Altitude Acclimatization Research Articles

Mountain Emergency Medicine Review, 1st edition

Mountain Emergency Medicine Review, 1st edition

Chronic Hypoxia Blunts the Hypoxic Ventilatory Response in Neonatal and Adult Rats

Chronic hypoxia (CH) may affect the control of breathing differently in neonatal versus adult mammals. It is widely accepted that CH blunts the hypoxic ventilatory response (HVR) in neonatal rats but augments hypoxic ventilation in adult rats. However, there is also evidence that longer durations of CH can progressively attenuate the HVR in adult rats too. Therefore, we predicted that short durations of CH (3 days) would blunt the HVR in neonatal rats and augment the HVR in adult rats, but that longer durations of CH (7 days) would blunt the HVR in adult rats. To test these predictions, rats were exposed to 12% O2 (CH) or room air (Control) for 3 days as neonates (from P0 to P3, or from P7 to P10) or as young adults. Baseline ventilation (21% O2) and the acute HVR (12% O2) were measured by plethysmography immediately following the exposure. The adult rats were then returned to the CH and Control chambers for 4 more days before repeating the breathing measurements. Although Sprague‐Dawley rats were used in all experiments, adults from two different commercial suppliers (Charles River Laboratories and Envigo) were used to determine whether genetic background might influence the results. Baseline ventilation was greater in all CH groups regardless of their age, consistent with ventilatory acclimatization. With the exception of CH rats at P10 in which peak hypoxic ventilation (i.e., minute ventilation during the first minute of 12% O2) was also greater than in Controls, hypoxic ventilation was generally similar between CH and Control groups or reduced in the CH group. Accordingly, the change in ventilation from baseline (i.e., HVR) was blunted by CH regardless of the age of the rats, the duration of the CH exposure (adults only), or the substrain of Sprague‐Dawley rat (adults only). The order in which test gases were presented during breathing measurements (i.e., 21% O2 – 12% O2 vs. 12% O2 – 21% O2) did not influence the calculated HVR in adult rats. We conclude that the respiratory plasticity elicited by normobaric CH is similar across ages in Sprague‐Dawley rats.

Proteomic and Morphological Profiling of Mice Ocular Tissue During High-altitude Acclimatization Process: An Animal Study at Lhasa.

PurposeHigh-altitude environment mainly with hypobaric hypoxia could induce pathological alterations in ocular tissue. Previous studies have mostly focused on sporadic case reports and simulated high-altitude hypoxia experiments. This aim of this study was to explore the proteomic and morphological changes of ocular tissue in mice at real altitude environment.MethodsIn this study, mice were flown from Chengdu (elevation: 500 m) to Lhasa (elevation: 3600 m). After exposure for 1day, 3, 6, 10, 20, 30, and 40days, the mice were euthanatized to obtain blood and ocular tissue. Serological tests, ocular pathological examinations, integral ocular proteomics analysis, and Western blot were conducted.ResultsWe focused on acute phase (1–3 days) and chronic phase (>30 days) during high-altitude acclimatization. Serum interleukin-1 was increased at 3 days, while superoxide dismutase, interleukin-6, and tumor necrosis factor-α showed no statistical changes. H&E staining demonstrated that the cornea was edematous at 3 days and exhibited slower proliferation at 30 days. The choroid showed a consistently significant thickening, while there existed no noticeable changes in retinal thickness. Overall, 4073 proteins were identified, among which 71 and 119 proteins were detected to have significant difference at 3 days and 40 days when compared with the control group. Functional enrichment analysis found the differentiated proteins at 3 days exposure functionally related with response to radiation, dephosphorylation, negative regulation of cell adhesion, and erythrocyte homeostasis. Moreover, the differential profiles of the proteins at 40 days exposure exhibited changes of regulation of complement activation, regulation of protein activation cascade, regulation of humoral immune response, second-messenger-mediated signaling, regulation of leukocyte activation, and cellular iron homeostasis. Interestingly, we found the ocular proteins with lactylation modification were increased along high-altitude adaptation.ConclusionThis is the first work reporting the ocular proteomic and morphological changes at real high-altitude environment. We expect it would deep the understanding of ocular response during altitude acclimatization.

Absence of Erythropoietin and Cardio‐respiratory Responses to Hypobaric Hypoxia in Olfactory Receptor 78 Null mice

Hypobaric hypoxia (HH) evokes a series of physiological adaptations, including carotid body (CB)–dependent ventilatory acclimatization to hypoxia (VAH), elevated blood pressure (BP), and stimulation of erythropoietin (Epo) gene in the kidney. Olfactory receptor 78 (Olfr78) is a G‐protein coupled receptor that has been implicated in CB response to acute hypoxia. Given that both CB and kidney express Olfr78, we tested the hypothesis that Olfr78 plays a role in the cardio‐respiratory and renal Epo gene responses to HH. Studies were performed on wild type (WT) and Olfr78 null mice reared in room air (control) or exposed to 18h of HH (0.4 atmospheres). HH treated WT exhibited: 1) VAH manifested as increased baseline breathing, and enhanced hypoxic ventilatory response (HVR; 12% O2); 2) elevated BP and plasma norepinephrine levels; and 3) increased baseline CB sensory nerve activity and augmented CB sensory nerve response to subsequent acute hypoxia‐ all these responses to HH are either markedly attenuated or absent in Olfr78 null mice. WT mice responded to HH with activation of the renal Epo gene expression and elevated plasma Epo levels, and these effects were attenuated or absent in Olfr78 null mice. The attenuated Epo activation by HH was accompanied with markedly reduced hypoxia‐inducible factor (HIF)‐2α protein and reduced activation of HIF‐2 target gene Sod‐1 in Olfr78 null mice, suggesting impaired transcriptional activation of HIF‐2 contributes to attenuated Epo responses to HH. These results suggest a role for Olfr78 in physiological adaptations to HH experienced at high altitude

The Effect of High-Altitude Acclimatisation on Ultra-Short Heart Rate Variability.

IntroductionHigh-altitude (HA) exposure affects heart rate variability (HRV) and has been inconsistently linked to acute mountain sickness (AMS). The influence of increasing HA exposure on ultra-short HRV and its relationship to gold standard HRV measures at HA has not been examined.MethodsThis was a prospective observational study of adults aged ≥ 18 years undertaking a HA trek in the Dhaulagiri region of the Himalayas. Cardiac inter-beat-intervals were obtained from a 10-s recording of supra-systolic blood pressure (Uscom BP+ device) immediately followed by 300 s single lead ECG recording (CheckMyHeart device). HRV was measured using the RMSSD (root mean square of successive differences of NN intervals) at sea level (SL) in the United Kingdom and at 3,619, 4,600, and 5,140 m at HA. Oxygen saturations (SpO2) were measured using finger-based pulse oximetry. The level of agreement between the 10 and 300 s RMSSD values were examined using a modified Bland–Altman relative-difference analysis.ResultsOverall, 89 participants aged 32.2 ± 8.8 years (range 18–56) were included of which 70.8% were men. HA exposure (SL vs. 3,619 m) was associated with an initial increase in both 10 s (45.0 [31.0–82.0]) vs. 58.0 [33.0–119.0] ms) and 300 s (45.67 [33.24–70.32] vs. 56.48 [36.98–102.0] ms) in RMSSD. Thereafter at 4,600 and 5,140 m both 10 and 300 s RMSSD values were significantly lower than SL. From a total of 317 paired HRV measures the 10 and 300 s RMSSD measures were moderately correlated (Spearman r = 0.66; 95% CI: 0.59–0.72; p < 0.0001). The median difference (bias) in RMSSD values (300 s − 10 s) was −2.3 ms with a lower and upper limit of agreement of −107.5 and 88.61 ms, respectively with no differences with altitude. Overall, 293/317 (92.4%) of all paired HRV values fell within the 95% CI limits of agreement. Neither HRV method was predictive of AMS.ConclusionIncreasing HA affects ultra-short HRV in a similar manner to gold-standard 300 s. Ultra-short HRV has a moderate agreement with 300 s measurements. HRV did not predict AMS.

LATE-BREAKING ABSTRACTS XIII ISMM World Congress on Mountain Medicine 2021 June 14–16, 2021 Virtual Meeting

LATE-BREAKING ABSTRACTS XIII ISMM World Congress on Mountain Medicine 2021 June 14–16, 2021 Virtual Meeting

Спосіб інтенсивної терапії загального переохолодження

Актуальність. Загальне переохолодження є однією з найбільш складних проблем сучасної інтенсивної терапії критичних станів. Метою роботи були вивчення ефективності розробленого способу інтенсивної терапії загального переохолодження, оцінка його впливу на швидкість корекції патофізіологічних зрушень і рівень летальності пацієнтів у критичному або термінальному стані. Матеріали та методи. Обстежено 50 пацієнтів (середній вік — 43,00 ± 3,62 року), стан яких був оцінений відповідно до класифікації стадій загального переохолодження Швейцарського товариства гірської медицини. Пацієнти були розподілені на 2 групи: I група (n = 25) — з активним зігріванням системою конвекційного обігріву Warm Air 135 (CSZ, США) та інфузією 37 °С кристалоїдних розчинів у таких дозах: при легкому ступені — 20–30 мл/кг; помірного та тяжкого ступеня — 50–70 мл/кг, із включенням колоїдних розчинів. II група (n = 25) — із пасивним зігріванням і стандартним комплексом інтенсивної терапії, що включав інфузію кристалоїдних і колоїдних розчинів кімнатної температури в дозі 20–30 мл/кг. Вивчалися езофагальна і тімпанітна температури, показники гемодинаміки (артеріальний тиск, частота серцевих скорочень, середній артеріальний тиск), ступінь неврологічного дефіциту за шкалою коми Глазго, швидкість зігрівання. Результати. Вихідна температура ядра тіла у I групі становила 29,03 ± 2,76 °С, у II групі — 31,50 ± 1,97 °С. Мінімальне та максимальне значення температури ядра тіла в I групі становили 24,3 і 33,6 °С; у II — 27,2 і 34,5 °С відповідно. Початковий рівень середнього артеріального тиску становив у I групі 49,86 ± 20,71 мм рт.ст., у II — 70,45 ± 11,72 мм рт.ст.; через 48 годин — 76,65 ± 12,27 мм рт.ст. та 60,82 ± 36,39 мм рт.ст. відповідно. Швидкість досягнення нормотермії (36,0 °С) у I і II групах становила 6,48 ± 3,47 години та 9,20 ± 6,52 години відповідно. Рівень летальності в I групі — 12 %, у II — 48 %, указані відмінності були вірогідними. Висновки. Використання вказаного вище способу інтенсивної терапії загального переохолодження дозволяє знизити летальність на 25 %.

Chapter 4 - Adaptive cardiorespiratory changes to chronic continuous and intermittent hypoxia

This chapter reviews cardiorespiratory adaptations to chronic hypoxia (CH) experienced at high altitude and cardiorespiratory pathologies elicited by chronic intermittent hypoxia (CIH) occurring with obstructive sleep apnea (OSA). Short-term CH increases breathing (ventilatory acclimatization to hypoxia) and blood pressure (BP) through carotid body (CB) chemo reflex. Hyperplasia of glomus cells, alterations in ion channels, and recruitment of additional excitatory molecules are implicated in the heightened CB chemo reflex by CH. Transcriptional activation of hypoxia-inducible factors (HIF-1 and 2) is a major molecular mechanism underlying respiratory adaptations to short-term CH. High-altitude natives experiencing long-term CH exhibit blunted hypoxic ventilatory response (HVR) and reduced BP due to desensitization of CB response to hypoxia and impaired processing of CB sensory information at the central nervous system. Ventilatory changes evoked by long-term CH are not readily reversed after return to sea level. OSA patients and rodents subjected to CIH exhibit heightened CB chemo reflex, increased hypoxic ventilatory response, and hypertension. Increased generation of reactive oxygen species (ROS) is a major cellular mechanism underlying CIH-induced enhanced CB chemo reflex and the ensuing cardiorespiratory pathologies. ROS generation by CIH is mediated by nontranscriptional, disrupted HIF-1 and HIF-2-dependent transcriptions as well as epigenetic mechanisms.

Elucidating the combined effect of intermittent hypoxia training and acetazolamide on hypoxia induced hematological and physiological changes

As the number of people travelling to altitude increases, the risk of life threatening medical emergencies also increases. It is important that we have effective strategies to minimize the risk of altitude illness. In this study, an attempt was made to investigate the combined effect of non-pharmacological (Intermittent hypoxia training; IHT) and pharmacological (acetazolamide; ACZ) intervention as a prophylactic strategy in order to minimize the risk of high altitude hypoxic related problems using rats as an animal model. Male Sprague Dawley rats were subjected to IHT for 4 h consecutively for 5 days at 12% FiO2 under normobaric conditions with and without oral ACZ administration at 25 mg/kg body weight. Validation of the intervention was performed by exposing the rats to extreme hypoxia (EH) at 8% FiO2 to further assess the effect of IHT and ACZ on hypoxic acclimatization. The principal findings of this study is that the combined effect of IHT and ACZ improves the arterial oxygenation by alterations in hemodynamics and in blood gasometry, thereby resulting into an increase in the oxygen carrying capacity of the blood with increase in SpO2 (peripheral oxygen saturation). The present study showed that the combined effect of IHT with ACZ could be refined as a prophylactic measure for better outcomes during altitude ascent and rapid altitude acclimatization rather than IHT or ACZ alone.

Proceedings of the Birmingham Medical Research Expeditionary Society and British Mountain Medicine Society Conference, September 2021.

Proceedings of the Birmingham Medical Research Expeditionary Society and British Mountain Medicine Society Conference, September 2021.

Association of Genes of the NO Pathway with Altitude Disease and Hypoxic Pulmonary Hypertension.

Chronic intermittent hypoxia leads to high-altitude pulmonary hypertension, which is associated with high asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthesis. Therefore, we aimed to understand the relation of single nucleotide polymorphisms in this pathway to high-altitude pulmonary hypertension (HAPH). We genotyped 69 healthy male Chileans subjected to chronic intermittent hypoxia. Acclimatization to altitude was determined using the Lake Louise Score and the presence of acute mountain sickness. Echocardiography was performed after six months in 24 individuals to estimate pulmonary arterial pressure. The minor allele of dimethylarginine dimethylaminohydrolase (DDAH)1 rs233112 was associated with high-baseline plasma ADMA concentration, while individuals homozygous for the major allele of DDAH2 rs805304 had a significantly greater increase in ADMA during chronic intermittent hypoxia. The major allele of alanine glyoxylate aminotransferase-2 (AGXT2) rs37369 was associated with a greater reduction of plasma symmetric dimethylarginine (SDMA). Several genes were associated with high-altitude pulmonary hypertension, and the nitric oxide synthase (NOS)3 and DDAH2 genes were related to acute mountain sickness. In conclusion, DDAH1 determines baseline plasma ADMA, while DDAH2 modulates ADMA increase in hypoxia. AGXT2 may be up-regulated in hypoxia. Genomic variation in the dimethylarginine pathway affects the development of HAPH and altitude acclimatization.

Ward, Milledge &amp; West’s High Altitude Medicine and Physiology, Sixth Edition

Ward, Milledge & West’s High Altitude Medicine and Physiology, sixth edition, is the latest edition of this venerable, but hardly stodgy, book. As with the second through the fifth editions, it continues to improve. The book has come of age with the addition to the title of Michael Ward, James Milledge, and John West, authors of the first 3 editions. Milledge and West continued to the fifth edition and have now passed the baton to new, younger authors. Andrew Luks, the lead author of the sixth edition, joined as an author in the fifth edition. The other authors are all new to the book. Like Dr Luks, all of them are well-respected experts in the subject. The style is less sparse than in previous editions, but still clear and consistent. The authors have rewritten most of the material, rather than just revising the chapters, and have added a wealth of new material. New material includes updates throughout the book, based on new studies published since the fifth edition in 2013, and expansion of many areas, such as genetics and geography. The number of pages and the type size are about the same as in the fifth edition. The format of the sixth edition is larger to accommodate the additional material. The book is now divided into 3 sections: The Environment and Its People, Physiologic Responses to Hypoxia, and Clinical High Altitude Medicine. The chapters have been reorganized and rearranged. The 27 chapters, decreased from 29 in the fifth edition, are divided into many more subsections, making it easier to find information on specific topics. Another welcome change is that the references are now at the end of each chapter rather than at the back of the book. Every chapter is thoroughly referenced. Although any new textbook is already out of date by the time it is printed, this edition is as up to date as possible, with references as recent as 2020. The authors have once again anticipated future trends, pointing the way forward to help readers remain current between editions. Examples include genomic studies of high altitude adaptation and susceptibility to altitude illness, which continue to proliferate, and altitude preacclimatization. New studies of preacclimatization are likely after recently reported ascents of Mount Everest with climbers flying directly to base camp after arriving in Nepal. The authors mention that future editions are likely to include significant new information in these areas as well as others. My worst, but still minor, disappointment is that the iconic frontispiece photo of the original authors on skis during the 1960 Silver Hut expedition that graced the first 3 editions is still missing from the sixth edition. Ward, Milledge & West’s High Altitude Medicine and Physiology continues to be the foremost reference work on its subjects. It was a great pleasure to review the latest edition. I congratulate the authors on freshening and expanding the text. I recommend it to both experts and neophytes with clinical or research interests in high altitude. Before you put it on your bookshelf, preferably in easy reach so that you can refer to it often, you will probably want to read some, or even all, of the chapters.

TMT-Based Plasma Proteomics Reveals Dyslipidemia Among Lowlanders During Prolonged Stay at High Altitudes.

Acute exposure to high altitude perturbs physiological parameters and induces an array of molecular changes in healthy lowlanders. However, activation of compensatory mechanisms and biological processes facilitates high altitude acclimatization. A large number of lowlanders stay at high altitude regions from weeks to months for work and professional commitments, and thus are vulnerable to altitude-associated disorders. Despite this, there is a scarcity of information for molecular changes associated with long-term stay at high altitudes. In the present study, we evaluated oxygen saturation (SpO2), heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) of lowlanders after short- (7 days, HA-D7) and long-term (3 months, HA-D150) stay at high altitudes, and used TMT-based proteomics studies to decipher plasma proteome alterations. We observed improvements in SpO2 levels after prolonged stay, while HR, SBP, and DBP remained elevated as compared with short-term stay. Plasma proteomics studies revealed higher levels of apolipoproteins APOB, APOCI, APOCIII, APOE, and APOL, and carbonic anhydrases (CA1 and CA2) during hypoxia exposure. Biological network analysis also identified profound alterations in lipoprotein-associated pathways like plasma lipoprotein assembly, VLDL clearance, chylomicron assembly, chylomicron remodeling, plasma lipoprotein clearance, and chylomicron clearance. In corroboration, lipid profiling revealed higher levels of total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL) for HA-D150 whereas high density lipoproteins (HDL) levels were lower as compared with HA-D7 and sea-level indicating dyslipidemia. We also observed higher levels of proinflammatory cytokines IL-6, TNFα, and CRP for HA-D150 along with oxidized LDL (oxLDL), suggesting vascular inflammation and proartherogenic propensity. These results demonstrate that long-term stay at high altitudes exacerbates dyslipidemia and associated disorders.

Altitude acclimatization via hypoxia-mediated oxidative eustress involves interplay of protein nitrosylation and carbonylation: A redoxomics perspective

AimHypoxia is an important feature of multiple diseases like cancer and obesity and also an environmental stressor to high altitude travelers. Emerging research suggests the importance of redox signaling in physiological responses transforming the notion of oxidative stress into eustress and distress. However, the behavior of redox protein post-translational modifications (PTMs), and their correlation with stress acclimatization in humans remains sketchy. Scant information exists about modifications in redoxome during physiological exposure to environmental hypoxia. In this study, we investigated redox PTMs, nitrosylation and carbonylation, in context of extended environmental hypoxia exposure. MethodsThe volunteers were confirmed to be free of any medical conditions and matched for age and weight. The human global redoxome and the affected networks were investigated using TMT-labeled quantitative proteo-bioinformatics and biochemical assays. The percolator PSM algorithm was used for peptide-spectrum match (PSM) validation in database searches. The FDR for peptide matches was set to 0.01. 1-way ANOVA and Tukey's Multiple Comparison test were used for biochemical assays. p-value<0.05 was considered statistically significant. Three independent experiments (biological replicates) were performed. Results were presented as Mean ± standard error of mean (SEM). Key findingsThis investigation revealed direct and indirect interplay between nitrosylation and carbonylation especially within coagulation and inflammation networks; interlinked redox signaling (via nitrosylation‑carbonylation); and novel nitrosylation and carbonylation sites in individual proteins. SignificanceThis study elucidates the role of redox PTMs in hypoxia signaling favoring tolerance and survival. Also, we demonstrated direct and indirect interplay between nitrosylation and carbonylation is crucial to extended hypoxia tolerance.

HIGH ALTITUDE PULMONARY EDEMA (HAPE)

 Introduction: High altitude pulmonary edema (HAPE) is one of the acute, severe, non-cardiogenic disease that could be life threatening, occurs upon either the first or subsequent exposure to high altitude. It is triggered by a shortage of oxygen after ascending high altitude. The most effective therapeutic approach for HAPE is to immediately descend from high altitude and to give oxygenation, maintaining arterial saturation over 90%, as well as letting the patient rest from strenuous physical activity. The use of portable hyperbaric chamber is also deemed effective in certain circumstance, and nifedipine can also be used to treat HAPE, even as additional treatment in condition that the patients had yet to descend and oxygenation is still not administrable. Case Report: We reported a case at Rs. Dr. Saiful Anwar, a 23-year old male with High Altitude Pulmonary Edema (HAPE). Diagnosis established from anamnesis, physical examination, and laboratory tests. Patient complained shortness of breath when climbing Mt. Semeru, in which the patient reached an altitude of 2700 mdpl in 2 days. Physical examination showed oxygen saturation 46-49% with NRBM 10 lpm, and rhonchi breath sound in all lung areas. Laboratory examination showed leukocytosis, blood gas analysis showed hypocarbia, severe hipoxemia, metabolic acidosis, and type I respiratory failure. Ches XRay showed wide, irregular infiltrate in both lungs. Based on those, the patient was diagnosed with HAPE. In this case, the patient was given oxygenation.Conclussion: In this case, the patient was diagnosed with HAPE based on anamnesis, physical examination, and laboratory tests. Oxygenation given to the patient improved his condition.Key words: High altitude disease, Acclimatization, Pathophysiology, Management and treatment

Investigation of vascular endothelial growth factor receptor-dependent neuroplasticity on rat nucleus tractus solitarius and phrenic nerve after chronic sustained hypoxia.

The neuronal system that controls respiration creates plasticity in response to physiological changes. Chronic sustained hypoxia causes neuroplasticity that contributes to ventilatory acclimatization to hypoxia (VAH). The purpose of this study is to explain the potential roles of the VAH mechanism developing because of chronic sustained hypoxia on respiratory neuroplasticity of vascular endothelial growth factor (VEGF) receptor activationon the nucleus tractus solitarius (NTS) and phrenic nerve. In this study 24 adult male Sprague-Dawley rats were used. Subjects were separated into four groups, amoderate-sham (mSHAM), severed-sham (sSHAM), moderate chronic sustained hypoxia (mCSH), and severed chronic sustained hypoxia (sCSH). Normoxic group (mSHAM and sSHAM) rats were exposed to 21% O₂ level (7 days) in the normobaric room while hypoxia group (mCSH and sCSH) rats were exposed to 13% and 10% O₂ level (7 days). Different protocols were applied for normoxic and hypoxia groups and ventilation, respiratory frequency, and tidal volume measurements were made with whole-body plethysmography. After the test HIF-1α, erythropoietin (EPO), and VEGFR-2 expressions on the NTS region in the medulla oblongata and phrenic nerve motor neurons in spinal cord tissue were analyzed using the immunohistochemical stain method. Examinations on the medulla oblongata and spinal cord tissues revealed that HIF-1α, EPO, and VEGFR-2 expressions increased inhypoxia groups compared to normoxic groups while a similar increase was also seen when respiratory parameters were assessed. Consequently, learning about VAH-related neuroplasticity mechanisms developed as a result of chronic continuous hypoxia will contribute to developing new therapeutical approaches to various diseases causing respiratory failure using brain plasticity without recourse to medicines.

A “School Of Clinical Ethics”: Clinical Ethics Education for Clinicians and Philosophy Students

"The presentation intends to present and illustrate an experience of teaching clinical ethics realized with a group of clinicians and philosophy students and held at the Philosophy Department of the University of Trento, Italy (Spring 2013 and Spring 2015). The class was intended to train clinicians and students to the main concepts of clinical ethics and to a specific methodology to approach clinical matters with ethical and philosophical tools. The class offered a space and time of listening, confronting, debating and learning. The opportunity to dialogue and to reflect, starting form clinical cases presented by clinicians and to realize an ethical analysis of them, combining languages and competences, resulted extremely relevant for clinicians, for students involved and for the teachers themselves. It represented – as well – a first and previous step to start some action-research in specific clinical units, as the local Intensive Care Unit, the Transplantation Coordination Unit and the Mountain Medicine and Ethics Lab. "

Urological Emergencies and Diseases in Wilderness Expeditions.

When considering medical emergencies that might affect an expedition, urologic emergencies are typically not included. However, the reality is that manageable and prevalent urologic disease processes can pose significant challenges for the wilderness medicine physician and warrant consideration. The purpose of this review is to identify and discuss the most commonly encountered urologic emergencies and diseases in the wilderness setting and to prepare the expedition medicine physician for management of these urgent conditions. A PubMed and Internet search for urologic emergencies and diseases in wilderness conditions was conducted. We also searched bibliographies for useful supplemental literature and material from leading mountain medicine and wilderness medicine societies as well as population-based studies for common urologic diseases. Urologic emergencies and diseases on expeditions and in wilderness conditions have been reported primarily with retrospective case series and case reports. The most commonly reported urologic emergencies in this setting include urologic trauma, renal calculi, and urinary retention. Parasitic infections in the urinary tract also have been reported to cause urinary symptoms and urinary retention in wilderness conditions. Although urologic diseases in such conditions are uncommon, significant morbidity and even potentially life-threatening sequelae to urologic emergencies were found to occur. Major genitourinary emergencies in expedition medicine are uncommon but involve both potentially manageable urgent conditions and serious life-threatening conditions best treated with urgent stabilization and occasionally medical evacuation. The opportunity exists for increased awareness for management strategies for urologic conditions in the often remote or extreme environments of an expedition.

The influence of short-term high-altitude acclimatization on cerebral and leg tissue oxygenation post-orthostasis.

Orthostasis at sea level decreases brain tissue oxygenation and increases risk of syncope. High altitude reduces brain and peripheral muscle tissue oxygenation. This study determined the effect of short-term altitude acclimatization on cerebral and peripheral leg tissue oxygenation index (TOI) post-orthostasis. Seven lowlanders completed a supine-to-stand maneuver at sea level (450m) and for 3 consecutive days at high altitude (3776m). Cardiorespiratory measurements and near-infrared spectroscopy-derived oxygenation of the frontal lobe (cerebral TOI) and vastus lateralis (leg TOI) were measured at supine and 5-min post-orthostasis. After orthostasis at sea level, cerebral TOI decreased [mean Δ% (95% confidential interval): - 4.5%, (- 7.5, - 1.5), P < 0.001], whilst leg TOI was unchanged [- 4.6%, (- 10.9, 1.7), P = 0.42]. High altitude had no effect on cerebral TOI following orthostasis [days 1-3: - 2.3%, (- 5.3, 0.7); - 2.4%, (- 5.4, 0.6); - 2.1%, (- 5.1, 0.9), respectively, all P > 0.05], whereas leg TOI decreased [days 1-3: - 12.0%, (- 18.3, - 5.7); - 12.1%, (- 18.4, - 5.8); - 10.2%, (- 16.5, - 3.9), respectively, all P < 0.001]. This response did not differ with days spent at high altitude, despite evidence of cardiorespiratory acclimatization [increased peripheral oxygen saturation (supine: P = 0.01; stand: P = 0.02) and decreased end-tidal carbon dioxide (supine: P = 0.003; stand: P = 0.01)]. Cerebral oxygenation is preferentially maintained over leg oxygenation post-orthostasis at high altitude, suggesting different vascular regulation between cerebral and peripheral circulations. Short-term acclimatization to high altitude did not alter cerebral and leg oxygenation responses to orthostasis.

Travel to altitude with neurological disorders — recommendation of the UIAA Medical Commission

The present review examines several neurological conditions and the problems posed by travelling to high altitude, and in particular whether the underlying disease is likely to worsen. The neurological conditions include migraine and other types of headaches, transient ischemia of the brain, occlusive cerebral artery diseases, intracranial haemorrhage and vascular malformations, intracranial space occupying mass, multiple sclerosis, peripheral neuropathies, neuromuscular disorders, epileptic seizures, dementia and Parkinson’s disease. Attempts will be made to classify the risk posed by each condition and to provide recommendations regarding medical evaluation, advice for or against travelling to altitude and effective prophylactic measures. Some individual cases should only be advised after careful examination and risk evaluation either in an outpatient mountain medicine service or by a physician with knowledge of travelling and high altitude risks. Recent developments in diagnostic methods and treatment of neurological conditions are also mentioned.