Altitude-related Illness Research Articles

Effectiveness of Continuous Positive Airway Pressure in Alleviating Hypoxemia and Improving Exertional Capacity at Altitude.

Strickland, Brian, Elan Small, Mary Ryan, and Ryan Paterson. Effectiveness of continuous positive airway pressure in alleviating hypoxemia and improving exertional capacity at altitude. High Alt Med Biol. 00:000-000, 2024. Introduction: Decreased oxygen saturation and exercise tolerance are commonly experienced at high altitude. Continuous positive airway pressure (CPAP) devices have become increasingly portable and battery powered, providing a potentially unique new therapeutic modality for treatment of altitude-related illnesses. This study evaluated the potential use of CPAP devices to improve and maintain oxygen saturation at altitude, both at rest and with exertion, to evaluate the feasibility of using this device at altitude. Methods: Subjects were taken to Mount Blue Sky and monitored while they hiked to the summit (4,350 m), maintaining a consistent level of exertion. Subjects hiked for 0.7 km both with and without CPAP set to 10 cmH2O pressure. Continuous vital signs were collected during the hike and recovery period. Results: All subjects completed the hike wearing CPAP devices at a vigorous level of exertion. Mean oxygen saturation of the CPAP group (M = 83.8%, SD = 3.72) was significantly higher than that of the control group during exertion (M = 78.7%, SD = 2.97); p = 0.005. Recovery after exertion was quicker in the CPAP group than the control group. Three subjects experienced claustrophobia requiring a brief pause, but were able to complete their exercise trial without removing equipment or experiencing adverse events. When pauses from claustrophobia were excluded, there was no difference in completion time between the groups (p = 0.06). Conclusion: CPAP reliably improved oxygen saturation at rest and during vigorous exertion at high altitude. Its ability to correct hypoxemia, even with physical exertion, may prove useful after further study as a portable self-carried device to prevent and treat altitude-related illness, or to improve safety in high-altitude rescues.

High Altitude Illness among Rapidly Ascending Pilgrims to Kailash Mansarovar.

High altitude pilgrims typically ascend rapidly, are not well prepared for the austere environment and tend to have multiple co-morbidities. Here, we list the trend of altitude and other illnesses who visited Humla district hospital (2,950 meters) following very rapid ascent to Kailash Mansarovar (4,500 meters). A prospective study was conducted among 55 patients at the Humla District Hospital from September 2019 - August 2022. Patients who fell ill during pilgrimage and brought to the hospital were included. The patients were assessed with medical history and clinical examination. Lake Louise Score Acute Mountain Sickness Score (2018) was used for the diagnosis of Acute Mountain Sickness. A total of 56 evacuees visited the hospital which included 55 patients and 1 brought dead. The mean age was 50.63 ±10.91 years. Sixteen patients (29.1%) developed symptoms within 24 hours and 15 patients (27.3%) within 48 hours of ascent. Headache 42 (76.4%) was the most common complain. Mild acute mountain sickness (30.9%; 17 patients) was the most common altitude related illness while 14 patients (25.4%) were diagnosed with non-altitude related illnesses. Twelve patients (21.8%) had co-morbidities like hypertension and diabetes mellitus. In the rapidly ascending pilgrims, majority of travelers requiring medical attention are suffering from some form of altitude illnesses. Hence, proper planning and public awareness about slow and gradual ascent profile is necessary to make the travel safer.

Alterations in gut microbiota and metabolites associated with altitude-induced cardiac hypertrophy in rats during hypobaric hypoxia challenge.

The gut microbiota is involved in host responses to high altitude. However, the dynamics of intestinal microecology and their association with altitude-related illness are poorly understood. Here, we used a rat model of hypobaric hypoxia challenge to mimic plateau exposure and monitored the gut microbiome, short-chain fatty acids (SCFAs), and bile acids (BAs) over 28 d. We identified weight loss, polycythemia, and pathological cardiac hypertrophy in hypoxic rats, accompanied by a large compositional shift in the gut microbiota, which is mainly driven by the bacterial families of Prevotellaceae, Porphyromonadaceae, and Streptococcaceae. The aberrant gut microbiota was characterized by increased abundance of the Parabacteroides, Alistipes, and Lactococcus genera and a larger Bacteroides to Prevotella ratio. Trans-omics analyses showed that the gut microbiome was significantly correlated with the metabolic abnormalities of SCFAs and BAs in feces, suggesting an interaction network remodeling of the microbiome-metabolome after the hypobaric hypoxia challenge. Interestingly, the transplantation of fecal microbiota significantly increased the diversity of the gut microbiota, partially inhibited the increased abundance of the Bacteroides and Alistipes genera, restored the decrease of plasma propionate, and moderately ameliorated cardiac hypertrophy in hypoxic rats. Our results provide an insight into the longitudinal changes in intestinal microecology during the hypobaric hypoxia challenge. Abnormalities in the gut microbiota and microbial metabolites contribute to the development of high-altitude heart disease in rats.

Markers of cardiovascular risk and their reversibility with acute oxygen therapy in Kyrgyz highlanders with high altitude pulmonary hypertension

BackgroundHigh altitude pulmonary hypertension (HAPH), a chronic altitude related illness, is associated with hypoxemia, dyspnea and reduced exercise performance. We evaluated ECG and pulse wave-derived markers of cardiovascular risk in highlanders with HAPH (HAPH+) in comparison to healthy highlanders (HH) and lowlanders (LL) and the effects of hyperoxia. MethodsWe studied 34 HAPH+ and 54 HH at Aksay (3250m), and 34 LL at Bishkek (760m), Kyrgyzstan. Mean pulmonary artery pressure by echocardiography was mean±SD 34±3, 22±5, 16±4mmHg, respectively (p<0.05 all comparisons). During quiet rest, breathing room air or oxygen in randomized order, we measured heart-rate adjusted QT interval (QTc), an ECG-derived marker of increased cardiovascular mortality, and arterial stiffness index (SI), a marker of cardiovascular disease derived from pulse oximetry plethysmograms. ResultsPulse oximetry in HAPH+, HH and LL was, mean±SD, 88±4, 92±2 and 95±2%, respectively (p<0.05 vs HAPH+, both comparisons). QTc in HAPH+, HH and LL was 422±24, 405±27, 400±28ms (p<0.05 HAPH+ vs. others); corresponding SI was 10.5±1.9, 8.4±2.6, 8.5±2.0m/s, heart rate was 75±8, 68±8, 70±10 bpm (p<0.05, corresponding comparisons HAPH+ vs. others). In regression analysis, HAPH+ was an independent predictor of increased QTc and SI when controlled for several confounders. Oxygen breathing increased SI in HH but not in HAPH+, and reduced QTc in all groups. ConclusionsOur data suggest that HAPH+ but not HH may be at increased risk of cardiovascular mortality and morbidity compared to LL. The lack of a further increase of the elevated SI during hyperoxia in HAPH+ may indicate dysfunctional control of vascular tone and/or remodelling.

Altered cardiac repolarisation in highlanders with high-altitude pulmonary hypertension during wakefulness and sleep.

High-altitude pulmonary hypertension (HAPH) is an altitude-related illness associated with hypoxaemia that may promote sympathetic excitation and prolongation of the QT interval. The present case-control study tests whether QT intervals, markers of malignant cardiac arrhythmias, are prolonged in highlanders with HAPH (HAPH+) compared to healthy highlanders (HH) and healthy lowlanders (LL). The mean pulmonary artery pressure (mPAP) was measured by echocardiography in 18 HAPH+ (mPAP, 34mmHg) and 18 HH (mPAP, 23mmHg) at 3,250m, and 18 LL (mPAP, 18mmHg) at 760m, Kyrgyzstan (p<.05 all mPAP comparisons). Groups were matched for age, sex and body mass index. Electrocardiography and pulse oximetry were continuously recorded during nocturnal polysomnography. The heart rate-adjusted QT interval, QTc, was averaged over consecutive 1-min periods. Overall, a total of 26,855 averaged 1-min beat-by-beat periods were semi-automatically analysed. In HAPH+, maximum nocturnal QTc was longer during sleep (median 456ms) than wakefulness (432ms, p<.05) and exceeded corresponding values in HH (437 and 419ms) and LL (430 and 406ms), p<.05, respectively. The duration of night-time QTc >440ms was longer in HAPH+ (median 144min) than HH and LL (46 and 14min, p<.05, respectively). HAPH+ had higher night-time heart rate (median 78beats/min) than HH and LL (66 and 65beats/min, p<.05, respectively), lower mean nocturnal oxygen saturation than LL (88% versus 95%, p<.05) and more cyclic oxygen desaturations (median 24/hr) than HH and LL (13 and 3/hr, p<.05, respectively). In conclusion, HAPH was associated with higher night-time heart rate, hypoxaemia and longer QTc versus HH and LL, and may represent a substrate for increased risk of malignant cardiac arrhythmias.

Evaluation of renal excretion and pharmacokinetics of furosemide in rats after acute exposure to high altitude at 4300 m.

With studies indicative of altered renal excretion under high altitude-induced hypobaric hypoxia, the consideration of better therapeutic approaches has long been the aim of research on the management of high altitude related illness. The pharmacokinetics of drugs such as furosemide might be altered under hypoxic conditions, making it essential to establish different dose-regimens to maintain therapeutic efficacy or to avoid toxic side effects at high altitude. Simultaneously, drug-drug interactions (DDIs) mediated by OAT1 occur at high altitude, severely affecting furosemide pharmacokinetics. This study investigated the influence of acute exposure to high altitude at 4300m on the renal excretion of furosemide in rats. Significant changes in physiological parameters and kidney histopathology were found after acute high altitude exposure. Compared with low altitude, the pharmacokinetics of furosemide and the expression level of OAT1 in kidney were significantly changed after rapid ascent to high altitude. Additionally, the down-regulated OAT1 expression further sustained the potential mechanism for the decreased renal excretion of furosemide, resulting in extended residence of the drug in the human body. The elevation of AUC, Cmax , MRT, t1/2 of furosemide, and decreased CL at high altitude further reinforced the current findings. Moreover, the absorption of furosemide was markedly increased and renal excretion significantly declined after co-administration of captopril, resulting in local drug interaction at high altitude. In conclusion, acute exposure to high altitude may significantly affect the renal excretion of furosemide and the pharmacokinetic parameters of furosemide were altered after co-administration of captopril, which may then impact the conventional therapeutic dosage.

Soluble Urokinase-Type Plasminogen Activator Receptor Plasma Concentration May Predict Susceptibility to High Altitude Pulmonary Edema.

Introduction. Acute exposure to high altitude induces inflammation. However, the relationship between inflammation and high altitude related illness such as high altitude pulmonary edema (HAPE) and acute mountain sickness (AMS) is poorly understood. We tested if soluble urokinase-type plasminogen activator receptor (suPAR) plasma concentration, a prognostic factor for cardiovascular disease and marker for low grade activation of leukocytes, will predict susceptibility to HAPE and AMS. Methods. 41 healthy mountaineers were examined at sea level (SL, 446 m) and 24 h after rapid ascent to 4559 m (HA). 24/41 subjects had a history of HAPE and were thus considered HAPE-susceptible (HAPE-s). Out of the latter, 10/24 HAPE-s subjects were randomly chosen to suppress the inflammatory cascade with dexamethasone 8 mg bid 24 h prior to ascent. Results. Acute hypoxic exposure led to an acute inflammatory reaction represented by an increase in suPAR (1.9 ± 0.4 at SL versus 2.3 ± 0.5 at HA, p < 0.01), CRP (0.7 ± 0.5 at SL versus 3.6 ± 4.6 at HA, p < 0.01), and IL-6 (0.8 ± 0.4 at SL versus 3.3 ± 4.9 at HA, p < 0.01) in all subjects except those receiving dexamethasone. The ascent associated decrease in PaO2 correlated with the increase in IL-6 (r = 0.46, p < 0.001), but not suPAR (r = 0.27, p = 0.08); the increase in IL-6 was not correlated with suPAR (r = 0.16, p = 0.24). Baseline suPAR plasma concentration was higher in the HAPE-s group (2.0 ± 0.4 versus 1.8 ± 0.4, p = 0.04); no difference was found for CRP and IL-6 and for subjects developing AMS. Conclusion. High altitude exposure leads to an increase in suPAR plasma concentration, with the missing correlation between suPAR and IL-6 suggesting a cytokine independent, leukocyte mediated mechanism of low grade inflammation. The correlation between IL-6 and PaO2 suggests a direct effect of hypoxia, which is not the case for suPAR. However, suPAR plasma concentration measured before hypoxic exposure may predict HAPE susceptibility.

Sleep at high altitude: guesses and facts.

Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease.

Travelling to altitude

The increasing popularity of adventure and activity holidays means that more people are being exposed to the physiological rigors of high altitude. For some, this forms part of the physical challenge, whereas for others, it may pose an unexpected difficulty. Holiday planning, therefore, takes on a new medical dimension. Experience of working in prevention and management of altitude-related illness has illustrated that personal preparation for this testing environment is mixed; many expedition members have a good understanding and recognition through years of experience and personal interest; whereas others arrive armed with prescribed medications at the request of the commercial expedition operator with no guidance as to how to use them, and many are ignorant of the real risks of death that high altitude imposes. GPs should be prepared to help address the medical risk assessment that travel to altitude necessitates.

Continuous Positive Airway Pressure as Adjunct Treatment of Acute Altitude Illness

Altitude related illness occurs in unacclimatized individuals ascending to altitudes over 2500 m. Treatment usually involves descending to lower altitudes and pharmacological therapies. There are very few cases, studies, or recommendations regarding the use of positive pressure ventilation in acute mountain sickness (AMS) or high altitude pulmonary edema (HAPE). This case describes the use of CPAP as part of the treatment of a trekker diagnosed with AMS and HAPE in a remote location at 4200 m in Nepal.

Effect of intermittent hypoxic training on cardiovascular responses to altitude (2800 m)

Introduction: Intermittent hypoxic exposure (IHE) prior to ascent to high altitude is postulated as a beneficial pre-conditioning strategy in the prevention of high altitude illness. Variations in arterial stiffness and endothelial function (vascular tone) may also be important in the pathogenesis of altitude related illness. The influence of IHE pre-conditioning on cardiovascular adaptations (notably arterial stiffness and vascular tone) to altitude is less clear. This study explored the impact of normobaric IHE pre-conditioning on acute cardiovascular adaptations to high altitude. Method: Participants were assigned to one of three intervention groups: control (no IHE), IHE at rest (IHE-rest) or IHE with training (IHE-training) matched for fitness, age and sex. In the 14- day period prior to a high altitude expedition IHE groups completed 10×2 hour hypoxic exposures in an environmental chamber (12.2% O2 equivalent to 4300 m), at rest (IHE-rest) or rest plus 20 minutes running at 80% heart rate reserve (calculated from individual predetermined VO2max at altitude). Arterial stiffness (SI) and vascular tone (RI) responses were recorded using a non-invasive finger photoplethysmography technique at sea-level (baseline), pre and post IHE intervention period, 12 and 72 hours post arrival at altitude (Lukla, Nepal, 2800 m). Results: Thirty apparently healthy participants (18 male, 12 female, age range 20-62 years) free from cardiovascular disease were recruited (n = 10 per condition). Two-way repeated measures (intervention x time) ANOVA revealed no main effect for intervention for SI (control_1.07±1.41 m.s-1, IHE-rest _0.50±0.65 m.s-1, IHE-training_1.07±0.81 m.s-1; P = 0.083) or RI (control_3.3±4.4%, IHE-rest_7.6±25.6%, IHE-training 7.2±18.1%; P = 0.174). There were no between-group interaction effects for any cardiovascular measurements (P = 0.059 for RI; P = 0.112 for SI) Conclusion: Intermittent hypoxic exposure prior to ascent to high altitude does not significantly alter vascular tone or arterial stiffness in apparently healthy adults. The impact of IHE preconditioning on endothelial function at higher altitudes and in the prevention of altitude related illness remains to be elucidated.

Acute Mountain Sickness: Pathophysiology, Prevention, and Treatment

Barometric pressure falls with increasing altitude and consequently there is a reduction in the partial pressure of oxygen resulting in a hypoxic challenge to any individual ascending to altitude. A spectrum of high altitude illnesses can occur when the hypoxic stress outstrips the subject's ability to acclimatize. Acute altitude-related problems consist of the common syndrome of acute mountain sickness, which is relatively benign and usually self-limiting, and the rarer, more serious syndromes of high-altitude cerebral edema and high-altitude pulmonary edema. A common feature of acute altitude illness is rapid ascent by otherwise fit individuals to altitudes above 3000 m without sufficient time to acclimatize. The susceptibility of an individual to high-altitude syndromes is variable but generally reproducible. Prevention of altitude-related illness by slow ascent is the best approach, but this is not always practical. The immediate management of serious illness requires oxygen (if available) and descent of more than 300 m as soon as possible. In this article, we describe the setting and clinical features of acute mountain sickness and high-altitude cerebral edema, including an overview of the known pathophysiology, and explain contemporary practices for both prevention and treatment exploring the comprehensive evidence base for the various interventions.

Altitude-Related Illness and Retinal Vascular Geometry: A Hypothesis

High Altitude Medicine & BiologyVol. 9, No. 4 LETTERS TO THE EDITORAltitude-Related Illness and Retinal Vascular Geometry: A HypothesisMichael Andrew WilliamsMichael Andrew WilliamsSearch for more papers by this authorPublished Online:30 Dec 2008https://doi.org/10.1089/ham.2008.1020AboutSectionsPDF/EPUB ToolsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail "Altitude-Related Illness and Retinal Vascular Geometry: A Hypothesis." , 9(4), pp. 341–342FiguresReferencesRelatedDetails Volume 9Issue 4Dec 2008 Information© 2008 Mary Ann Liebert, Inc.To cite this article:Michael Andrew Williams.Altitude-Related Illness and Retinal Vascular Geometry: A Hypothesis.High Altitude Medicine & Biology.Dec 2008.341-342.http://doi.org/10.1089/ham.2008.1020Published in Volume: 9 Issue 4: December 30, 2008PDF download

Cerebrovascular Responses to Hypoxia and Hypocapnia in Ethiopian High Altitude Dwellers

Cerebrovascular responses to hypoxia and hypocapnia in Peruvian altitude dwellers are impaired. This could contribute to the high incidence of altitude-related illness in Andeans. Ethiopian high altitude dwellers may show a different pattern of adaptation to high altitude. We aimed to examine cerebral reactivity to hypoxia and hypocapnia in healthy Ethiopian high altitude dwellers. Responses were compared with our previous data from Peruvians. We studied 9 Ethiopian men at their permanent residence of 3622 m, and one day after descent to 794 m. We continuously recorded cerebral blood flow velocity (CBFV; transcranial Doppler). End-tidal oxygen (P(ET)o(2)) was decreased from 100 mm Hg to 50 mm Hg with end-tidal carbon dioxide (P(ET)co(2)) clamped at the subject's resting level. P(ET)co(2) was then manipulated by voluntary hyper- and hypoventilation, with P(ET)o(2) clamped at 100 mm Hg (normoxia) and 50 mm Hg (hypoxia). During spontaneous breathing, P(ET)co(2) increased after descent, from 38.2+/-1.0 mm Hg to 49.8+/-0.6 mm Hg (P<0.001). There was no significant response of CBFV to hypoxia at either high (-0.19+/-3.1%) or low (1.1+/-2.9%) altitudes. Cerebrovascular reactivity to normoxic hypocapnia at high and low altitudes was 3.92+/-0.5%.mm Hg(-1) and 3.09+/-0.4%.mm Hg(-1); reactivity to hypoxic hypocapnia was 4.83+/-0.7%.mm Hg(-1) and 2.82+/-0.5%.mm Hg(-1). Responses to hypoxic hypocapnia were significantly smaller at low altitude. The cerebral circulation of Ethiopian high altitude dwellers is insensitive to hypoxia, unlike Peruvian high altitude dwellers. Cerebrovascular responses to P(ET)co(2) were greater in Ethiopians than Peruvians, particularly at high altitude. This, coupled with their high P(ET)co(2) levels, would lead to high cerebral blood flows, and may be advantageous for altitude living.

Evidence for a Genetic Basis for Altitude-Related Illness

Altitude-related illnesses are a family of interrelated pulmonary, cerebral, hematological, and cardiovascular medical conditions associated with the diminished oxygen availability at moderate to high altitudes. The acute forms of these debilitating and potentially fatal conditions, which include acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE), often develop in incompletely acclimatized lowlanders shortly after ascent, whereas, the chronic conditions, such as chronic mountain sickness (CMS) and high altitude pulmonary hypertension (HAPH), usually afflict native or long-term highlanders and may reflect a loss of adaptation. Anecdotal reports of particularly susceptible people or families are frequently cited as evidence that certain individuals have an innate susceptibility (or resistance) to developing these conditions and, in recent decades, there have been a number of studies designed to characterize the physiology of individuals predisposed to these conditions, as well as to identify the specific genetic variants that contribute to this predisposition. This paper reviews the epidemiological evidence for a genetic component to the various forms of altitude-related illness, such as innate susceptibility, familial clustering, and patterns of population susceptibility, as well as the molecular evidence for specific genetic risk factors. While the evidence supports some role for genetic background in the etiology of altitude-related illness, limitations in individual studies and a general lack of corroborating research limit the conclusions that can be drawn about the extent of this contribution and the specific genes or pathways involved. The paper closes with suggestions for future work that could support and expand on previous studies, as well as provide new insights.

Medical Recommendations for Women Going to Altitude

High Altitude Medicine & BiologyVol. 6, No. 1 POSITION PAPERMedical Recommendations for Women Going to AltitudeA Medical Commission UIAA Consensus PaperDominique Jean, Conxita Leal, Susi Kriemler, Heleen Meijer, and Lorna G. MooreDominique JeanSearch for more papers by this author, Conxita LealSearch for more papers by this author, Susi KriemlerSearch for more papers by this author, Heleen MeijerSearch for more papers by this author, and Lorna G. MooreSearch for more papers by this authorPublished Online:16 Mar 2005https://doi.org/10.1089/ham.2005.6.22AboutSectionsPDF/EPUB ToolsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail FiguresReferencesRelatedDetailsCited bySport Climbing During Pregnancy26 May 2022Ventilatory Response to Hypoxia and Tolerance to High Altitude in Women: Influence of Menstrual Cycle, Oral Contraception, and Menopause Jean-Paul Richalet, François Lhuissier, and Dominique Jean17 March 2020 | High Altitude Medicine & Biology, Vol. 21, No. 1Schwangerschaft, Antikonzeptiva und BergsteigenHigh-Altitude MedicineQueen of the mountain: successful pregnancy while exercising up to 5,300 mJournal of Applied Physiology, Vol. 125, No. 2Travel During Pregnancy: Considerations for the Obstetric ProviderObstetrical & Gynecological Survey, Vol. 72, No. 2Athletes at High Altitude10 February 2016 | Sports Health: A Multidisciplinary Approach, Vol. 8, No. 2Lebensführung und Ernährung in der Schwangerschaft15 September 2016Wilderness Preparticipation Evaluation and Considerations for Special PopulationsWilderness & Environmental Medicine, Vol. 26, No. 4Wilderness Preparticipation Evaluation and Considerations for Special PopulationsClinical Journal of Sport Medicine, Vol. 25, No. 5Prevention of high altitude illnessTravel Medicine and Infectious Disease, Vol. 12, No. 1Lebensführung und Ernährung in der Schwangerschaft16 April 2015High-Altitude MedicineTravel to High Altitude during Pregnancy: Frequently Asked Questions and Recommendations for Clinicians Dominique Jean and Lorna G. Moore22 June 2012 | High Altitude Medicine & Biology, Vol. 13, No. 2Work in Hypoxic Conditions-Consensus Statement of the Medical Commission of the Union Internationale des Associations d'Alpinisme (UIAA MedCom)25 March 2011 | The Annals of Occupational Hygiene, Vol. 76LebensführungOccupational Aspects of Work in Hypoxic Conditions - The New Recommendation of the Medical Commission of the Union Internationale des Associations d'Alpinisme (UIAA MedCom)26 April 2010 | Medicina Sportiva, Vol. 14, No. 1Journeys to High Altitude—Risks and Recommendations for Travelers with Preexisting Medical Conditions1 January 2010 | Journal of Travel Medicine, Vol. 17, No. 1The ecology and evolutionary endocrinology of reproduction in the human female3 November 2009 | American Journal of Physical Anthropology, Vol. 140, No. S49Respiratory Physiology in Pregnancy30 January 2009Maximum Exercise Responses of Men and Women Mountaineering Trainees on Induction to High Altitude (4350 m) by TrekkingWilderness & Environmental Medicine, Vol. 19, No. 3Medication and Dosage Considerations in the Prophylaxis and Treatment of High-Altitude IllnessChest, Vol. 133, No. 3Advice for Women TravelersHigh-altitude MedicineWomen in the WildernessEvidence for a Genetic Basis for Altitude-Related Illness Jim L. Rupert and Michael S. Koehle9 June 2006 | High Altitude Medicine & Biology, Vol. 7, No. 2Beratungsgrundlagen zur Lebens führung in der Schwangerschaft Volume 6Issue 1Mar 2005 InformationCopyright 2005, Mary Ann Liebert, Inc.To cite this article:Dominique Jean, Conxita Leal, Susi Kriemler, Heleen Meijer, and Lorna G. Moore.Medical Recommendations for Women Going to Altitude.High Altitude Medicine & Biology.Mar 2005.22-31.http://doi.org/10.1089/ham.2005.6.22Published in Volume: 6 Issue 1: March 16, 2005Keywordsacute mountain sicknessclimbingcontraceptionhigh altitude pulmonary edemahigh altitude peripheral edemahypoxiaintrauterine growth restrictionmountaineeringpregnancyPDF download

Pharmacotherapy for Altitude-Related Illness

Altitude-related illness is a frequent cause of morbidity and occasional mortality among recreational sports travelers in the United States and throughout the world. High-altitude illness describes the cerebral and pulmonary syndromes (acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema) that can occur in unacclimatized persons ascending too rapidly to high altitude. The pathogenesis of these syndromes is primarily hypobaric hypoxia that causes compensatory changes in the brain and lungs, resulting in hyperperfusion of microvascular beds, increased capillary pressure, and a microvascular leak with resulting edema and a characteristic constellation of symptoms. Prevention and treatment involve education about rate of ascent; diet; alcohol intake; physical activity; oxygen; hyperbaric chambers; and pharmacotherapy, including acetazolamide, dexamethasone, nifedipine, and salmeterol in selected circumstances.

Altitude-related illness in children

[] ~ ntil relatively recently, clinical illness related to exposure to high altitude was a concern mainly of mountaineers and physiologists. As our understanding of these conditions has grown, however, it has become clear that children are among those at highest risk of having altitude-related illnesses. In addition, with the growth of the populations of the mountainous regions of North America, as well as the advent of jet travel to those areas, greater numbers of children are either living at or vlsiting areas of sufficientaltitude to cause clinical illness. The rapidity of the ascent to altitude allowed by modem jet travel also allows less time for acclimatization and may increase the risk of these conditions developing. Finally, a number of pediatric illnesses are associated with either acute or chronic hypoxemia, and there may be lessons of relevance to the care of these children to be learned from the effects of altitude exposure. All of these factors combine to make altitude-related illness in children a topic of clinical relevance to pediatric practitioners. Despite intense research over the last half century, however, much of the basic pathophysiologic mechanism of illness related to altitude remains obscure. Although recent progress has been made toward identifying at least some therapeutic interventions for these conditions, approximately 20 deaths per year worldwide are ascribed to high-altitude pulmonary edema alone, and the number of hospital visits and mined vacations attributable to altitude-related ' illness as a whole is undoubtedly much higher. Unfortunately, little of the research on the physiologic and pathophysiologic

Altitude-related illness in two California national parks.

High-altitude illness encompasses a spectrum of disorders related to the hypoxia experienced by individuals at elevation. Altitude-related illness has been well described in the United States, but there are no studies published in the medical literature looking at the occurrence of high-altitude illness within the US National Parks system. The purpose of this study is to describe the incidence, treatment, and outcomes of visitors to Sequoia and Kings Canyon National Parks who presented to emergency medical services (EMS) personnel with signs and symptoms consistent with high-altitude illness. We conducted a retrospective review of all EMS patient care records (PCRs) from Sequoia and Kings Canyon National Parks during the study period of June 1992 to August 1995. There were 23 cases of altitude-related illness identified by EMS personnel in the parks during the 38-month study period, including five cases of high-altitude pulmonary edema and 19 cases of acute mountain sickness. One patient died, nine patients were transported to local hospitals, nine patients were assisted in their descent and then released from medical care, and four patients were treated and then allowed to continue their travels. There was an average of 5.9 cases per year of high-altitude illness and an incidence of one case per 27 EMS contacts. We conclude that altitude-related illness does occur in Sequoia and Kings Canyon National Parks and, although high-altitude illness accounts for only 4% of EMS contacts, caring for these patients uses a significant amount of national park resources. We suggest continued training of emergency medical technicians and park medics in the recognition and treatment of these disorders. We also support education of hikers to reduce or prevent the morbidity associated with altitude-related illness.

Environment-dependent sports emergencies

As more individuals participate in sports and outdoor activities, the frequency of environmentally related illnesses will increase. Participants in sporting events of long duration and those requiring particularly inclement weather and adverse conditions are especially prone to developing injury. Hypothermia, heat-related illnesses, and high-altitude illnesses are multisystem emergencies that require immediate, specific therapeutic maneuvers. Physicians must be able to recognize the signs and symptoms of these medical emergencies and institute definitive care. Rapid core rewarming, airway control, and prolonged cardiopulmonary resuscitation are the key factors in managing the hypothermic patient. Adequate cooling and volume resuscitation provide the basis for treating the hyperthermic patient. The patient with high altitude-related illness should be returned to a lower elevation and given supplemental oxygen. Specific intervention depends on the patient's presentation. Environmental illnesses cause severe morbidity and mortality and are frequently within the control of the sport participant. Thus physicians must educate their patients on basic preventive measures if they are going to participate in outdoor sporting activities.