High Altitude Illness

Davis, P. R.; Pattinson, Kyle T.S.; Mason, Nicholas; Richards, Pamela Spence; Hillebrandt, David

doi:10.1136/jramc-157-01-03

Cited by 16 publications

(19 citation statements)

References 21 publications

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“…20% of the population, approximately 10 million people, live at altitudes between 2,500 and 3,500 masl, 3 a level classifi ed as high altitude. 4,5 As the altitude increases, the barometric pressure and inspired pressure of oxygen fall, leading to diminished P ao 2 and Pa o 2 . Th is causes a compensatory increase of the ventilation with Pa co 2 reduction, favoring the occurrence of central apnea (CA) and periodic breathing (PB) during sleep.…”

mentioning

confidence: 99%

Overnight Polysomnographic Characteristics and Oxygen Saturation of Healthy Infants, 1 to 18 Months of Age, Born and Residing At High Altitude (2,640 Meters)

Duenas-Meza

Bazurto-Zapata

Gozal

et al. 2015

Chest

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confidence: 99%

Overnight Polysomnographic Characteristics and Oxygen Saturation of Healthy Infants, 1 to 18 Months of Age, Born and Residing At High Altitude (2,640 Meters)

Duenas-Meza

Bazurto-Zapata

Gozal

et al. 2015

Chest

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“…6) More and more studies were concerned on the prophylaxis and therapy of AMS. [7][8][9] In vitro hypoxia and in vivo whole-body hypoxia can cause tissue release reactive oxygen species (ROS) which are potentially damaging to the cardiovascular system. 10) Hypoxia rapidly increases the levels of free radicals in organism, which is thought to overwhelm the reserves of scavengers.…”

mentioning

confidence: 99%

The Antioxidative Effect of a Novel Free Radical Scavenger 4′-Hydroxyl-2-substituted Phenylnitronyl Nitroxide in Acute High-Altitude Hypoxia Mice

Fan

Jing

et al. 2013

Biological & Pharmaceutical Bulletin

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Acute mountain sickness is caused by sub-acute hypoxia in healthy individuals going rapidly to altitude. Both tissue hypoxia in vitro and whole-body hypoxia in vivo have been found to promote the release of reactive oxygen species. Nitronyl nitroxide can trap free radicals such as ·NO or ·OH, and may therefore be efficient protective agents. This study assessed the ability of nitronyl nitroxide to against acute mountain sickness as a free radical scavenger in acute high-altitude hypoxia mice model. Normobaric hypoxia and hypobaric hypoxia model were used to estimate the protect effects of nitronyl nitroxide against acute mountain sickness. Low pressure oxygen compartment system was used to stimulate high-altitude hypobaric hypoxia environment. Mice in nitronyl nitroxide groups survived longer than acetazolamide group in normobaric hypoxia test. Hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) increased in both cerebrum and myocardium in vehicle group. The results indicated more radicals were generated during high-altitude hypobaric hypoxia environment. In therapeutic groups H 2 O 2 and MDA were significantly reduced while the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were similar to normal group. These results demonstrated that nitronyl nitroxide was an efficient tissue radical scavenger and a potential protective agent for acute mountain sickness.Key words nitronyl nitroxide; antioxidant; free radical scavenger; acute high-altitude hypoxia More than 140 million people worldwide live >2500 m above sea level. Eighty million live in Asia, and 35 million live in the Andean mountains. The latter region has its major population density living above 3500 m.1) Barometric pressure falls with increasing altitude and consequently in the partial pressure of oxygen reduced. This leads to a hypoxic challenge to any individual ascending to altitude. A spectrum of highaltitude illnesses can occur when the hypoxic stress outstrips the subject's ability to acclimatize.2) Acute mountain sickness (AMS) is a condition affecting otherwise healthy individuals going rapidly to altitude. It is caused by sub-acute hypoxia in susceptible subjects.3) Acute hypoxia induces pulmonary vascular permeability and contributes to forms of noncardiogenic pulmonary edema such as high-altitude pulmonary edema and acute respiratory distress syndrome.4,5) AMS can sharply limit people's recreation and working at high altitude, especially in the first few days following arrival at a new, higher altitude. 6)More and more studies were concerned on the prophylaxis and therapy of AMS. 7-9)In vitro hypoxia and in vivo whole-body hypoxia can cause tissue release reactive oxygen species (ROS) which are potentially damaging to the cardiovascular system. 10) Hypoxia rapidly increases the levels of free radicals in organism, which is thought to overwhelm the reserves of scavengers. The radicals then damage cell walls, reduce the flexibility of blood vessels, destroy enzymes, and cause other molecular damage...

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“…To compensate this, the body reacts with tachycardia, hyperventilation, hypocapnia and metabolic It is extremely important to know the rate of ascent suggested for each pick. A few reports mention that over 3000 mts only 300 mts should be climbed per day [9,10].…”

Section: Discussionmentioning

confidence: 99%

High Altitude Retinal Hemorrhage

Borrone¹,

Torres²

2017

J Clin Exp Ophthalmol

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Objective: sudden atmospheric pressure changes can generate vascular modifications in the retina. We present a clinical case of retinal hemorrhage related to high altitude and propose to revise its pathophysiology. Methods:A case presentation with review of literature.Results: 36 year old Male patient came to our institute with sudden diminished vision in the right eye associated with loss of consciousness while climbing a mountain. In the ophthalmological examination, we could appreciate in the right eye a macular hemorrhage and in both eyes few diffuse hemorrhages in mild periphery. The patient lost follow-up and return after 1 year for a check-up. He had spontaneous resolution of all hemorrhages.Conclusion: the acute mountain sickness affects mostly not climatized people. Changes in atmospheric pressure generate reduction of the partial pressure of oxygen in the blood. This can lead to vascular changes in the retina. This change may not appear if there is a proper climatization while climbing a mountain. The presence of high altitude retinopathy alerts about cerebral oedema related to high altitude.

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High Altitude Illness

Cited by 16 publications

References 21 publications

Overnight Polysomnographic Characteristics and Oxygen Saturation of Healthy Infants, 1 to 18 Months of Age, Born and Residing At High Altitude (2,640 Meters)

Overnight Polysomnographic Characteristics and Oxygen Saturation of Healthy Infants, 1 to 18 Months of Age, Born and Residing At High Altitude (2,640 Meters)

The Antioxidative Effect of a Novel Free Radical Scavenger 4′-Hydroxyl-2-substituted Phenylnitronyl Nitroxide in Acute High-Altitude Hypoxia Mice

High Altitude Retinal Hemorrhage

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