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Respiration 2019 28;97(2):125-134. Epub 2018 Sep 28.

Department of Pulmonology, University Hospital Zurich, Zurich,

Background: Changes in pulmonary hemodynamics and cardiac function in patients with chronic obstructive pulmonary disease (COPD) traveling to altitude have not been assessed despite an increasing prevalence of the disease.

Objectives: We hypothesized that pulmonary artery pressure (PAP) significantly increases and cardiac function deteriorates during exposure to hypobaric hypoxia as encountered by traveling to moderate altitude or air flight.

Methods: A total of 37 patients (17 female; median age [quartiles] 66 years [60; 69] with COPD GOLD grade 2-3 [FEV1 57% predicted (49; 71)]) living < 800 m underwent echocardiography in Zurich (490 m) and after 1 night at Davos Jakobshorn (2,590 m) in a randomized order of allocation. Read More

Front Physiol 2018 22;9:752. Epub 2018 Jun 22.

Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.

To evaluate the effects of acute exposure to high altitude and preventive dexamethasone treatment on postural control in patients with chronic obstructive pulmonary disease (COPD). In this randomized, double-blind parallel-group trial, 104 lowlanders with COPD GOLD 1-2 age 20-75 years, living near Bishkek (760 m), were randomized to receive either dexamethasone (2 × 4 mg/day p.o. Read More

Chest 2018 Oct 10;154(4):788-797. Epub 2018 Jul 10.

Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland; Kyrgyz-Swiss High Altitude Clinic and Medical Research Center, Tuja-Ashu, Kyrgyz Republic; Department of Respiratory Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyz Republic. Electronic address:

Background: Patients with COPD may experience acute mountain sickness (AMS) and other altitude-related adverse health effects (ARAHE) when traveling to high altitudes. This study evaluated whether dexamethasone, a drug used for the prevention of AMS in healthy individuals, would prevent AMS/ARAHE in patients with COPD.

Methods: This placebo-controlled, double-blind, parallel-design trial included patients with COPD and Global Initiative for Obstructive Lung Disease grade 1 to 2 who were living below 800 m. Read More

Physiol Behav 2018 05 16;188:262-269. Epub 2018 Feb 16.

Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada.

With exposure to acute normobaric hypoxia, global cerebral oxygen delivery is maintained via increases in cerebral blood flow (CBF); therefore, regional and localized changes in oxygen tension may explain neurocognitive impairment. Neurovascular coupling (NVC) is the close temporal and regional relationship of CBF to changes in neural activity and may aid in explaining the localized CBF response with cognitive activation. High-altitude related cognitive impairment is likely affected by hypocapnic cerebral vasoconstriction that may influence regional CBF regulation independent of hypoxia. Read More

Int J Appl Basic Med Res 2017 Oct-Dec;7(4):272-274

Department of Physical Medicine and Rehabilitation, AIIMS, Bhubaneswar, Odisha, India.

Sickle cell trait is a highly prevalent condition. It is not a disease. However, it has been associated with few rare complications. Read More

Arch Bronconeumol 2018 03 15;54(3):115-116. Epub 2017 Jul 15.

Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia, Lima, Perú.

Front Physiol 2017 30;8:366. Epub 2017 May 30.

Department of Automation, Biocybernetics and Robotics, Jozef Stefan InstituteLjubljana, Slovenia.

Obesity is associated with numerous chronic ailments and represents one of the major health and economic issues in the modernized societies. Accordingly, there is an obvious need for novel treatment approaches. Recently, based on the reports of reduced appetite and subsequent weight loss following high-altitude sojourns, exposure to hypoxia has been proposed as a viable weight-reduction strategy. Read More

High Alt Med Biol 2017 Jun 22;18(2):163-170. Epub 2017 May 22.

6 Department of Surgical Sciences, Uppsala University , Uppsala, Sweden .

Counter, S. Allen, Leo H. Buchanan, Fernando Ortega, Anthony B. Read More

High Alt Med Biol 2017 Jun 16;18(2):121-127. Epub 2017 May 16.

1 Division of Wilderness Medicine, Department of Emergency Medicine, Massachusetts General Hospital , Harvard Medical School, Boston, Massachusetts.

Phillips, Lara, Buddha Basnyat, Yuchiao Chang, Erik R. Swenson, and N. Stuart Harris. Read More

Mediators Inflamm 2016 9;2016:1942460. Epub 2016 Jun 9.

Medical Intensive Care Unit, University Hospital of Zurich, 8091 Zurich, Switzerland.

Introduction. Acute exposure to high altitude induces inflammation. However, the relationship between inflammation and high altitude related illness such as high altitude pulmonary edema (HAPE) and acute mountain sickness (AMS) is poorly understood. Read More

Heart 2016 08 23;102(16):1296-301. Epub 2016 May 23.

Department of Cardiology, Center for Congenital Heart Disease, Inselspital, University Hospital, University of Bern, Bern, Switzerland.

Objective: High altitude-related hypoxia induces pulmonary vasoconstriction. In Fontan patients without a contractile subpulmonary ventricle, an increase in pulmonary artery pressure is expected to decrease circulatory output and reduce exercise capacity. This study investigates the direct effects of short-term high altitude exposure on pulmonary blood flow (PBF) and exercise capacity in Fontan patients. Read More

Wilderness Environ Med 2015 Dec;26(4 Suppl):S76-91

Longs Peak Sports Medicine, Longmont, Colorado (Dr Madden).

Children, older adults, disabled and special needs athletes, and female athletes who participate in outdoor and wilderness sports and activities each face unique risks. For children and adolescents traveling to high altitude, the preparticipation physical evaluation should focus on risk assessment, prevention strategies, early recognition of altitude-related symptoms, management plans, and appropriate follow-up. As the risk and prevalence of chronic disease increases with age, both older patients and providers need to be aware of disease and medication-specific risks relative to wilderness sport and activity participation. Read More

Trop Med Int Health 2016 Jan 12;21(1):41-51. Epub 2015 Nov 12.

Central American Population Center, University of Costa Rica, San José, Costa Rica.

Objectives: Recent studies in Central America indicate that mortality attributable to chronic kidney disease (CKD) is rising rapidly. We sought to determine the prevalence and regional variation of CKD and the relationship of biologic and socio-economic factors to CKD risk in the older-adult population of Costa Rica.

Methods: We used data from the Costa Rican Longevity and Health Aging Study (CRELES). Read More

Clin J Sport Med 2015 Sep;25(5):443-55

*Clinical Outcomes Research, Intermountain Healthcare, Salt Lake City, Utah; †Department of Family Medicine, University of Colorado, Denver, Colorado; ‡CJW Sports Medicine, Richmond, Virginia; §Anne Arundel Medical Center, Orthopedic and Sports Medicine Center, Annapolis, Maryland; ¶Missouri State University, Springfield, Missouri; ‖Department of Emergency Medicine, University of Colorado, Aurora, Colorado; **Big Island Family Medicine Center, Lynchburg, Virginia; and ††Longs Peak Sports Medicine, Longmont, Colorado.

Children, older adults, disabled and special needs athletes, and female athletes who participate in outdoor and wilderness sports and activities each face unique risks. For children and adolescents traveling to high altitude, the preparticipation physical evaluation should focus on risk assessment, prevention strategies, early recognition of altitude-related symptoms, management plans, and appropriate follow-up. As the risk and prevalence of chronic disease increases with age, both older patients and providers need to be aware of disease and medication-specific risks relative to wilderness sport and activity participation. Read More

J Appl Physiol (1985) 2015 Dec 30;119(12):1466-80. Epub 2015 Jul 30.

Sleep Disorders Center, Pulmonary Division, University Hospital of Zurich, Zurich; Switzerland; Zurich Center for Human Integrative Physiology, University of Zurich, Zurich, Switzerland; and.

Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0. Read More

Exp Physiol 2015 Aug 5;100(8):905-14. Epub 2015 Jul 5.

Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland.

New Findings: What is the central question of this study? Cerebral hypoxia impairs cognitive function and exercise performance and may result in brain damage. Residents at high altitude, in particular those with high-altitude pulmonary hypertension, are prone to hypoxaemia due to the exposure to reduced barometric pressure and impaired pulmonary gas exchange. Whether highlanders have a reduced cerebral oxygenation has not been studied. Read More

Sleep Breath 2016 Mar 19;20(1):5-13. Epub 2015 Apr 19.

Kafkas University School of Medicine, Kars, Turkey.

Purpose: Repetitive obstruction of larynx during sleep can lead to daytime pulmonary hypertension and alterations in right ventricular morphology and function in a small fraction of obstructive sleep apnea syndrome (OSAS) patients. Environmental effects, particularly high altitude, can modify the effects of OSAS on pulmonary circulation, since altitude-related hypoxia is related with pulmonary vasoconstriction. This potential interaction, however, was not investigated in previous studies. Read More

Wilderness Environ Med 2015 Sep 8;26(3):319-26. Epub 2015 Apr 8.

Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA (Drs Pitman and Harris).

Objective: To investigate whether ultrasonography can be used for field volume status assessment and to determine whether a detectable difference in intravascular volume exists in individuals with acute mountain sickness (AMS) compared with those without.

Methods: Study was performed at the Himalayan Rescue Association Clinic in Manang, Nepal, located on the Annapurna trekking circuit at an altitude of 3519 m (11545 feet). A convenience sample was taken from individuals trekking over 5 to 8 days from 760 m (2490 feet) to 3519 m (11,545 feet), comparing asymptomatic trekkers vs those who experienced AMS. Read More

Neurol Clin Pract 2015 Apr;5(2):102-107

Department of Neurology, University of Missouri, Columbia.

Problems at altitude are most often thought of in trained athletes summiting extremes of elevation. A more common group that needs consideration is the average person with obstructive sleep apnea who must travel to high altitudes for business or pleasure. While the altitudes involved are not likely to be as extreme as for those athletes climbing peaks like Mt. Read More

Pediatr Pulmonol 2014 Nov 27;49(11):E144-6. Epub 2014 May 27.

Division of Pediatric Pulmonology, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California.

We report a case of a young boy with recurrent episodes of syncope at elevated altitude. While not conforming to common presentations of altitude sickness, the differential diagnoses and possible etiologies are discussed. Read More

Pulm Circ 2013 Sep 11;3(3):499-506. Epub 2013 Nov 11.

1 Department of Internal Medicine, Universities of Giessen and Marburg Lung Center, Giessen, Germany.

Abstract Pulmonary hypertension (PH) is a chronic, complex, and progressive disease that eventuates in fatality. Research efforts over the past decades have resulted in therapeutic options that improve quality of life and prolong survival of patients, but they do not offer a cure. We propose a philosophical model that a disturbed balance of yin and yang results in pulmonary vascular remodeling, the hallmark of PH pathology. Read More

High Alt Med Biol 2013 Dec;14(4):405-7

1 Himalayan Rescue Association , Kathmandu, Nepal .

Altitude related illness occurs in unacclimatized individuals ascending to altitudes over 2500 m. Treatment usually involves descending to lower altitudes and pharmacological therapies. There are very few cases, studies, or recommendations regarding the use of positive pressure ventilation in acute mountain sickness (AMS) or high altitude pulmonary edema (HAPE). Read More

PLoS One 2013 13;8(9):e74220. Epub 2013 Sep 13.

IFHAD: Innovation For Health And Development, Laboratory of Research and Development 218, Universidad Peruana Cayetano Heredia, San Martin de Porres, Lima, Peru ; Research Department of Infection and Population Health and the School of Medicine, University College London, London, United Kingdom.

Background: Tuberculosis infection, disease and mortality are all less common at high than low altitude and ascent to high altitude was historically recommended for treatment. The immunological and mycobacterial mechanisms underlying the association between altitude and tuberculosis are unclear. We studied the effects of altitude on mycobacteria and antimycobacterial immunity. Read More

Heart Lung Circ 2013 Jan 2;22(1):31-7. Epub 2012 Sep 2.

Kafkas University School of Medicine, Kars, Turkey.

Introduction: Pulmonary vasculature is affected in patients with chronic pulmonary obstructive disease (COPD). As a result of increased pulmonary resistance, right ventricular morphology and function are altered in COPD patients. High altitude and related hypoxia causes pulmonary vasoconstriction, thereby affecting the right ventricle. Read More

Dtsch Arztebl Int 2011 Dec 9;108(49):839-47; quiz 848. Epub 2011 Dec 9.

Medizinische Universitätsklinik Heidelberg, Innere Medizin VII Sportmedizin.

Background: High-altitude travel, for mountain climbing, trekking, or sightseeing, has become very popular. Therefore, the awareness of its dangers has increased, and many prospective travelers seek medical advice before setting forth on their trip.

Methods: We selectively searched the literature for relevant original articles and reviews about acclimatization to high altitude and about high-altitude-related illnesses, including acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) (search in Medline for articles published from 1960-2010). Read More

Clin Toxicol (Phila) 2011 Aug 23;49(7):629-40. Epub 2011 Aug 23.

Department of Emergency Medicine, Drexel University College of Medicine, Philadelphia, PA 19102, USA.

Context: Mining operations conducted at high altitudes provide health challenges for workers as well as for medical personnel.

Objective: To review the literature regarding adverse health effects and toxic exposures that may be associated with mining operations conducted at altitude and to discuss pre-placement screening, acclimatization issues, and on-site surveillance strategies.

Methods: We used the Ovid ( http://ovidsp. Read More

High Alt Med Biol 2010 ;11(3):183-8

Internal Medicine II, Section of Sports and Rehabilitation Medicine, University Hospital Ulm, Ulm, Germany.

Tourism to high altitude is very popular and includes elderly people with both manifest and subclinical coronary heart disease (CHD). Thus, risk assessment regarding high altitude exposure of patients with CHD is of increasing interest, and individual recommendations are expected despite the lack of sufficient scientific evidence. The major factor increasing cardiac stress is hypoxia. Read More

Prog Cardiovasc Dis 2010 May-Jun;52(6):467-84

Warwick Medical School, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK.

Barometric pressure falls with increasing altitude and consequently there is a reduction in the partial pressure of oxygen resulting in a hypoxic challenge to any individual ascending to altitude. A spectrum of high altitude illnesses can occur when the hypoxic stress outstrips the subject's ability to acclimatize. Acute altitude-related problems consist of the common syndrome of acute mountain sickness, which is relatively benign and usually self-limiting, and the rarer, more serious syndromes of high-altitude cerebral edema and high-altitude pulmonary edema. Read More

High Alt Med Biol 2010 ;11(1):27-30

School of Human Kinetics, University of British Columbia, Vancouver, BC, Canada.

Endothelial nitric oxide synthase (eNOS) is a vascular enzyme that produces nitric oxide, a transient signaling molecule that by vasodilatation regulates blood flow and pressure. Nitric oxide is believed to play roles in both short-term acclimatization and long-term evolutionary adaptation to environmental hypoxia. Several laboratories, including ours, have shown that variants in NOS3 (the gene encoding eNOS) are overrepresented in individuals with altitude-related illnesses such as high altitude pulmonary edema (HAPE) and acute mountain sickness (AMS), suggesting that NOS3 genotypes contribute to altitude tolerance. Read More

NeuroRehabilitation 2010 ;26(1):73-84

Denver Health and Hospitals, 777 Bannock Street MC#4000, Denver, CO 80204, USA.

As increasing numbers of people live, work, and play at high altitudes, awareness of the neurological consequences of hypobaric hypoxic environments becomes paramount. Despite volumes of studies examining the pathophysiology of altitude sickness, the underlying mechanisms of the spectrum of altitude related illnesses is still elusive. High altitude headache, acute mountain sickness, high altitude cerebral edema and other neurological presentations including sleep disturbances and seizures at high altitude are reviewed. Read More

High Alt Med Biol 2009 ;10(3):239-45

Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria.

Little information is available on the prevalence of acute mountain sickness (AMS) in the Eastern Alps compared with the Western Alps. Because of differences regarding the populations of mountaineers, we hypothesized that the prevalence differs between the Eastern and Western Alps. Thus, we determined the prevalence and risk factors of AMS at four different altitudes in the Eastern Alps of Austria. Read More

Aviat Space Environ Med 2009 Feb;80(2):102-7

Respiratory Physiology Laboratory, 4th floor Riverside Block, Christchurch Hospital, private bag 4710, Christchurch 8001, New Zealand.

Introduction: Exposure to altitude invariably involves some form of physical activity. There are limited data available to help predict the response to activity at altitude in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to investigate the response to acute altitude exposure at rest and during exercise in patients with COPD. Read More

High Alt Med Biol 2008 ;9(3):199-207

University Cayetano Heredia, Av. Velasco Astete 911, Lima 41, Peru.

There are numerous publications on altitude-related diseases in adults. In addition, an International Consensus Statement published in 2001 deals with altitude-related illnesses occurring in lowland children who travel to high altitudes. However, despite the millions of children living permanently at high altitudes around the world, there are few publications on altitude-related diseases and pulmonary hemodynamics in this pediatric population. Read More

Expert Opin Pharmacother 2008 Jan;9(1):119-27

University Hospital (Selly Oak), The Diabetes Centre, Raddlebarn Road, Selly Oak, B29 6JD, Birmingham, UK.

The pharmacotherapy of prevention and treatment of acute altitude- related problems - acute mountain sickness, high-altitude cerebral oedema and high-altitude pulmonary oedema - is reviewed. Drug therapy is only part of the answer to the medical problems of high altitude; prevention should include slow ascent and treatment of the more severe illnesses should include appropriate descent. Carbonic anhydrase inhibitors, in particular acetazolamide, remain the most effective drugs in preventing, to a large extent, the symptoms of acute mountain sickness, and can be used in the immediate management of the more severe forms of altitude-related illnesses. Read More

BMC Infect Dis 2007 Sep 19;7:109. Epub 2007 Sep 19.

KNCV Tuberculosis Foundation, The Hague, The Netherlands.

Background: Studies show that tuberculosis notification declines with increasing altitude. This can be due to declining incidence or declining case detection. In Vietnam notification rates of new smear-positive tuberculosis in the central mountainous provinces (26/100,000 population) are considerably lower than in Vietnam in general (69/100,000 population). Read More

High Alt Med Biol 2007 ;8(3):213-24

Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA.

While high altitude adaptations have been studied extensively, limited research has examined moderate altitude (MA: 1500 to 3000 m) adaptations and their time course, despite the fact that millions of people sojourn to or reside at MA. We retrospectively examined long-term MA acclimatization by analyzing recurring physical fitness test results and hematological data among 2147 college-age male cadets previously residing at either sea level (SL) or MA and currently attending the U.S. Read More

High Alt Med Biol 2007 ;8(3):206-12

School of Human Kinetics, University of British Columbia, Vancouver, Canada.

Acute Mountain Sickness (AMS), the most common and least serious of the altitude-related illnesses, is frequently experienced by sojourners traveling above 2500 m. Although altitude and rate of ascent are likely the most critical factors in determining whether the condition will develop in a person, interindividual variation and patterns of susceptibility suggest that there may be genetic risk factors as well. We hypothesized that variants in the gene that encodes the beta-2 adrenergic receptor (the principal catecholamine receptor in the lungs) are involved in the etiology of AMS and tested this hypothesis in cohorts of Nepalese individuals who developed or did not develop AMS when attending the Purnima Festival at Lake Gosain Kunda at 4380. Read More

Pulm Pharmacol Ther 2007 16;20(4):388-95. Epub 2006 Nov 16.

Critical Care Medicine Directorate, University Hospital of Wales, Cardiff, UK.

Cough is a troublesome condition which affects many visitors to high altitude. Traditionally it has been attributed to the inspiration of the cold, dry air which characterizes the high altitude environment. This aetiology was brought into question by observations and experiments in long duration hypobaric chamber studies in which cough still occurred despite controlled temperature and humidity. Read More

High Alt Med Biol 2006 ;7(2):150-67

School of Human Kinetics, University of British Columbia, Canada.

Altitude-related illnesses are a family of interrelated pulmonary, cerebral, hematological, and cardiovascular medical conditions associated with the diminished oxygen availability at moderate to high altitudes. The acute forms of these debilitating and potentially fatal conditions, which include acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE), often develop in incompletely acclimatized lowlanders shortly after ascent, whereas, the chronic conditions, such as chronic mountain sickness (CMS) and high altitude pulmonary hypertension (HAPH), usually afflict native or long-term highlanders and may reflect a loss of adaptation. Anecdotal reports of particularly susceptible people or families are frequently cited as evidence that certain individuals have an innate susceptibility (or resistance) to developing these conditions and, in recent decades, there have been a number of studies designed to characterize the physiology of individuals predisposed to these conditions, as well as to identify the specific genetic variants that contribute to this predisposition. Read More

Clin Chest Med 2005 Sep;26(3):395-404, v

Division of Pulmonary and Critical Medicine, University of Colorado Health Sciences Center, 4220 East 9th Avenue, C-272, Denver, CO 80262, USA.

High-altitude-related pulmonary disease is a spectrum of acute and chronic illnesses with a well-described epidemiology. The risk for these illnesses is related to well-known environmental risk factors and lesser-known but important genetic factors. Prevention of acute high-altitude illness is possible in most visitors from lower elevations. Read More

Clin Sports Med 2005 Jul;24(3):695-718, x

Department of Family Medicine, University of Virginia Health System, PO Box 800729, Charlottesville, VA 22908, USA.

This article examines environmental illness in athletes. Causes, symptoms, and treatment of heat-related illness, cold-related illness, and altitude-related illness are discussed. Read More

High Alt Med Biol 2004 ;5(4):410-9

Département de Médecine Communautaire, Hôpitaux Universitaires, Geneva, Switzerland.

Acute altitude exposure may lead to acute mountain sickness (AMS). Increased awareness of altitude-related health hazards in trekkers may accompany a decrease in AMS prevalence. We compared awareness and AMS prevalence in trekkers in two cohorts on an altitude trek up to 5400 m and assessed risk factors for AMS by repeating an observational cohort study 12 yr after an initial study. Read More

J Appl Physiol (1985) 2005 Jan;98(1):384-9

Department of Pediatrics, University of Colorado Health Sciences Center, Denver, CO, USA.

Pulmonary hypertension had long been suspected in high-altitude natives of the Andes. However, it remained for a team of Peruvian scientists led by Dante Penaloza to provide not only the first clear evidence that humans living at high altitude did indeed have chronic, and occasionally severe, pulmonary hypertension, but more importantly, that this was a consequence of structural changes in the pulmonary vascular bed. Novel histological findings by one of the team, Javier Arias-Stella, indicated that hypoxia-induced thickening of the pulmonary arteriolar walls was the primary cause of the elevated pressure. Read More

Exp Physiol 2005 Jan 4;90(1):103-10. Epub 2004 Oct 4.

Institute for Cardiovascular Research, University of Leeds, Leeds LS2 9JT, UK.

High altitude (HA) dwellers have an exceptionally high tolerance to orthostatic stress, and this may partly be related to their high packed cell and blood volumes. However, it is not known whether their orthostatic tolerance would be changed after relief of the altitude-related hypoxia. Furthermore, orthostatic tolerance is known also to be influenced by the efficiency of the control of peripheral vascular resistance and by the effectiveness of cerebral autoregulation and these have not been reported in HA dwellers. Read More

Heart Lung 2004 Jan-Feb;33(1):3-12

Department of Acute/Tertiary Care, School of Nursing, Pittsburgh, Pennsylvania, USA.

This second section of a 2-part review on high-altitude-related disorders focuses on strategies for prevention of high-altitude illness, identification of populations at increased risk for high-altitude illness, and effects of high altitude on selected chronic medical conditions. Practical aspects of advising and educating patients traveling to high altitude will be discussed, with special reference to pregnant women, infants and young children, healthy elders, and chronic medical conditions that may place persons at greater risk for high-altitude illness. The special concerns of pre-verbal children will be covered relative to the risks of high altitude for those too young to voice symptoms of illness and, thus, at-risk for potential serious consequences caused by delay in diagnosis and treatment. Read More

High Alt Med Biol 2003 ;4(4):419-30

Alaska Native Medical Center, Anchorage, Alaska 99508, USA.

The goal of this paper is to review how preexisting ocular conditions may be affected by altitude exposure. Such preexisting conditions include dry eye problems, monocular visual loss, and potential problems following refractive surgery procedures, as well as the possible changes associated with some forms of retinal and optic nerve diseases. Although most such altitude-related visual difficulties are relatively minor, some have resulted in serious morbidity or even death at high altitude. Read More

Heart Lung 2003 Nov-Dec;32(6):353-9

Department of Acute/Tertiary Care, School of Nursing, University of Pittsburgh, Pennsylvania 15261, USA.

As increasing numbers of people choose to sojourn or retire to the mountains, high-altitude illness is becoming a pathological phenomenon about which healthcare providers should have greater awareness. Hypoxia is the primary cause of high-altitude illness, but other stressors on the sympathetic nervous system, such as cold and exertion, also contribute to disease development and progression. Although variable across persons, symptoms of high-altitude disorders usually occur at altitudes over 7000 feet, and typically in 1 of 3 forms: acute mountain sickness (AMS), high-altitude cerebral edema (HACE), or high-altitude pulmonary edema (HAPE). Read More

Aviat Space Environ Med 2003 Sep;74(9):922-7

Division of Cardiology, McGill University, Montreal, Quebec, Canada.

Background: Individuals with pulmonary and cardiac disorders are particularly at risk of developing hypoxemia at altitude. Our objective is to describe the normal and maladaptive physiological responses to altitude-related hypoxia, to review existing methods and guidelines for preflight assessment of air travelers, and to provide recommendations for treatment of hypoxia at altitude.

Data Synthesis: Falling partial pressure of oxygen with altitude results in a number of physiologic adaptations including hyperventilation, pulmonary vasoconstriction, altered ventilation/perfusion matching, and increased sympathetic tone. Read More

High Alt Med Biol 2003 ;4(1):93-8

A review of six patients requiring medical assessment prior to joining commercial mountaineering trips. Medical problems encountered include malaria risk with immunosuppression, renal transplant recipients climbing at altitude, coronary artery disease risk at altitude, cardiac pacemaker function at altitude, and diabetes with remote-area travel. Cases also illustrate personal and commercial risk assessment and potential international differences in legal duty of care. Read More

Chest 2003 Jan;123(1):49-53

Emergency Department, Hopital de Moutiers, Moutiers, France.

Study Objectives: To describe a group of patients who acquired pulmonary edema at a moderate altitude of 1,400 to 2,400 m.

Design: Observational, retrospective chart review (1992-2000) of a series of 52 consecutive patients admitted for high-altitude pulmonary edema (HAPE) that occurred at 1,400 to 2,400 m.

Setting: Emergency department of a community hospital in the French Alps (altitude, 500 m). Read More