Acute High-Altitude Illnesses

Bärtsch, Peter; Swenson, Erik R.

doi:10.1056/nejmcp1214870

Cited by 456 publications

(459 citation statements)

References 46 publications

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“…Clinical aspects HAPE occurs in healthy individuals at altitudes >2500-3000 m within 1-5 days after arrival [52]. It is rarely observed below these altitudes and after 1 week of acclimatisation.…”

Section: Hapementioning

confidence: 99%

“…A similar increase in HAPE incidence of 2.5% versus 15.5% occurs when an altitude of 5500 m is reached by trekking over 4-6 days as opposed to airlift. In those with a history of radiographically documented HAPE, the likelihood of developing HAPE is 60% with a 1-2-day ascent to the same altitude [52,53].…”

Section: Hapementioning

confidence: 99%

“…This recommendation, the specifics of which vary slightly depending on the resource cited [52,101,102], derives largely from observational data [103,104] and has only been examined in a prospective, randomised manner in a single study [24]. Because local terrain and logistical factors often prevent adherence to these specific altitude limits on a day-by-day basis, individuals should instead focus on the ascent rate averaged over the entire trip [105].…”

Section: Nonpharmacological Measures Slow Ascentmentioning

confidence: 99%

“…However, pharmacological prophylaxis is not necessary in all high-altitude travellers, and instead should be initiated based on an assessment of the risk of acute altitude illness associated with a planned trip that accounts for the individual's prior performance at high altitude, if known, and features of the planned ascent, such as the altitude reached on the first day, the number of planned rest days and the anticipated increase in sleeping elevation once >2500-3000 m (table 3) [52,102]. Pharmacological prophylaxis should be strongly considered for moderate-high-risk ascent profiles, but is not necessary in low-risk situations.…”

Section: Pharmacological Measuresmentioning

confidence: 99%

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Acute high-altitude sickness

2017

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At any point 1-5 days following ascent to altitudes ⩾2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases.

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Section: Hapementioning

confidence: 99%

Section: Hapementioning

confidence: 99%

Section: Nonpharmacological Measures Slow Ascentmentioning

confidence: 99%

Section: Pharmacological Measuresmentioning

confidence: 99%

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Acute high-altitude sickness

2017

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“…Occurrence of overt or clinical form of HAPE is dependent on quantum of hypoxia exposure (altitude achieved), rate of ascent, duration of hypoxia exposure and amount of physical activity undertaken at that altitude by the individual [9].Therefore, assuming that an individual resistant to HAPE at 3400 m will not suffer from it at 4500 m seems to be an anomaly. Possibly, results of the present study could have been very interesting if chemokine levels were studied in these individuals after exposure to simulated hypoxia equivalent to 3400 m for a longer duration (like 24 h) as clinical HAPE is known to occur after an exposure to hypoxia of 2 or more days after an ascent to altitudes above 3000 m [11].…”

Section: To the Editormentioning

confidence: 94%

Chemokines in High Altitude Pulmonary Edema

Bhattachar

Sikri

2016

Ind J Clin Biochem

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Partial Pressure of Arterial Oxygen in Healthy Adults at High Altitudes

Forrer,

Gaisl,

Sevik

et al. 2023

JAMA Netw Open

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ImportanceWith increasing altitude, the partial pressure of inspired oxygen decreases and, consequently, the Pao2 decreases. Even though this phenomenon is well known, the extent of the reduction as a function of altitude remains unknown.ObjectiveTo calculate an effect size estimate for the decrease in Pao2 with each kilometer of vertical gain among healthy unacclimatized adults and to identify factors associated with Pao2 at high altitude (HA).Data SourcesA systematic search of PubMed and Embase was performed from database inception to April 11, 2023. Search terms included arterial blood gases and altitude.Study SelectionA total of 53 peer-reviewed prospective studies in healthy adults providing results of arterial blood gas analysis at low altitude (&lt;1500 m) and within the first 3 days at the target altitude (≥1500 m) were analyzed.Data Extraction and SynthesisPrimary and secondary outcomes as well as study characteristics were extracted from the included studies, and individual participant data (IPD) were requested. Estimates were pooled using a random-effects DerSimonian-Laird model for the meta-analysis.Main Outcomes and MeasuresMean effect size estimates and 95% CIs for reduction in Pao2 at HA and factors associated with Pao2 at HA in healthy adults.ResultsAll of the 53 studies involving 777 adults (mean [SD] age, 36.2 [10.5] years; 510 men [65.6%]) reporting 115 group ascents to altitudes between 1524 m and 8730 m were included in the aggregated data analysis; 13 of those studies involving 305 individuals (mean [SD] age, 39.8 [13.6] years; 185 men [60.7%]) reporting 29 ascents were included in the IPD analysis. The estimated effect size of Pao2 was −1.60 kPa (95% CI, −1.73 to −1.47 kPa) for each 1000 m of altitude gain (τ2 = 0.14; I2 = 86%). The Pao2 estimation model based on IPD data revealed that target altitude (−1.53 kPa per 1000 m; 95% CI, −1.63 to −1.42 kPa per 1000 m), age (−0.01 kPa per year; 95% CI, −0.02 to −0.003 kPa per year), and time spent at an altitude of 1500 m or higher (0.16 kPa per day; 95% CI, 0.11-0.21 kPa per day) were significantly associated with Pao2.Conclusions and RelevanceIn this systematic review and meta-analysis, the mean decrease in Pao2 was 1.60 kPa per 1000 m of vertical ascent. This effect size estimate may improve the understanding of physiological mechanisms, assist in the clinical interpretation of acute altitude illness in healthy individuals, and serve as a reference for physicians counseling patients with cardiorespiratory disease who are traveling to HA regions.

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Acute High-Altitude Illnesses

Cited by 456 publications

References 46 publications

Acute high-altitude sickness

Acute high-altitude sickness

Chemokines in High Altitude Pulmonary Edema

Partial Pressure of Arterial Oxygen in Healthy Adults at High Altitudes

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