Category Archives: Surgery

Doc Talk: an Interview with Emergency Medicine Physician Dr. Jack Gervais

While doing a clinical rotation with Dr. Chris at the Ebert Family Clinic in Frisco, CO I had the pleasure of interviewing local emergency medicine physician, Dr. Jack Gervais.

To start off, if you don’t mind just telling us about yourself, where you work, and how you got into the ED

Dr. Jack Gervais: I grew up in Summit County and then did my undergrad at the University of Denver, and then medical school at University of Colorado in Denver as well, and then did a three-year residency for emergency medicine in Portland, Maine. Then I came back to Frisco in 2011, so this was my first job out of residency, and I’ve been here ever since. As far as what got me into emergency medicine, it just kind of seemed like a good mix of everything, really, and I like doing procedures but didn’t necessarily want to be a surgeon, and so I kind of gravitated towards that.

What percent of your practice involves tourists?

Dr. Jack Gervais: It depends on the season. Obviously during the higher tourist seasons it goes up, but I would say probably on average maybe 50-60% and then during the heavy winter tourism times it’s probably more like 80%, and fall and spring much less.

Let’s say that there is a visitor in Frisco who brought a pulse oximeter with them. At what point, with either their O2 saturation or their symptoms, would you recommend that they go to the ER or seek oxygen administration?

Dr. Jack Gervais: It really depends primarily on the symptoms. People can be symptomatic with a fairly typical kind of mountain sickness symptoms and have a normal oxygenation. We consider anything above 88-90% acceptable.  We get a lot of patients that come in with an ankle injury and their O2 saturation is 85% and they’re really asymptomatic. 

Certainly, anybody who’s symptomatic we will offer O2 to them even if they have a normal saturation. Anybody around 85-86% if they’re not having symptoms and they’re going home in a day or two, I offer oxygen to them, but I don’t necessarily say “oh you have to be on oxygen ’cause you’re 85%”. Anybody who’s under 80%, I would say absolutely should be on O2 regardless ’cause they’re going to end up getting worse.

Let’s say they’re skiing, they check their oxygen saturation, and it’s 85% but they feel fine. Would you say “keep going and be aware if you develop symptoms”? 

Dr. Jack Gervais: Yeah, I think that’s reasonable. People tend to do worse at night, so someone is 85% when they’re standing in the day, they’re probably in the 80s at night. So, what I’ll often do with people with those kind of borderline sats is offer them oxygen. It’s really easy to get the delivery from the various companies so it’s pretty straightforward, more of a cost issue for some people, but I tell them “use it when you sleep the whole time you’re here”. Probably most tourists would benefit from sleeping on oxygen regardless because you don’t know how low they’re getting at night. I would guess most people are sleeping in the mid 80s and don’t realize it. That leads to the headaches and waking up at night and those sorts of things that we see a lot.

What conditions do you see here at altitude and how commonly, i.e. cases of Acute Mountain Sickness (AMS), HAPE (High Altitude Pulmonary Edema), HACE (High Altitude Cerebral Edema), sleep problems, blood pressure issues, etc.?

Dr. Jack Gervais: Typical AMS would be shortness of breath, headache, and nausea being the most common. Any combination of those in people who recently traveled from lower elevation or when locals come back from as few as 4 days of vacation can be AMS. People reset really quickly after they descend, we see a lot of people who get reentry HAPE. Kids will go down for spring break in Florida and come back and get HAPE.

It’s tough to say exactly what incidences, I would estimate probably 20-25% at least people visiting from lower elevation — and that’s when it’s just semantics, but it’s elevation, not altitude, and everybody says “altitude sickness”. Altitude is your height above the ground used by pilots. Elevation is how high you are above sea level, but anyway we see that all the time. That’s pretty simple, you know, basically treat the symptoms: something for nausea and actually ibuprofen has been studied in comparison to acetazolamide and is essentially as effective at preventing acute mountain sickness. I tell everyone just put yourself on an NSAID as long as there’s no clear contraindications to it.

I see at least 12 patients a month with HAPE, so it’s something we see really commonly.  This year is kind of weird though ’cause we’re not having as much tourism. We see a lot more when a storm comes in ’cause the pressure drops-so that 10% drop in barometric pressure is like going up another 500 feet, and so that will often kind of push people over the edge. Again, we tend to see a lot of people who get worse at night because they sleep with low O2 saturation or they struggle through the night and come in first thing in the morning saying “I didn’t sleep at all last night, I’ve got this terrible headache, I’ve got this cough”.

HACE is fairly rare here, but not impossible at this elevation. It’s certainly seen more in high trekkers on Everest and in South America. I would say at the hospital we probably have maybe 3-4 cases a year.

Sleep problems are super common, a lot of people wake up feeling short of breath, they’re dehydrated, they get headaches and of course everything else people are doing on vacation exacerbates all that. We actually have this joke of the Summit County Syncope Syndrome: visiting from low elevation, hot tub, alcohol, overexertion, and cannabis. If you have 3/5, there is no way that your syncope is a dangerous cause!

I don’t know why people bring their blood pressure monitors on vacation, but we definitely see a rise in baseline blood pressure at higher elevation. They say, “I have a little headache” (it’s probably from their acute mountain sickness), they check their blood pressure and its 160 and they end up in the ER, which they don’t need to be.

There are actually some folks at the altitude research center in Denver [who] have a little publication about it, but I certainly see a lot of first-time seizures or breakthrough seizures in people who have never had a seizure before. I think it’s just that little bit of change in oxygenation to the brain if you have a seizure predisposition. We see a lot of people that either have their first-time seizure, and there’s nothing else going on, or they’re really well controlled at home, come up and have a breakthrough seizure a couple of days in.

 One other thing about HAPE that’s interesting is people will come in and they’re like, “oh I haven’t slept for the last two nights, I feel terrible, I’ve had a splitting headache,” and I assume they’ve had that for 24-72 hours before they actually come in. Which means they’ve been sitting around with [low oxygen] — most of the HAPE we see is certainly below 80%. I presume these people have been walking around with sats in the 70s for 24-48 hours and it’s amazing that they’re fine. If you were walking around with your O2 saturation in the 70s at sea level, you’d be dead! So, it’s not just a hypoxia that kills people when they have respiratory illness, it’s got to be the hypercarbia and acidosis and all the other stuff that goes along with it.

HAPE tends to also settle in around day 2-3, some people get it quickly but most of the people say I felt fine on day one, I skied yesterday, felt a little crummy night 2, and then day 3 they feel terrible, night 3 can’t sleep and they’ve got HAPE.

 It’s interesting to see the nurses check in a patient with an O2 sat of 50% and it is really no big deal, just put him in any room — it’s not like a big STEMI activation or something. We stick them on oxygen and no one freaks out. People freak out on their first shift if they’re new and it took me a good year to kind of get used to that.  

 Often, we don’t really need to do anything if we can fix them with oxygen and determine from history and physical that there’s nothing else going on. But that gets tricky ’cause you always worry all these people traveling and they’ve got a little bloody cough, they’re tachycardic and hypoxic, so trying to figure out who we want to work up for a PE (pulmonary embolism) is probably our biggest conundrum. A lot of people will get a little bit of a troponin bump just from probably that hypoxic constraint on the heart so that can be a little tricky to figure out who needs to go get a cardiac work up.  

What does a classic HAPE patient look like?

Dr. Jack Gervais: A healthy 26-year-old male who’s got the classic story of progressive increase in shortness of breath, feel like there’s fluid in their lungs, a raspy cough, a little pink sputum, and their sat’s 65% and they get better pretty quickly on oxygen.

What is the typical treatment for HAPE?

Dr. Jack Gervais: The treatment for HAPE patients is to put them on high flow oxygen, around 15 liters.  So, with HAPE, patients get inflammation and acute pulmonary hypertension which causes fluid buildup in the lungs. So, oxygen is really good at reversing that. We oxygenate the lungs which opens up those blood vessels, reduces the pulmonary hypertension, and that fluid can start to resorb in the lungs.

The typical HAPE patient is in the emergency department for 1-3 hours depending on how bad they were and how they’re doing on the high flow oxygen. We wean them down, with a goal of getting them on a nasal cannula with 3-4 liters of O2, which is what the O2 concentrators and portable O2 tanks can manage. And if we can keep someone above 90% on 3-4L they go home with an oxygen prescription. I tell those people to be on oxygen for 24 hours and to just rest and see how it goes, see how you feel. If you start feeling bad again you should be on oxygen. Rarely we see patients come back in because they aren’t doing well, and those people who do, we tell them, “OK you’re out, time to go down to Denver until your plane leaves”.

Are there any medications you use to treat high altitude illnesses?

Dr. Jack Gervais: I don’t tend to use a lot of other medicines. If the oxygen works, why bother adding a bunch of side effects from medications. Some providers tend to be a lot more into giving nifedipine, a calcium channel blocker, which does reduce pulmonary hypertension. A lot of them will use dexamethasone, but it doesn’t so much help with the respiratory component it tends to help more with the headache aspect, but the oxygen will often fix that too. Dexamethasone is also the temporizing treatment for HACE, but they need to descend immediately. People will use Acetazolamide (Diamox), but it’s really only effective if you start it 2-3 days before you come up to the higher elevation. Starting it after you’ve already got acute mountain sickness is probably worthless and it’s got some funky side effects that makes anything carbonated taste weird and it’s a diuretic so you’re adding dehydration to someone who’s already a little dehydrated.

I tend to be more of a minimalist, so I treat the symptoms and give oxygen if they need it and pretty much leave it at that. I was just listening to a podcast talking about inhaled vasodilators. Inhaled/nebulized nitroglycerin — it goes directly to the pulmonary vessels as a vasodilator, but you don’t get the systemic vasodilation that you would with nifedipine or oral nitroglycerin. This was talking more for acute exacerbations of chronic pulmonary hypertension among other things, but I have to wonder if that would work for our patients.

I know you mentioned ibuprofen, but are there any other over-the-counter options you might suggest someone try for AMS?

Dr. Jack Gervais: There are a whole bunch of supplements and stuff that claim to help with altitude sickness, they’re just not studied in any real scientific way to know for sure. For me it’s really just treating the symptoms, so I usually use Zofran for the nausea or Phenergan if there’s a contraindication, and then alternating Tylenol and ibuprofen and oxygen if needed. So, nothing else as far as a preventative that I’m aware of. If you kind of get into the naturopathic realm there’s probably a whole bunch of suggestions out there.

Everyone fixates on staying hydrated which is important. You’re losing extra fluid and if you’re used to living in Florida, you’re going to lose A LOT of fluid when you come up to higher elevation because of the dry air. I tell most people to try and double what you would drink at home. Hydration is really most effective with the headache part of it. It doesn’t change whether you’re going to get HAPE or not. 

Oh, and the little oxygen cans you see in the convenience stores … those are garbage! For oxygen to be effective it needs to be on continuously. Even if you puffed on that thing for a minute and could get your O2 saturation up from 85% to 90% it’s going to drop right back down. In the hospital, if you turn the oxygen off, their saturation will be back where it was within minutes, so yeah, those things are just a total waste of money.

What has been your experience with COVID-19? 

Dr. Jack Gervais: Luckily, we have had it much better off than places like New York, LA, and even down in Denver. I think that part of it is that overall, we have a pretty healthy population compared to a lot of the bigger city areas and suburbs. There have been some studies out there suggesting that people living in higher elevations do better with COVID than lower elevations and I don’t know if it’s just ’cause your body and your pulmonary system has adapted in some way that helps you deal with COVID, but we’ve certainly had some perfectly healthy local folks get pretty sick from it. 

When the tourists were gone back in March/April/May it was great because everyone is local and if you had respiratory symptoms it was probably COVID. Now that the tourists are coming back, it’s a lot harder to tell clinically, and the other thing is the x-ray in HAPE and the x-ray in COVID look very much the same.

We had one patient in particular who came in and said, “I got here yesterday, had a positive COVID test 14 days ago,” and of course they thought they were fine to come up to the mountains, and sure enough they were short of breath. The people who are foolishly traveling either with active COVID or on the tail end of it do not adapt very well when they get up to this elevation, but most of them just need some oxygen.

We finally have rapid tests at the hospital, so it makes it much easier to kind of tell people “this is just altitude” or “this is altitude plus COVID” or “this is straight-up COVID”. In the summer when we didn’t have a rapid test, we’d get these people who have the overlapping symptoms that could be either. It’s tough to tell them what they should do as far as self-quarantine and isolation.  Can you travel? Can you go try to ski tomorrow because it was just altitude sickness?  

The treatment for COVID ends up being the same: oxygen if you need it and then actually dexamethasone has shown to be effective for patients with COVID who are requiring oxygen.

Even before COVID we would send patients home on oxygen with pneumonia or URI symptoms fairly routinely, which is really not a thing in other places. If you need oxygen with pneumonia in Portland, ME you’re getting admitted. If I called Dr. Chris and said I’ve got a kid of yours who looks like they’ve got bronchiolitis or a URI or even COVID, their sat’s 85% — the answer is almost always going to be “oh, put them on oxygen and if they are OK on a reasonable amount of oxygen they’re probably OK to go home”.

Do you admit COVID patients to the hospital up here if needed?

Dr. Jack Gervais: It’s been really tricky for us to figure out who we can reasonably admit here versus transfer to Denver. Both need to have a higher level of care and be at lower elevation. We have kept COIVID patients here successfully. The thing is, even if you live up here and are used to the altitude you’ve got a respiratory process and you’re hypoxic as a result, it makes sense that you would probably do better down in Denver and probably have less of an oxygen requirement and hopefully not progress to high flow oxygen. You can get someone on high flow here but then they’re stuck here until they get better or they get intubated to be transferred.

What is the most memorable case that you have seen in the ER related to high altitude?

Dr. Jack Gervais: So, I had a professional snowboarder who had gone back to sea level for the summer and then flew back out here and had a shoulder surgery in Vail and was staying in Summit County. He was a day or two post-op and had probably been back in the mountains for three or four days so kind of fit the time frame to develop altitude sickness, and he’s probably on a muscle relaxant, some opiates, some respiratory depressants. So, this is the very end of the night shift, I had a STEMI going on in the other room and this guy comes in at 84-85%. He didn’t look super sick but needed some oxygen. I’m like, “oh, he probably took too much oxycodone,” and so I throw him on some oxygen while I go back and deal with this STEMI.

 I go back, and he wasn’t any better! He was still at like 86% on high flow oxygen. So, we got a chest x-ray and he had a little bit of fluid here and there, so it looks like probably early HAPE, or potentially pneumonia, but fit with more of an altitude issue exacerbated by his post-op care.  So, we put him on Bipap and he’s not getting any better and now he’s low 80s on Bipap, so we intubate him.

Now he’s getting worse and now he’s dropping his blood pressure. This is over probably an hour, so this guy is sick, and we could not get him oxygenated even on max vent support. We were begging him, and I thought he was going to just die right in front of me. Finally, he dropped his blood pressure more and we’re like “well, maybe he’s septic, maybe he aspirated, and this is pneumonia.” So, we give him norepinephrine, which is a vasopressor, it constricts all the blood vessels to help increase the blood pressure and adds ionotropic support to make the heartbeat stronger. Then his blood pressure finally got better, and his oxygen got better, and he went down to the ICU in Denver and I’m like, “thank God I didn’t kill this guy at the end of a 13 hour night shift”.

So, it turns out — and this is what makes it the most interesting — he had a PFO, patent foramen ovale — so, a hole in his heart. It’s very common, but people tend to not notice because in general, the pressure in the left side of your heart outweighs the pressure in your right significantly so that patent foramen ovale stays closed against the septum.

Like I was saying earlier, HAPE is caused by acute pulmonary hypertension which then raises the pressures on the right side of your heart. So, he blew open his PFO and now had a right to left shunt — so blood from the right side of the heart doesn’t go up through the lungs and oxygenate, it goes straight to the left and goes back out into the body unoxygenated. That’s why everything we did made him worse. When you put someone on Bipap, and especially when you intubate them, you’ve got that positive pressure that increases the intrathoracic pressure, which increases the preload on the heart.

Dr. Chris Ebert-Santos: 30% of the population may have PFO!

Dr. Jack Gervais: Coincidentally, the norepinephrine that I put him on trying to treat as sepsis increased the after load — the arterial resistance, which then increased the pressure on the left side of the heart enough that it was able to squeeze his PFO back down.

Dr. Chris Ebert-Santos: The ironic thing is that it’s so random! All of this altitude stuff is SO random, even people who have had AMS or HAPE or whatever they may never get again. I mean 90% probably never have a recurrence.

Dr. Jack Gervais: Yeah people get really frustrated and say “I’ve been here 10 times before, it can’t be altitude sickness” — that can happen, and it does. People have this myth of like, “I used to live here, I’m fine,” and it’s absolutely false.

Another interesting thing you see at altitude is people with sickle cell trait (so not full-blown sickle cell disease, generally thought to be a harmless and completely asymptomatic condition) will get splenic infarcts when they come up. You almost can’t even find reports of it in the literature, but I probably see 8 or 10 a year. It’s kind of easy to pin down, the person is like, “I just got here, I’ve got this left upper quadrant pain, no trauma” — not much in your left upper quadrant, so most of the time the minute they hit triage you know what’s going on. We treat just like you would any sickle cell crisis: fluids, pain medicine, oxygen.

I know you mentioned the myth about people who have lived here before believing they aren’t able to get mountain sickness, but do you have any other myths that you frequently have to clarify?

Dr. Jack Gervais: The big one we run into is people who are taking acetazolamide wrong and are surprised that they’re having altitude sickness. People start getting symptoms and they call their doctor and they may prescribe it too late and I just tell them, “don’t bother”. 

People who think they’ve got an infection or bronchitis so their doctor back home calls in antibiotics, which they don’t need even if it is bronchitis. Or the people who ignore it for 2-4 days to assume it’s the bronchitis and say “the antibiotics aren’t working, doctor what’s wrong?” Well, your lungs are filling up with fluid! The good news is HAPE tends to be gradually progressive over hours to days, not minutes. Very rarely we see patients who are really actively dying from HAPE. In 10 years I have probably seen hundreds if not 1,000 HAPE patients and I’ve only probably had 2-3 who were really, really hard to fix. Probably 10-20 that I’ve had to put on Bipap and transfer down. I think I’ve maybe only intubated 1-2. People get in trouble if they’re up high — 20,000 feet on Mount Everest, don’t have oxygen, that’s where you’d end up dying with HAPE. 

Dr. Chris Ebert-Santos: And how many die at home?

Dr. Jack Gervais: I would say a handful. I’ve had at least one lady who was camping. Had HAPE-like symptoms and came in dying, she was the one I intubated, and she actually lived. I had a guy camping last summer who sounded like (from what his mom described) altitude-related symptoms, although he was just up from the Front Range. I don’t know what they ever found on him, but he was dead when the paramedics got to him. I would say it’s a handful, but not dozens a year.

Thank you for your time Dr. Gervais. Is there anything more you would like to share about high altitude medicine?

Dr. Jack Gervais: I would say probably anybody with any serious cardiac or pulmonary comorbidities who is going to vacation here should really be on oxygen at least at night. That would prevent a huge number of these problems. I actually see a lot of people (locals) who sleep on oxygen at night even if they’re 40 and healthy and don’t really have any issues and they just sleep much better.

And the other thing is you know, especially the people who have lived up in Leadville for 60 years tend to develop a gradually progressive chronic pulmonary hypertension which adds to blood pressure management issues and so that’s an issue we definitely see. So I tell anybody who has any sort of symptoms and is going to be here for a while, “just buy yourself a (oxygen) concentrator, keep it at your house,” that way when they come up for a week vacation every winter they’ve got it and just sleep with O2 every night and avoid all the hassle. And don’t bring your blood pressure cuff on vacation!!

There’s a cardiologist who works over in Vail, he was really convinced that living at altitude is really bad for your chronic blood pressure issues.

Dr. Chris Ebert-Santos: Our interview with three other high-altitude physicians in primary care and cardiology say their standard is “if you’re 50 and you’ve lived here 10 years and you want to live here for another 10 years you should be sleeping on oxygen.”

Rachel Mader is a second-year physician assistant student at Red Rocks Community College. She was born and raised in Colorado Springs and attended Colorado State University where she graduated with a bachelor’s in biology. Before starting PA school, Rachel worked as a Physical Therapy Aide at CSU Health and Medical Center, a CNA at a nursing home, and a Clinical Assistant at Children’s Hospital in Colorado Springs. In her spare time she enjoys spending time with her family, friends, and pets, and eating at new restaurants.

Increased Risks of Orthopedic Surgery at Altitude

With orthopedic surgeries becoming more common at higher altitudes, it is important that we understand the increased risks of surgery at higher elevations. Patients locally (Eagle, Summit, Pitkin, Grand, Lake and other high-altitude counties in Colorado) and those that travel from all over the world to undergo surgery by our orthopedic surgeons are at an increased risk for complications post-surgery. Patients that have surgery at a lower altitude and return to higher elevations post-surgery are also at higher risk for post-operative complications. These risks are higher for everyone having surgery at altitude regardless if you live at higher elevations or are from sea level.

High altitude is defined as 8-12,000 feet. However, increased surgical risks are seen starting at 4000 feet. There are no differences for increased risk if you are acclimated to the altitude (live here) or are visiting. The increased risk of surgery at high altitude is the same for all.

High altitude increases the coagulation state of blood (clotting ability) and hyperventilation (breathe out more than you breathe in), and oxygen saturation of blood and tissues is 10% lower at high altitude compared to low altitudes, leading to a hypoxic state. The hyperventilation state promotes the hypercoagulable state which causes the immune system to respond with a pro-inflammatory state. Acclimation does occur, we adapt, are able to breathe easier and function normally as our bodies make more red blood cells to compensate for the lower available oxygen in the air. However, the hypercoagulability of blood remains, because the hyperventilation state is sustained at high elevations (even if you live here). At high elevations there are physiological differences in pulmonary circulation (blood through the lungs), heart function, and fluid imbalances which induce dehydration that accompanies blood changes contributing to the increased risk of surgery at high elevations.

Risk factors for blood clots from orthopedic surgery for the general population include: decreased mobility or sitting around more, length of surgery (greater than 4 hours increases blood clot risk), joint replacements, smoking, diabetes, and other illnesses.

In general, there is a 40-60% chance of a blood clot following knee or hip replacement surgery. At altitude that risk doubles. There is a 3.8 times greater risk of thromboembolism (blood clots) for knee surgeries at high elevations. Total shoulder replacement surgery also demonstrates a 2-times greater risk of pulmonary embolism at altitude or 39.5%, compared to a 15% chance at sea-level. For rotator cuff repair of the shoulder, there is also an increased risk for blood clots. There is a 1.4-times greater risk for pulmonary embolism (blood clot in the lungs) for lumbar fusions at high altitude. Higher elevation is an independent risk factor for blood clots which lasts up to 90 days post orthopedic surgery.

Anesthesia at high altitude has its own risk. The sustained hyperventilation state at high altitude also leaves the patient more vulnerable to hypoxia and pulmonary edema with anesthesia. These risks can be minimized, however remain elevated for surgeries requiring general anesthesia above 4000 feet.

For patients returning to high altitude following surgery at lower elevations, there exists multiple risks due to hypercoagulable state, increased inflammatory response, and hyperventilation that higher elevations induce. Acclimatization to high altitude is lost within 2 days of being at a lower elevation and can take 3-4 months to achieve again. In as little as 2 hours after arriving at high altitude, the body initiates the above changes and this puts the post-operative patient returning to altitude at risk for a multitude of complications: dehydration, thromboembolisms, hypoxia, atelectasis, and pulmonary edema.

I recently spoke with a patient that grew up in Leadville (10,151 feet) and lives in Summit County (average of 7947 feet). She underwent hip surgery (twice) in Denver. Upon returning to Summit County, she developed high altitude pulmonary edema (HAPE) both times. When she underwent an ankle surgery in Edwards, the surgeon prophylactically treated her for high altitude sickness given her previous history. She did not develop HAPE, but was hypoxic and required oxygen therapy following surgery for a few days. She is a prime example that even those living their entire lives at altitude are susceptible to these increased risks from surgery.

These risks can be minimized by drinking plenty of fluids, using compression socks (TED hose) or sequential compression devices (SCDs), blood thinners (aspirin, Eliquis, or the like), doing ankle pumps and glute squeezes, and getting up and walking around every 1.5-2 hours for 10-15 minutes, all of which help decrease the likelihood that patients will experience blood clots following orthopedic surgeries.

To reduce respiratory or lung related complications it is important to do deep breathing exercises or incorporate the use of an inspirometer post-surgery, use supplemental oxygen if necessary, as well as continue to do these exercises after returning from a lower elevation for at least 2-3 weeks.

High altitude is an independent risk factor for orthopedic surgery complications. However, these increased risks have been seen in trauma patients and other surgical patients as well. The hyperventilation state, hypercoagulability, and elevated inflammatory response are not isolated to orthopedic patients, but exists in everyone living at and visiting higher elevations.

— Jessica Guthrie, BSN, RN

References

Cancienne, J., Diduch, D., & Werner, B. (2017). High altitude is an independent risk factor for postoperative symptomatic venous thromboembolism after knee arthroscopy: A matched case-control study of Medicare patients. Arthroscopy: The Journal of Arthroscopic and Related Surgery 33(2). https://dx.doi.org/10.1016/j.artho.2016.07.031

Damodar, D., Donnally, C., Sheu, J., Law, T., Roche, M., & Hernandez, V. (2018). High altitude an independent risk factor for venous thromboembolisms after total hip arthroplasty. Journal of Arthroplasty 33(8), 2627-2630. https://doi.org/10.1016/j.arth.2018.03.045

Damodar, D., Vakharia, R., Vakharia, A., Sheu, J., Donnally, C., Levy, J., Kaplan, L., & Munoz, J. (2018). A Higher altitude is an independent risk factor for venous thromboembolisms following total shoulder arthroplasty. Journal of Orthopedics 15(4). https://doi.org/10.1016/j.jor.2018.09.003

Donnally, C., Vakharia, A., Sheu, J., Vakharia, R., Damodar, D., Shenoy, K., & Gjolaj, J. (2019). High altitude is an independent risk factor for developing pulmonary embolism, but not a deep vein thrombosis following a 1 to 2 level lumbar fusion. Global Spine Journal 9(7) 729-734. https://doi.org/10.1177/2192568219828349

Tyson, J., Bjerke, B., Genuario, J., & Noonan, T. (2016). Thromboembolic events after arthroscopic knee surgery: Increased risk at high elevation. Arthroscopy: The Journal of Arthroscopic and Related Surgery 32(11), 2350-2354. https://dx.doi.org/10.1016/j.arthro.2016.04.008

Wani, Z. & Sharma, M. (2017). High altitude and anesthesia. Journal of Cardiac Critical Care 1(1), 30-33. https://doi.org/10.1055;s-0037-1604203