Blood and Haemostasis

Bärtsch, Peter; Milledge, Jim

doi:10.1007/978-1-4614-8772-2_10

Cited by 3 publications

(3 citation statements)

References 66 publications

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“…Compared to the Himalayas and the Andes, it is often possible to return from high-altitude terrain very fast, maybe even with the help of a cable car. Third, the altitude is relatively low compared to the Himalayas or Andes, so in the highest areas, the partial oxygen pressure is still only reduced to approximately fifty percent compared to sea level [ 16 , 17 , 18 , 19 , 28 , 29 ]. Nevertheless, the SAC central registry was analyzed from 2009 to 2020.…”

Section: Discussionmentioning

confidence: 99%

Rescue Emergencies Due to High-Altitude Illnesses Are Rare in Switzerland

Gasser

Stouder

2022

IJERPH

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Background: Despite a potential high risk of acute mountain sickness (AMS) in the Swiss Alps, there is a lack of analyses concerning its relevance over longer periods. In consequence, the aim of this study is to analyze the prevalence of AMS in comparison to other causes of mountain emergencies in recent years in Switzerland. Material and Methods: Based on the central registry of mountain emergencies of the Swiss Alpine Club (SAC), all cases in the period between 2009 and 2020 were analyzed for AMS including the most severe forms of high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE). Emergencies were assessed for the severity of the event with a National Advisory Committee for Aeronautics (NACA) score. Results: From a total of 4596 high-altitude mountaineering emergencies identified in the observational period, a total number of 352 cases of illnesses were detected. Detailed analysis revealed 85 cases of AMS, 5 cases of HAPE, and 1 case of HACE. The average altitude was 3845 ± 540 m. Most cases were in the canton of Valais, especially in the Monte Rosa region and the mountains of the Mischabel group (Täschhorn, Dom, Südlenz, Nadelhorn, Hohberghorn). There were only three deaths related to high-altitude illnesses; all the other events could be identified as moderate to severe but not life-threatening. Discussion: An emergency due to AMS that requires rescue is unlikely in the Swiss Alps. This does not imply that AMS is not a concern. However, the facts that the maximal altitude is relatively low and that fast self-descents often seem possible probably minimize the likelihood that mountaineers with symptoms contact emergency services.

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Section: Discussionmentioning

confidence: 99%

Rescue Emergencies Due to High-Altitude Illnesses Are Rare in Switzerland

Gasser

Stouder

2022

IJERPH

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“…This is also observed in the decrease of the typical highaltitude symptomatology quantified through LLS, which usually peaks after 2 days at altitude, and then decreases consistently to almost baseline after 60 hours. Although variations in iron status markers are uncommon during short altitude exposure (Piperno et al, 2011;Goetze et al, 2013;Bärtsch and Milledge, 2014), the finding of increased serum ferritin at 24 hours, which coincides with peak LLS, might FIG. 2. Plasma Epo, sEpoR, and Epo/sEpoR during high-altitude exposure.…”

Section: Discussionmentioning

confidence: 99%

“…However, the erythropoietic process continues and reaches a steady-state at a substantially higher hematocrit level despite circulating Epo concentration close to sea-level values. This phenomenon is known as the ''Epo paradox'' (Bärtsch and Milledge, 2014) and implies that only a marginally increased plasma Epo concentration is required to support continued erythropoiesis and to sustain erythropoietic drive under chronic hypoxic conditions. Because the half-life of RBCs is *3 months, their rate of destruction results much slower than their rate of production under this long-term altitude exposure, and therefore a higher steady-state hematocrit value is maintained.…”

Section: Introductionmentioning

confidence: 99%

High-Altitude Hypoxia Decreases Plasma Erythropoietin Soluble Receptor Concentration in Lowlanders

Vizcardo‐Galindo

León‐Velarde

Villafuerte

2020

High Altitude Medicine & Biology

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Vizcardo-Galindo, Gustavo, Fabiola León-Velarde, and Francisco C. Villafuerte. High-altitude hypoxia decreases plasma erythropoietin soluble receptor concentration in lowlanders. High Alt Med Biol. 21:92-98, 2020. Background: The soluble form of the erythropoietin (Epo) receptor (sEpoR) is an endogenous antagonist of Epo. Decreasing plasma sEpoR increases free Epo, thereby increasing the availability of the hormone. In humans, shortterm intermittent normobaric hypoxia exposure reduces sEpoR concentration in plasma. However, whether similar changes occur during continuous hypoxia, such as during high-altitude exposure with ongoing acclimatization, is yet unknown. Therefore, this study aimed to characterize the time-course concentration profile of sEpoR, and also of Epo, reticulocyte count (RC), and hematocrit in healthy lowlanders during 4 days at high altitude.Methods: Twenty-two men residents at sea level traveled by road (*7 hours) from Lima to Cerro de Pasco (4340 m) for 72 hours. Oxygen saturation as measured by pulse oximetry (SpO 2 ), heart rate, systolic and diastolic blood pressure, Lake Louise Score, sEpoR, Epo, RC, and hematocrit were evaluated every 12 hours, starting 12 hours before the ascent. Results: Plasma sEpoR decreased by 19% and remained below baseline values throughout high-altitude exposure. In parallel, Epo levels increased during the first hours, reaching a peak at 48 hours, and then progressively decreased until 72 hours. As a result, the Epo-to-sEpoR ratio (Epo/sEpoR) remained significantly elevated compared with baseline values. RC increased linearly until the end of the protocol, and hematocrit only showed a marginal increase. Conclusion: Our results show that high-altitude hypoxia causes a significant and stable reduction of plasma sEpoR concentration within the first 24 hours, whereas plasma Epo constantly decreases after having reached a maximum by 48 hours. This simultaneous change leads to a relatively high Epo/sEpoR after 72 hours at high altitude. The early increase in hematocrit likely relates to hemoconcentration, but the steady increase in RC reflects a sustained erythropoietic drive that will lead to elevate hematocrit to a new steady state after acclimatization.

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Altitude physiology then (1921) and now (2021): Meat on the bones

Wagner

2022

Physiological Reviews

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Blood and Haemostasis

Cited by 3 publications

References 66 publications

Rescue Emergencies Due to High-Altitude Illnesses Are Rare in Switzerland

Rescue Emergencies Due to High-Altitude Illnesses Are Rare in Switzerland

High-Altitude Hypoxia Decreases Plasma Erythropoietin Soluble Receptor Concentration in Lowlanders

Altitude physiology then (1921) and now (2021): Meat on the bones

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