Assessment Of Acute Mountain Sickness Research Articles

Assessment of Acute Mountain Sickness: Comparing the Chinese AMS Score to the Lake Louise Score.

Wu, Yu, Wenqi Zhao, Bao Liu, Jianyang Zhang, Zhifeng Zhong, Simin Zhou, Jiaxin Xie, Yuqi Gao, Peng Li, and Jian Chen. Assessment of Acute Mountain Sickness: Comparing the Chinese Ams Score to the Lake Louise Score. High Alt Med Biol 25:164-173, 2024. Objective: To compare the ability of the Chinese AMS Score (CAS) to detect acute mountain sickness (AMS) using the 2018 version of the Lake Louise Score (LLS) as reference. Methods: After flying from Chengdu (altitude: 500 m) to Lhasa (3,658 m), 2,486 young men completed a questionnaire. The questionnaire contained LLS and CAS items. An LLS ≥3 and/or a CAS ≥cutoff were used as the criteria for AMS. Hierarchical cluster analysis and two-step cluster analysis were used to investigate relationships between the symptoms. Results: AMS incidence rates were 33.8% (n = 840) with the LLS and 59.3% (n = 1,473) with the CAS (χ2 = 872.5, p < 0.001). The LLS and CAS had a linear relationship (orthogonal regression, Pearson r = 0.91, p < 0.001). With the LLS as the standard, the CAS had high diagnostic accuracy (area under the curve = 0.95, 95% confidence interval: 0.94-0.96). However, with the CAS, 25.5% (n = 633) more participants were labeled as having AMS than with the LLS (false positives). Two clusters were identified: one with headache only (419 participants, 66.2%) and one without headache but with other symptoms (214 participants, 33.8%). Reducing the weight of headache in the CAS allowed to align CAS and LLS. Conclusion: In comparison to the LLS, the CAS has a sensitivity close to 100% but lacks specificity given the high rate of false positives. The different weight of headaches may be the main reason for the discrepancy.

IoT-Enabled Intelligent Dynamic Risk Assessment of Acute Mountain Sickness: The Role of Event-Triggered Signal Processing

The rapid developments in Internet of Medical Things open up new avenues for personalized healthcare. Continuously monitored physiological data can be collected by wearable devices and are transmitted to a remote server for real-time monitoring and diagnosis. This article concerns a risk assessment problem of acute mountain sickness (AMS) with data transmitted according to an event-triggered transmission schedule. An event-triggered signal processing approach is introduced to reconstruct the untransmitted information, based on which, a dynamic SpO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\bf 2}$</tex-math></inline-formula> index (DSI) is further proposed for AMS risk evaluation. The performance of the proposed approach is analyzed through physiological data collected in a proof-of-the-concept study ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> =12). Statistical significant correlation of the DSI with AMS ground truth including Lake Louise score, deep sleep duration, deep sleep ratio, and mean SpO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\bf 2}$</tex-math></inline-formula> during sleep is observed. More importantly, it is observed that the proposed event-triggered signal processing procedure can dramatically reduce the data transmission rate while maintaining the performance of the DSI assessment, through comparison of the DSI obtained using the proposed event-triggered approach with those obtained based on event-triggered raw data and continuously transmitted time-triggered data. The obtained results indicate the feasibility of adopting event-triggered data scheduling and signal processing to achieve AMS risk evaluation using data from wearable devices with limited communication/battery resources.

A slow feature based LSTM network for susceptibility assessment of acute mountain sickness with heterogeneous data

Objective:Acute mountain sickness (AMS) is a syndrome that occurs when an individual rapidly rises to a high altitude and fails to adapt to acute hypobaric hypoxia physiologically. The aim of this paper is to develop an intelligent approach for the individual susceptibility assessment of AMS based on dynamic heterogeneous data monitored by multiple wearable devices. Methods:In this paper, the adaptive domain of hypoxia tolerance (ADHT) is established based on k-means clustering and mutual information (MI). Furthermore, a slow feature based long short-term memory (LSTM) learner is proposed to evaluate an individual’s ability to tolerate hypoxia, which is used as the susceptibility evaluation of AMS. Results:The proposed method’s performance is evaluated by using the heterogeneous physiological data of 18 subjects, augmented to 396 samples. The maximum MI value (0.3946) between cluster results and the lake louise score is retained to establish ADHT. The classification accuracy of the slow feature based LSTM method reaches 85.71% and the area under the ROC curve reaches 0.925. Comparing with other benchmark and deep learning approaches, the proposed method perform best in term of accuracy, precision, specificity and Matthews correlation coefficient. Conclusion:The results show that the proposed method is feasible in classifying individual hypoxia tolerance and evaluating AMS susceptibility. The system takes full advantage of dynamic heterogeneous data during offline modeling, and only needs the IHT data fed back by wearable devices during online monitoring. Significance:The method improves the convenience of susceptibility assessment of AMS.

Assessment of Acute Mountain Sickness Using 1993 and 2018 Versions of the Lake Louise Score in a Large Chinese Cohort.

Chen, Renzheng, Yong Wang, Chen Zhang, Xiaolin Luo, Jie Yang, Chuan Liu, and Lan Huang. Assessment of acute mountain sickness using 1993 and 2018 versions of the Lake Louise Score in a large Chinese cohort. High Alt Med Biol. 22:362-368, 2021. Background: This study uses Lake Louise Score (LLS) in its original (LLS1993) and new (LLS2018) versions to assess acute mountain sickness (AMS) and aims to provide more clinical information about the AMS scoring system. Methods: We enrolled 1,026 male Chinese soldiers who traveled from an altitude of 500 to 3,700 m by airplane in 2.5 hours. We observed each subject's symptoms after arrival at 3,700 m in 24 and 48 hours. Each item was dropped from LLS1993 to evaluate its sensitivity and effect on AMS diagnosis. The relationship between each symptom and AMS was assessed by correlation analysis. Exploratory and confirmatory factor analyses evaluated the factor structure of LLS, while the ordinal alpha coefficient was calculated to determine its internal consistency. Results: Four hundred fifty-nine subjects were not followed up on day 2. We defined two observed cohorts (cohort 1, n = 1,026 and cohort 2, n = 567). Headache was the most common symptom in 24 hours, while sleep disturbance was the fourth-most common symptom at 24 hours and the most common symptom at 48 hours. When we dropped gastrointestinal symptoms, the drop rate was lowest in each situation (1.0% in cohort 1, 1.3% in cohort 2 at 24 hours, and 5.7% in cohort 2 at 48 hours, respectively). The incidence of AMS decreased from 18.4% at 24 hours to 36.4% at 48 hours when lost sleep disturbance in cohort 2. Moreover, the statistical method of Mantel/Haenszel square test was used for correlation analysis and the results showed a correlation between sleep disturbance and AMS. Besides, both LLS1993 and LLS2018 had acceptable internal consistencies, and all items had good loading coefficients in LLS1993. Conclusions: We have demonstrated that there could be an association between sleep disturbance and AMS diagnosis. Both LLS1993 and LLS2018 applied to young Chinese men.

Subjective assessment of acute mountain sickness: investigating the relationship between the Lake Louise Self-Report, a visual analogue scale and psychological well-being scales.

PurposeThere is an ongoing discussion how to assess acute mountain sickness (AMS) in real life conditions. Next to more-item scales with a cut off like the Lake Louise Self-Report (LLS), some authors suggested to use visual analog scales (VAS) to assess AMS. This study tried to contribute to this question using VAS items used for the Subjective Ratings of Drug Effects, including an additional single item for AMS. Furthermore, we investigated if instruments developed to assess psychological well-being might predict AMS assessed via LLS or VAS.Methods32 (19 Female) adult persons with known AMS susceptibility filled in questionnaires (Feeling Scale, Felt Arousal Scale, Activation Deactivation Check List, LLS, VAS) at a height of 3650 m above sea level.ResultsCorrelation and regression analysis suggest a moderate to high relationship between the LLS score and the VAS items, including one VAS item asking for the severity of AMS, as well as psychological well-being.ConclusionIn conclusion, using VAS items to assess AMS can be a more precise alternative to questionnaires like LLS, for people knowledgeable with AMS. Furthermore, researchers should be aware that psychological well-being might be an important parameter influencing the assessment of AMS.

Comparison of Scoring Systems for Assessment of Acute Mountain Sickness

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.

Identifying the lowest effective dose of acetazolamide for the prophylaxis of acute mountain sickness: systematic review and meta-analysis

Objectives To assess the efficacy of three different daily doses of acetazolamide in the prevention of acute mountain sickness and to determine the lowest effective dose.Design Systematic review and meta-analysis.Data...

Structural and Functional Changes of the Human Macula during Acute Exposure to High Altitude

BackgroundThis study aimed to quantify structural and functional changes at the macula during acute exposure to high altitude and to assess their structure/function relationship. This work is related to the Tuebingen High Altitude Ophthalmology (THAO) study.Methodology/Principal FindingsSpectral domain optical coherence tomography and microperimetry were used to quantify changes of central retinal structure and function in 14 healthy subjects during acute exposure to high altitude (4559 m). High-resolution volume scans and fundus-controlled microperimetry of the posterior pole were performed in addition to best-corrected visual acuity (BCVA) measurements and assessment of acute mountain sickness. Analysis of measurements at altitude vs. baseline revealed increased total retinal thickness (TRT) in all four outer ETDRS grid subfields during acute altitude exposure (TRTouter = 2.80±1.00 μm; mean change±95%CI). This change was inverted towards the inner four subfields (TRTinner = −1.89±0.97 μm) with significant reduction of TRT in the fovea (TRTfoveal = −6.62±0.90 μm) at altitude. BCVA revealed no significant difference compared to baseline (0.06±0.08 logMAR). Microperimetry showed stable mean sensitivity in all but the foveal subfield (MSfoveal = −1.12±0.68 dB). At baseline recordings before and >2 weeks after high altitude exposure, all subjects showed equal levels with no sign of persisting structural or functional sequels.Conclusions/SignificanceDuring acute exposure to high altitude central retinal thickness is subject to minor, yet statistically significant changes. These alterations describe a function of eccentricity with an increase in regions with relatively higher retinal nerve fiber content and vascular arcades. However, these changes did not correlate with measures of central retinal function or acute mountain sickness. For the first time a quantitative approach has been used to assess these changes during acute, non-acclimatized high altitude exposure.

Visual Analogue Scores in Assessment of Acute Mountain Sickness

Acute mountain sickness (AMS) is common on ascent to high altitude, with self assessment being the current method used to assess symptoms. The Lake Louise Self-Report Score (LLSRS) and the Environmental Symptoms Questionnaire (ESQ) are widely used and validated. A Visual Analogue Scale (VAS) may be used as a simpler alternative for AMS assessment. Our aims were to compare a VAS using lines of length 100 mm, for both individual symptoms of AMS and self-assessed overall AMS with both LLSRS and a shortened Environmental Symptoms Questionnaire (ESQc) on ascent to 4392 m. We set out to suggest a specific score as a cut off point for diagnosis of AMS when using the VAS. There were significant positive correlations (p<0.01), between VAS and both LLSRS and ESQc scores for overall AMS and a composite AMS score derived from the individual symptom scores at 4392 m. The sensitivity and specificity of the VAS were calculated as 0.67 and 0.98, respectively, when using the LLSRS as the standard test for comparison, and 0.91 and 0.96, respectively, when using the ESQc for comparison. The cut off point for diagnosis of AMS was calculated to be 22 mm or above when using a VAS for overall AMS or 15 mm or above when using the VAS composite score, when using LLSRS as the comparative test. Our results show significant correlations between the VAS and the LLSRS and ESQc, when assessing AMS at 4392 m. Our study suggests that a VAS could provide a simple alternative method of assessing AMS at high altitude.

Heart rate variability during two sequential mountaineering expeditions

This study was undertaken to assess the duration of altitude acclimatization retention in individuals after initial exposure to a maximum altitude of 5360m during a mountaineering expedition. Spectral heart rate variability analysis accompanied by an assessment of acute mountain sickness using the Lake Louise Scoring System was performed during two sequential mountaineering expeditions to altitudes of 5360m and 5642m, with a period of 30 days between each expedition. Subjects displayed varying degrees of alterations in heart rate variability during the initial expedition, which indicated differing degrees of dysadaptation and stress development. Their Lake Louise Scores accounted for the presence of acute mountain sickness throughout the trip. During the subsequent expedition, the subjects' heart rate variability measures were within the normal range, and there were no signs of acute mountain sickness. All three subjects who underwent step-by-step exposure to altitudes of 5360m displayed differing degrees of alterations in heart rate variability in conjunction with differing degrees of acute mountain sickness. All subjects also developed acclimatization to hypoxic conditions at this altitude, which was preserved for 30 days, and was sufficient to prevent them from showing any significant alterations in heart rate variability when re-exposed to the same altitude.

Con: Headache Should not Be a Required Symptom for the Diagnosis of Acute Mountain Sickness

High Altitude Medicine & BiologyVol. 12, No. 1 PRO and CON edited by Erik R. SwensonCon: Headache Should not Be a Required Symptom for the Diagnosis of Acute Mountain SicknessJohn B. WestJohn B. WestSearch for more papers by this authorPublished Online:31 Mar 2011https://doi.org/10.1089/ham.2010.1068AboutSectionsView articleView Full TextPDF/EPUB ToolsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetailsCited ByEvaluation of the Lake Louise Score for Acute Mountain Sickness and Its 2018 Version in a Cohort of 484 Trekkers at High Altitude Jean-Paul Richalet, Chantal Julia, and François J. Lhuissier13 December 2021 | High Altitude Medicine & Biology, Vol. 22, No. 4Akute HöhenkrankheitCharacteristics of Headache and Relationship to Acute Mountain Sickness at 4559 Meters Michael Schneider and Peter Bärtsch21 December 2018 | High Altitude Medicine & Biology, Vol. 19, No. 4The influence of hypoxia and prolonged exercise on attentional performance at high and extreme altitudes: A pilot study3 October 2018 | PLOS ONE, Vol. 13, No. 10Isolated psychosis during exposure to very high and extreme altitude – characterisation of a new medical entity5 December 2017 | Psychological Medicine, Vol. 48, No. 11Exploration of Acute Phase Proteins and Inflammatory Cytokines in Early Stage Diagnosis of Acute Mountain Sickness Chi Wang, Hui Jiang, Jinyan Duan, Jingwen Chen, Qi Wang, Xiaoting Liu, and Chengbin Wang1 June 2018 | High Altitude Medicine & Biology, Vol. 19, No. 2The 2018 Lake Louise Acute Mountain Sickness Score Robert C. Roach, Peter H. Hackett, Oswald Oelz, Peter Bärtsch, Andrew M. Luks, Martin J. MacInnis, J. Kenneth Baillie, , Eric Achatz, Edi Albert, Jon S. Andrews, James D. Anholm, Mohammad Zahid Ashraf, Paul Auerbach, Buddha Basnyat, Beth A. Beidleman, R.R. Berendsen, Marc Moritz Berger, Konrad E. Bloch, Hermann Brugger, Annalisa Cogo, Ricardo Gonzalez Costa, Andrew Cumpstey, Allen Cymerman, Tadej Debevec, Catriona Duncan, David Dubowitz, Angela Fago, Michael Furian, Matt Gaidica, Prosenjit Ganguli, Michael P.W. Grocott, Debra Hammer, David Hall, David Hillebrandt, Matthias Peter Hilty, Gigugu Himashree, Benjamin Honigman, Ned Gilbert-Kawai, Bengt Kayser, Linda Keyes, Michael Koehle, Samantha Kohli, Arlena Kuenzel, Benjamin D. Levine, Mona Lichtblau, Jamie Macdonald, Monika Brodmann Maeder, Marco Maggiorini, Daniel Martin, Shigeru Masuyama, John McCall, Scott McIntosh, Gregoire Millet, Fernando Moraga, Craig Mounsey, Stephen R. Muza, Samuel Oliver, Qadar Pasha, Ryan Paterson, Lara Phillips, Aurélien Pichon, Philipp A. Pickerodt, Matiram Pun, Manjari Rain, Drummond Rennie, Ge Ri-Li, Steven Roy, Samuel Verges, Tatiana Batalha Cunha dos Santos, Robert B. Schoene, Otto D. Schoch, Surinderpal Singh, Talant Sooronbaev, Craig D. Steinback, Mike Stembridge, Glenn Stewart, Tsering Stobdan, Giacomo Strapazzon, Andrew W. Subudhi, Erik Swenson, A. A. Roger Thompson, Martha Tissot van Patot, Rosie Twomey, Silvia Ulrich, Nicolas Voituron, Dale R. Wagner, Shih-hao Wang, John B. West, Matt Wilkes, Gabriel Willmann, Michael Yaron, and Ken Zafren1 March 2018 | High Altitude Medicine & Biology, Vol. 19, No. 1Wearable physiological sensors and real-time algorithms for detection of acute mountain sicknessJournal of Applied Physiology, Vol. 124, No. 3Does This Patient Have Acute Mountain Sickness?JAMA, Vol. 318, No. 18Physiological and psychological factors associated with onset of high-altitude headache in Chinese men upon acute high-altitude exposure at 3700 m5 May 2016 | Cephalalgia, Vol. 37, No. 4Acute high-altitude sickness31 January 2017 | European Respiratory Review, Vol. 26, No. 143Subjective assessment of acute mountain sickness: investigating the relationship between the Lake Louise Self-Report, a visual analogue scale and psychological well-being scales22 September 2016 | SpringerPlus, Vol. 5, No. 1Drug Use and Misuse in the Mountains: A UIAA MedCom Consensus Guide for Medical Professionals Enrico Donegani, Peter Paal, Thomas Küpper, Urs Hefti, Buddha Basnyat, Anna Carceller, Pierre Bouzat, Rianne van der Spek, and David Hillebrandt1 September 2016 | High Altitude Medicine & Biology, Vol. 17, No. 3Acute Mountain Sickness Symptoms Depend on Normobaric versus Hypobaric HypoxiaBioMed Research International, Vol. 2016High AltitudeAkute Höhenkrankheit (AMS)20 May 2015Network Analysis Reveals Distinct Clinical Syndromes Underlying Acute Mountain Sickness22 January 2014 | PLoS ONE, Vol. 9, No. 1Acute Mountain Sickness and High Altitude Cerebral Oedema9 November 2013Altitude Sickness in Climbers and Efficacy of NSAIDs Trial (ASCENT): Randomized, Controlled Trial of Ibuprofen Versus Placebo for Prevention of Altitude IllnessWilderness & Environmental Medicine, Vol. 23, No. 4Does Ibuprofen Prevent Acute Mountain Sickness?Wilderness & Environmental Medicine, Vol. 23, No. 4Acute Mountain Sickness without Headache at Low Altitude1 November 2012 | JRSM Short Reports, Vol. 3, No. 11Short-term intermittent hypoxia reduces the severity of acute mountain sickness1 August 2012 | Scandinavian Journal of Medicine & Science in Sports, Vol. 22, No. 5 Volume 12Issue 1Apr 2011 InformationCopyright 2011, Mary Ann Liebert, Inc.To cite this article:John B. West.Con: Headache Should not Be a Required Symptom for the Diagnosis of Acute Mountain Sickness.High Altitude Medicine & Biology.Apr 2011.23-25.http://doi.org/10.1089/ham.2010.1068Published in Volume: 12 Issue 1: March 31, 2011PDF download

Visual Analog Scale (VAS) for Assessment of Acute Mountain Sickness (AMS) on Aconcagua

The Lake Louise AMS Self-Report Score (LLSelf) is a commonly used, validated assessment of acute mountain sickness (AMS). We compared LLSelf and visual analog scales (VAS) to quantify AMS on Aconcagua (6962 m). Prospective observational cohort study at Plaza de Mulas base camp (4365 m), Aconcagua Provincial Park, Argentina. Volunteers climbing in January 2009 were enrolled at base camp and ascended at their own pace. They completed the LLSelf, an overall VAS [VAS(o)], and 5 individual VAS [VAS(i)] corresponding to the items of the LLSelf when symptoms were maximal. Composite VAS [VAS(c)] was calculated as the sum of the 5 VAS(i). A total of 127 volunteers consented to the study. Response rate was 52.0%. AMS occurred in 77.3% of volunteers, while 48.5% developed severe AMS. Median (interquartile range, IQR) LLSelf was 4 (3-7). Median (IQR) VAS(o) was 36 mm (23-59). VAS(o) was linear and correlated with LLSelf: slope = 6.7 (95% CI: 4.4-9.0), intercept = 3.0 (95% CI: -10.0-16.1), ρ = 0.71, τ = 0.55, R(2) = 0.45, p < 0.001. Median (IQR) VAS(c) was 29 (13-44). VAS(c) was also linear and correlated with LLSelf: slope = 5.9 (95% CI: 4.9-6.9), intercept = -0.6 (95% CI: -6.3-5.1), ρ = 0.83, τ = 0.68, R(2) = 0.73, p < 0.001. The relationship between the 5 VAS(i) and LLSelf(i) was less significant and less linear than that between VAS(o), VAS(c), and LLSelf. While both VAS(o) and VAS(c) for assessment of AMS appear to be linear with respect to LLSelf, the amount of scatter within the VAS is considerable. The LLSelf remains the gold standard for the diagnosis of AMS.

Comparing Questionnaires for the Assessment of Acute Mountain Sickness

Exposure to high altitude in nonacclimatized subjects may lead to acute mountain sickness (AMS). AMS is a syndrome characterized by headache accompanied by one or more other symptoms, such as light-headedness, dizziness, loss of appetite, nausea, vomiting, fatigue, lassitude, and trouble sleeping. Assessing the presence and degree of AMS can be done using self-administered questionnaires like the Lake Louise Questionnaire (LLQ) and the Environmental Symptoms Questionnaire-III (ESQ-III). We compared LLQ and ESQ-III in 266 trekkers of different nationalities trekking over a 5400-m-high pass to assess if the two questionnaires identify the same population as suffering from AMS and to see whether using English questionnaires poses problems for nonnative English-speaking persons. The use of English questionnaires by nonnative English speakers influenced the outcome for some nationalities. For criterion scores yielding similar prevalence of AMS, ESQ-III labeled 20% of cases differently (AMS or no AMS) when compared to LLQ. Correlations between similar individual questions of ESQ-III and LLQ were variable, and there was considerable scatter between ESQ-III and LLQ scores. In conclusion, English questionnaires may pose problems in some international settings, and ESQ-III and LLQ may identify different populations as suffering from AMS.

Reliability And Utility of A Visual Analog Scale for The Assessment of Acute Mountain Sickness

Acute mountain sickness (AMS) is a common condition that affects people that ascend too rapidly to high altitude. It is typically assessed with the Lake Louise AMS Self-report Score (LLSelf) that uses a categorical numeric rating scale to answer five questions addressing AMS-related symptoms, such as headache. A 100-mm visual analog scale (VAS) is commonly used to assess subjective phenomena such as pain, but this scale has never been used for the self-assessment of AMS. The purpose of this study was to compare a VAS score to the total LLSelf and to evaluate the test-retest and interrater reliability of the VAS when used as an assessment of AMS. Participants (N = 356) completed both the LLSelf and the VAS on the summit of Mt. Whitney (4419 m). There was a significant relationship (r = 0.65, p < 0.01) between the LLSelf (2.8 +/- 2.0, mean +/- SD) and the VAS (14.4 +/- 14.1 mm). Fifty-seven participants were randomly selected for reliability testing of the VAS. Both test-retest reliability (ICC = 0.996, 95% CI = 0.992 to 0.998) and interrater reliability (ICC = 1.000, 95% CI = 0.999 to 1.000) were high. The mean difference in the VAS score between tests was <1 mm, as was the difference between raters. These results demonstrate excellent reliability for the VAS as an assessment of AMS.

The Clinical Assessment of Acute Mountain Sickness

During three expeditions to high altitude the Birmingham Medical Research Expeditionary Society has studied the effects of the ascents on its members. The severity of acute mountain sickness (AMS) produced was assessed by three methods, interview, self assessment and peer review. Physical examination was unhelpful. The results of the three methods were closely correlated. Clinical interview permitted allowances to be made for individual factors such as fatigue. There was no tendency for self assessment to indicate effects consistently more or less than the other methods. Peer review revealed a wide spread of opinions but the large number of observers allowed the derivation of plausible mean values. Correlation of AMS with arterial pH and PaCO2 showed little relationship but correlation with PaO2 was good, particularly for self assessment. As all the methods are subjective a combination of techniques is recommended for future expeditions.

Birmingham Medical Research Expeditionary Society 1977 Expedition: changes in renal function observed during a trek to high altitude.

Changes in renal function were observed in 17 subjects during the course of a trek to high altitude. Comparison was made between these changes and the clinical assessment of acute mountain sickness (AMS). Periods of natriuresis occurred during ascent and descent, that during ascent being related to a fall in plasma aldosterone. Alterations in serum and urinary potassium suggested that potassium retention occurred during the ascent to altitude. No significant correlation occurred between changes in renal function and the severity of AMS before the illness being clinically apparent. When this was so, the severity of AMS correlated with a decreasing urine output, increasing positive fluid balance and a decreasing excretion of sodium and potassium; these changes were produced in part by a decrease in glomerular filtration rate.