Ibuprofen Compared to Acetazolamide for the Prevention of Acute Mountain Sickness: A Randomized Placebo-Controlled Trial.

INTRODUCTION: Acetazolamide is recommended for the prevention of acute mountain sickness (AMS); however, its use is limited in some areas because of side effects. Previous studies report ibuprofen to be similar to or slightly inferior to acetazolamide. This randomized, triple-blinded, parallel-group, placebo-controlled trial was designed to compare ibuprofen with acetazolamide for the prevention of AMS. METHODS: Four hundred forty-three healthy Asian Indian men with a mean age of 29 (range: 20-49) years were randomized into three groups A, B, and P at 350m (SL). Acetazolamide (A): 85 mg; ibuprofen (B): 600 mg; or placebo (P): calcium carbonate was administered thrice daily, starting one day prior and continuing for three days after arrival at 3500m (HA). Participants were evaluated for AMS using the Lake Louise Questionnaire and for pulse, BP, SpO2, and respiratory rate twice daily for the first two days during rest and once a day for days three to six at HA. RESULTS: Of the 443 participants recruited at SL, 139 could not be airlifted due to logistical limitations, and 304 were available for follow-up at HA. Among these, 254 had ascended as per protocol. By intent to treat (IT) (N = 304; A = 99, B = 102, P = 103), the incidence of AMS (LLQS>/=3) was 12%, 5%, and 13%, and the incidence of severe AMS was 1%, 2%, and 6%, in groups A, B, and P, respectively. Using per protocol analysis (PP) (N = 254; A = 83, B = 87, P = 84), the incidence of AMS was 12%, 6%, and 13% in groups A, B, and P, respectively. The relative risk for developing AMS vs. placebo was A-0.96 (CI:0.46-2.0, p=0.91), B-0.39 (CI:0.14-1.04, p=0.06), A-0.94 (CI:0.42-2.1, p=0.88), and B-0.45 (0.16-1.24, p=0.12) by IT and PP, respectively. CONCLUSION: Ibuprofen is effective in males for the prevention of AMS with rapid ascent to 3500 m-rest for the first two days. Acetazolamide was superior to ibuprofen in the prevention of moderate-to-severe AMS.

High-altitude hypoxia promotes BRD4-mediated activation of the Wnt/ß-catenin pathway and disruption of intestinal barrier.

Hypobaric hypoxia, commonly experienced at elevated altitudes, presents significant physiological challenges. Our investigation is centered on the impact of the bromodomain protein 4 (BRD4) under these conditions, especially its interaction with the Wnt/ß-Catenin pathway and resultant effects on glycolytic inflammation and intestinal barrier stability. By combining transcriptome sequencing with bioinformatics, we identified BRD4's key role in hypoxia-related intestinal anomalies. Clinical parameters of altitude sickness patients, including serum BRD4 levels, inflammatory markers, and barrier integrity metrics, were scrutinized. In vitro studies using CCD 841 CoN cells depicted expression changes in BRD4, Interleukin (IL)-1ß, IL-6, and ß-Catenin. Transepithelial electrical resistance (TEER) and FD4 analyses assessed barrier resilience. Hypoxia-induced mouse models, analyzed via H&E staining and Western blot, provided insights into barrier and protein alterations. Under hypoxic conditions, marked BRD4 expression variations emerged. Elevated serum BRD4 in patients coincided with intensified Wnt signaling, inflammation, and barrier deterioration. In vitro, findings showed hypoxia-induced upregulation of BRD4 and inflammatory markers but a decline in Occludin and ZO1, affecting barrier strength-effects mitigated by BRD4 inhibition. Mouse models echoed these patterns, linking BRD4 upregulation in hypoxia to barrier perturbations. Hypobaric hypoxia-induced BRD4 upregulation disrupts the Wnt/ß-Catenin signaling, sparking glycolysis-fueled inflammation and weakening intestinal tight junctions and barrier degradation.

Continuous Positive Airway Pressure in the Treatment of Pediatric High Altitude Pulmonary Edema: A Case Study.

Treatment of high altitude pulmonary edema (HAPE) can be challenging and is further complicated in the pediatric patient in the prehospital environment. The following case presents a decompensating pediatric patient with HAPE in the prehospital aeromedical environment. It illustrates the potential benefit of continuous positive airway pressure (CPAP) as a treatment modality in the treatment of HAPE.

[Pretravel medical consultation]. / Reisemedizinische Beratung.

Many patients seek pretravel advice during routine consultations in a general practice so that basic knowledge of travel medicine is warranted. Using the example of trips to Bali, Peru and Tanzania, the most relevant topics of a pretravel consultation for these popular destinations are depicted. These include vaccinations, malaria prevention and recommendations on exposure prophylaxis for insect bites. Furthermore, special risk situations, such as travel to high altitudes or freshwater contact are discussed. In special cases, the advice of an expert in travel medicine is needed.

Clinical effect of double plasma molecular adsorption system in treatment of patients with chronic liver failure in high-altitude areas / 临床肝胆病杂志

ObjectiveTo investigate the differences in clinical features and mortality rate between native patients with chronic liver failure （CHF） and migrated patients with CHF after treatment with double plasma molecular adsorption system （DPMAS） in high-altitude areas. MethodsA total of 63 patients with CHF who received DPMAS treatment in the intensive care unit of General Hospital of Tibet Military Command from January 2016 to December 2021 were enrolled， and according to their history of residence in high-altitude areas， they were divided into native group with 29 patients and migrated group with 34 patients. The two groups were compared in terms of baseline data and clinical features before and after DPMAS treatment. The independent-samples t test was used for comparison of normally distributed continuous data between groups， and the paired t-test was used for comparison before and after treatment within each group； the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between groups， and the Wilcoxon signed rank sum test was used for comparison before and after treatment within each group； the chi-square test was used for comparison of categorical data between groups. The Kaplan-Meier method was used to plot survival curves， and the Log-rank test was used for comparison of the risk of death. ResultsCompared with the native group， the migrated group had a significantly higher proportion of Chinese Han patients （χ2=41.729， P<0.001）， and compared with the migrated group， the native group had a significantly longer duration of the most recent continuous residence in high-altitude areas （Z=3.364， P<0.001）. Compared with the native group， the migrated group had significantly higher MELD score and incidence rates of hepatic encephalopathy， hepatorenal syndrome， and gastrointestinal bleeding （Z=2.318， χ2=6.903， 5.154， and 6.262， all P<0.05）. Both groups had significant changes in platelet count （PLT）， hemoglobin count （HGB）， alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， albumin， total bilirubin （TBil）， direct bilirubin （DBil）， lactate dehydrogenase （LDH）， creatinine （Cr）， and international normalized ratio （INR） after DPMAS treatment （all P<0.05）. Before DPMAS treatment， compared with the native group， the migrated group had significantly higher levels of ALT， AST， TBil， DBil， LDH， Cr， BUN， and INR （all P<0.05） and a significantly lower level of HGB （P<0.05）； after DPMAS treatment， compared with the native group， the migrated group had significantly greater reductions in PLT and HGB （both P<0.05） and still significantly higher levels of ALT， AST， TBil， DBil， LDH， BUN， and INR （all P<0.05）. The 60-day mortality rate of patients after DPMAS treatment was 52.5% （95% confidence interval ［CI］： 41.7 — 63.8） in the native group and 81.3% （95%CI： 77.9 — 85.6） in the migrated group. Compared with the native group （hazard ratio ［HR］=0.47， 95%CI： 0.23 — 0.95）， the migrated group had a significant increase in the risk of death on day 60 （HR=2.14， 95%CI： 1.06 — 4.32， P=0.039）. ConclusionCompared with the native patients with CHF in high-altitude areas， migrated patients have a higher degree of liver impairment， a lower degree of improvement in liver function after DPMAS treatment， and a higher mortality rate. Clinical medical staff need to pay more attention to migrated patients with CHF， so as to improve their survival rates.

Menopause and High Altitude: A Scoping Review-UIAA Medical Commission Recommendations.

Mateikaite-Pipiriene, Kaste, Dominique Jean, Peter Paal, Lenka Horakova, Susi Kriemler, Alison J. Rosier, Marija Andjelkovic, Beth A. Beidleman, Mia Derstine, Jacqueline Pichler Hefti, David Hillebrandt, and Linda E. Keyes for the UIAA MedCom writing group on Women's Health in the Mountains. Menopause and high altitude: A scoping review-UIAA Medical Commission Recommendations. High Alt Med Biol 00:000-000, 2023. Background: Older people are an important fraction of mountain travelers and climbers, many of them postmenopausal women. The aim of this work was to review health issues that older and postmenopausal women may experience at high altitude, including susceptibility to high-altitude illness. Methods: We performed a scoping review for the UIAA Medical Commission series on Women's Health in the mountains. We searched PubMed and Cochrane libraries and performed an additional manual search. The primary search focused on articles assessing lowland women sojourning at high altitude. Results: We screened 7,165 potential articles. The search revealed three relevant articles, and the manual search another seven articles and one abstract. Seven assessed menopausal low-altitude residents during a high-altitude sojourn or performing hypoxic tests. Four assessed high-altitude residents. We summarize the results of these 11 studies. Conclusions: Data are limited on the effects of high altitude on postmenopausal women. The effects of short-term, high-altitude exposure on menopause symptoms are unknown. Menopause has minimal effect on the physiological responses to hypoxia in physically fit women and does not increase the risk of acute mountain sickness. Postmenopausal women have an increased risk of urinary tract infections, which may be exacerbated during mountain travel. More research is needed on the physiology and performance of older women at high altitude.

Effect of acute altitude exposure on physiological parameters and glucose metabolism in healthy lowland Peruvians.

BACKGROUND: High altitude exposure triggers a series of physiological changes to maintain homeostasis. Although longer-term (days to years) acclimatization processes are well studied, less is known about the physiological changes upon rapid ascent. We took advantage of Peru's geography to measure the first physiological changes following rapid transport from a low to a high-altitude environment among lowlanders. METHODS: Blood glucose, insulin, C-peptide, and salivary cortisol among healthy lowland Peruvians were measured before and after glucose ingestion at 40 m and upon arrival at 3470 m. Resting heart rate, blood oxygen saturation, and blood pressure were also monitored. RESULTS: At high altitude, we find a significant ( p<0.05) increase in heart rate and a decrease in blood oxygen saturation and salivary cortisol. Additionally, baseline levels of blood glucose, plasma C-peptide, and cortisol were reduced ( p<0.05). Blood glucose, plasma insulin, and plasma C-peptide returned to baseline or below faster at high altitude after glucose ingestion. CONCLUSIONS: Although many overlapping environmental and physiological factors are present in the high-altitude environment, the first steps of acclimatization in this population appear to be caused by increased energy expenditure and glucose metabolism to maintain oxygen homeostasis until the longer-term acclimatization mechanisms become more significant.

Yoga Breathing (Maheshwarananda's Modified Bhujangini Pranayama): A Randomized Study in Hypobaric Hypoxemia at 3,650 m Elevation.

Hypobaric hypoxemia represents a risk factor for body integrity and challenges its homeostasis. We examined whether practicing Maheshwarananda's modified bhujangini pranayama yoga breathing technique would influence hypobaric hypoxemia at an altitude of 3,650 m. An international randomized two-period, two-sequence crossover intervention study was conducted in September 2019 in the Himalayas. We compared 5-minute testing periods of pranayama breathing with normal resting breathing in 20 subjects divided randomly into two groups of 10 individuals; all had a daily practice of Maheshwarananda's modified bhujangini pranayama and were nonsmokers, lacto vegetarians, and alcohol abstainers. We measured the arterial saturation by pulse oximetry (SpO2; our primary outcome variable), end-tidal carbon dioxide partial pressure (EtCO2), respiratory rate, and heart rate at two altitudes: (1) 378 m (T0); and (2) 3,650 m (T1 = 2nd day, T2 = 4th day at the camp) immediately after finishing each testing period. We also monitored the presence of acute mountain sickness using the Lake Louise Scoring System. Mean SpO2 at 3,650 m increased right after the yoga breathing exercise from 88.60% to 90.35% at T1, and from 88.35% to 90.60% at T2 (T1 p = 0.007, T2 p = 0.004). No significant changes were observed in heart rate or EtCO2. The mean rate of normal control resting breathing was 13/min; the mean rate was 7/min during the yoga breathing. Right after Maheshwarananda's modified bhujangini pranayama hypobaric hypoxemia decreased as measured by SpO2, whereas EtCO2 and heart rate stayed comparable with the control resting breathing.

Challenges in the management of high-altitude illnesses and emergencies in Bhutan and Nepal.

Many popular tourist attractions and trekking routes in Bhutan and Nepal are situated between 3000 and 6000 m in elevation. High-altitude emergencies are becoming more common and medical providers must be aware of the practical and medical issues in managing these disorders. We reflect on the challenges in providing high-altitude emergency medical services in Bhutan and Nepal.

A Randomized Phase 2 Study to Evaluate Efficacy and Safety of AR36 for Prevention of Acute Mountain Sickness.

INTRODUCTION: AR36 is a pharmaceutical-grade plant extract used to support cardiovascular health in traditional Chinese medicine. Studies suggest that AR36 may prevent acute mountain sickness (AMS) during gradual ascent to high altitude. This randomized, placebo-controlled Phase 2 trial aimed to evaluate dosing regimens and assess efficacy and safety of AR36 for AMS prevention during rapid ascent. METHODS: Participants received placebo, low-dose AR36 (225 mg twice daily for 14 d prior and 5 d at altitude), or high-dose AR36 (12 d placebo, 300 mg twice daily for 2 d prior and 5 d at altitude). The primary efficacy outcome was 1993 Lake Louise Scoring System (LLSS) score on the morning after ascent. Safety was assessed through the proportion of treatment-emergent adverse events (TEAEs). RESULTS: One hundred thirty-two participants were randomized. Mean±SD age was 31.4±8.6 (range, 19-54) y. Baseline characteristics did not differ across groups. Lake Louise Scoring System scores on Day 16 in the placebo, low-dose, and high-dose groups were 4.03 (2.88), 4.42 (3.17), and 3.5 (2.31), respectively (placebo versus low-dose, P=0.462; placebo versus high-dose, P=0.574; n=110). The incidence of AMS on Day 16 was 66.7% in the placebo, 61.1% in the low-dose, and 55.3% in the high-dose group (P=0.66). The proportion of TEAEs in the placebo, low-dose, and high-dose groups was 38.4% (81), 28.4% (60), and 33.2% (70), respectively (P=0.205; n=127). There was no statistical difference between groups in LLSS, incidence of AMS, or TEAEs. CONCLUSIONS: AR36 did not improve LLSS or AMS incidence using the current regimens. AR36 was well tolerated.

Women's Health at High Altitude: An Introduction to a 7-Part Series by the International Climbing and Mountaineering Federation Medical Commission.

Horakova, Lenka, Peter Paal, Jacqueline Pichler Hefti, Marija Andjelkovic, Beth A. Beidleman, Mia Derstine, David Hillebrandt, Dominique Jean, Kaste Mateikaite-Pipiriene, Alison J. Rosier, Susi Kriemler, and Linda E. Keyes. Women's health at high altitude: An introduction to a 7-part series by the International Climbing and Mountaineering Federation Medical Commission. High Alt Med Biol. 24:243-246, 2023. Background: Women have been traveling to high altitude since the inception of modern mountaineering. Although there are distinct female-specific features such as menstruation and menopause relevant to adaptation to and performance at high altitude, very little data exist on women's high-altitude health. To summarize what is known to date, the Medical Commission of the International Climbing and Mountaineering Federation (UIAA) has created a series of articles on women's health, high altitude illness, and performance at high altitude. Methods: Assembling an international author team, two types of manuscripts were developed: (1) reviews on female-specific topics such as pregnancy; (2) reviews on sex differences in high-altitude related illnesses, nutrition, cold injuries, and mortality. Results: The literature search yielded 7,165 articles, with 482 studies meeting the inclusion criteria for full-text review. The authors of individual chapters reviewed these articles and performed additional hand searches. Conclusions: Some important questions on women sojourning and exercising at high altitude have been studied, but many are still awaiting a qualified and evidence-based response. Our seven reviews, to be published in future issues of this journal, summarize what is known about lowland women sojourning at high altitude, provide recommendations, and highlight knowledge gaps in high altitude women's medicine.

Possibility for Children with Medical Complexities to Reach a 3000-m Peak: A Report of 2 Cases.

With the recent development of neonatal medicine, the number of children with medical complexities (CMCs) is increasing. Outdoor activities are important for their psychosocial development, and the principles of accessibility should be addressed. We report the experience of 2 CMCs' high-altitude mountaineering with the necessary support. The participants were a 3-y-old girl with cerebral palsy, symptomatic epilepsy, and a ventriculoperitoneal shunt (Child A) and a 6-y-old girl who underwent bilateral Glenn operations at 11 mo for hypoplastic left heart syndrome (Child B). The support staff consisted of 4 doctors, 1 nurse, 5 nonmedical staff , 3 members from a mountaineering association, and 2 people from an oxygen company. The climbing schedule was 2 days. On the first day, we took a bus to a hut at an altitude of 2450 m and stayed overnight to acclimatize to the altitude. On the second day, we took the beginner's route, which took 3 h to climb 500 m, and our team made an attempt on the summit. During the attempt, Child B panicked. Although her lung sounds did not raise suspicions of pulmonary edema, we decided to leave the mountain with her because her transcutaneous oxygen saturation decreased. Child A had no apparent health problems and made it to the summit. Although CMCs' alpine climbing requires careful planning and staffing considering the risk of high-altitude sickness, our case suggests the feasibility of such activities with CMCs as part of accessibility.

Adaptation and altitude sickness: A 40-year bibliometric analysis and collaborative networks.

Introduction: We analyze the scientific production and collaboration networks of studies based on adaptation and altitude diseases in the period 1980-2020. Methods: The publications were extracted from journals indexed in Scopus. The bibliometric analysis was used to analyze the scientific production, including the number of annual publications, the documents, and the characteristics of the publications. With the VOSviewer software, the analysis of collaborative networks, productivity of the countries, as well as the analysis of the co-occurrence of keywords were visualized. Results: 15,240 documents were registered, of which 3,985 documents were analyzed. A significant trend was observed in the number of publications (R 2: 0.9847; P: < 0.001), with annual growth of 4.6%. The largest number of publications were original articles (77.8%), these published more frequently in the journal "Altitude Medicine and Biology". The largest number of countries were from Europe and Asia; however, the largest collaboration network was with the United States. Of the countries with high altitudes, China and Peru ranked first in scientific productivity. The research priorities were on the adaptation mechanism (37.1%), mainly anoxia and respiratory function. Acute mountain sickness (18.4%) and pulmonary edema (14.7%) were the most reported diseases. Of the top 10 institutions, "University of Colorado" and "Universidad Peruana Cayetano Heredia" contributed more than 100 publications. Conclusions: Scientific production on adaptation and altitude illnesses continues to grow. The United States and United Kingdom present collaborative networks with high-altitude countries. The research is aimed at studying the mechanisms of adaptation to altitude and acute mountain sickness.

¿Cuándo realizar biopsia renal en un paciente diabético?. A propósito de un caso en una ciudad de altura

Se reporta el caso de un paciente varón de 54 años, habitante de una ciudad de altura, con antecedentes de diabetes mellitus tipo 2 e hipertensión arterial en tratamiento, con microhematuria persistente, elevación de creatinina, presencia de proteinuria y ausencia de retinopatía diabética, a quien se le realizó biopsia renal por sospecha de glomerulopatía no diabética asociada. La biopsia renal confirmó el diagnóstico histopatológico de glomeruloesclerosis nodular diabética. Debido a que usualmente no se realiza biopsia renal en pacientes diabéticos, se presenta este caso y se revisa sus indicaciones. Asimismo, planteamos que la altura pudo influir en el deterioro de la función renal.

We report the case of a 54-year-old male patient, high altitude city dweller, with a history of type 2 diabetes mellitus and arterial hypertension in treatment, with persistent microscopic hematuria, creatinine elevation, presence of proteinuria and absence of diabetic retinopathy, who underwent renal biopsy for suspected associated non-diabetic glomerulopathy. Kidney biopsy confirmed the histopathological diagnosis of diabetic nodular glomerulosclerosis Because renal biopsy is usually not performed in diabetic patients, this case is presented and its indications are reviewed. Also, we propose that high altitude could influence in the renal function impairment.

[Establishment and Evaluation of a Mice Model of High-Altitude Cerebral Edema]. / é«˜åŽŸè„‘æ°´è‚¿å°é¼ æ¨¡åž‹çš„å»ºç«‹ä¸Žé‰´å®š.

Objective: To establish an animal model of high-altitude cerebral edema (HACE), to explore the altitude and oxygen partial pressure conditions that can lead to obvious clinical manifestations of HACE, and to lay the foundation for further research of the pathogenic mechanisms and intervention strategies of HACE. Methods: Male BALB/c mice of 8 weeks old were randomly assigned to Control and HACE groups. The Control group (n=10) was treated with normobaric and normoxic conditions, while the HACE groups were placed in hypobaric hypoxic (HH) chambers for the durations of 6 h, 12 h, 24 h, 48 h and 72 h, respectively, receiving treatments of simulated HH conditions at the altitudes of 4000 m (n=10 for each group receiving different durations of HH treatment), 5000 m (n=10 for each group receiving different durations of HH treatment), and 6000 m (n=10 for each group receiving different durations of HH treatment). HE staining was performed to observe the morphological changes of the brain tissue and the appropriate simulated altitude conditions were selected accordingly for the construction and evaluation of the best HACE model. The HACE model was evaluated in the following ways, the mouse brain was weighed and the cerebral edema was measured accordingly, Evans blue (EB) was injected to determine the permeability of the blood-brain barrier (BBB), and the cell apoptosis was determined by immunofluorescence staining. Results: There were no deaths in the groups treated with the HH conditions of the altitudes of 4000 m and 5000 m, while the mortality in the 6000 m altitude treatment groups was 12.2%. HE staining showed no significant changes in brain morphology or structure in the group receiving HH treatment for the altitude of 4000 m. A small amount of brain cell edema was observed in the groups receiving 48 h and 72 h of HH treatment for the altitude of 5000 m. The groups receiving HH treatment for the altitude of 6000 m demonstrated the most prominent modeling effect. HE staining showed increased volume and swelling of brain cells in all the 6000 m groups, especially in the 24 h, 48 h and 72 h treatment groups. In all the 6000 m groups, cell arrangement disorder, gap enlargement, and nuclear contraction were observed. Evaluation of the modeling effect demonstrated that, in the HACE mice model constructed with the HH conditions for the altitude of 6000 m, cerebral edema and EB permeability increased after 12 h HH treatment and there was no obvious apoptosis in the modeling groups receiving different durations of treatment. Conclusion: The HACE model can be established effectively by simulating conditions at the altitude of 6000 m (the atmospheric pressure being 47.19 kPa and the oxygen partial pressure being 9.73 kPa) with a HH chamber.

Bibliometric analysis of main diseases due to exposure to altitude in the world / Análise bibliométrica das principais doenças decorrentes da exposição à altitude no mundo

Introduction: Around 140 million people in the world live-in high-altitude regions; however, there are few bibliometric studies. Objective: Describe the scientific production of the main diseases due to exposure to altitude in the world. Methods: Observational study, bibliometric type. After a systematic search in Scopus, original articles were included, whose main variable was mountain sickness, high-altitude cerebral edema and high-altitude pulmonary edema. Characteristics of each study were manually extracted and analyzed using descriptive statistics. Results: 2305 articles were found on mountain sickness (n=1531), high-altitude pulmonary edema (n=549) and high-altitude cerebral edema (n=225), respectively, in Scopus. Regarding the most influential journal was High Altitude Medicine and Biology in all three diseases, the country with the highest number of articles was the United States (458, 168 and 75), the most used language was English (91.31%, 85.33% and 84.19%), the author with the highest number of publications was Bartsh P. (2.94%, 18.60% and 3.42%) and most of the articles were open access (41.08%, 42.06% and 76.53%), respectively. Conclusion: The scientific production of original articles on mountain sickness, high-altitude pulmonary edema and high-altitude cerebral edema in Scopus has increased in recent years; however, it is still scarce compared to other diseases.

Introdução: Cerca de 140 milhões de pessoas no mundo vivem em regiões de grande altitude, porém, existem poucos estudos bibliométricos. Objetivo: Descrever a produção científica sobre as principais doenças decorrentes da exposição à altitude no mundo. Métodos: Estudo observacional, do tipo bibliométrico. Após busca sistemática no Scopus, foram incluídos artigos originais, cuja variável principal foi mal da montanha, edema cerebral de altitude e edema pulmonar de altitude. As características de cada estudo foram extraídas manualmente e analisadas por meio de estatística descritiva. Resultados: Foram encontrados 2.305 artigos sobre mal da montanha (n=1.531), edema pulmonar de altitude (n=549) e edema cerebral de altitude (n=225), respectivamente no Scopus. Em relação ao periódico mais influente foi High Altitude Medicine and Biology nas três doenças, o país com maior número de artigos foi os Estados Unidos (458, 168 e 75), o idioma mais utilizado foi o inglês (91,31%, 85,33% e 84,19%), o autor com maior número de publicações foi Bartsh P. (2,94%, 18,60% e 3,42%) e a maioria dos artigos foi de acesso aberto (41,08%, 42,06% e 76,53%), respectivamente. Conclusão: A produção científica de artigos originais sobre mal da montanha, edema pulmonar de altitude e edema cerebral de altitude em Scopus tem aumentado nos últimos anos, porém ainda é escassa em comparação com outras doenças

Certain issues for medical evacuation and support after traumatic brain injury at high altitude / 中华创伤杂志

Traumatic brain injury (TBI) is much more complex considering the unique pathophysiological changes under high-altitude hypoxic environment. Moreover, because of limited source of medical transportation and facilities at high altitude, TBI patients often lack urgent and standard treatment and have to be transported to the district medical center at high altitude or even the neurotrauma center at plain region as soon as possible. The transportation has high risk and takes serious effect on lives and prognosis of the TBI patients. Up to date, the evacuation and support process for TBI patients in the western plateau region of China has been improved through years of practice, but there are still deficiencies compared to the Critical Care Air Transport Team (CCATT). The authors sought to discuss certain issues related to medical evacuation and support after TBI at high altitude from aspects of early damage control operation and timely safety medical transportation, aiming to improve the survival rate, neurological outcomes and life quality for these patients.

A Study on the Molecular Mechanism of High Altitude Heart Disease in Children.

Objective: High altitude heart disease (HAHD) is a common pediatric disease in high altitude areas. It usually occurs in people who have lived for a long time or have lived for more than 2500m above sea level. Its common inducement is respiratory tract infection. The clinical differential diagnosis is difficult because the symptoms of HAHD are similar to those of congenital heart disease; Due to the limitation of medical conditions, many patients are in the state of losing follow-up or not seeking medical treatment, resulting in poor prognosis of HAHD and becoming a high-altitude disease with high mortality. Clarifying the molecular mechanism of HAHD, developing early molecular screening technology and accurate treatment methods of HAHD are the key to improve the ability of prevention and treatment of HAHD. Methods: First, the literature in the PubMed and CNKI databases were screened based on keywords and abstracts. Then, the literature for the study was identified based on the fitness between the content of the literature, the research objectives, and the timeliness of the literature. Finally, a systematic molecular mechanism of HAHD was established by investigating the literature and sorting out the genetic adaptations of Tibetan populations compared with low-altitude populations that migrated to the plateau. Results: With the investigation of the 48 papers screened, it was found that genes capable of enhancing the hypoxic ventilatory response and resistance to pulmonary hypertension were all correlated with the hypoxia-inducible factor (HIF) pathway, consisting mainly of three pathways, HIF-1α, HIF-2α, and NO. Conclusion: The low prevalence of HAHD in Tibetan aboriginal children was mainly due to the genetic adaptation of the Tibetan population to the high altitude environment, which coordinated the cellular response to hypoxia by regulating the downstream hypoxia control genes in the HIF pathway.

Haemodynamic Adaptive Mechanisms at High Altitude: Comparison between European Lowlanders and Nepalese Highlanders.

Background: Exposure to high altitudes determines several adaptive mechanisms affecting in a complex way the whole cardiovascular, respiratory, endocrine systems because of the hypobaric hypoxic condition. The aim of our study was to evaluate the circulatory adaptive mechanisms at high altitudes, during a scientific expedition in the Himalayas. Methods: Arterial distensibility was assessed measuring carotid-radial and carotid-femoral pulse wave velocity. Tests were carried out at several altitudes, from 1350 to 5050 m above sea level, on 8 lowlander European researchers and 11 highlander Nepalese porters. Results: In Europeans, systolic blood pressure and pulse pressure increased slightly but significantly with altitude (p < 0.05 and p < 0.001, respectively). Norepinephrine showed a significant increase after the lowlanders had spent some time at high altitude (p < 0.001). With increasing altitude, a progressive increase in carotid-radial and carotid-femoral pulse wave velocity values was observed in lowlanders, showing a particularly significant increase (p < 0.001) after staying at high altitude (carotid-radial pulse wave velocity, median value (interquartile range) from 9.2 (7.9−10.0) to 11.2 (10.9−11.8) m/s and carotid-femoral pulse wave velocity from 8.5 (7.9−9.0) to 11.3 (10.9−11.8) m/s). At high altitudes (3400 and 5050 m above sea level), no significant differences were observed between highlanders and lowlanders in hemodynamic parameters (blood pressure, carotid-radial and carotid-femoral pulse wave velocity). Conclusions: The progressive arterial stiffening with altitude observed in European lowlanders could explain the increase in systolic and pulse pressure values observed at high altitudes in this ethnic group. Further studies are needed to evaluate the role of aortic stiffening in the pathogenesis of acute mountain sickness.

The combined use of acetazolamide and Rhodiola in the prevention and treatment of altitude sickness.

Background: Altitude sickness (AS), which is caused by rapid exposure to low amounts of oxygen at high elevations, poses a great threat to humans working and traveling in these conditions. Acute mountain sickness includes high-altitude pulmonary edema and high-altitude cerebral edema. Acetazolamide (AZ) is often used to treat pulmonary edema caused by hypoxia. Additionally, the medicinal plant Rhodiola rosea L. (Rh) is often used to prevent AS in the Qinghai-Tibet plateau. However, the mechanisms of action of Rh and AZ in the treatment of AS remain unclear. To date, no research has been conducted to determine whether their combined use has better efficacy in the treatment and prevention of AS than their separate use. Methods: We used the method of network pharmacology to analyze the mechanisms of Rh and AZ in combination in the prevention and treatment of AS, and also verified our results. Results: The hypoxia-inducible factor (HIF)-1 signaling pathway, which is related to hypoxia, and other pathways related to pulmonary hypertension, became more enriched after the combined use of the 2 drugs. Additionally, Rh and AZ regulated most nodes in the AS network. Further, compared to their separate use, the combined use of Rh and AZ further downregulated the gene expression of HIF-1α and improved hemodynamics in rats, and thus helped the body to reduce its sensitivity to hypoxic environments and pulmonary artery pressure. Conclusions: This study provides evidence supporting the combined use of AZ and Rh in the treatment of AS.