some people will experience severe forms of Acute Altitude Illness called High-Altitude Pulmonary Edema or High-Altitude Cerebral Edema. These are life-threatening conditions that can cause death in both adults and children if not treated promptly by a medical professional.

What are the signs and symptoms of Acute Altitude Illness in adults?

  • Headache
  • Nausea
  • Vomiting
  • Decreased appetite
  • Fatigue
  • Shortness of breath on exertion
  • Decreased exercise tolerance
  • Chest tightness
  • Hypoxia

What are the signs and symptoms of Acute Altitude Illness in children?

  • Fussiness
  • Poor feeding
  • Pale or blue-tinged skin
  • Sleeping too much or too little

What is the treatment for Acute Altitude Illness (AAI)?

The best treatment for AAI is supplemental oxygen through a nasal cannula and descent to a lower elevation. You will need to visit a healthcare provider, clinic, or hospital to get supplemental oxygen if your oxygen level drops below 89%. Visitors to high-altitude areas may be hesitant to abandon their vacation plans in order to descend to a lower altitude. A healthcare provider may be able to prescribe medications to help you recover from AAI. However, if your low oxygen level does not improve with supplemental oxygen and medication, it is important to descend to an area of lower altitude.

Studies show that acetazolamide, dexamethasone, and tadalafil are medications that can potentially treat Acute Altitude Illness and/or High-Altitude Pulmonary Edema. A healthcare provider may prescribe these medications for you if appropriate.

What increases the chance that I will experience Acute Altitude Illness?

  • Traveling by airplane from low altitude to high altitude.
  • Being a resident of low altitude
  • Past episode of Acute Altitude Illness
  • Physical exertion at high altitude, especially in colder temperatures

What can be done to prevent Acute Altitude Illness and High-Altitude Pulmonary Edema?

  • A slower ascent will decrease your risk of AAI. Dr. Adnan recommends spending the night in Denver after air travel if you are planning to visit a high-altitude area.
  • Avoid strenuous exercise like skiing, hiking, and mountain biking for 48-72 hours after arrival to a high-altitude area.
  • Buy a pulse oximeter to check your oxygen level. A level above 89% is normal at high-altitude and does not require treatment.
  • Ask your healthcare provider about taking Diamox (acetazolamide) for 2-3 days before you arrive at a high-altitude destination. You will need a prescription for this medication.
  • Avoid medications that decrease your respiratory rate like opiates, sleeping medications, benzodiazepines, and barbiturates.

References

Schafermeyer, R. W. DynaMed. Acute Altitude Illnesses. EBSCO Information Services. https://www.dynamed.com/condition/acute-altitude-illnesses. Accessed November 19, 2021. Simancas-Racines D, Arevalo-Rodriguez I, Osorio D, Franco JVA, Xu Y, Hidalgo R. Interventions for treating acute high altitude illness. Cochrane Database of Systematic Reviews 2018, Issue 6. Art. No.: CD009567. DOI: 10.1002/14651858.CD009567.pub2. Accessed 03 November 2021.

Sasha Scott is a physician assistant student at Drexel University in Philadelphia, PA. She is originally from Indianapolis, IN and attended Purdue University for undergrad. Sasha enjoys running, cross stitching, cooking, and exploring Philadelphia when she is not studying!