Article

Efficacy of Danshen (Salvia miltiorrhiza) Dripping Pills for Prevention of Acute Mountain Sickness: A Randomized, Double-Blind, Placebo-Controlled Trial

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

A randomized, double-blind, placebo-controlled trial was conducted to investigate the efficacy of prophylaxis by administering compound Danshen dripping pills (CDDPs) on acute mountain sickness (AMS). To this end, a total number of 58 healthy low-altitude inhabitants residing in Beijing were randomized to two treatment sequences, receiving either 270mg CDDPs or placebo during an 11-day trip in Tibet, China, at an altitude of more than 3000 m. The Lake Louise Scoring System (LLSS) was also utilized to access AMS incidence and severity, twice a day, during the research period. AMS was further diagnosed when headaches and LLSS≥ 3 were present. A total of 54 subjects completed the study and no significant difference was observed in the number of individuals with AMS between the groups. However, during the whole observation period, the LLSS values for comprehensive AMS symptoms in the group receiving CDDPs indicated lower occurrence than those in the placebo (CON) group. It is noteworthy that, on day 3 (arrival at Lhasa, altitude 3658 m), AMS symptoms (LLSS=3.79) in the CON group had clearly aggravated (P=0.0475) in contrast to those in the group with administration of CDDPs (LLSS=2.31). Besides, arterial oxygen saturation (SaO2) value for those taking CDDPs was significantly higher than that in the CON group (87.86% vs. 85.72%, P=0.0388) on day 10. These preliminary findings suggested that CDDPs might be regarded as an effective prophylaxis for AMS to a certain extent without any specific adverse effects, relieving clinical manifestations of AMS, especially after rapid ascents (Clinical Trial Registry Number: NCT03270787).

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

Full-text available
Article
Context Previous studies indicate that compound Danshen Dripping Pill (CDDP) improves the adaptation to high-altitude exposure. However, its mechanism of action is not clear. Objective To explore the protective effect of CDDP on hypobaric hypoxia (HH) and its possible mechanism. Materials and methods A meta-analysis of 1051 human volunteers was performed to evaluate the effectiveness of CDDP at high altitudes. Male Sprague-Dawley rats were randomized into 5 groups (n = 6): control at normal pressure, model, CDDP-170 mg/kg, CDDP-340 mg/kg and acetazolamide groups. HH was simulated at an altitude of 5500 m for 24 h. Animal blood was collected for arterial blood-gas analysis and cytokines detection and their organs were harvested for pathological examination. Expression levels of AQP1, NF-κB and Nrf2 were determined by immunohistochemical staining. Results The meta-analysis data indicated that the ratio between the combined RR of the total effective rate and the 95% CI was 0.23 (0.06, 0.91), the SMD and 95% CI of SO2 was 0.37 (0.12, 0.62). Pre-treatment of CDDP protected rats from HH-induced pulmonary edoema and heart injury, left-shifted oxygen-dissociation curve and decreased P50 (30.25 ± 3.72 vs. 37.23 ± 4.30). Mechanistically, CDDP alleviated HH-reinforced ROS by improving SOD and GPX1 while inhibiting pro-inflammatory cytokines and NF-κB expression. CDDP also decreased HH-evoked D-dimer, erythrocyte aggregation and blood hemorheology, promoting AQP1 and Nrf2 expression. Discussion and conclusions Pre-treatment with CDDP could prevent HH-induced tissue damage, oxidative stress and inflammatory response. Suppressed NF-κB and up-regulated Nrf2 might play significant roles in the mechanism of CDDP.
Full-text available
Article
Background: Mountain guides work daily in remote areas and high-altitude locations where specific hypoxia-related and common medical problems may occur. Arrival of rescue teams can be delayed, so mountain guides often have to rely on their own capabilities to provide first aid. Therefore, IFMGA-recognized Swiss mountain guides receive a specific medical education and are equipped with a dedicated medical kit. This specific education has never been evaluated. Methods: A questionnaire was sent to all Swiss mountain guides through their national association. This questionnaire evaluates guides' activity, type, and frequency of medical events encountered, medical education, and use of the medical kit. Furthermore, clinical vignettes were used to evaluate their subjective and objective knowledge about prevention and treatment of specific altitude-related diseases. Results: A total of 467 guides completed the questionnaire, 54 (11.6%) of them were identified as high-altitude guides (HA-guides), because they spent ≥10 nights above 4000 meters each year. Mountain guides are more exposed to altitude-specific pathologies, such as Acute Mountain Sickness (AMS), High-Altitude Pulmonary Edema (HAPE), and High-Altitude Cerebral Edema (HACE) than to general medical conditions. A majority of participants (in particular HA-guides) considered altitude-related medical knowledge essential but judged their own education as insufficient. A majority of mountain guides were aware of nonpharmacological preventive measures and able to recognize altitude-related diseases. Mountain guides declared themselves as very confident in treating altitude-related diseases. Objective assessment of their knowledge showed some gaps, in particular related to the use of specific medications like nifedipine and dexamethasone. Conclusions: Swiss mountain guides' education in altitude medicine may be improved, in particular concerning the recognition and treatment of severe conditions such as HAPE and HACE. Better knowledge may be especially important for HA-guides. These data have induced experts in the field to adapt the guides teaching curriculum and medical kit.
Full-text available
Article
To provide guidance to clinicians about best preventive and therapeutic practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for prevention and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. Recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to prevention and management of each form of acute altitude illness that incorporate these recommendations. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in 2010 and subsequently updated as the WMS Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness in 2014.
Full-text available
Article
Present study was planned to evaluate the alterations in renal and hepatic profile induced by overt hyperthyroidism as well as its subclinical form. A total of 179 subjects comprising both genders and fulfiling the exclusion and inclusion criteria were recruited for this prospective investigation. Sixty healthy controls, thirty four subclinical, fifty overt hyperthyroid and thirty five follow-up subjects having 3 months of anti-thyroid therapy were recruited. Commercially available diagnostic kits were used to determine the serum levels of FT4, FT3, TSH, Creatinine, AST and ALT. Prominent reduction (P<0.001) of creatinine was observed in overt hyperthyroid state, when compared with controls. However, significant (P<0.05) improvement was noticed in it in post treatment group. Pronounced elevation (P<0.001) of ALT was observed in overt state when compared with controls. Subclinical subjects also manifested significant (P<0.05) up regulation, whereas, pronounced reduction (P<0.01) was observed in ALT in post therapeutic condition. Prominent elevation (P<0.001) of AST in both overt as well as subclinical thyroid states have been observed when compared with healthy controls. Whereas, significant reduction (P<0.05) of AST was observed in post treatment group. Conclusively, hyperthyroid conditions markedly influence normal hepatic and renal function, whereas, treatments achieving euthyroid state after anti-thyroid therapy also influence these deviations.
Full-text available
Article
Objective Trials of ginkgo biloba extract (GBE) for the prevention of acute mountain sickness (AMS) have been published since 1996. Because of their conflicting results, the efficacy of GBE remains unclear. We performed a systematic review and meta-analysis to assess whether GBE prevents AMS. Methods The Cochrane Library, EMBASE, Google Scholar and PubMed databases were searched for articles published up to 20 May 2017. Only randomised controlled trials were included. AMS was defined as an Environmental Symptom Questionnaire Acute Mountain Sickness-Cerebral score ≥0.7 or Lake Louise Score ≥3 with headache. The main outcome measure was the relative risk (RR) of AMS in participants receiving GBE for prophylaxis. Meta-analyses were conducted using random-effects models. Sensitivity analyses, subgroup analyses and tests for publication bias were conducted. Results Seven study groups in six published articles met all eligibility criteria, including the article published by Leadbetter et al, where two randomised controlled trials were conducted. Overall, 451 participants were enrolled. In the primary meta-analysis of all seven study groups, GBE showed trend of AMS prophylaxis, but it is not statistically significant (RR=0.68; 95% CI 0.45 to 1.04; p=0.08). The I² statistic was 58.7% (p=0.02), indicating substantial heterogeneity. The pooled risk difference (RD) revealed a significant risk reduction in participants who use GBE (RD=−25%; 95% CI, from a reduction of 45% to 6%; p=0.011) The results of subgroup analyses of studies with low risk of bias, low starting altitude (<2500 m), number of treatment days before ascending and dosage of GBE are not statistically significant. Conclusion The currently available data suggest that although GBE may tend towards AMS prophylaxis, there are not enough data to show the statistically significant effect of GBE on preventing AMS. Further large randomised controlled studies are warranted.
Full-text available
Article
Roach, Robert C., Peter H. Hackett, Oswald Oelz, Peter Bärtsch, Andrew M. Luks, Martin J. MacInnis, J. Kenneth Baillie, and The Lake Louise AMS Score Consensus Committee. The 2018 Lake Louise Acute Mountain Sickness Score. High Alt Med Biol 00:000-000, 2018.- The Lake Louise Acute Mountain Sickness (AMS) scoring system has been a useful research tool since first published in 1991. Recent studies have shown that disturbed sleep at altitude, one of the five symptoms scored for AMS, is more likely due to altitude hypoxia per se, and is not closely related to AMS. To address this issue, and also to evaluate the Lake Louise AMS score in light of decades of experience, experts in high altitude research undertook to revise the score. We here present an international consensus statement resulting from online discussions and meetings at the International Society of Mountain Medicine World Congress in Bolzano, Italy, in May 2014 and at the International Hypoxia Symposium in Lake Louise, Canada, in February 2015. The consensus group has revised the score to eliminate disturbed sleep as a questionnaire item, and has updated instructions for use of the score.
Full-text available
Article
.—We hypothesized that exercise would cause greater severity and incidence of acute mountain sickness (AMS) in the early hours of exposure to altitude. After passive ascent to simulated high altitude in a decompression chamber [barometric pressure = 429 Torr, ∼4,800 m (J. B. West, J. Appl. Physiol. 81: 1850–1854, 1996)], seven men exercised (Ex) at 50% of their altitude-specific maximal workload four times for 30 min in the first 6 h of a 10-h exposure. On another day they completed the same protocol but were sedentary (Sed). Measurements included an AMS symptom score, resting minute ventilation (V˙e), pulmonary function, arterial oxygen saturation ([Formula: see text]), fluid input, and urine volume. Symptoms of AMS were worse in Ex than Sed, with peak AMS scores of 4.4 ± 1.0 and 1.3 ± 0.4 in Ex and Sed, respectively ( P < 0.01); but restingV˙e and[Formula: see text] were not different between trials. However, [Formula: see text] during the exercise bouts in Ex was at 76.3 ± 1.7%, lower than during either Sed or at rest in Ex (81.4 ± 1.8 and 82.2 ± 2.6%, respectively, P< 0.01). Fluid intake-urine volume shifted to slightly positive values in Ex at 3–6 h ( P = 0.06). The mechanism(s) responsible for the rise in severity and incidence of AMS in Ex may be sought in the observed exercise-induced exaggeration of arterial hypoxemia, in the minor fluid shift, or in a combination of these factors.
Full-text available
Article
At any point 1-5 days following ascent to altitudes ≥2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases.
Full-text available
Article
Objective: To quantify efficacy and harm of pharmacological prevention of acute mountain sickness. Data sources: Systematic search (Medline, Embase, Cochrane Library, internet, bibliographies, authors) in any language, up to October 1999. Study selection: Randomised placebo controlled trials. Data extraction: Dichotomous data on efficacy and harm from 33 trials (523 subjects received 13 different interventions, 519 a placebo). Data synthesis: At above 4000 m the mean incidence of acute mountain sickness with placebo was 67% (range 25% to 100%); incidence depended on the rate of ascent, but not on the altitude or the mode of ascent. Across all ascent rates, dexamethasone 8–16 mg prevented acute mountain sickness (relative risk 2.50 (95% confidence interval 1.71 to 3.66); number needed to treat (NNT) 2.8 (2.0 to 4.6)), without evidence of dose responsiveness. Acetazolamide 750 mg was also efficacious (2.18 (1.52 to 3.15); NNT 2.9 (2.0 to 5.2)), but 500 mg was not. In two trials, adverse reaction (including depression) occurred after dexamethasone was stopped abruptly (4.45 (1.08 to 18); NNT 3.7 (2.5 to 6.9)). With acetazolamide, paraesthesia (4.02 (1.71 to 9.43); NNT 3.0 (2.0 to 6.0)) and polyuria (4.24 (1.92 to 9.37); NNT 3.6 (2.5 to 6.2)) were reported. Data were sparse on nifedipine, frusemide (furosemide), dihydroxyaluminium-sodium, spironolactone, phenytoin, codeine, phenformin, antidiuretic hormone, and ginkgo biloba. Conclusions: At above 4000 m, with a high ascent rate, fewer than three subjects need to be treated with prophylactic dexamethasone 8–16 mg or acetazolamide 750 mg for one subject not to experience acute mountain sickness who would have done so had they all received a placebo. Acetazolamide 500 mg does not work.
Full-text available
Article
Compound Danshen dripping pill (CDDP) is commonly used to treat coronary heart disease (CHD) in China. However, clinical practice has not been informed by evidence from relevant systematic reviews (SRs). This overview aims at summarizing evidence from SRs on CDDP for the treatment of CHD. We included SRs of randomized controlled trials (RCTs) on CDDP in treating CHD until March 2014 by searching the Cochrane Library, PubMed, EMBASE and four Chinese databases. Data were extracted according to a pre-designed form. We assessed the quality of SRs according to AMSTAR and graded the quality of evidence in the included SRs using the GRADE approach. All data analyses were descriptive. About 13 SRs involving a total of 34,071 participants with angina or acute myocardial infarction (AMI) were included. Few SRs assessed endpoints (5/13, 38.5%) and quality of life (QOL) (4/13, 30.8%). Most of the SRs suggested that CDDP had potential benefits for patients with CHD, such as improving symptoms and electrocardiogram (ECG) results, with few adverse reactions, while benefits in endpoints were unproved. Moreover, the overall quality of evidence in the SRs was poor, ranging from "very low" to "moderate", and most of the included SRs were of "low" (3/13, 23.1%) or "moderate" (9/13, 69.2%) quality with many serious flaws. Current SRs suggested potential benefits of CDDP for the treatment of CHD. However, high-quality evidence is warranted to support the application of CDDP in treating CHD.
Full-text available
Article
Background. Contrast-induced nephropathy (CIN) limits the outcome of percutaneous coronary intervention (PCI). Objective. To investigate whether pretreatment with Compound Danshen Dripping Pills (CDDP) will decrease the incidence of CIN after PCI. Methods. A total of 229 patients with acute coronary syndrome (ACS) undergoing PCI were divided into the control group (n = 114) and the CDDP (containing salvia miltiorrhiza and sanqi) group (n = 115; given 20 CDDP pills, three times daily before PCI). Serum creatinine, creatinine clearance (CrCl), high-sensitivity C-reactive protein (hsCRP), P-selectin, and intercellular adhesion molecule-1 (ICAM-1) were measured at admission and 24 and 48 h after PCI. Results. CrCl decreased after PCI but recovered after 48 h. In the CDDP group, CrCl recovered more rapidly (P < 0.05). The procedure increased the hsCRP, P-selectin, and ICAM-1 levels, but these levels were less in the CDDP group (P < 0.05). Conclusions. Pretreatment with CDDP can decrease the occurrence of CIN in patients undergoing PCI, suggesting that the early use of CDDP is an appropriate adjuvant pharmacological therapy before PCI.
Full-text available
Article
Background: Acute mountain sickness (AMS) can occur in anyone going to a high altitude. Non-steroidal anti-inflammatory drugs (NSAIDs) have been studied for the prevention of AMS with mixed results. In this systematic review, we analyze all existing data on the use of NSAIDs to prevent AMS using the Lake Louise Scoring System (LLSS) in different randomized clinical trials (RCTs). Methods: Electronic literature searches for relevant studies were identified through MEDLINE, EMBASE, SCOPUS, and Cochrane library up to June 2013. RCTs involving NSAIDs compared to placebo in patients undergoing ascent to a height of at least 3,800 m were included. Odds ratios (OR) were calculated and combined using fixed-effect model meta-analysis if I (2)=0%. Differences between groups were calculated using the inverse variance of the standard mean differences. Between-study heterogeneity was assessed using the I (2) statistics. Results: In three clinical trials involving 349 patients, AMS using LLSS occurred in 26.92% of patients on NSAIDs and 43.71% on placebo (OR 0.43; CI [confidence interval] 0.27-0.69, I (2)=0%, p=0.0005), NNT=6. Minor outcome of end point Spo2 was not significant in the two groups (IV=0.74; 95% CI -0.20-1.69, I (2)=81%, p=0.12). Similarly, a change in Spo2 from baseline was also not significant in the two groups (IV=0.05; 95% CI -0.28-0.37, I (2)=44%, p=0.78). Conclusion: NSAIDs might be a safe and effective alternative for the prevention of AMS. However, further larger population studies and studies comparing NSAIDs to acetazolamide and dexamethasone in the future may provide further data to its relative efficacy.
Full-text available
Article
Objective: The use of pulse oximetry (Spo2) to identify subjects susceptible to acute mountain sickness (AMS) is the subject of debate. To obtain more reliable data, we monitored Spo2 for 24 hours at altitude to investigate the ability to predict impending AMS. Methods: The study was conducted during the climb from Alagna (1154 m) to Capanna Regina Margherita (4559 m), with an overnight stay in Capanna Gnifetti (3647 m). Sixty subjects (11 women) were recruited. Each subject was fitted with a 24-hour recording finger pulse oximeter. The subjects rode a cable car to 3275 m and climbed to 3647 m, where they spent the night. Results: In the morning, 24 subjects (6 women) had a Lake Louise Questionnaire score (LLS) ≥ 3 (AMS(+)), and 15 subjects (4 women) exhibited moderate-to-severe disease (LLS ≥ 5 = AMS(++)). At Alagna, Spo2 did not differ between the AMS(-) and AMS(+) subjects. At higher stations, all AMS(+) subjects exhibited a significantly lower Spo2 than did the AMS(-) subjects: at 3275 m, 85.4% vs 87.7%; resting at 3647 m, 84.5% vs 86.4%. The receiver operating characteristics curve analysis resulted in a rather poor discrimination between the AMS(-) subjects and all of the AMS(+) subjects. With the cutoff LLS ≥ 5, the sensitivity was 86.67%, the specificity was 82.25%, and the area under the curve was 0.88 (P < .0001) for Spo2 ≤ 84% at 3647 m. Conclusions: We conclude that AMS(+) subjects exhibit a more severe and prolonged oxygen desaturation than do AMS(-) subjects starting from the beginning of altitude exposure, but the predictive power of Spo2 is accurate only for AMS(++).
Full-text available
Article
Objectives. We aimed to assess the current clinical evidence of Chinese herbal medicine for AMS. Methods. Seven electronic databases were searched until January 2013. We included randomized clinical trials testing Chinese herbal medicine against placebo, no drugs, Western drugs, or a combination of routine treatment drugs against routine treatment drugs. Study selection, data extraction, quality assessment, and data analyses were conducted according to Cochrane standards. Results. Nine randomized trials were included. The methodological quality of the included trials was evaluated as low. Two trials compared prescriptions of Chinese formula used alone with Western drugs. A meta-analysis showed a beneficial effect in decreasing the score of AMS (MD: -2.23 [-3.98, -0.49], P = 0.01). Only one trial compared prescriptions of Chinese formula used alone with no drugs. A meta-analysis showed a significant beneficial effect in decreasing the score of AMS (MD: -6.00 [-6.45, -5.55], P < 0.00001). Four trials compared Chinese formula used alone with placebo. A meta-analysis also showed a significant beneficial effect in decreasing the score of AMS (MD: -1.10 [-1.64, -0.55], P < 0.0001). Two trials compared the combination of Chinese formula plus routine treatment drugs with routine treatment drugs. A meta-analysis showed a beneficial effect in decreasing the score of AMS (MD: -5.99 [-11.11, -0.86], P = 0.02). Conclusions. No firm conclusion on the effectiveness and safety of Chinese herbal medicine for AMS can be made. More rigorous high-quality trials are required to generate a high level of evidence and to confirm the results.
Full-text available
Article
Rhodiola crenulata (R. crenulata) is widely used to prevent acute mountain sickness in the Himalayan areas and in Tibet, but no scientific studies have previously examined its effectiveness. We conducted a randomized, double-blind, placebo-controlled crossover study to investigate its efficacy in acute mountain sickness prevention. Healthy adult volunteers were randomized to 2 treatment sequences, receiving either 800 mg R. crenulata extract or placebo daily for 7 days before ascent and 2 days during mountaineering, before crossing over to the alternate treatment after a 3-month wash-out period. Participants ascended rapidly from 250 m to 3421 m on two separate occasions: December 2010 and April 2011. The primary outcome measure was the incidence of acute mountain sickness, as defined by a Lake Louise score >= 3, with headache and at least one of the symptoms of nausea or vomiting, fatigue, dizziness, or difficulty sleeping. One hundred and two participants completed the trial. There were no demographic differences between individuals taking Rhodiola-placebo and those taking placebo-Rhodiola. No significant differences in the incidence of acute mountain sickness were found between R. crenulata extract and placebo groups (all 60.8%; adjusted odds ratio (AOR) =1.02, 95% confidence interval (CI) =0.69--1.52). The incidence of severe acute mountain sickness in Rhodiola extract vs. placebo groups was 35.3% vs. 29.4% (AOR = 1.42, 95% CI = 0.90--2.25). R. crenulata extract was not effective in reducing the incidence or severity of acute mountain sickness as compared to placebo.Trial registration: ClinicalTrials.gov NCT01536288.
Full-text available
Article
Sudden exposure of nonacclimatized individuals to high altitude can easily lead to high altitude illnesses. High altitude pulmonary edema (HAPE) is the most lethal form of high altitude illness. The present study was designed to investigate the ability of Rhodiola crenulata extract (RCE), an herbal medicine traditionally used as an antiacute mountain sickness remedy, to attenuate hypoxia-induced pulmonary injury. Exposure of animals to hypobaric hypoxia led to a significant increase in pathological indicators for pulmonary edema, including the lung water content, disruption of the alveolar-capillary barrier, and protein-rich fluid in the lungs. In addition, hypobaric hypoxia also increased oxidative stress markers, including (ROS) production, (MDA) level, and (MPO) activity. Furthermore, overexpression of plasma (ET-1), (VEGF) in (BALF), and (HIF-1 α ) in lung tissue was also found. However, pretreatment with RCE relieved the HAPE findings by curtailing all of the hypoxia-induced lung injury parameters. These findings suggest that RCE confers effective protection for maintaining the integrity of the alveolar-capillary barrier by alleviating the elevated ET-1 and VEGF levels; it does so by reducing hypoxia-induced oxidative stress. Our results offer substantial evidence to support arguments in favor of traditional applications of Rhodiola crenulata for antihigh altitude illness.
Full-text available
Article
Acetazolamide is used to prevent acute mountain sickness (AMS). We assessed efficacy and harm of acetazolamide for the prevention of AMS, and tested for dose-responsiveness. We systematically searched electronic databases (until April 2011) for randomized trials comparing acetazolamide with placebo for the prevention of AMS. For each dose, risk ratios were aggregated using a Mantel-Haenszel fixed effect model. Numbers needed to treat (NNT) to benefit one subject with each dose were calculated for different baseline risks. Modes of ascent were taken as proxies of baseline risks. Twenty-four trials were included; 1011 subjects received acetazolamide 250, 500, or 750 mg day⁻¹; 854 received placebo. When climbing, median speed of ascent was 14 m/h, average AMS rate in controls was 34%, and NNT to prevent AMS with acetazolamide 250, 500, and 750 mg/day compared with placebo was 6.5, 5.9, and 5.3. When ascending by transport and subsequent climbing (speed of ascent 133 m/h) or by transport alone (491 m/h), average AMS rate in controls was 60%, and NNT with acetazolamide 250, 500, and 750 mg/day was 3.7, 3.3, and 3.0. In hypobaric chambers, median speed of ascent was 4438 m/h, average AMS rate in controls was 86%, and NNT with acetazolamide 250, 500, and 750 mg/day was 2.6, 2.3, and 2.1. The risk of paresthesia was increased with all doses. The risk of polyuria and taste disturbance was increased with 500 and 750 mg/day. The degree of efficacy of acetazolamide for the prevention of AMS is limited when the baseline risk is low, and there is some evidence of dose-responsiveness.
Full-text available
Article
FULCO, C. S., B. A. BEIDLEMAN, and S. R. MUZA. Effectiveness of preacclimatization strategies for high-altitude exposure. Exerc. Sport Sci. Rev., Vol. 41, No. 1, pp. 55-63, 2013. Acute mountain sickness (AMS) and large decrements in endurance exercise performance occur when unacclimatized individuals rapidly ascend to high altitudes. Six altitude and hypoxia preacclimatization strategies were evaluated to determine their effectiveness for minimizing AMS and improving performance during altitude exposures. Strategies using hypobaric chambers or true altitude were much more effective overall than those using normobaric hypoxia (breathing, <20.9% oxygen).
Full-text available
Article
Acute mountain sickness (AMS) describes a constellation of symptoms that is usually self-limited and benign. However, it may impair judgement and physical abilities at high altitudes and interfere with the pleasure of recreational activities. Severe cases may be fatal. Acclimatization is an effective prevention, but is not always practical or possible. Therefore, pharmacologic prophylaxis of AMS is an active area of research.This study used meta-analytic techniques to evaluate the published literature regarding pharmacologic prophylaxis of AMS with acetazolamide and dexamethasone. Twenty eligible reports were located via a computer-assisted search, reference lists and review articles. Dependent measures for this study were the percentage of patients with AMS and the percentage of patients with specific symptoms associated with AMS.An effect size (ES) is the standardized mean difference between experimental and control groups or the conversion from the point-biserial correlation between treatment and effect and allows integration of the results of independent studies. In this study, a negative ES indicates that the prophylaxis regimen exerted a protective effect; the greater the magnitude of the ES the greater its effect. The overall average weighted ES was −0.59 (95% confidence interval (CI) = −0.41 to −0.77) when both drugs’ results were pooled. The average weighted ES for studies comparing acetazolamide to placebo was −0.61 and it was −0.32 for studies comparing dexamethasone to placebo. The average ES was −0.38 when all of the reported symptoms were pooled together.This report confirms the effectiveness of pharmacologic prophylaxis against AMS with acetazolamide or dexamethasone. Acetazolamide appears to be more effective, but inconsistencies in dexamethasone dosing, environmental conditions, and rate of ascent confound interpretation. This meta-analysis points out areas for future research.
Full-text available
Article
Multiple studies have explored pharmacologic interventions to prevent acute mountain sickness. A systematic review of this subject published in 2000 found that both acetazolamide and dexamethasone were effective. Since 2000, a number of other agents have been reported to be beneficial. This EBEM review evaluates the most current evidence on this topic. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, SPORTDiscus, Emergency Medical Abstracts, and ClinicalTrials.gov from 2000 to July 2011. Only randomized placebo-controlled trials with an N greater than or equal to 50 and systematic reviews were reviewed. Standard criteria for assessing trial quality were independently assessed by 2 authors. Seven hundred eighty-six citations were retrieved, of which 105 were reviewed in their entirety. Eleven randomized controlled trials and 1 systematic review appeared to meet inclusion criteria; however, 4 randomized controlled trials were excluded for high risk of bias. The remaining 7 randomized controlled trials investigated antioxidants, magnesium, sumatriptan, gabapentin, acetazolamide, and Ginkgo biloba. No trials studying dexamethasone met our criteria. Acetazolamide was associated with a reduction in acute mountain sickness symptoms, with a number needed to treat ranging from 8 to 3 among 3 trials and at doses ranging from 250 to 750 mg daily. Sumatriptan showed benefit in 1 trial (number needed to treat=4), as did gabapentin (number needed to treat=6). Antioxidants, magnesium, and G biloba were not efficacious. Reported adverse events included somnolence with gabapentin and paresthesias with acetazolamide. The systematic review affirmed our results but did not capture trials studying antioxidants, magnesium, sumatriptan, or gabapentin. Acetazolamide is effective for the prevention of acute mountain sickness but may be associated with paresthesias. Sumatriptan and gabapentin are beneficial but require further study.
Full-text available
Article
Acute mountain sickness (AMS) is a common problem while ascending at high altitude. AMS may progress rapidly to fatal results if the acclimatization process fails or symptoms are neglected and the ascent continues. Extensively reduced arterial oxygen saturation at rest (R-Spo₂) has been proposed as an indicator of inadequate acclimatization and impending AMS. We hypothesized that climbers less likely to develop AMS on further ascent would have higher Spo₂ immediately after exercise (Ex-Spo₂) at high altitudes than their counterparts and that these postexercise measurements would provide additional value for resting measurements to plan safe ascent. The study was conducted during eight expeditions with 83 ascents. We measured R-Spo₂ and Ex-Spo₂ after moderate daily exercise [50 m walking, target heart rate (HR) 150 bpm] at altitudes of 2400 to 5300 m during ascent. The Lake Louise Questionnaire was used in the diagnosis of AMS. Ex-Spo₂ was lower at all altitudes among those climbers suffering from AMS during the expeditions than among those climbers who did not get AMS at any altitude during the expeditions. Reduced R-Spo₂ and Ex-Spo₂ measured at altitudes of 3500 and 4300 m seem to predict impending AMS at altitudes of 4300 m (p < 0.05 and p < 0.01) and 5300 m (both p < 0.01). Elevated resting HR did not predict impending AMS at these altitudes. Better aerobic capacity, younger age, and higher body mass index (BMI) were also associated with AMS (all p < 0.01). In conclusion, those climbers who successfully maintain their oxygen saturation at rest, especially during exercise, most likely do not develop AMS. The results suggest that daily evaluation of Spo₂ during ascent both at rest and during exercise can help to identify a population that does well at altitude.
Full-text available
Article
Hypoxia often causes body water deficits (hypohydration, HYPO); however, the effects of HYPO on aerobic exercise performance and prevalence of acute mountain sickness (AMS) at high altitude (ALT) have not been reported. We hypothesized that 1) HYPO and ALT would each degrade aerobic performance relative to sea level (SL)-euhydrated (EUH) conditions, and combining HYPO and ALT would further degrade performance more than one stressor alone; and 2) HYPO would increase the prevalence and severity of AMS symptoms. Seven lowlander men (25 ± 7 yr old; 82 ± 11 kg; mean ± SD) completed four separate experimental trials. Trials were 1) SL-EUH, 2) SL-HYPO, 3) ALT-EUH, and 4) ALT-HYPO. In HYPO, subjects were dehydrated by 4% of body mass. Subjects maintained hydration status overnight and the following morning entered a hypobaric chamber (at SL or 3,048 m, 27°C) where they completed 30 min of submaximal exercise immediately followed by a 30-min performance time trial (TT). AMS was measured with the Environmental Symptoms Questionnaire-Cerebral Score (AMS-C) and the Lake Louise Scoring System (LLS). The percent change in TT performance, relative to SL-EUH, was -19 ± 12% (334 ± 64 to 278 ± 87 kJ), -11 ± 10% (334 ± 64 to 293 ± 33 kJ), and -34 ± 22% (334 ± 64 to 227 ± 95 kJ), for SL-HYPO, ALT-EUH, and ALT-HYPO, respectively. AMS symptom prevalence was 2/7 subjects at ALT-EUH for AMS-C and LLS and 5/7 and 4/7 at ALT-HYPO for AMS-C and LLS, respectively. The AMS-C symptom severity score (AMS-C score) tended to increase from ALT-EUH to ALT-HYPO but was not significant (P = 0.07). In conclusion, hypohydration at 3,048 m 1) degrades aerobic performance in an additive manner with that induced by ALT; and 2) did not appear to increase the prevalence/severity of AMS symptoms.
Full-text available
Article
Cellular hypoxia is the common final pathway of brain injury that occurs not just after asphyxia, but also when cerebral perfusion is impaired directly (eg, embolic stroke) or indirectly (eg, raised intracranial pressure after head injury). We Review recent advances in the understanding of neurological clinical syndromes that occur on exposure to high altitudes, including high altitude headache (HAH), acute mountain sickness (AMS), and high altitude cerebral oedema (HACE), and the genetics, molecular mechanisms, and physiology that underpin them. We also present the vasogenic and cytotoxic bases for HACE and explore venous hypertension as a possible contributory factor. Although the factors that control susceptibility to HACE are poorly understood, the effects of exposure to altitude (and thus hypobaric hypoxia) might provide a reproducible model for the study of cerebral cellular hypoxia in healthy individuals. The effects of hypobaric hypoxia might also provide new insights into the understanding of hypoxia in the clinical setting.
Full-text available
Article
Circulating adhesion molecules (CAMs), surface proteins expressed in the vascular endothelium, have emerged as risk factors for cardiovascular disease (CVD). CAMs are involved in intercellular communication that are believed to play a role in atherosclerosis. A Chinese medicine, the "Dantonic Pill" (DP) (also known as the "Cardiotonic Pill"), containing three Chinese herbal material medica, Radix Salviae Miltiorrhizae, Radix Notoginseng and Borneolum Syntheticum, has been used in China for the prevention and management of CVD. Previous laboratory and animal studies have suggested that this preparation reduces both atherogenesis and adhesion molecule expression. A parallel double blind randomized placebo-controlled study was conducted to assess the effects of the DP on three species of CAM (intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 and endothelial cell selectin (E-selectin)) in participants with mild-moderate hypercholesterolemia. Secondary endpoints included biochemical and hematological variables and clinical effects. Forty participants were randomized to either treatment or control for 12 weeks. Treatment with DP was associated with a statistically significant decrease in ICAM-1 (9% decrease, P = .03) and E-Selectin (15% decrease, P = .004). There was no significant change in renal function tests, liver function tests, glucose, lipids or C-reactive protein levels and clinical adverse effects did not differ between the active and the control groups. There were no relevant changes in participants receiving placebo. These results suggest that this herbal medicine may contribute to the development of a novel approach to cardiovascular risk reduction.
Full-text available
Article
750 mg per day of acetazolamide in the prevention of acute mountain sickness (AMS), as recommended in the meta-analysis published in 2000 in the British Medical Journal, may be excessive and is controversial. To determine if the efficacy of low-dose acetazolamide 125 mg bd (250 mg), as currently used in the Himalayas, is significantly different from 375 mg bd (750 mg) of acetazolamide in the prevention of AMS, we designed a prospective, double-blind, randomized, placebo-controlled trial. The participants were sampled from a diverse population of (non-Nepali) trekkers at Namche Bazaar (3440 m) in Nepal on the Everest trekking route as they ascended to study midpoints (4280 m/4358 m) and the endpoint, Lobuje (4928 m), where data were collected. Participants were randomly assigned to receive 375 mg bd of acetazolamide (82 participants), 125 mg bd of acetazolamide (74 participants), or a placebo (66 participants), beginning at 3440 m for up to 6 days as they ascended to 4928 m. The results revealed that composite AMS incidence for 125 mg bd was similar to the incidence for 375 mg bd (24% vs. 21%, 95% confidence interval, -12.6%, 19.8%), in contrast to significantly greater AMS (51%) observed in the placebo group (95% confidence interval for differences: 8%, 46%; 12%, 49% for low and high comparisons, respectively). Both doses of acetazolamide improved oxygenation equally (82.9% for 250 mg daily and 82.8% for 750 mg daily), while placebo endpoint oxygen saturation was significantly less at 80.7% (95% confidence interval for differences: 0.5%, 3.9% and 0.4%, 3.7% for low and high comparisons, respectively). There was also more paresthesia in the 375-mg bd group (p < 0.02). We conclude that 125 mg bd of acetazolamide is not significantly different from 375 mg bd in the prevention of AMS; 125 mg bd should be considered the preferred dosage when indicated for persons ascending to altitudes above 2500 m.
Full-text available
Article
The role of dexamethasone to reduce delayed emesis following highly emetogenic chemotherapy is proven, but there is less evidence of benefit after mild-moderately emetogenic regimens. Here, we develop and evaluate a Dexamethasone Symptom Questionnaire (DSQ) to assess the side effects of dexamethasone in the week after patients receive moderately emetogenic chemotherapy. The DSQ was first optimised with the aid of a focus group. Sixty patients receiving oral dexamethasone for prophylaxis of delayed emesis after moderately emetogenic chemotherapy for cancer completed and then evaluated the DSQ. Patients reported that the DSQ was clearly worded and addressed items important to them. Patients receiving dexamethasone reported moderate-severe problems with insomnia (45%), indigestion/epigastric discomfort (27%), agitation (27%), increased appetite (19%), weight gain (16%) and acne (15%) in the week following chemotherapy. The side effects of dexamethasone may outweigh its benefits when used with moderately emetogenic chemotherapy. A randomised, double-blind crossover trial is underway to determine the effect of dexamethasone on nausea and vomiting, and the impact of side effects of dexamethasone and of nausea and vomiting on quality of life.
Full-text available
Article
Acute mountain sickness is common among not acclimatized persons ascending to high altitude; the underlying mechanism is unknown, but may be related to cerebral edema. Nine healthy male students were studied before and after 6-h exposure to isobaric hypoxia. Subjects inhaled room air enriched with N(2) to obtain arterial O(2) saturation values of 75 to 80%. Acute mountain sickness was assessed with the environmental symptom questionnaire, and cerebral edema with 3 T magnetic resonance imaging in 18 regions of interest in the cerebral white matter. The main outcome measures were development of intra- and extracellular cerebral white matter edema assessed by visual inspection and quantitative analysis of apparent diffusion coefficients derived from diffusion-weighted imaging, and B0 signal intensities derived from T2-weighted imaging. Seven of nine subjects developed acute mountain sickness. Mean apparent diffusion coefficient increased 2.12% (baseline, 0.80+/-0.09; 6 h hypoxia, 0.81+/-0.09; P=0.034), and mean B0 signal intensity increased 4.56% (baseline, 432.1+/-98.2; 6 h hypoxia, 450.7+/-102.5; P<0.001). Visual inspection of magnetic resonance images failed to reveal cerebral edema. Cerebral acute mountain sickness scores showed a negative correlation with relative changes of apparent diffusion coefficients (r=-0.83, P=0.006); there was no correlation with relative changes of B0 signal intensities. In conclusion, isobaric hypoxia is associated with mild extracellular (vasogenic) cerebral edema irrespective of the presence of acute mountain sickness in most subjects, and severe acute mountain sickness with additional mild intracellular (cytotoxic) cerebral edema.
Full-text available
Article
To determine the impact of sumatriptan prophylaxis on acute mountain sickness (AMS) and altitude headache development within 24 hours of ascent, we designed a double-blind, randomized, clinical trial. A prospective, double-blind, randomized, placebo-controlled trial was conducted in Tochal Mountain Hotel at an altitude of 3,500 meters above sea level during October 2006 to November 2006. A total of 102 Iranian adults were assigned to receive either sumatriptan succinate (50mg) or placebo within 1 hour of ascent. AMS incidence was measured by Lake Louise AMS score > or = 3 with headache and one other symptom. Secondary outcome measures included severity of syndrome (Lake Louise scores > or = 5), incidence of headache, and severity of headache. Based on intention-to-treat analysis, AMS was more prevalent in placebo group (n = 23 [45.1%]) than sumatriptan group (n = 12 [23.5%]; p = 0.02). Headache also had a greater rate for placebo users (placebo vs sumatriptan group: 29 [56.9%] vs 17 [33.3%]; p = 0.02). No association was detected between sumatriptan prophylaxis and AMS or altitude headache severity. Sumatriptan prophylaxis is effective to prevent AMS development. Furthermore, our findings confirm cerebral vasodilative and edematous mechanisms of AMS progression, whereas sumatriptan is a selective 5-hydroxytryptamine(1) receptor subtype agonist and a selective cerebral vasoconstrictor as a result (http://www.controlled-trials.com/ISRCTN87201238/).
Article
High altitude illness encompasses a spectrum of clinical entities to include: acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. These illnesses occur as a result of a hypobaric hypoxic environment. Although a mild case of acute mountain sickness may be self-limited, high altitude cerebral edema and high altitude pulmonary edema represent critical emergencies that require timely intervention. This article reviews recent advances in the prevention and treatment of high altitude illness, including new pharmacologic strategies for prophylaxis and revised treatment guidelines.
Article
This study simultaneously quantified the effects of normobaric hypoxia (NH), hypobaric hypoxia (HH), exercise duration, and exposure time on acute mountain sickness severity (AMS-C). Thirty-six subjects (27.7 ± 7.8 yr) participated in a partial repeated measures study, completing two of six conditions: normobaric normoxia (NN: 300 m/984 ft equivalent), NH or HH (Po2 = 91 mmHg; 4400 m/14,436 ft equivalent), combined with moderate intensity cycling for 10 or 60 min. Subjects completed the Environmental Symptoms Questionnaire and oxygen saturation (Spo2) was measured before, 1.5 h, 4 h, and 6.5 h into an 8-h exposure, and 1.5 h post-exposure. We fit multiple linear regression models with cluster adjusted standard errors on the exposure times using NH, HH, and long exercise as indicator variables, and AMS-C as the outcome variable. The Spo2 and pre-exposure AMS-C score were used as covariates. NH and HH led to substantial and progressively increasing AMS-C, but NN did not. The effect of HH on AMS-C was significantly different from NH, with AMS-C in HH being 1.6 times higher than in NH. HH led to significantly increasing AMS-C, regardless of the exercise duration, while NH only did so in combination with longer exercise. Increases in AMS-C were each independently related to NH, HH, and long duration exercise, with HH affecting AMS-C more severely. This suggests that hypobaria may affect AMS development above the level induced by hypoxia alone. This further suggests that NH and HH may not be interchangeable for studying AMS and that exercise duration may impact physiological responses. DiPasquale DM, Strangman GE, Harris NS, Muza SR. Hypoxia, hypobaria, and exercise duration affect acute mountain sickness. Aerosp Med Hum Perform. 2015; 86(7):614-619.
Article
Compound Danshen Dripping Pill (CDDP) has been used for the treatment of coronary heart disease for decades. We aimed to increase the understanding of the mechanisms by evaluating the urinary metabolomics of CDDP using Gas Chromatography-Mass Spectrometer (GC-MS) in a myocardial ischaemia (MI) rat model. One hundred Sprague-Dawley rats were divided into Con (normal saline and no surgery), Con+ (107mg/kgd CDDP solution and no surgery), Sham (normal saline and surgery without aorta ligation), Mod (normal saline and surgery with aorta ligation), and Mod+ (107mg/kgd CDDP solution and surgery with aorta ligation) groups. Urine samples on days 0, 3, 14, and 28 were tested using GC-MS and analyzed with PCA and partial least squares-discriminant analysis models. In the Mod group, creatine kinase and malondialdehyde levels were higher, and superoxide-dismutase levels were lower; the same variables normalized in the Mod+ group. CDDP resulted in improvement in the Mod+ group, as indicated by the reduced necrosis in the myocardial tissue. A total of 36 metabolites were identified in the urine samples, and 8 metabolites (malate, succinate, creatinine, methionine, cysteine, serine, phenylalanine, and tyrosine) were increased remarkably and recovered to normal levels after treatment with CDDP. Differentially expressed metabolites implied that energy, amino acid, fatty acid, and polyol metabolism might be disrupted by MI and reversed by CDDP. Urinary metabolomics provide a dynamic monitoring approach that highlights interference by MI and the therapeutic effects of CDDP on MI in rats throughout the recovery process. Copyright © 2015 Elsevier B.V. All rights reserved.
Article
Approximately 26.8% of China's land area has an elevation of 3000m above sea level or higher. Because of recent demands for economic development and new construction in highland areas, many people have relocated from the plains to high plateau regions and have to face the possibility of contracting acute mountain sickness. Therefore, prevention and treatment strategies are necessary to reduce the incidence of acute mountain sickness in people who rapidly ascend to plateau areas. This paper describes the Chinese experience when large numbers of people moved to the plateau and the steps that were taken to deal with this illness. These steps included implementing basic prevention measures, increasing medical awareness among populations ascending to high altitudes, and installing standardized medical management systems to prevent and treat acute mountain sickness before, during, and after ascent. The incidence of acute mountain sickness can be reduced by improving prevention and treatment and by implementing the recommendations described in this manuscript.
Article
Abstract Wagner, Dale R., Masaru Teramoto, Jonathan R. Knott, and Jack P. Fry Comparison of Scoring Systems for Assessment of Acute Mountain Sickness. High Alt Med Biol. 13:245-251, 2012.-The purpose of this study was to compare three commonly used scoring systems of acute mountain sickness (AMS)-the 5-item Lake Louise Self-report (LLS), the 11-item abridged version of the Environmental Symptoms Questionnaire (ESQ-III), and a 100 mm visual analog scale (VAS)-on climbers (N=63; 34.6±9.9 years) making a 1-day ascent of a 5640 m peak after a rest of ∼10 h at 4260 m. The prevalence of AMS was 63% when defined as LLS ≥3, 49% when defined as either LLS ≥5 or ESQ-III ≥0.7, and 41% when defined as the combined LLS and ESQ-III criteria. Despite the agreement in prevalence between the LLS ≥5 and ESQ-III ≥0.7, there was a discrepancy in AMS classification in 16% of the cases. A VAS cut-off point corresponding to the combined LLS and ESQ-III criteria was 16 mm. The sensitivity and specificity of the VAS for diagnosing AMS compared to combined LLS and ESQ-III criteria were 85% and 92%, respectively. All of the scoring systems were significantly correlated (τ=0.60 to 0.73, p<0.01); however, residual scores were large. We cannot recommend interchanging the diagnostic results from the LLS, ESQ-III, and VAS, and standardization is needed for the administration of the VAS.
Article
The aim of this prospective observational cohort study was to investigate relationships between acute mountain sickness (AMS) and physical and mental health during a high altitude expedition. Forty-four participants (mean age, 34 ± 13 y; body mass index, 23.6 ± 3.5 kg·m(2) ; 57% male) completed the Dhaulagiri base camp trek in Nepal, a 19-day expedition attaining 5,372 m. Participants self-reported the following daily physical and mental health: AMS (defined by Lake Louise diagnosis and individual and total symptom scores), upper respiratory symptoms, diarrhea, and anxiety, plus physiological and behavioral factors. The rate of Lake Louise-defined AMS per 100 person days was 9.2 (95% CI: 7.2-11.7). All investigated illnesses except diarrhea increased with altitude (all p < 0.001 by analysis of variance). Total AMS symptom score was associated with a lower arterial oxygen saturation, higher resting heart rate, more upper respiratory and diarrhea symptoms, greater anxiety, and lower fluid intake (all p < 0.02 by longitudinal multiple regression analyses). However, only upper respiratory symptoms, heart rate, arterial oxygen saturation, and fluid intake predicted future AMS symptoms [eg, an increase in upper respiratory symptoms by 5 units predicted an increase in the following day's AMS total symptom score by 0.72 units (0.54-0.89)]. Upper respiratory symptoms and anxiety increasingly contributed to symptom burden as altitude was gained. Data were consistent with increased heart rate, decreased arterial oxygen saturation, reduced fluid intake, and upper respiratory symptoms being causally associated with AMS. Upper respiratory symptoms and fluid intake are the simplest targets for intervention to reduce AMS during high altitude exposure.
Article
Objective physiologic data on sleep and nocturnal breathing at initial exposure and during acclimatization to high altitude are scant. We tested the hypothesis that acute exposure to high altitude induces quantitative and qualitative changes in sleep and that these changes are partially reversed with acclimatization. Prospective observation. One night in a sleep laboratory at 490 meters, the first and the third night in a mountain hut at 4559 meters. Sixteen healthy mountaineers. Altitude exposure. Polysomnography, questionnaire evaluation of sleep and acute mountain sickness. Compared to 490 m, median nocturnal oxygen saturation decreased during the 1st night at 4559 m from 96% to 67%, minute ventilation increased from 4.4 to 6.3 L/min, and the apnea-hypopnea index increased from 0.1 to 60.9/h; correspondingly, sleep efficiency decreased from 93% to 69%, and slow wave sleep from 18% to 6% (P < 0.05, all instances). During the 3rd night at 4559 m, oxygen saturation was 71%, slow wave sleep 11% (P < 0.05 vs. 1st night, both instances) and the apnea/hypopnea index was 86.5/h (P = NS vs. 1st night). Symptoms of AMS and of disturbed sleep were significantly reduced in the morning after the 3rd vs. the 1st night at 4559 m. In healthy mountaineers ascending rapidly to high altitude, sleep quality is initially impaired but improves with acclimatization in association with improved oxygen saturation, while periodic breathing persists. Therefore, high altitude sleep disturbances seem to be related predominantly to hypoxemia rather than to periodic breathing.
Article
To ascertain whether climbing a mountain over 3000 meters high produces any alterations in ventilation, whether such alterations are modified by acclimatization, and whether they correlate with changes in arterial oxygen saturation (SaO2) or the development of acute mountain sickness (AMS). The following parameters were measured in 8 unacclimatized mountaineers who climbed Aneto (3404 m) and spent 3 days at the summit: forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), airway response to inhaled terbutaline, SaO2, and the symptoms of AMS. At the summit, mean (SD) FEV1 declined by 12.3% (5.7%) and mean FVC by 7.6% (6.7%) while the ratio of FEV1 to FVC remained normal. The means for both parameters were higher on the following day. No airway response to bronchodilator treatment was observed. The restriction disappeared entirely on descent. At the peak, SaO2 increased progressively as the climbers became acclimatized. During the ascent, FEV1 correlated with SaO2 (r=0.79). One participant who suffered from AMS had a ratio of FEV1 to FVC less than 70% and the worst SaO2 during the 3 days on the summit. Obstruction preceded the AMS symptoms, did not respond to bronchodilator treatment, and disappeared when the climber descended. The mountaineers who climbed over 3000 meters presented restriction that correlated with hypoxemia. This restriction did not respond to bronchodilator treatment, improved with acclimatization, and disappeared on descent. One person with AMS presented obstruction that did not respond to terbutaline and disappeared on descent.
Article
Compound salvia pellet (CSP), consisting of active herbal ingredients extracted from Danshen (salvia miltiorrhiza), Sanqi (panax notoginseng), and Borneol (Cinnamomum camphora), is taken most frequently by patients with angina pectoris in China. To determine the efficacy and safety of CSP for the treatment of stable angina pectoris (SAP), a meta-analysis was undertaken. An extensive search including MEDLINE, EMBASE, BA, Chinese Biomedical Database (CBM), and Chinese Cochrane Centre Controlled Trials Register from 1994 to 2004 was performed. Data were extracted independently from the included trials by two reviewers. Statistical software (RevMan 4.1) provided by the Cochrane Collaboration was applied. Twenty-seven randomized controlled trials (RCTs) (n=3722), regardless of language or publication status, were identified. Generally, the methodological quality of the trials, assessed by the Jadad scale, was low, except for one with 3 points. Statistical pooling of the results showed that, compared with nitrates, CSP treatment had significant effect on the improvement of angina symptoms (RR=1.13, 95%CI=[1.07, 1.20]), showed greater increased effect on the improvement of electrocardiogram (ECG) results (RR=1.39, 95%CI=[1.28, 1.50]), and the percentage of patients with adverse events was significantly decreased in the treatment of CSP in comparison with nitrates (2.4% vs. 29.7%). CSP has significant effect on the improvement of angina symptoms and ECG results with few adverse events. However, the methodological quality of clinical trials with CSP for SAP needs to be improved, and the outcome measures should include mortality, quality of life, and other end-points.
Article
Droma, Yunden, Masayuki Hanaoka, Buddha Basnyat, Amit Arjyal, Pritam Neupane, Anil Pandit, Dependra Sharma, and Keishi Kubo. Symptoms of acute mountain sickness in Sherpas exposed to extremely high altitude. High Alt. Med. Biol. 7:312-314, 2006.--The aim of this field interview was to investigate the current state of affairs concerning acute mountain sickness (AMS) in high-altitude residents, specifically the Sherpas at 3440 m above sea level, when they are exposed rapidly to altitudes significantly higher than their residing altitudes. Out of 105 Sherpas (44 men and 61 women, 31.2 +/- 0.8 yr), 104 had mountain-climbing experiences to 5701.4 +/- 119.1-m altitude in average 3.5 times each year. On the other hand, only 68 out of 111 non-Sherpas (29.9 +/- 0.8 yr) had experience of 1.4 +/- 1.5 climbs to an average 2688.6 +/- 150.4-m altitude in their mountaineering histories (p < 0.0001). Among the 104 Sherpas, 45 (43.3%) complained of at least one AMS symptom (headache, gastrointestinal symptoms, weakness, dizziness, and difficulty sleeping) in their experiences of mountaineering at an average 5518.9 +/- 195.9-m altitude. And 16 out of the 68 non-Sherpas (23.5%) reported the AMS symptoms at a mean altitude of 2750.0 +/- 288.8 m. Moreover, we also noticed that the Sherpa women showed a significantly higher Sa(O(2) ) (93.9 +/- 0.2%) than did Sherpa men (92.4 +/- 0.3%, p = 0.0001) at an altitude of 3440 m. The brief field interview evidenced that Sherpas might suffer from AMS when exposed to altitudes significantly higher than their residing altitude.
High-altitude headache and acute mountain sickness
  • F J Carod-Artal
Carod-Artal, F.J., 2014. High-altitude headache and acute mountain sickness. Neurologia, 29: 533-540. https://doi.org/10.1016/j.nrleng.2012.04.021
Acute mountain sickness: influence of susceptibility, preexposure and ascent rate
  • M Schneider
  • D Bernasch
  • J Weymann
  • R Holle
  • P Bartsch
Schneider, M., Bernasch, D., Weymann, J., Holle, R. and Bartsch, P., 2002. Acute mountain sickness: influence of susceptibility, preexposure and ascent rate. Med. Sci. Sports Exerc., 34: 1886-1891. https:// doi.org/10.1097/00005768-200212000-00005