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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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Berger MM, Hüsing A, Niessen N, Schiefer LM, Schneider M, Bärtsch P, Jöckel KH. Prevalence and knowledge about acute mountain sickness in the Western Alps. PLoS One 2023; 18:e0291060. [PMID: 37708123 PMCID: PMC10501682 DOI: 10.1371/journal.pone.0291060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/21/2023] [Indexed: 09/16/2023] Open
Abstract
OBJECTIVE To assess the prevalence of acute mountain sickness (AMS) in 1370 mountaineers at four different altitudes in the Western Alps. We also examined the influence of potential risk factors and the knowledge about AMS on its prevalence. METHODS In this observational cross-sectional study AMS was assessed on the day of ascent by the Lake Louise score (LLS, cut-off ≥3, version 2018) and the AMS-Cerebral (AMS-C) score of the environmental symptom questionnaire (cut-off ≥0,70). The latter was also obtained in the next morning. Knowledge regarding AMS and high-altitude cerebral edema (HACE) and the potential risk factors for AMS were evaluated by questionnaires. RESULTS On the day of ascent, the prevalence of AMS assessed by the LLS and AMS-C score was 5.8 and 3.9% at 2850 m, 2.1 and 3.1% at 3050 m, 14.8 and 10.1% at 3650 m, and 21.9 and 15% at 4559 m, respectively. The AMS prevalence increased overnight from 10.1 to 14.5% and from 15 to 25.2% at 3650 m and 4559 m, respectively, and was unchanged at 2850 m and 3050 m. A history of AMS, higher altitude, lower degree of pre-acclimatization, and younger age were identified as risk factors for developing AMS. Slow ascent was weakly associated with AMS prevalence, and sex and knowledge about AMS and HACE were indistinct. CONCLUSION AMS is common at altitudes ≥ 3650 m and better knowledge about AMS and HACE was not associated with less AMS in mountaineers with on average little knowledge.
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Affiliation(s)
- Marc Moritz Berger
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Anika Hüsing
- Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
| | - Nicolai Niessen
- Department of Internal Medicine, Klinikum Garmisch-Partenkirchen, Garmisch-Partenkirchen, Germany
| | | | - Michael Schneider
- Institute for Health Services Research and Clinical Epidemiology, Philipps-Universitaet Marburg, Marburg, Germany
| | - Peter Bärtsch
- Department of Internal Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Karl-Heinz Jöckel
- Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
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Wu Y, Zhou S, Li Y, Huang P, Zhong Z, Dong H, Tian H, Jiang S, Xie J, Li P. Remote ischemic preconditioning improves spatial memory and sleep of young males during acute high-altitude exposure. Travel Med Infect Dis 2023; 53:102576. [PMID: 37068619 DOI: 10.1016/j.tmaid.2023.102576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/28/2023] [Accepted: 04/14/2023] [Indexed: 04/19/2023]
Abstract
OBJECTIVE The high-altitude hypoxia environment will cause poor acclimatization in a portion of the population. Remote ischemic preconditioning(RIPC)has been demonstrated to prevent cardiovascular and cerebrovascular diseases under ischemic or hypoxic conditions. However, its role in improving acclimatization and preventing acute mountain sickness (AMS) at high altitude has been undetermined. This study aims to estimate the effect of RIPC on acclimatization of individuals exposed to high altitude. METHODS The project was designed as a randomized controlled trial with 82 healthy young males, who received RIPC training once a day for 7 consecutive days. Then they were transported by aircraft to a high altitude (3680 m) and examined for 6 days. Lake Louise Score(LLS) of AMS, physiological index, self-reported sleep pattern, and Pittsburgh Sleep Quality Index(PSQI)score were applied to assess the acclimatization to the high altitude. Five neurobehavioral tests were conducted to assess cognitive function. RESULTS The result showed that the RIPC group had a significantly lower AMSscore than the control group (2.43 ± 1.58 vs 3.29 ± 2.03, respectively; adjusted mean difference-0.84, 95% confidence interval-1.61 to -0.06, P = 0.036). and there was no significant difference in AMS incidence between the two groups (25.0% vs 28.57%, P = 0.555). The RIPC group performed better than the control group in spatial memory span score (11[9-12] vs 10[7.5-11], P=0.025) and the passing digit (7[6-7.5] vs 6[5-7], P= 0.001). Spatial memory was significantly higher in the high-altitude RIPC group than in the low-altitude RIPC group (P<0.01). And the RIPC group obtained significantly lower self-reported sleep quality score (P = 0.024) and PSQI score (P = 0.031). CONCLUSIONS The RIPC treatment improved spatial memory and sleep quality in subjects exposed to acute hypoxic exposure and this may lead to improved performance at high altitude.
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Affiliation(s)
- Yu Wu
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Simin Zhou
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Yaling Li
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Pei Huang
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Zhifeng Zhong
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Huaping Dong
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Huaijun Tian
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China
| | - Shuai Jiang
- Department of Health, The 12th Integrated Training Base of Army, Chongqing, China
| | - Jiaxin Xie
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China.
| | - Peng Li
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China; Key Laboratory of High Altitude Medicine, Army Medical University, Chongqing, China.
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Zhong Z, Dong H, Wu Y, Zhou S, Li H, Huang P, Tian H, Li X, Xiao H, Yang T, Xiong K, Zhang G, Tang Z, Li Y, Fan X, Yuan C, Ning J, Li Y, Xie J, Li P. Remote ischemic preconditioning enhances aerobic performance by accelerating regional oxygenation and improving cardiac function during acute hypobaric hypoxia exposure. Front Physiol 2022; 13:950086. [PMID: 36160840 PMCID: PMC9500473 DOI: 10.3389/fphys.2022.950086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 08/08/2022] [Indexed: 12/02/2022] Open
Abstract
Remote ischemic preconditioning (RIPC) may improve exercise performance. However, the influence of RIPC on aerobic performance and underlying physiological mechanisms during hypobaric hypoxia (HH) exposure remains relatively uncertain. Here, we systematically evaluated the potential performance benefits and underlying mechanisms of RIPC during HH exposure. Seventy-nine healthy participants were randomly assigned to receive sham intervention or RIPC (4 × 5 min occlusion 180 mm Hg/reperfusion 0 mm Hg, bilaterally on the upper arms) for 8 consecutive days in phases 1 (24 participants) and phase 2 (55 participants). In the phases 1, we measured the change in maximal oxygen uptake capacity (VO2max) and muscle oxygenation (SmO2) on the leg during a graded exercise test. We also measured regional cerebral oxygenation (rSO2) on the forehead. These measures and physiological variables, such as cardiovascular hemodynamic parameters and heart rate variability index, were used to evaluate the intervention effect of RIPC on the changes in bodily functions caused by HH exposure. In the phase 2, plasma protein mass spectrometry was then performed after RIPC intervention, and the results were further evaluated using ELISA tests to assess possible mechanisms. The results suggested that RIPC intervention improved VO2max (11.29%) and accelerated both the maximum (18.13%) and minimum (53%) values of SmO2 and rSO2 (6.88%) compared to sham intervention in hypobaric hypoxia exposure. Cardiovascular hemodynamic parameters (SV, SVRI, PPV% and SpMet%) and the heart rate variability index (Mean RR, Mean HR, RMSSD, pNN50, Lfnu, Hfnu, SD1, SD2/SD1, ApEn, SampEn, DFA1and DFA2) were evaluated. Protein sequence analysis showed 42 unregulated and six downregulated proteins in the plasma of the RIPC group compared to the sham group after HH exposure. Three proteins, thymosin β4 (Tβ4), heat shock protein-70 (HSP70), and heat shock protein-90 (HSP90), were significantly altered in the plasma of the RIPC group before and after HH exposure. Our data demonstrated that in acute HH exposure, RIPC mitigates the decline in VO2max and regional oxygenation, as well as physiological variables, such as cardiovascular hemodynamic parameters and the heart rate variability index, by influencing plasma Tβ4, HSP70, and HSP90. These data suggest that RIPC may be beneficial for acute HH exposure.
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Affiliation(s)
- Zhifeng Zhong
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Huaping Dong
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yu Wu
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Simin Zhou
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Hong Li
- Department of Anesthesiology, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Pei Huang
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Huaijun Tian
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiaoxu Li
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
| | - Heng Xiao
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Tian Yang
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
| | - Kun Xiong
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
| | - Gang Zhang
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhongwei Tang
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yaling Li
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xueying Fan
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Chao Yuan
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jiaolin Ning
- Department of Anesthesiology, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yue Li
- Department of Anesthesiology, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jiaxin Xie
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Jiaxin Xie, ; Peng Li,
| | - Peng Li
- Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of High Altitude Medicine, PLA, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Jiaxin Xie, ; Peng Li,
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Bärtsch P. The Impact of Nocebo and Placebo Effects on Reported Incidence of Acute Mountain Sickness. High Alt Med Biol 2021; 23:8-17. [PMID: 34964659 DOI: 10.1089/ham.2021.0078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bärtsch Peter. The impact of nocebo and placebo effects on reported incidence of acute mountain sickness. High Alt Med Biol 00:000-000, 2021. Well comparable studies reporting acute mountain sickness (AMS) in nonacclimatized, acutely exposed individuals performed at 3,450-3,650 m (9 studies) and 4,559-4,675 m (18 studies) at real altitude or in hypobaric or in normobaric hypoxic chambers were analyzed with the hypothesis that the study design impacts occurrence of AMS. Individual symptoms and overall scores of AMS were not different between the three modalities of exposure to a comparable degree of hypoxia, indicating that hypobaria has, if at all, minimal influence on AMS. Studies not focusing versus those focusing on AMS report lower scores and prevalence of AMS at 3,500 m, but not at 4,559 m, while frequent assessment may be associated with more severe AMS. These data suggest that focusing on AMS creates expectations of getting AMS (nocebo effects) and increases its prevalence, while not paying attention reduces negative expectations and thus AMS. On the other hand, interventions promising improvement may cause positive expectations (placebo effect). Information about purpose and dangers of a study, repeated assessments for AMS, previous experiences of AMS, and observation of illness in other study participants are major factors contributing to negative expectations and thus nocebo effects increasing AMS. They should be considered when designing studies and subject information and be reported in detail in publications of studies on AMS.
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Affiliation(s)
- Peter Bärtsch
- Department of Internal Medicine, University Clinic, Heidelberg, Germany
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Klein M, Kaestner L, Bogdanova AY, Minetti G, Rudloff S, Lundby C, Makhro A, Seiler E, Cromvoirt A, Fenk S, Simionato G, Hertz L, Recktenwald S, Schäfer L, Haider T, Fried S, Borsch C, Marti HH, Sander A, Mairbäurl H. Absence of neocytolysis in humans returning from a 3-week high-altitude sojourn. Acta Physiol (Oxf) 2021; 232:e13647. [PMID: 33729672 DOI: 10.1111/apha.13647] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 12/26/2022]
Abstract
AIMS Total haemoglobin mass (tot-Hb) increases during high-altitude acclimatization. Normalization of tot-Hb upon descent is thought to occur via neocytolysis, the selective destruction of newly formed erythrocytes. Because convincing experimental proof of neocytolysis is lacking, we performed a prospective study on erythrocyte survival after a stay at the Jungfraujoch Research Station (JFJRS; 3450 m). METHODS Newly formed erythrocytes of 12 male subjects (mean age 23.3 years) were age cohort labelled in normoxia (110 m) and during a 19-day high-altitude sojourn by ingestion of 13 C2- and 15 N-labelled glycine respectively. Elimination dynamics for erythrocytes produced in normoxia and at high altitude were measured by isotope ratio mass spectrometry of haem, by determining tot-Hb, reticulocyte counts, erythrocyte membrane protein 4.1a/4.1b ratio and by mathematical modelling. RESULTS Tot-Hb increased by 4.7% ± 2.7% at high altitude and returned to pre-altitude values within 11 days after descent. Elimination of 13 C- (normoxia) and 15 N- (high altitude) labelled erythrocytes was not different. Erythropoietin levels and counts of CD71-positive reticulocytes decreased rapidly after descent. The band 4.1a/4.1b ratio decreased at altitude and remained low for 3-4 days after descent and normalized slowly. There was no indication of haemolysis. CONCLUSION We confirm a rapid normalization of tot-Hb upon descent. Based on the lack of accelerated removal of age cohorts of erythrocytes labelled at high altitude, on patterns of changes in reticulocyte counts and of the band 4.1a/4.1b ratio and on modelling, this decrease did not occur via neocytolysis, but by a reduced rate of erythropoiesis along with normal clearance of senescent erythrocytes.
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Affiliation(s)
- Marie Klein
- Medical Clinic VII Sports Medicine University Hospital Heidelberg Heidelberg Germany
- Translational Pneumology University Hospital Heidelberg Heidelberg Germany
| | - Lars Kaestner
- Experimental Physics Dynamics of Fluids Group Saarland University Saarbrücken Germany
- Theoretical Medicine and Biosciences Campus University HospitalSaarland University Homburg Germany
| | - Anna Y. Bogdanova
- Red Blood Cell Research Group Institute of Veterinary Physiology University of Zürich Zürich Switzerland
| | - Giampaolo Minetti
- Department of Biology and Biotechnology "L Spallanzani" Laboratories of Biochemistry University of Pavia Pavia Italy
| | - Silvia Rudloff
- Analytical Platform Stable Isotopes, and Cell Biology Institute of Nutritional Sciences Justus Liebig University Giessen Giessen Germany
| | - Carsten Lundby
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research Rigshospitalet University of Copenhagen Hillerød Denmark
- Inland Norway University of Applied Sciences Lillehammer Norway
| | - Asya Makhro
- Red Blood Cell Research Group Institute of Veterinary Physiology University of Zürich Zürich Switzerland
| | - Elena Seiler
- Red Blood Cell Research Group Institute of Veterinary Physiology University of Zürich Zürich Switzerland
| | - Ankie Cromvoirt
- Red Blood Cell Research Group Institute of Veterinary Physiology University of Zürich Zürich Switzerland
| | - Simone Fenk
- Red Blood Cell Research Group Institute of Veterinary Physiology University of Zürich Zürich Switzerland
| | - Greta Simionato
- Experimental Physics Dynamics of Fluids Group Saarland University Saarbrücken Germany
- Theoretical Medicine and Biosciences Campus University HospitalSaarland University Homburg Germany
- Institute for Clinical and Experimental Surgery Saarland UniversityCampus University Hospital Homburg Germany
| | - Laura Hertz
- Experimental Physics Dynamics of Fluids Group Saarland University Saarbrücken Germany
| | - Steffen Recktenwald
- Experimental Physics Dynamics of Fluids Group Saarland University Saarbrücken Germany
| | - Larissa Schäfer
- Department of Anaesthesiology and Intensive Care Medicine University Hospital SalzburgParacelsus Medical University Salzburg Austria
| | - Thomas Haider
- Department of Cardiology University Hospital Zürich Zürich Switzerland
| | - Sebastian Fried
- Department of Anaesthesiology University Hospital Heidelberg Heidelberg Germany
| | - Christian Borsch
- Analytical Platform Stable Isotopes, and Cell Biology Institute of Nutritional Sciences Justus Liebig University Giessen Giessen Germany
| | - Hugo H. Marti
- Institute of Physiology and Pathophysiology University of Heidelberg Heidelberg Germany
| | - Anja Sander
- Institute of Medical Biometry and Informatics University Hospital Heidelberg Heidelberg Germany
| | - Heimo Mairbäurl
- Medical Clinic VII Sports Medicine University Hospital Heidelberg Heidelberg Germany
- Translational Pneumology University Hospital Heidelberg Heidelberg Germany
- Translational Lung Research Centre Heidelberg (TLRC) Part of the German Centre for Lung Research (DZL) Heidelberg Germany
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Wang Z, Lv B, Zhang L, Gao R, Zhao W, Wang L, Min Z, Mi Z, Song Y, Zhang J, Yu Y, Ji X, Li J, Wu L. Repeated remote ischaemic preconditioning can prevent acute mountain sickness after rapid ascent to a high altitude. Eur J Sport Sci 2021; 22:1304-1314. [PMID: 33977839 DOI: 10.1080/17461391.2021.1927197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND The aim of the present study was to assess the effectiveness of 4 different remote ischaemic preconditioning (RIPC) protocols varying in duration and frequency for preventing acute mountain sickness (AMS). Methods: The participants in the four RIPC groups received different RIPC treatments in the arms at a low altitude; the control group did not receive a specific sham treatment. The participants were then flown to a High Altitude (3650 m). The primary outcome was the incidence and severity of AMS evaluated by the Lake Louise score (LLS) after arrival; vital signs were collected simultaneously. We performed an intention-to-treat analysis. Results: A total of 250 participants were included with 50 participants in each group. The total AMS incidence in all participants was 26.4%. A total of 20 AMS cases (40%) occurred in the control group, whereas 15 AMS cases (30%) occurred both in the RIPC A and RIPC B groups (relative risk 1.3; 95% confidence interval 0.8 - 2.3; χ2 = 1.099; p = 0.29), and 8 AMS cases (16%) occurred both in the RIPC C and D groups (RR 2.5; 95% CI 1.2 - 5.2; χ2 = 7.143, p < 0.01), with significantly lower LLSs in the RIPC C and D groups (F = 6.51, p <0.001). Conclusion: This study demonstrated that a four-week RIPC intervention but not a one-week regimen reduced AMS incidence and severity; however, a placebo effect might have contributed to the results of this study. METHODS The participants in the four RIPC groups received different RIPC treatments in the arms at a low altitude; the control group did not receive a specific sham treatment. The participants were then flown to a High Altitude (3650 m). The primary outcome was the incidence and severity of AMS evaluated by the Lake Louise score (LLS) after arrival; vital signs were collected simultaneously. We performed an intention-to-treat analysis. RESULTS A total of 250 participants were included with 50 participants in each group. The total AMS incidence in all participants was 26.4%. A total of 20 AMS cases (40%) occurred in the control group after arrival at high altitude, whereas 15 AMS cases (30%) occurred both in the RIPC A and RIPC B groups (relative risk 1.3; 95% confidence interval 0.8 - 2.3; χ2 = 1.099; p = 0.29), and 8 AMS cases (16%) occurred both in the RIPC C and D groups (RR 2.5; 95% CI 1.2 - 5.2; χ2 = 7.143, p < 0.01), with significantly lower LLSs in the RIPC C and D groups (F = 6.51, p <0.001). CONCLUSION This study demonstrated that a four-week RIPC intervention but not a one-week regimen reduced AMS incidence and severity; however, a placebo effect might have contributed to the results of this study.
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Affiliation(s)
- Zhen Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Bo Lv
- Department of Neurology, PKUCare Zibo Hospital, Zibo, People's Republic of China.,Department of Neurology, People's Hospital of Yuncheng County, Heze, People's Republic of China
| | - Lin Zhang
- Department of Emergency, People's Hospital of Rizhao, Rizhao, People's Republic of China
| | - Ran Gao
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Wenbo Zhao
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Lin Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Zhaojun Min
- Department of Geriatric Medicine, People's Hospital of Lhasa, Lhasa, People's Republic of China
| | - Zhen Mi
- Department of Geriatric Medicine, People's Hospital of Lhasa, Lhasa, People's Republic of China
| | - Yang Song
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Jing Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Yabin Yu
- Capital Institute of Pediatrics, Beijing, People's Republic of China
| | - Xunming Ji
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China.,Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Junjie Li
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Liyong Wu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, People's Republic of China
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Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041692. [PMID: 33578749 PMCID: PMC7916528 DOI: 10.3390/ijerph18041692] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/13/2022]
Abstract
Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.
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Berger MM, Sareban M, Bärtsch P. Acute mountain sickness: Do different time courses point to different pathophysiological mechanisms? J Appl Physiol (1985) 2020; 128:952-959. [DOI: 10.1152/japplphysiol.00305.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Acute mountain sickness (AMS) is a syndrome of nonspecific symptoms (i.e., headache, anorexia, nausea, vomiting, dizziness, and fatigue) that may develop in nonacclimatized individuals after rapid exposure to altitudes ≥2,500 m. In field studies, mean AMS scores usually peak after the first night at a new altitude. Analyses of the individual time courses of AMS in four studies performed at 3,450 m and 4,559 m revealed that three different patterns are hidden in the above-described overall picture. In 41% of those who developed AMS (i.e., AMS-C score >0.70), symptoms peaked on day 1, in 39%, symptoms were most prominent on day 2, and in 20%, symptoms were most prominent on day 3. We suggest to name the different time courses of AMS type I, type II, and type III, respectively. Here, we hypothesize that the variation of time courses of AMS are caused by different pathophysiological mechanisms. This assumption could explain why no consistent correlations between an overall assessment of AMS and single pathophysiological factors have been found in a large number of studies over the past 50 yr. In this paper, we will briefly review the fundamental mechanisms implicated in the pathophysiology of AMS and discuss how they might contribute to the three different AMS time courses.
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Affiliation(s)
- Marc M. Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, Germany
| | - Mahdi Sareban
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Peter Bärtsch
- Department of Internal Medicine, University of Heidelberg, Heidelberg, Germany
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Bergmann A, Jovanovska E, Schilling T, Hedenstierna G, Föllner S, Schreiber J, Hachenberg T. Early and late effects of remote ischemic preconditioning on spirometry and gas exchange in healthy volunteers. Respir Physiol Neurobiol 2020; 271:103287. [DOI: 10.1016/j.resp.2019.103287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/06/2019] [Accepted: 09/05/2019] [Indexed: 12/14/2022]
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The Hen or the Egg: Impaired Alveolar Oxygen Diffusion and Acute High-altitude Illness? Int J Mol Sci 2019; 20:ijms20174105. [PMID: 31443549 PMCID: PMC6747186 DOI: 10.3390/ijms20174105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/18/2019] [Accepted: 08/20/2019] [Indexed: 01/11/2023] Open
Abstract
Individuals ascending rapidly to altitudes >2500 m may develop symptoms of acute mountain sickness (AMS) within a few hours of arrival and/or high-altitude pulmonary edema (HAPE), which occurs typically during the first three days after reaching altitudes above 3000-3500 m. Both diseases have distinct pathologies, but both present with a pronounced decrease in oxygen saturation of hemoglobin in arterial blood (SO2). This raises the question of mechanisms impairing the diffusion of oxygen (O2) across the alveolar wall and whether the higher degree of hypoxemia is in causal relationship with developing the respective symptoms. In an attempt to answer these questions this article will review factors affecting alveolar gas diffusion, such as alveolar ventilation, the alveolar-to-arterial O2-gradient, and balance between filtration of fluid into the alveolar space and its clearance, and relate them to the respective disease. The resultant analysis reveals that in both AMS and HAPE the main pathophysiologic mechanisms are activated before aggravated decrease in SO2 occurs, indicating that impaired alveolar epithelial function and the resultant diffusion limitation for oxygen may rather be a consequence, not the primary cause, of these altitude-related illnesses.
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Caru M, Levesque A, Lalonde F, Curnier D. An overview of ischemic preconditioning in exercise performance: A systematic review. JOURNAL OF SPORT AND HEALTH SCIENCE 2019; 8:355-369. [PMID: 31333890 PMCID: PMC6620415 DOI: 10.1016/j.jshs.2019.01.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/29/2018] [Accepted: 12/03/2018] [Indexed: 06/10/2023]
Abstract
Ischemic preconditioning (IPC) is an attractive method for athletes owing to its potential to enhance exercise performance. However, the effectiveness of the IPC intervention in the field of sports science remains mitigated. The number of cycles of ischemia and reperfusion, as well as the duration of the cycle, varies from one study to another. Thus, the aim of this systematic review was to provide a comprehensive review examining the IPC literature in sports science. A systematic literature search was performed in PubMed (MEDLINE) (from 1946 to May 2018), Web of Science (sport sciences) (from 1945 to May 2018), and EMBASE (from 1974 to May 2018). We included all studies investigating the effects of IPC on exercise performance in human subjects. To assess scientific evidence for each study, this review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The electronic database search generated 441 potential articles that were screened for eligibility. A total of 52 studies were identified as eligible and valid for this systematic review. The studies included were of high quality, with 48 of the 52 studies having a randomized, controlled trial design. Most studied showed that IPC intervention can be beneficial to exercise performance. However, IPC intervention seems to be more beneficial to healthy subjects who wish to enhance their performance in aerobic exercises than athletes. Thus, this systematic review highlights that a better knowledge of the mechanisms generated by the IPC intervention would make it possible to optimize the protocols according to the characteristics of the subjects with the aim of suggesting to the subjects the best possible experience of IPC intervention.
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Affiliation(s)
- Maxime Caru
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Quebec H3T 1J4, Canada
- Department of Psychology, University of Paris-Nanterre, Nanterre 92000, France
- Laboratoire EA 4430 – Clinique Psychanalyse Developpement (CliPsyD), University of Paris-Nanterre, Nanterre 92000, France
- CHU Ste-Justine Research Center, CHU Ste-Justine, Montreal H3T 1C5, Canada
| | - Ariane Levesque
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Quebec H3T 1J4, Canada
- CHU Ste-Justine Research Center, CHU Ste-Justine, Montreal H3T 1C5, Canada
- Department of Psychology, McGill University, Montreal, Quebec H3A 1G1, Canada
| | - François Lalonde
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Quebec H3T 1J4, Canada
- Department of Physical Activity Sciences, Faculty of Sciences, Université du Québec à Montréal, Montreal, Quebec H2L 2C4, Canada
| | - Daniel Curnier
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Quebec H3T 1J4, Canada
- CHU Ste-Justine Research Center, CHU Ste-Justine, Montreal H3T 1C5, Canada
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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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15
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Almohanna AM, Wray S. Hypoxic conditioning in blood vessels and smooth muscle tissues: effects on function, mechanisms, and unknowns. Am J Physiol Heart Circ Physiol 2018; 315:H756-H770. [PMID: 29702009 DOI: 10.1152/ajpheart.00725.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypoxic preconditioning, the protective effect of brief, intermittent hypoxic or ischemic episodes on subsequent more severe hypoxic episodes, has been known for 30 yr from studies on cardiac muscle. The concept of hypoxic preconditioning has expanded; excitingly, organs beyond the heart, including the brain, liver, and kidney, also benefit. Preconditioning of vascular and visceral smooth muscles has received less attention despite their obvious importance to health. In addition, there has been no attempt to synthesize the literature in this field. Therefore, in addition to overviewing the current understanding of hypoxic conditioning, in the present review, we consider the role of blood vessels in conditioning and explore evidence for conditioning in other smooth muscles. Where possible, we have distinguished effects on myocytes from other cell types in the visceral organs. We found evidence of a pivotal role for blood vessels in conditioning and for conditioning in other smooth muscle, including the bladder, vascular myocytes, and gastrointestinal tract, and a novel response in the uterus of a hypoxic-induced force increase, which helps maintain contractions during labor. To date, however, there are insufficient data to provide a comprehensive or unifying mechanism for smooth muscles or visceral organs and the effects of conditioning on their function. This also means that no firm conclusions can be drawn as to how differences between smooth muscles in metabolic and contractile activity may contribute to conditioning. Therefore, we have suggested what may be general mechanisms of conditioning occurring in all smooth muscles and tabulated tissue-specific mechanistic findings and suggested ideas for further progress.
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Affiliation(s)
- Asmaa M Almohanna
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine University of Liverpool , Liverpool , United Kingdom.,Princess Nourah bint Abdulrahman University , Riyadh , Saudi Arabia
| | - Susan Wray
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine University of Liverpool , Liverpool , United Kingdom
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De Smet S, D'Hulst G, Poffé C, Van Thienen R, Berardi E, Hespel P. High-intensity interval training in hypoxia does not affect muscle HIF responses to acute hypoxia in humans. Eur J Appl Physiol 2018; 118:847-862. [PMID: 29423544 DOI: 10.1007/s00421-018-3820-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 01/31/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE The myocellular response to hypoxia is primarily regulated by hypoxia-inducible factors (HIFs). HIFs thus conceivably are implicated in muscular adaptation to altitude training. Therefore, we investigated the effect of hypoxic versus normoxic training during a period of prolonged hypoxia ('living high') on muscle HIF activation during acute ischaemia. METHODS Ten young male volunteers lived in normobaric hypoxia for 5 weeks (5 days per week, ~ 15.5 h per day, FiO2: 16.4-14.0%). One leg was trained in hypoxia (TRHYP, 12.3% FiO2) whilst the other leg was trained in normoxia (TRNOR, 20.9% FiO2). Training sessions (3 per week) consisted of intermittent unilateral knee extensions at 20-25% of the 1-repetition maximum. Before and after the intervention, a 10-min arterial occlusion and reperfusion of the leg was performed. Muscle oxygenation status was continuously measured by near-infrared spectroscopy. Biopsies were taken from m. vastus lateralis before and at the end of the occlusion. RESULTS Irrespective of training, occlusion elevated the fraction of HIF-1α expressing myonuclei from ~ 54 to ~ 64% (P < 0.05). However, neither muscle HIF-1α or HIF-2α protein abundance, nor the expression of HIF-1α or downstream targets selected increased in any experimental condition. Training in both TRNOR and TRHYP raised muscular oxygen extraction rate upon occlusion by ~ 30%, whilst muscle hyperperfusion immediately following the occlusion increased by ~ 25% in either group (P < 0.05). CONCLUSION Ten minutes of arterial occlusion increased HIF-1α-expressing myonuclei. However, neither normoxic nor hypoxic training during 'living high' altered muscle HIF translocation, stabilisation, or transcription in response to acute hypoxia induced by arterial occlusion.
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Affiliation(s)
- Stefan De Smet
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Gommaar D'Hulst
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.,Laboratory of Exercise and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Chiel Poffé
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Ruud Van Thienen
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Emanuele Berardi
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Peter Hespel
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium. .,Bakala Academy-Athletic Performance Center, KU Leuven, Leuven, Belgium.
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Roach RC, Wagner PD, Ainslie PN, Hackett PH. Translation in Progress: Hypoxia 2017. J Appl Physiol (1985) 2017; 123:922-925. [PMID: 29025903 DOI: 10.1152/japplphysiol.00846.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 11/22/2022] Open
Affiliation(s)
- Robert C Roach
- University of Colorado Altitude Research Center, Department of Medicine, Anschutz Medical Campus, Aurora, Colorado;
| | - Peter D Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Canada; and
| | - Peter H Hackett
- University of Colorado Altitude Research Center, Department of Medicine, Anschutz Medical Campus, Aurora, Colorado.,Institute for Altitude Medicine, Telluride, Colorado
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