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Liu B, Yuan M, Yang M, Zhu H, Zhang W. The Effect of High-Altitude Hypoxia on Neuropsychiatric Functions. High Alt Med Biol 2024; 25:26-41. [PMID: 37815821 DOI: 10.1089/ham.2022.0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023] Open
Abstract
Liu, Bo, Minlan Yuan, Mei Yang, Hongru Zhu, and Wei Zhang. The effect of high-altitude hypoxia on neuropsychiatric functions. High Alt Med Biol. 25:26-41, 2024. Background: In recent years, there has been a growing popularity in engaging in activities at high altitudes, such as hiking and work. However, these high-altitude environments pose risks of hypoxia, which can lead to various acute or chronic cerebral diseases. These conditions include common neurological diseases such as acute mountain sickness (AMS), high-altitude cerebral edema, and altitude-related cerebrovascular diseases, as well as psychiatric disorders such as anxiety, depression, and psychosis. However, reviews of altitude-related neuropsychiatric conditions and their potential mechanisms are rare. Methods: We conducted searches on PubMed and Google Scholar, exploring existing literature encompassing preclinical and clinical studies. Our aim was to summarize the prevalent neuropsychiatric diseases induced by altitude hypoxia, the potential pathophysiological mechanisms, as well as the available pharmacological and nonpharmacological strategies for prevention and intervention. Results: The development of altitude-related cerebral diseases may arise from various pathogenic processes, including neurovascular alterations associated with hypoxia, cytotoxic responses, activation of reactive oxygen species, and dysregulation of the expression of hypoxia inducible factor-1 and nuclear factor erythroid 2-related factor 2. Furthermore, the interplay between hypoxia-induced neurological and psychiatric changes is believed to play a role in the progression of brain damage. Conclusions: While there is some evidence pointing to pathophysiological changes in hypoxia-induced brain damage, the precise mechanisms responsible for neuropsychiatric alterations remain elusive. Currently, the range of prevention and intervention strategies available is primarily focused on addressing AMS, with a preference for prevention rather than treatment.
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Affiliation(s)
- Bo Liu
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
- Zigong Mental Health Center, Zigong, China
| | - Minlan Yuan
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
| | - Mei Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China School of Basic Medical Sciences and Forensic Medicine, Chengdu, Sichuan
| | - Hongru Zhu
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
| | - Wei Zhang
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, China
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Luks AM, Beidleman BA, Freer L, Grissom CK, Keyes LE, McIntosh SE, Rodway GW, Schoene RB, Zafren K, Hackett PH. Wilderness Medical Society Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness: 2024 Update. Wilderness Environ Med 2024; 35:2S-19S. [PMID: 37833187 DOI: 10.1016/j.wem.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 04/14/2023] [Accepted: 05/17/2023] [Indexed: 10/15/2023]
Abstract
To provide guidance to clinicians about best practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for prevention, diagnosis, and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. Recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches for managing each form of acute altitude illness that incorporate these recommendations as well as recommendations on how to approach high altitude travel following COVID-19 infection. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in Wilderness & Environmental Medicine in 2010 and the subsequently updated WMS Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness published in 2014 and 2019.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA
| | - Beth A Beidleman
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, MA
| | - Luanne Freer
- Everest ER, Himalayan Rescue Association, Kathmandu, Nepal
| | - Colin K Grissom
- Pulmonary and Critical Care Medicine, Intermountain Healthcare and the University of Utah, Salt Lake City, UT
| | - Linda E Keyes
- Department of Emergency Medicine, Section of Wilderness Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO
| | - Scott E McIntosh
- Department of Emergency Medicine, University of Utah Health, Salt Lake City, UT
| | - George W Rodway
- Department of Family Medicine-Sports Medicine, University of Nevada, Reno School of Medicine, Reno, NV
| | - Robert B Schoene
- Division of Pulmonary and Critical Care Medicine, Sound Physicians, St. Mary's Medical Center and Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, CA
| | - Ken Zafren
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA
- Himalayan Rescue Association, Kathmandu, Nepal
| | - Peter H Hackett
- Altitude Research Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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Zhu Y, Li Q, Wu Y, Peng X, Xiang X, Lau B, Tzang F, Liu L, Li T. Protective Effect of Modified Hemoglobin on Rabbits and Goats in High-Altitude Sickness. Adv Biol (Weinh) 2023; 7:e2200307. [PMID: 37097708 DOI: 10.1002/adbi.202200307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/06/2023] [Indexed: 04/26/2023]
Abstract
The prevalence and severity of high-altitude sickness increases with increasing altitude. Prevention of hypoxia caused by high-altitude sickness is an urgent problem. As a novel oxygen-carrying fluid, modified hemoglobin can carry oxygen in a full oxygen partial pressure environment and release oxygen in a low oxygen partial pressure environment. It is unclear whether modified hemoglobin can improve hypoxic injury on a plateau. Using hypobaric chamber rabbit (5000 m) and plateau goat (3600 m) models, general behavioral scores and vital signs, hemodynamic, vital organ functions, and blood gas are measured. The results show that the general behavioral scores and vital signs decrease significantly in the hypobaric chamber or plateau, and the modified hemoglobin can effectively improve the general behavioral scores and vital signs in rabbits and goats, and reduce the degree of damage to vital organs. Further studies reveal that arterial partial pressure of oxygen (PaO2 ) and arterial oxygen saturation (SaO2 ) on the plateau decrease rapidly, and the modified hemoglobin could increase PaO2 and SaO2 ; thus, increasing the oxygen-carrying capacity. Moreover, modified hemoglobin has few side effects on hemodynamics and kidney injury. These results indicate that modified hemoglobin has a protective effect against high-altitude sickness.
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Affiliation(s)
- Yu Zhu
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Qinghui Li
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Yue Wu
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Xiaoyong Peng
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Xinming Xiang
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Billy Lau
- New Beta Innovation Limited, Kowloon Bay, Hong Kong, Hong Kong SAR, 999077, China
| | - Feichuen Tzang
- New Beta Innovation Limited, Kowloon Bay, Hong Kong, Hong Kong SAR, 999077, China
| | - Liangming Liu
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Tao Li
- State Key Laboratory of Trauma, Burns, and Combined Injury, Department of Shock and Transfusion, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
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Tannheimer M, Lechner R. Initial Treatment of High-Altitude Pulmonary Edema: Comparison of Oxygen and Auto-PEEP. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16185. [PMID: 36498257 PMCID: PMC9737163 DOI: 10.3390/ijerph192316185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 11/27/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Improvement of oxygenation is the aim in the therapy of high-altitude pulmonary edema (HAPE). However, descent is often difficult and hyperbaric chambers, as well as bottled oxygen, are often not available. We compare Auto-PEEP (AP-Pat), a special kind of pursed lips breathing, against the application of bottled oxygen (O2-Pat) in two patients suffering from HAPE. METHODS We compare the effect of these two different therapies on oxygen saturation measured by pulse oximetry (SpO2) over time. RESULT In both patients SpO2 increased significantly from 65-70% to 95%. Above 80% this increase was slower in AP-Pat compared with O2-Pat. Therapy started immediately in AP-Pat but was delayed in O2-Pat because of organizational and logistic reasons. CONCLUSIONS The well-established therapies of HAPE are always the option of choice, if available, and should be started as soon as possible. The advantage of Auto-PEEP is its all-time availability. It improves SpO2 nearly as well as 3 L/min oxygen and furthermore has a positive effect on oxygenation lasting for approximately 120 min after stopping. Auto-PEEP treatment does not appear inferior to oxygen treatment, at least in this cross-case comparison. Its immediate application after diagnosis probably plays an important role here.
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Affiliation(s)
- Markus Tannheimer
- Department of Sport and Rehabilitation Medicine, University of Ulm, Leimgrubenweg 14, 89075 Ulm, Germany
- Department of General and Visceral Surgery, Krankenhaus Blaubeuren, Ulmer Straße 26, 89143 Blaubeuren, Germany
| | - Raimund Lechner
- Department of Anesthesiology, Intensive Care, Emergency Medicine and Pain Therapy, Bundeswehr Hospital Ulm, Oberer Eselsberg 40, 89081 Ulm, Germany
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Aksel G, Çorbacıoğlu ŞK, Özen C. High-altitude illness: Management approach. Turk J Emerg Med 2019; 19:121-126. [PMID: 31687609 PMCID: PMC6819752 DOI: 10.1016/j.tjem.2019.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 09/15/2019] [Accepted: 09/15/2019] [Indexed: 11/30/2022] Open
Abstract
In high altitudes, usually above 2500 m, travelers are faced with decreased partial pressure of oxygen along with decreased barometric pressure. High-altitude illness, a syndrome of acute mountain sickness, high-altitude cerebral edema and high-altitude pulmonary edema, occurs due to the hypobaric hypoxia when there is inadequate acclimatization. This review provides detailed information about pathophysiology, clinical features, prevention and treatment strategies for high-altitude illness according to the current literature.
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Affiliation(s)
- Gökhan Aksel
- University of Health Sciences, Ümraniye Training and Research Hospital, Emergency Medicine Clinic, İstanbul, Turkey
| | - Şeref Kerem Çorbacıoğlu
- University of Health Sciences, Keçiören Training and Research Hospital, Emergency Medicine Clinic, Ankara, Turkey
| | - Can Özen
- Emergency Department, King's College Hospital, London, UK
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Luks AM, Auerbach PS, Freer L, Grissom CK, Keyes LE, McIntosh SE, Rodway GW, Schoene RB, Zafren K, Hackett PH. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update. Wilderness Environ Med 2019; 30:S3-S18. [PMID: 31248818 DOI: 10.1016/j.wem.2019.04.006] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 04/12/2019] [Accepted: 04/19/2019] [Indexed: 12/16/2022]
Abstract
To provide guidance to clinicians about best preventive and therapeutic practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for prevention and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. Recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to prevention and management of each form of acute altitude illness that incorporate these recommendations. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in 2010 and subsequently updated as the WMS Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness in 2014.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA.
| | - Paul S Auerbach
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA
| | - Luanne Freer
- Yellowstone National Park, WY; Midway Atoll National Wildlife Refuge, Honolulu, HI; Everest ER, Himalayan Rescue Association, Kathmandu, Nepal
| | - Colin K Grissom
- Division of Pulmonary and Critical Care Medicine, Intermountain Medical Center, Salt Lake City, UT; Division of Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, UT
| | - Linda E Keyes
- Department of Emergency Medicine, University of Colorado, Denver, CO; Boulder Community Health, Boulder, CO
| | - Scott E McIntosh
- Division of Emergency Medicine, University of Utah, Salt Lake City, UT
| | - George W Rodway
- University of California, Davis School of Nursing, Sacramento, CA
| | - Robert B Schoene
- Division of Pulmonary and Critical Care Medicine, Sound Physicians, St. Mary's Medical Center, San Francisco, CA
| | - Ken Zafren
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA; Himalayan Rescue Association, Kathmandu, Nepal
| | - Peter H Hackett
- Altitude Research Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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Molano Franco D, Nieto Estrada VH, Gonzalez Garay AG, Martí‐Carvajal AJ, Arevalo‐Rodriguez I. Interventions for preventing high altitude illness: Part 3. Miscellaneous and non-pharmacological interventions. Cochrane Database Syst Rev 2019; 4:CD013315. [PMID: 31012483 PMCID: PMC6477878 DOI: 10.1002/14651858.cd013315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND High altitude illness (HAI) is a term used to describe a group of mainly cerebral and pulmonary syndromes that can occur during travel to elevations above 2500 metres (˜ 8200 feet). Acute mountain sickness (AMS), high altitude cerebral oedema (HACE), and high altitude pulmonary oedema (HAPE) are reported as potential medical problems associated with high altitude ascent. In this, the third of a series of three reviews about preventive strategies for HAI, we assessed the effectiveness of miscellaneous and non-pharmacological interventions. OBJECTIVES To assess the clinical effectiveness and adverse events of miscellaneous and non-pharmacological interventions for preventing acute HAI in people who are at risk of developing high altitude illness in any setting. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) in January 2019. We adapted the MEDLINE strategy for searching the other databases. We used a combination of thesaurus-based and free-text search terms. We scanned the reference lists and citations of included trials and any relevant systematic reviews that we identified for further references to additional trials. SELECTION CRITERIA We included randomized controlled trials conducted in any setting where non-pharmacological and miscellaneous interventions were employed to prevent acute HAI, including preacclimatization measures and the administration of non-pharmacological supplements. We included trials involving participants who are at risk of developing high altitude illness (AMS or HACE, or HAPE, or both). We included participants with, and without, a history of high altitude illness. We applied no age or gender restrictions. We included trials where the relevant intervention was administered before the beginning of ascent. DATA COLLECTION AND ANALYSIS We used the standard methodological procedures employed by Cochrane. MAIN RESULTS We included 20 studies (1406 participants, 21 references) in this review. Thirty studies (14 ongoing, and 16 pending classification (awaiting)) will be considered in future versions of this suite of three reviews as appropriate. We report the results for the primary outcome of this review (risk of AMS) by each group of assessed interventions.Group 1. Preacclimatization and other measures based on pressureUse of simulated altitude or remote ischaemic preconditioning (RIPC) might not improve the risk of AMS on subsequent exposure to altitude, but this effect is uncertain (simulated altitude: risk ratio (RR) 1.18, 95% confidence interval (CI) 0.82 to 1.71; I² = 0%; 3 trials, 140 participants; low-quality evidence. RIPC: RR 3.0, 95% CI 0.69 to 13.12; 1 trial, 40 participants; low-quality evidence). We found evidence of improvement of this risk using positive end-expiratory pressure (PEEP), but this information was derived from a cross-over trial with a limited number of participants (OR 3.67, 95% CI 1.38 to 9.76; 1 trial, 8 participants; low-quality evidence). We found scarcity of evidence about the risk of adverse events for these interventions.Group 2. Supplements and vitaminsSupplementation of antioxidants, medroxyprogesterone, iron or Rhodiola crenulata might not improve the risk of AMS on exposure to high altitude, but this effect is uncertain (antioxidants: RR 0.58, 95% CI 0.32 to 1.03; 1 trial, 18 participants; low-quality evidence. Medroxyprogesterone: RR 0.71, 95% CI 0.48 to 1.05; I² = 0%; 2 trials, 32 participants; low-quality evidence. Iron: RR 0.65, 95% CI 0.38 to 1.11; I² = 0%; 2 trials, 65 participants; low-quality evidence. R crenulata: RR 1.00, 95% CI 0.78 to 1.29; 1 trial, 125 participants; low-quality evidence). We found evidence of improvement of this risk with the administration of erythropoietin, but this information was extracted from a trial with issues related to risk of bias and imprecision (RR 0.41, 95% CI 0.20 to 0.84; 1 trial, 39 participants; very low-quality evidence). Regarding administration of ginkgo biloba, we did not perform a pooled estimation of RR for AMS due to considerable heterogeneity between the included studies (I² = 65%). RR estimates from the individual studies were conflicting (from 0.05 to 1.03; low-quality evidence). We found scarcity of evidence about the risk of adverse events for these interventions.Group 3. Other comparisonsWe found heterogeneous evidence regarding the risk of AMS when ginkgo biloba was compared with acetazolamide (I² = 63%). RR estimates from the individual studies were conflicting (estimations from 0.11 (95% CI 0.01 to 1.86) to 2.97 (95% CI 1.70 to 5.21); low-quality evidence). We found evidence of improvement when ginkgo biloba was administered along with acetazolamide, but this information was derived from a single trial with issues associated to risk of bias (compared to ginkgo biloba alone: RR 0.43, 95% CI 0.26 to 0.71; 1 trial, 311 participants; low-quality evidence). Administration of medroxyprogesterone plus acetazolamide did not improve the risk of AMS when compared to administration of medroxyprogesterone or acetazolamide alone (RR 1.33, 95% CI 0.50 to 3.55; 1 trial, 12 participants; low-quality evidence). We found scarcity of evidence about the risk of adverse events for these interventions. AUTHORS' CONCLUSIONS This Cochrane Review is the final in a series of three providing relevant information to clinicians, and other interested parties, on how to prevent high altitude illness. The assessment of non-pharmacological and miscellaneous interventions suggests that there is heterogeneous and even contradictory evidence related to the effectiveness of these prophylactic strategies. Safety of these interventions remains as an unclear issue due to lack of assessment. Overall, the evidence is limited due to its quality (low to very low), the relative paucity of that evidence and the number of studies pending classification for the three reviews belonging to this series (30 studies either awaiting classification or ongoing). Additional studies, especially those comparing with pharmacological alternatives (such as acetazolamide) are required, in order to establish or refute the strategies evaluated in this review.
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Affiliation(s)
- Daniel Molano Franco
- Fundacion Universitaria de Ciencias de la Salud, Hospital de San JoséDepartment of Critical CareCarrera 19 # 8‐32BogotaBogotaColombia11001
| | - Víctor H Nieto Estrada
- Los Cobos Medical Centre. Grupo Investigacion GRIBOSDepartment of Critical CareBogotaBogotaColombia
| | | | | | - Ingrid Arevalo‐Rodriguez
- Hospital Universitario Ramón y Cajal (IRYCIS), CIBER Epidemiology and Public Health (CIBERESP)Clinical Biostatistics UnitCtra. Colmenar Km. 9,100MadridSpain28034
- Cochrane Associate Centre of MadridMadridSpain
- Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio Espejo, Universidad Tecnológica EquinoccialCochrane EcuadorQuitoEcuador
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Savina Y, Leal S, Zellner P, Becker F, Piris M, Cauchy E. The Effect of a 300 mBar Increase in Barometric Pressure on Digital Microcirculation in Healthy Subjects Exposed to High Altitude: Is the Use of a Portable Hyperbaric Chamber to Treat Frostbite and/or Hypothermia in the Field Indicated? (Flow_Pulse Study). High Alt Med Biol 2019; 20:56-60. [PMID: 30615485 DOI: 10.1089/ham.2018.0069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION Hypothermia and frostbite occur when there is a significant decrease in central and peripheral body temperature in individuals exposed to cold windy conditions, often at high altitude or in a mountain environment. Portable hyperbaric chambers increase the barometric pressure and thereby the partial pressure of oxygen inside the chamber, and their use is a well-known treatment for altitude illness. This study aims to show that a portable hyperbaric chamber could also be used to treat hypothermia and frostbite in the field, when rescue or descent is impossible or delayed. METHODS During a European research program (SOS-MAM, Flow Pulse study) measurements were taken from 27 healthy nonacclimatized voluntary subjects (21 men, 6 women, mean age 41 ± 17) at an altitude of 3800 m (Chamonix Mountain Lab, Aiguille du Midi, France) right before and immediately after spending 1 hour in a portable hyperbaric chamber at 300 mbar. We measured digital cutaneous temperature (Tcut), digital cutaneous blood flow (Fcut), digital tissue oxygenation (TcPO2), blood oxygen saturation (SpO2), heart rate, and core temperature. Air temperature inside the chamber (Tchamb) was measured throughout the whole session. RESULTS We observed significant increases in Tchamb: 9.3°C compared with the outside temperature, Tcut: +7.5°C (±6.2°C 71%), Fcut: +58PU (±89) (+379%), TcPO2: +18 mmHg (±11.9) (304%), and SpO2: 13%. CONCLUSION This study shows that a portable hyperbaric chamber can be used to treat frostbite and/or hypothermia in the field at altitude when descent or rescue is impossible or even simply delayed.
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Affiliation(s)
- Yann Savina
- 1 IFREMMONT (Institut de Formation et de Recherche en Médecine de Montagne) Hôpital de Chamonix, Hôpital de Chamonix, Chamonix, France
| | - Sandra Leal
- 1 IFREMMONT (Institut de Formation et de Recherche en Médecine de Montagne) Hôpital de Chamonix, Hôpital de Chamonix, Chamonix, France
| | - Pascal Zellner
- 1 IFREMMONT (Institut de Formation et de Recherche en Médecine de Montagne) Hôpital de Chamonix, Hôpital de Chamonix, Chamonix, France
| | - François Becker
- 1 IFREMMONT (Institut de Formation et de Recherche en Médecine de Montagne) Hôpital de Chamonix, Hôpital de Chamonix, Chamonix, France.,2 Médecine Vasculaire, Hôpitaux Universitaires de Genève, Genève, Switzerland
| | - Monica Piris
- 1 IFREMMONT (Institut de Formation et de Recherche en Médecine de Montagne) Hôpital de Chamonix, Hôpital de Chamonix, Chamonix, France
| | - Emmanuel Cauchy
- 1 IFREMMONT (Institut de Formation et de Recherche en Médecine de Montagne) Hôpital de Chamonix, Hôpital de Chamonix, Chamonix, France
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Simancas‐Racines D, Arevalo‐Rodriguez I, Osorio D, Franco JVA, Xu Y, Hidalgo R. Interventions for treating acute high altitude illness. Cochrane Database Syst Rev 2018; 6:CD009567. [PMID: 29959871 PMCID: PMC6513207 DOI: 10.1002/14651858.cd009567.pub2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Acute high altitude illness is defined as a group of cerebral and pulmonary syndromes that can occur during travel to high altitudes. It is more common above 2500 metres, but can be seen at lower elevations, especially in susceptible people. Acute high altitude illness includes a wide spectrum of syndromes defined under the terms 'acute mountain sickness' (AMS), 'high altitude cerebral oedema' and 'high altitude pulmonary oedema'. There are several interventions available to treat this condition, both pharmacological and non-pharmacological; however, there is a great uncertainty regarding their benefits and harms. OBJECTIVES To assess the clinical effectiveness, and safety of interventions (non-pharmacological and pharmacological), as monotherapy or in any combination, for treating acute high altitude illness. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science, CINAHL, Wanfang database and the World Health Organization International Clinical Trials Registry Platform for ongoing studies on 10 August 2017. We did not apply any language restriction. SELECTION CRITERIA We included randomized controlled trials evaluating the effects of pharmacological and non-pharmacological interventions for individuals suffering from acute high altitude illness: acute mountain sickness, high altitude pulmonary oedema or high altitude cerebral oedema. DATA COLLECTION AND ANALYSIS Two review authors independently assessed the eligibility of study reports, the risk of bias for each and performed the data extraction. We resolved disagreements through discussion with a third author. We assessed the quality of evidence with GRADE. MAIN RESULTS We included 13 studies enrolling a total of 468 participants. We identified two ongoing studies. All studies included adults, and two studies included both teenagers and adults. The 13 studies took place in high altitude areas, mostly in the European Alps. Twelve studies included participants with acute mountain sickness, and one study included participants with high altitude pulmonary oedema. Follow-up was usually less than one day. We downgraded the quality of the evidence in most cases due to risk of bias and imprecision. We report results for the main comparisons as follows.Non-pharmacological interventions (3 studies, 124 participants)All-cause mortality and complete relief of AMS symptoms were not reported in the three included trials. One study in 64 participants found that a simulated descent of 193 millibars versus 20 millibars may reduce the average of symptoms to 2.5 vs 3.1 units after 12 hours of treatment (clinical score ranged from 0 to 11 ‒ worse; reduction of 0.6 points on average with the intervention; low quality of evidence). In addition, no complications were found with use of hyperbaric chambers versus supplementary oxygen (one study; 29 participants; low-quality evidence).Pharmacological interventions (11 trials, 375 participants)All-cause mortality was not reported in the 11 included trials. One trial found a greater proportion of participants with complete relief of AMS symptoms after 12 and 16 hours when dexamethasone was administered in comparison with placebo (47.1% versus 0%, respectively; one study; 35 participants; low quality of evidence). Likewise, when acetazolamide was compared with placebo, the effects on symptom severity was uncertain (standardized mean difference (SMD) -1.15, 95% CI -2.56 to 0.27; 2 studies, 25 participants; low-quality evidence). One trial of dexamethasone in comparison with placebo in 35 participants found a reduction in symptom severity (difference on change in the AMS score: 3.7 units reported by authors; moderate quality of evidence). The effects from two additional trials comparing gabapentin with placebo and magnesium with placebo on symptom severity at the end of treatment were uncertain. For gabapentin versus placebo: mean visual analogue scale (VAS) score of 2.92 versus 4.75, respectively; 24 participants; low quality of evidence. For magnesium versus placebo: mean scores of 9 and 10.3 units, respectively; 25 participants; low quality of evidence). The trials did not find adverse events from either treatment (low quality of evidence). One trial comparing magnesium sulphate versus placebo found that flushing was a frequent event in the magnesium sulphate arm (percentage of flushing: 75% versus 7.7%, respectively; one study; 25 participants; low quality of evidence). AUTHORS' CONCLUSIONS There is limited available evidence to determine the effects of non-pharmacological and pharmacological interventions in treating acute high altitude illness. Low-quality evidence suggests that dexamethasone and acetazolamide might reduce AMS score compared to placebo. However, the clinical benefits and harms related to these potential interventions remain unclear. Overall, the evidence is of limited practical significance in the clinical field. High-quality research in this field is needed, since most trials were poorly conducted and reported.
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Affiliation(s)
- Daniel Simancas‐Racines
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
| | - Ingrid Arevalo‐Rodriguez
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
- Hospital Universitario Ramon y Cajal (IRYCIS)Clinical Biostatistics UnitMadridSpain
- CIBER Epidemiology and Public Health (CIBERESP)MadridSpain
| | - Dimelza Osorio
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
| | - Juan VA Franco
- Instituto Universitario Hospital ItalianoArgentine Cochrane CentrePotosí 4234Buenos AiresBuenos AiresArgentinaC1199ACL
| | - Yihan Xu
- Nanyang Technological UniversityWee Kim Wee School of Communication and InformationRoom 702, Building 5, #1277 Changning RoadSingapore CitySingapore637718
| | - Ricardo Hidalgo
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
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Gonzalez Garay AG, Molano Franco D, Nieto Estrada VH, Martí‐Carvajal AJ, Arevalo‐Rodriguez I. Interventions for preventing high altitude illness: Part 2. Less commonly-used drugs. Cochrane Database Syst Rev 2018; 2018:CD012983. [PMID: 29529715 PMCID: PMC6494375 DOI: 10.1002/14651858.cd012983] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND High altitude illness (HAI) is a term used to describe a group of mainly cerebral and pulmonary syndromes that can occur during travel to elevations above 2500 metres (˜ 8200 feet). Acute mountain sickness (AMS), high altitude cerebral oedema (HACE) and high altitude pulmonary oedema (HAPE) are reported as potential medical problems associated with high altitude ascent. In this second review, in a series of three about preventive strategies for HAI, we assessed the effectiveness of five of the less commonly used classes of pharmacological interventions. OBJECTIVES To assess the clinical effectiveness and adverse events of five of the less commonly used pharmacological interventions for preventing acute HAI in participants who are at risk of developing high altitude illness in any setting. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) in May 2017. We adapted the MEDLINE strategy for searching the other databases. We used a combination of thesaurus-based and free-text search terms. We scanned the reference lists and citations of included trials and any relevant systematic reviews that we identified for further references to additional trials. SELECTION CRITERIA We included randomized controlled trials conducted in any setting where one of five classes of drugs was employed to prevent acute HAI: selective 5-hydroxytryptamine(1) receptor agonists; N-methyl-D-aspartate (NMDA) antagonist; endothelin-1 antagonist; anticonvulsant drugs; and spironolactone. We included trials involving participants who are at risk of developing high altitude illness (AMS or HACE, or HAPE, or both). We included participants with and without a history of high altitude illness. We applied no age or gender restrictions. We included trials where the relevant medication was administered before the beginning of ascent. We excluded trials using these drugs during ascent or after ascent. DATA COLLECTION AND ANALYSIS We used the standard methodological procedures employed by Cochrane. MAIN RESULTS We included eight studies (334 participants, 9 references) in this review. Twelve studies are ongoing and will be considered in future versions of this review as appropriate. We have been unable to obtain full-text versions of a further 12 studies and have designated them as 'awaiting classification'. Four studies were at a low risk of bias for randomization; two at a low risk of bias for allocation concealment. Four studies were at a low risk of bias for blinding of participants and personnel. We considered three studies at a low risk of bias for blinding of outcome assessors. We considered most studies at a high risk of selective reporting bias.We report results for the following four main comparisons.Sumatriptan versus placebo (1 parallel study; 102 participants)Data on sumatriptan showed a reduction of the risk of AMS when compared with a placebo (risk ratio (RR) = 0.43, CI 95% 0.21 to 0.84; 1 study, 102 participants; low quality of evidence). The one included study did not report events of HAPE, HACE or adverse events related to administrations of sumatriptan.Magnesium citrate versus placebo (1 parallel study; 70 participants)The estimated RR for AMS, comparing magnesium citrate tablets versus placebo, was 1.09 (95% CI 0.55 to 2.13; 1 study; 70 participants; low quality of evidence). In addition, the estimated RR for loose stools was 3.25 (95% CI 1.17 to 8.99; 1 study; 70 participants; low quality of evidence). The one included study did not report events of HAPE or HACE.Spironolactone versus placebo (2 parallel studies; 205 participants)Pooled estimation of RR for AMS was not performed due to considerable heterogeneity between the included studies (I² = 72%). RR from individual studies was 0.40 (95% CI 0.12 to 1.31) and 1.44 (95% CI 0.79 to 2.01; very low quality of evidence). No events of HAPE or HACE were reported. Adverse events were not evaluated.Acetazolamide versus spironolactone (1 parallel study; 232 participants)Data on acetazolamide compared with spironolactone showed a reduction of the risk of AMS with the administration of acetazolamide (RR = 0.36, 95% CI 0.18 to 0.70; 232 participants; low quality of evidence). No events of HAPE or HACE were reported. Adverse events were not evaluated. AUTHORS' CONCLUSIONS This Cochrane Review is the second in a series of three providing relevant information to clinicians and other interested parties on how to prevent high altitude illness. The assessment of five of the less commonly used classes of drugs suggests that there is a scarcity of evidence related to these interventions. Clinical benefits and harms related to potential interventions such as sumatriptan are still unclear. Overall, the evidence is limited due to the low number of studies identified (for most of the comparison only one study was identified); limitations in the quality of the evidence (moderate to low); and the number of studies pending classification (24 studies awaiting classification or ongoing). We lack the large and methodologically sound studies required to establish or refute the efficacy and safety of most of the pharmacological agents evaluated in this review.
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Affiliation(s)
- Alejandro G Gonzalez Garay
- National Institute of PediatricsMethodology Research UnitInsurgentes Sur 3700 ‐ CCol. Insurgentes Cuicuilco, CoyoacanMexico CityDistrito FederalMexico04530
| | - Daniel Molano Franco
- Fundacion Universitaria de Ciencias de la Salud, Hospital de San JoséDepartment of Critical CareCarrera 19 # 8‐32BogotaBogotaColombia11001
| | - Víctor H Nieto Estrada
- Fundacion Universitaria Sanitas, Colombia ClinicDepartment of Critical CareCarrera 19 # 8‐32BogotaBogotaColombia11001
| | | | - Ingrid Arevalo‐Rodriguez
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoAv. Mariscal Sucre s/n y Av. Mariana de JesúsQuitoEcuador
- Hospital Universitario Ramon y Cajal (IRYCIS)Clinical Biostatistics UnitMadridSpain
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11
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Nieto Estrada VH, Molano Franco D, Medina RD, Gonzalez Garay AG, Martí‐Carvajal AJ, Arevalo‐Rodriguez I. Interventions for preventing high altitude illness: Part 1. Commonly-used classes of drugs. Cochrane Database Syst Rev 2017; 6:CD009761. [PMID: 28653390 PMCID: PMC6481751 DOI: 10.1002/14651858.cd009761.pub2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND High altitude illness (HAI) is a term used to describe a group of cerebral and pulmonary syndromes that can occur during travel to elevations above 2500 metres (8202 feet). Acute hypoxia, acute mountain sickness (AMS), high altitude cerebral oedema (HACE) and high altitude pulmonary oedema (HAPE) are reported as potential medical problems associated with high altitude. In this review, the first in a series of three about preventive strategies for HAI, we assess the effectiveness of six of the most recommended classes of pharmacological interventions. OBJECTIVES To assess the clinical effectiveness and adverse events of commonly-used pharmacological interventions for preventing acute HAI. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), Embase (OVID), LILACS and trial registries in January 2017. We adapted the MEDLINE strategy for searching the other databases. We used a combination of thesaurus-based and free-text terms to search. SELECTION CRITERIA We included randomized-controlled and cross-over trials conducted in any setting where commonly-used classes of drugs were used to prevent acute HAI. DATA COLLECTION AND ANALYSIS We used standard methodological procedures as expected by Cochrane. MAIN RESULTS We included 64 studies (78 references) and 4547 participants in this review, and classified 12 additional studies as ongoing. A further 12 studies await classification, as we were unable to obtain the full texts. Most of the studies were conducted in high altitude mountain areas, while the rest used low pressure (hypobaric) chambers to simulate altitude exposure. Twenty-four trials provided the intervention between three and five days prior to the ascent, and 23 trials, between one and two days beforehand. Most of the included studies reached a final altitude of between 4001 and 5000 metres above sea level. Risks of bias were unclear for several domains, and a considerable number of studies did not report adverse events of the evaluated interventions. We found 26 comparisons, 15 of them comparing commonly-used drugs versus placebo. We report results for the three most important comparisons: Acetazolamide versus placebo (28 parallel studies; 2345 participants)The risk of AMS was reduced with acetazolamide (risk ratio (RR) 0.47, 95% confidence interval (CI) 0.39 to 0.56; I2 = 0%; 16 studies; 2301 participants; moderate quality of evidence). No events of HAPE were reported and only one event of HACE (RR 0.32, 95% CI 0.01 to 7.48; 6 parallel studies; 1126 participants; moderate quality of evidence). Few studies reported side effects for this comparison, and they showed an increase in the risk of paraesthesia with the intake of acetazolamide (RR 5.53, 95% CI 2.81 to 10.88, I2 = 60%; 5 studies, 789 participants; low quality of evidence). Budenoside versus placebo (2 parallel studies; 132 participants)Data on budenoside showed a reduction in the incidence of AMS compared with placebo (RR 0.37, 95% CI 0.23 to 0.61; I2 = 0%; 2 studies, 132 participants; low quality of evidence). Studies included did not report events of HAPE or HACE, and they did not find side effects (low quality of evidence). Dexamethasone versus placebo (7 parallel studies; 205 participants)For dexamethasone, the data did not show benefits at any dosage (RR 0.60, 95% CI 0.36 to 1.00; I2 = 39%; 4 trials, 176 participants; low quality of evidence). Included studies did not report events of HAPE or HACE, and we rated the evidence about adverse events as of very low quality. AUTHORS' CONCLUSIONS Our assessment of the most commonly-used pharmacological interventions suggests that acetazolamide is an effective pharmacological agent to prevent acute HAI in dosages of 250 to 750 mg/day. This information is based on evidence of moderate quality. Acetazolamide is associated with an increased risk of paraesthesia, although there are few reports about other adverse events from the available evidence. The clinical benefits and harms of other pharmacological interventions such as ibuprofen, budenoside and dexamethasone are unclear. Large multicentre studies are needed for most of the pharmacological agents evaluated in this review, to evaluate their effectiveness and safety.
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Affiliation(s)
- Víctor H Nieto Estrada
- Fundacion Universitaria Sanitas, Colombia ClinicDepartment of Critical CareCarrera 19 # 8‐32BogotaBogotaColombia11001
| | - Daniel Molano Franco
- Fundacion Universitaria de Ciencias de la Salud, Hospital de San JoséDepartment of Critical CareCarrera 19 # 8‐32BogotaBogotaColombia11001
| | - Roger David Medina
- Fundación Universitaria de Ciencias de la SaludDivision of ResearchCarrera 19 # 8‐32Bogotá D.C.Colombia
| | - Alejandro G Gonzalez Garay
- National Institute of PediatricsMethodology Research UnitInsurgentes Sur 3700 ‐ CCol. Insurgentes Cuicuilco, CoyoacanMexico CityDistrito FederalMexico04530
| | | | - Ingrid Arevalo‐Rodriguez
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoAv. Mariscal Sucre s/n y Av. Mariana de JesúsQuitoEcuador
- Hospital Universitario Ramon y Cajal (IRYCIS)Clinical Biostatistics UnitMadridSpain
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12
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Savica R. Environmental Neurologic Injuries. Continuum (Minneap Minn) 2017; 23:862-871. [PMID: 28570332 DOI: 10.1212/con.0000000000000470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE OF REVIEW This article discusses neurologic complications resulting from environmental injuries and the treatment modalities for these conditions. RECENT FINDINGS Recent advances include improved management of altitude sickness. Relatively uncommon conditions, such as keraunoparalysis (lightning-induced paralysis) and high-pressure neurologic syndrome, are areas of ongoing study. SUMMARY Environmental injuries may be associated with serious neurologic sequelae. This article reviews thermal and electrical injuries as well as injuries related to aviation, altitude, and diving. Recognition of signs and symptoms of such complex injuries and exposures will permit accurate diagnoses and improved outcomes.
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Davis C, Hackett P. Advances in the Prevention and Treatment of High Altitude Illness. Emerg Med Clin North Am 2017; 35:241-260. [PMID: 28411926 DOI: 10.1016/j.emc.2017.01.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
High altitude illness encompasses a spectrum of clinical entities to include: acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. These illnesses occur as a result of a hypobaric hypoxic environment. Although a mild case of acute mountain sickness may be self-limited, high altitude cerebral edema and high altitude pulmonary edema represent critical emergencies that require timely intervention. This article reviews recent advances in the prevention and treatment of high altitude illness, including new pharmacologic strategies for prophylaxis and revised treatment guidelines.
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Affiliation(s)
- Christopher Davis
- Department of Emergency Medicine, University of Colorado School of Medicine, 12401 East 17th Avenue, Aurora, CO 80045, USA.
| | - Peter Hackett
- Institute for Altitude Medicine, PO Box 1229, Telluride, CO 81435, USA
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14
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Luks AM, McIntosh SE, Grissom CK, Auerbach PS, Rodway GW, Schoene RB, Zafren K, Hackett PH. Wilderness Medical Society practice guidelines for the prevention and treatment of acute altitude illness: 2014 update. Wilderness Environ Med 2015; 25:S4-14. [PMID: 25498261 DOI: 10.1016/j.wem.2014.06.017] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/16/2014] [Indexed: 10/24/2022]
Abstract
To provide guidance to clinicians about best practices, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for prevention and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. These guidelines present the main prophylactic and therapeutic modalities for each disorder and provide recommendations about their role in disease management. Recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to prevention and management of each disorder that incorporate these recommendations. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in Wilderness & Environmental Medicine 2010;21(2):146-155.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, WA (Drs Luks and Schoene).
| | | | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT (Dr Grissom)
| | - Paul S Auerbach
- Department of Surgery, Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Drs Auerbach and Zafren)
| | - George W Rodway
- Division of Health Sciences, University of Nevada, Reno, NV (Dr Rodway)
| | - Robert B Schoene
- Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, WA (Drs Luks and Schoene); East Bay Regional Pulmonary and Critical Care Medicine Associates, Berkeley, CA (Dr Schoene)
| | - Ken Zafren
- Department of Surgery, Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Drs Auerbach and Zafren); Himalayan Rescue Association, Kathmandu, Nepal (Dr Zafren)
| | - Peter H Hackett
- Division of Emergency Medicine, Altitude Research Center, University of Colorado School of Medicine, Aurora and the Institute for Altitude Medicine, Telluride, CO (Dr Hackett)
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15
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Zhu HT, Bian C, Yuan JC, Liao XJ, Liu W, Zhu G, Feng H, Lin JK. Hyperbaric oxygen therapy ameliorates acute brain injury after porcine intracerebral hemorrhage at high altitude. Crit Care 2015; 19:255. [PMID: 26073666 PMCID: PMC4522125 DOI: 10.1186/s13054-015-0976-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 06/04/2015] [Indexed: 11/10/2022] Open
Abstract
Introduction Intracerebral hemorrhage (ICH) at high altitude is not well understood to date. This study investigates the effects of high altitude on ICH, and examines the acute neuroprotection of hyperbaric oxygen (HBO) therapy against high-altitude ICH. Methods Minipigs were placed in a hypobaric chamber for 72 h before the operation. ICH was induced by an infusion of autologous arterial blood (3 ml) into the right basal ganglia. Animals in the high-altitude ICH group received HBO therapy (2.5 ATA for 60 min) 30 min after ICH. Blood gas, blood glucose and brain tissue oxygen partial pressure (PbtO2) were monitored continuously for animals from all groups, as were microdialysis products including glucose, lactate, pyruvate and glutamate in perihematomal tissue from 3 to 12 h post-ICH. Results High-altitude ICH animals showed significantly lower PbtO2, higher lactate/pyruvate ratio (LPR) and glutamate levels than low-altitude ICH animals. More severe neurological deficits, brain edema and neuronal damage were also observed in high-altitude ICH. After HBO therapy, PbtO2 was significantly increased and LPR and glutamate levels were significantly decreased. Brain edema, neurological deficits and neuronal damage were also ameliorated. Conclusions The data suggested a more serious disturbance of tissue oxygenation and cerebral metabolism in the acute stage after ICH at high altitude. Early HBO treatment reduced acute brain injury, perhaps through a mechanism involving the amelioration of the derangement of cerebral oxygenation and metabolism following high-altitude ICH.
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Affiliation(s)
- Hai-tao Zhu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Chen Bian
- Department of Military Psychology, College of Psychology, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Ji-chao Yuan
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Xiao-jun Liao
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Wei Liu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Gang Zhu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
| | - Jiang-kai Lin
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing, 400038, China.
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Development and preliminary test of a new plateau hyperbaric chamber. Am J Emerg Med 2015; 33:1497-500. [PMID: 26277732 DOI: 10.1016/j.ajem.2015.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE The objective of this study is to validate the performance, define its limits, and provide details on a new plateau hyperbaric chamber at 355-, 2880-, and 4532-m high altitude. METHODS A new multiplace plateau hyperbaric chamber was designed to satisfy the needed of patients who have acute mountain sickness. Tests were conducted inside the chamber at 355-, 2880-, and 4532-m high altitude. The safely and conveniences of the new plateau hyperbaric chamber were estimated. RESULTS Minimum pressures of the main compartment can reach up to 0.029, 0.022, and 0.02 MPa at 355-, 2880-, and 4532-m high altitude. During pressurization, there was no leak of air around the chamber. The time lag of pressure equilibration between main and buffer compartment varies from 30.3±2.01 to 200.5±5.44 seconds and between buffer compartment and ambient pressure varies from 60.2±4.13 to 215.9±6.76 seconds. CONCLUSIONS The chamber can be applicated for acute mountain sickness treatment safety and convenience. However, further experience about animals and human within the chamber is needed to improve the hardware and establish conditions of effective utilization of this equipment in the high altitude.
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Leichtfried V, Basic D, Burtscher M, Gothe RM, Siebert U, Schobersberger W. Diagnosis and prediction of the occurrence of acute mountain sickness measuring oxygen saturation--independent of absolute altitude? Sleep Breath 2015; 20:435-42. [PMID: 26032284 DOI: 10.1007/s11325-015-1195-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 04/29/2015] [Accepted: 05/03/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE Commercialization of trekking tourism enables untrained persons to participate in trekking tours. Because hypoxia is one of the main purported triggers for acute mountain sickness (AMS), pulse oximetry, which measures arterial oxygen saturation (SPO2), is discussed to be a possible and useful tool for the diagnosis of AMS. The purpose of this study was to evaluate possible associations between SPO2 values and the occurrence of AMS. METHODS In 204 trekkers, SPO2 values (pulse oximetry) were measured and the Lake Louise Self-assessment Score (LLS) was administered over the first 7 days of their trekking tours. RESULTS During treks at altitudes of 2500-5500 m in Nepal, India, Africa, and South America, 100 participants suffered from mild AMS, 3 participants suffered from severe AMS, and 9 participants reported both mild and severe AMS. The lowest mean SPO2 was 85.5 (95 % confidence interval (CI), 83.9-86.1 %) on day 5. SPO2 and LLS exhibited a weak to moderate negative correlation for all days of the study (ρ ranging from -0.142 to -0.370). Calculation of time-shifted associations of 24 and 48 h resulted in the disappearance of most associations. Susceptibility to headaches (odds ratio (OR) 2.9-7.2) and a history of AMS (OR 2.2-3.1) were determined to be potential risk factors for the development of AMS. CONCLUSION Since there is no strong altitude-independent association between AMS and SPO2 during the first week of high-altitude adaptation, the implementation of pulse oximetry during trekking in order to detect and predict AMS remains questionable.
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Affiliation(s)
- Veronika Leichtfried
- Institute for Sports Medicine, Alpine Medicine and Health Tourism, UMIT-University for Health Sciences, Medical Informatics and Technology and TILAK Innsbruck, Eduard Wallnöfer Zentrum 1, 6060, Hall in Tirol, Austria.
| | - Daniel Basic
- Department of Internal Medicine III, University Hospital Innsbruck, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sport Science, Medical Section, University of Innsbruck, 6020, Innsbruck, Austria
| | - Raffaella Matteucci Gothe
- Institute of Public Health, Medical Decision Making and HTA, UMIT-University for Health Sciences, Medical Informatics and Technology, 6060, Hall in Tirol, Austria
| | - Uwe Siebert
- Institute of Public Health, Medical Decision Making and HTA, UMIT-University for Health Sciences, Medical Informatics and Technology, 6060, Hall in Tirol, Austria
| | - Wolfgang Schobersberger
- Institute for Sports Medicine, Alpine Medicine and Health Tourism, UMIT-University for Health Sciences, Medical Informatics and Technology and TILAK Innsbruck, Eduard Wallnöfer Zentrum 1, 6060, Hall in Tirol, Austria
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Carod-Artal F. Cefalea de elevada altitud y mal de altura. Neurologia 2014; 29:533-40. [DOI: 10.1016/j.nrl.2012.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/21/2012] [Indexed: 11/29/2022] Open
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Flaherty GT. Under pressure: Facilitating the emergency use of portable hyperbaric chambers at altitude. Travel Med Infect Dis 2014; 12:420-1. [DOI: 10.1016/j.tmaid.2014.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 11/28/2022]
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Cauchy E, Leal S, Magnan MA, Nespoulet H. Portable Hyperbaric Chamber and Management of Hypothermia and Frostbite: An Evident Utilization. High Alt Med Biol 2014; 15:95-6. [DOI: 10.1089/ham.2013.1095] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Shen G, Wu X, Tang C, Yan Y, Liu J, Guo W, Jing D, Lei T, Tian Y, Xie K, Luo E, Zhang J. An oxygen enrichment device for lowlanders ascending to high altitude. Biomed Eng Online 2013; 12:100. [PMID: 24103365 PMCID: PMC4124732 DOI: 10.1186/1475-925x-12-100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 09/24/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. METHODS The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. RESULTS The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01). CONCLUSIONS We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude.
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Affiliation(s)
- Guanghao Shen
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi 710032, People's Republic of China.
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Recommendations for resuscitation after ascent to high altitude and in aircrafts. Int J Cardiol 2013; 167:1703-11. [DOI: 10.1016/j.ijcard.2012.11.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 11/11/2012] [Indexed: 12/31/2022]
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Abstract
A 45-year-old healthy man wishes to climb Mount Kilimanjaro (5895 m) in a 5-day period, starting at 1800 m. The results of a recent exercise stress test were normal; he runs 10 km 4 or 5 times per week and finished a marathon in less than 4 hours last year. He wants to know how he can prevent becoming ill at high altitude and whether training or sleeping under normobaric hypoxic conditions in the weeks before the ascent would be helpful. What would you advise?
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Affiliation(s)
- Peter Bärtsch
- University Clinic, Department of Internal Medicine, Division VII Sports Medicine, Heidelberg, Germany.
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Abstract
Altitude illness is a broad category of disease encompassing acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) that can affect persons who travel to altitude without adequate acclimatization. Initial symptoms of AMS and the more serious HACE or HAPE can be subtle, and it is important that the practitioner be able to recognize and differentiate between these diagnoses because they can progress rapidly and be fatal if untreated. There are well-established criteria and many proven therapies both for prophylaxis and treatment of altitude illness; however, despite intense research efforts, the specific mechanisms of these complex diseases remain elusive. Adequate acclimatization via controlled ascent remains the most important factor in preventing altitude illness, although prophylactic pharmacotherapy also may be useful. Rapid descent remains the most important treatment factor, although treatment at altitude with various therapies is possible for mild cases with adequate resources.
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Affiliation(s)
- Richard P Eide
- Department of Family and Community Medicine, Eisenhower Army Medical Center, Fort Gordon, GA, USA
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Shen G, Xie K, Yan Y, Jing D, Tang C, Wu X, Liu J, Sun T, Zhang J, Luo E. The role of oxygen-increased respirator in humans ascending to high altitude. Biomed Eng Online 2012; 11:49. [PMID: 22898206 PMCID: PMC3467172 DOI: 10.1186/1475-925x-11-49] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 07/13/2012] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Acute mountain sickness (AMS) is common for people who live in low altitude areas ascending to the high altitude. Many instruments have been developed to treat mild cases of AMS. However, long-lasting and portable anti-hypoxia equipment for individual is not yet available. METHODS Oxygen-increased respirator (OIR) has been designed to reduce the risk of acute mountain sickness in acute exposure to low air pressure. It can increase the density of oxygen by increasing total atmospheric pressure in a mask. Male subjects were screened, and eighty-eight were qualified to perform the experiments. The subjects were divided into 5 groups and were involved in some of the tests at 4 different altitudes (Group 1, 2: 3700 m; Group 3,4,5: 4000 m, 4700 m, 5380 m) with and without OIR. These tests include heart rate, saturation of peripheral oxygen (SpO2), malondialdehyde (MDA), superoxide dismutase (SOD), blood lactate (BLA) and PWC (physical work capacity) -170. RESULTS The results showed that higher SpO2, lower heart rate (except during exercise) and better recovery of heart rate were observed from all the subjects 'with OIR' compared with 'without OIR' (P<0.05). Moreover, compared with 'without OIR', subjects 'with OIR' in Group 1 had lower concentrations of MDA and BLA, and a higher concentration of SOD (P<0.05), while subjects 'with OIR' in Group 2 showed better physical capacity (measured by the PWC-170) (P<0.05). The additional experiment conducted in a hypobaric chamber (simulating 4,000 m) showed that the partial pressure of oxygen in blood and arterial oxygen saturation were higher 'with OIR' than 'without OIR' (P<0.05). CONCLUSIONS We suggested that OIR may play a useful role in protecting people ascending to high altitude before acclimatization.
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Affiliation(s)
- Guanghao Shen
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, PR China.
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Martí-Carvajal AJ, Simancas-Racines D, Hidalgo R. Interventions for treating high altitude illness. Hippokratia 2012. [DOI: 10.1002/14651858.cd009567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Arturo J Martí-Carvajal
- Universidad Tecnológica Equinoccial; Facultad de Ciencias de la Salud Eugenio Espejo; Quito Ecuador
| | - Daniel Simancas-Racines
- Universidad Tecnológica Equinoccial; Facultad de Ciencias de la Salud Eugenio Espejo; Quito Ecuador
| | - Ricardo Hidalgo
- Universidad Tecnológica Equinoccial; Facultad de Ciencias de la Salud Eugenio Espejo; Quito Ecuador
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Schommer K, Bärtsch P. Basic medical advice for travelers to high altitudes. DEUTSCHES ARZTEBLATT INTERNATIONAL 2011; 108:839-47; quiz 848. [PMID: 22238560 DOI: 10.3238/arztebl.2011.0839] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 09/08/2011] [Indexed: 11/27/2022]
Abstract
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). RESULTS High-altitude-related illnesses are caused by hypoxia and the resulting hypoxemia in otherwise healthy persons who travel too high too fast, with too little time to become acclimatized. The individual susceptibility to high-altitude-related illness is a further risk factor that can only be recognized in persons who have traveled to high altitudes in the past. In an unselected group of mountain climbers, 50% had AMS at 4500 meters, while 0.5-1% had HACE and 6% had HAPE at the same altitude. Persons with preexisting illnesses, particularly of the heart and lungs, can develop symptoms of their underlying disease at high altitudes because of hypoxia. Thus, medical advice is based on an assessment of the risk of illness in relation to the intended altitude profile of the trip, in consideration of the prospective traveler's suitability for high altitudes (cardiopulmonary performance status, exercise capacity) and individual susceptibility to high-altitude-related illnesses, as judged from previous exposures. The symptoms and treatment of high-altitude-related illnesses should be thoroughly explained. CONCLUSION An understanding of the physiology of adaptation to high altitudes and of the pathophysiology and clinical manifestations of high-altitude-related illnesses provides a basis for the proper counseling of prospective travelers, through which life-threatening conditions can be prevented.
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Affiliation(s)
- Kai Schommer
- Medizinische Universitätsklinik Heidelberg, Innere Medizin VII Sportmedizin.
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Butler GJ, Al-Waili N, Passano DV, Ramos J, Chavarri J, Beale J, Allen MW, Lee BY, Urteaga G, Salom K. Altitude mountain sickness among tourist populations: a review and pathophysiology supporting management with hyperbaric oxygen. J Med Eng Technol 2010; 35:197-207. [PMID: 20836748 DOI: 10.3109/03091902.2010.497890] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In the mountain climbing community, conventional prevention of altitude mountain sickness (AMS) relies primarily on a formal acclimatization period. AMS symptoms during mountaineering climbs are managed with medication, oxygen and minor recompression (1524-2438 m altitude) using a portable chamber, such as the Gamow Bag. This is not always an acceptable therapy alternative in a predominantly elderly tourist population. The primary problem with reduced pressure at high altitude is hypoxaemia, which causes increased sympathetic activity, induces pulmonary venous constriction, while increasing pulmonary blood flow and regional perfusion. Rapid assents to altitude contribute to an increased incidence of decompression sickness (DCS). The treatment of choice for DCS is hyperbaric oxygenation, thus, treatment of high-altitude induced hypoxaemia using hyperbaric oxygenation (HBO(2)) is logical. Life Support Technologies group and the Center for Investigation of Altitude Medicine (CIMA, in Cusco, Peru) propose a comprehensive and multidisciplinary approach to AMS management. This approach encompasses traditional and advanced medical interventions including the use of a clinical HBO(2) chamber capable of recompression to three times greater than sea level pressure (3 atmosphere absolute (ATA)). The system uses a series of AMS hyperbaric treatment profiles that LST has previously developed to the US military and NASA, and that take greater advantage of vasoconstrictive effects of oxygen under true hyperbaric conditions of 1.25 ATA. These profiles virtually eliminate AMS rebound after the initial treatment often seen in conventional AMS treatment, where the patient is either treated at altitude, or does not recompress back to sea level or greater pressure (1.25 ATA), but returns directly to the same altitude where AMS symptoms first manifested.
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Affiliation(s)
- Gleen J Butler
- Life Support Technologies Group - NEWT Technologies, INC-New York, USA
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Luks AM, McIntosh SE, Grissom CK, Auerbach PS, Rodway GW, Schoene RB, Zafren K, Hackett PH. Wilderness Medical Society consensus guidelines for the prevention and treatment of acute altitude illness. Wilderness Environ Med 2010; 21:146-55. [PMID: 20591379 DOI: 10.1016/j.wem.2010.03.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 03/01/2010] [Accepted: 03/04/2010] [Indexed: 10/18/2022]
Abstract
To provide guidance to clinicians about best practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the prevention and treatment of acute mountain sickness (AMS), high altitude cerebral edema (HACE), and high altitude pulmonary edema (HAPE). These guidelines present the main prophylactic and therapeutic modalities for each disorder and provide recommendations for their roles in disease management. Recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to the prevention and management of each disorder that incorporate these recommendations.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, WA, USA.
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CPAP-Anwendung verbessert die Oxygenierung in normobarer und hypobarer Hypoxie. Wien Med Wochenschr 2008; 158:156-9. [DOI: 10.1007/s10354-007-0502-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 09/18/2007] [Indexed: 10/22/2022]
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Milledge JS. Altitude medicine and physiology including heat and cold: A review. Travel Med Infect Dis 2006; 4:223-37. [PMID: 16887744 DOI: 10.1016/j.tmaid.2005.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2005] [Accepted: 06/21/2005] [Indexed: 11/22/2022]
Abstract
With increasing numbers of people travelling to high altitude destinations for recreation or work, there is a need for practitioners of Travel Medicine to be familiar with altitude illnesses and the physiology of altitude. In mountainous areas travellers may also be exposed to problems of heat and cold. This article reviews these topics and gives practical advice on the management of the clinical problems involved, together with a discussion of underlying mechanisms, as far as they are understood at present.
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Abstract
High-altitude illness is the collective term for acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE). These syndromes can affect unacclimatized travelers shortly after ascent to high altitude (especially higher than 2500 m). AMS is relatively common and usually is mild and self-limiting; HACE and HAPE are uncommon but life-threatening. Gradual ascent is the best strategy for preventing or minimizing high-altitude illness, although chemoprophylaxis may be useful in some situations. Acetazolamide remains the chemoprophylactic agent of choice, although other drugs, such as gingko biloba, are being investigated. Immediate descent remains the cornerstone of treatment for HACE and HAPE, although pharmacologic and hyperbaric therapies may facilitate this process.
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Affiliation(s)
- David R. Murdoch
- Department of Pathology, Christchurch School of Medicine and Health Sciences, PO Box 4345, Christchurch, New Zealand.
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Abstract
High-altitude illness is the collective term for acute mountain sickness (AMS), high-altitude cerebral oedema (HACE), and high-altitude pulmonary oedema (HAPE). The pathophysiology of these syndromes is not completely understood, although studies have substantially contributed to the current understanding of several areas. These areas include the role and potential mechanisms of brain swelling in AMS and HACE, mechanisms accounting for exaggerated pulmonary hypertension in HAPE, and the role of inflammation and alveolar-fluid clearance in HAPE. Only limited information is available about the genetic basis of high-altitude illness, and no clear associations between gene polymorphisms and susceptibility have been discovered. Gradual ascent will always be the best strategy for preventing high-altitude illness, although chemoprophylaxis may be useful in some situations. Despite investigation of other agents, acetazolamide remains the preferred drug for preventing AMS. The next few years are likely to see many advances in the understanding of the causes and management of high-altitude illness.
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Abstract
Acute mountain sickness and high altitude cerebral edema are specific pathologies of high altitude exposure. The usual symptoms of acute mountain sickness are headache, nausea, vomiting, insomnia, lassitude, dizziness and ataxia. High altitude cerebral oedema is a severe state of acute mountain sickness with, in addition, alteration of mental status and consciousness. The pathophysiology of these 2 diseases are essentially due to an increase of intracranial pressure directly dependent of an increase of cerebral volume. Molecular and cellular mechanisms underlying acute mountain sickness and high altitude cerebral oedema are still poorly understood. The regulation of cerebral blood flow by nitric oxide seems to play a major role.
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Keller HR, Maggiorini M, Bärtsch P, Oelz O. Simulated descent v dexamethasone in treatment of acute mountain sickness: a randomised trial. BMJ (CLINICAL RESEARCH ED.) 1995; 310:1232-5. [PMID: 7767194 PMCID: PMC2549616 DOI: 10.1136/bmj.310.6989.1232] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Evaluation and comparison of the therapeutic efficacy of a portable hyperbaric chamber and dexamethasone in the treatment of acute mountain sickness. DESIGN Randomised trial during the summer mountaineering season. SETTING High altitude research laboratory in the Capanna Regina Margherita at 4559m above sea level (Alps Valais). SUBJECTS 31 climbers with symptoms of acute mountain sickness randomly assigned to different treatments. INTERVENTIONS One hour of treatment in the hyperbaric chamber at a pressure of 193 mbar or oral administration of 8 mg dexamethasone initially, followed by 4 mg after 6 hours. MAIN OUTCOME MEASURES Symptoms of acute mountain sickness (Lake Louise score, clinical score, and AMS-C score) before one and about 11 hours after beginning the different methods of treatment. Permitted intake of mild analgesics before treatment and in the follow up period. RESULTS After one hour of treatment compression with 193 mbar caused a significantly greater relief of symptoms of acute mountain sickness than dexamethasone (Lake Louise score: mean (SD) -4.6 (1.9) v -2.5 (1.8); clinical score: -4.0 (1.2) v -1.5 (1.4); AMS-C score: -1.24 (0.51) v -0.54 (0.59)). In contrast after about 11 hours subjects treated with dexamethasone suffered from significantly less severe acute mountain sickness than subjects treated with the hyperbaric chamber (-7.0 (3.6) v -1.6 (3.0); -4.1 (1.9) v -1.0 (1.5); -1.78 (0.73) v -0.75 (0.82) respectively). Intake of analgesics was similar in both groups. CONCLUSION Both methods were efficient in treatment of acute mountain sickness. One hour of compression with 193 mbar in the hyperbaric chamber, corresponding to a descent of 2250 m, led to short term improvement but had no long term beneficial effect. On the other hand, treatment with dexamethasone in an oral dose of 8 mg initially followed by 4 mg every 6 hours resulted in a longer term clinical improvement. For optimal efficacy the two methods should be combined if descent or evacuation is not possible.
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A'Court CH, Stables RH, Travis S. Doctor on a mountaineering expedition. BMJ (CLINICAL RESEARCH ED.) 1995; 310:1248-52. [PMID: 7767198 PMCID: PMC2549621 DOI: 10.1136/bmj.310.6989.1248] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Doctors are welcome members on mountaineering expeditions to remote areas, but practical advice on how to prepare and what kit to take can be difficult to find. This article is a ragbag of useful advice on diverse topics. It explains the necessary preparation, provides tips for a healthy expedition, and summarises the common disorders encountered at high altitude. The comprehensive drug and equipment lists and first aid kit for climbers were used for the 1992 Everest in winter expedition. They are there to be sacrificed to personal preference and the experience and size of individual expeditions.
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Affiliation(s)
- C H A'Court
- Intensive Therapy Unit, John Radcliffe Hospital, Oxford
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McMurray SJ. High altitude medicine for family physicians. CANADIAN FAMILY PHYSICIAN MEDECIN DE FAMILLE CANADIEN 1994; 40:711-8. [PMID: 8199523 PMCID: PMC2380085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
High altitude medicine deals with a continuum of diseases ranging from a mild discomfort to serious ailments affecting all organ systems, including the lungs, brain, and eyes. Decreased oxygen tension is the primary cause. The main principles of prevention are staging and graded ascent to allow acclimatization. Adventure travel to high altitude destinations is becoming increasingly popular; family physicians should be informed of the medical problems associated with such travel.
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Affiliation(s)
- B A Zlotnick
- Stanford University Medical Center, CA 94305, USA
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