High altitude medicine & biology最新文献

Hillebrandt, David, Anil Gurtoo, Thomas Kupper, Paul Richards, Volker Schöffl, Pankaj Shah, Rianne van der Spek, Nikki Wallis, and Jim Milledge. UIAA Medical Commission recommendations for mountaineers, hillwalkers, trekkers, and rock and ice climbers with diabetes. High Alt Med Biol. 24: 110-126.-The object of this advice article is not only to give the diabetic mountaineer general guidance but also to inform his or her medical team of practical aspects of care that may not be standard for nonmountaineers. The guidelines are produced in seven sections. The first is an introduction to the guidelines, and the second is an introduction to this medical problem and is designed to be read and understood by diabetic patients and their companions. The third section is for use in an emergency in mountains. The fourth is for rock, ice, and competition climbers operating in a less remote environment. These initial sections are deliberately written in simple language. The fifth and sixth sections are written for clinicians and those with skills to read more technical information, and the seventh looks at modern technology and its pros and cons in diabetes management in a remote area. Sections One and Two could be laminated and carried when in the mountains, giving practical advice.

Qile, Muge, Qiying Xu, Yi Ye, Huifang Liu, Drolma Gomchok, Juanli Liu, Tana Wuren, and Ri-Li Ge. Erythrocytes display metabolic changes in high-altitude polycythemia. High Alt Med Biol. 24:104-109, 2023. Background: Sphingosine-1-phosphate (S1P) levels are increased after acute exposure to high altitude; however, whether this effect is observed in chronic high-altitude hypoxia is unknown. Methods: We studied erythrocyte S1P levels in 13 subjects with high-altitude polycythemia (HAPC) and 13 control subjects and also used a mouse model of HAPC. HAPC subjects lived in Maduo (4,300 m altitude) for 10 years, whereas control subjects lived permanently in Xining (2,260 m). The mouse model of HAPC was established by stimulating an altitude of 5,000 m in a hypobaric chamber for 30 days. Hematology and S1P, CD73, 2,3-bisphosphoglycerate (2,3-BPG), and reticulocyte levels were measured. Results: The hemoglobin concentration and number of red blood cells were significantly elevated in human and mouse HAPC groups. Blood S1P levels in HAPC subjects and mice were higher than those in control groups (p < 0.05 and p < 0.001, respectively). 2,3-BPG and CD73 levels in HAPC subjects were significantly higher than those in control subjects (p < 0.05). No significant changes in reticulocyte levels were observed. Conclusions: The critical altitude-induced metabolic changes such as S1P retained high levels even after prolonged exposure, and it may inspire future research into therapeutic strategies for hypoxia-associated illnesses.

Apte, Chandrashekhar V. Barometric pressure at high altitude: revisiting West's prediction equation, and more. High Alt Med Biol. 24:85-93, 2023. Introduction: Since an earlier prediction equation to calculate barometric pressure at a given altitude had been tested against limited barometric pressure observations, its accuracy needed to be re-validated against additional pressure observations. Methods: Five-year (2016-2020) barometric pressure and altitude data were downloaded from an open-source website for 25 select locations. The calculated predicted pressure was compared with mean 5-year, mean monthly, and mean daily pressures. Percent prediction error and root mean square errors were used to assess accuracy of the prediction equation. Results: The original prediction equation was accurate to within 1% for locations only within 22° latitude. It was increasingly inaccurate at higher latitudes and also for means based on shorter time spans (e.g., mean monthly and daily pressures). A new prediction equation was proposed by developing a model using downloaded data. The new equation resulted in more accurate predictions for all latitudes and all time spans. The new equation also performed well when tested at seven new locations. Conclusions: Ideally, medical professionals at high altitude should rely on actual barometric pressure observations to assess hypoxic risk. In the absence of actual measurements, the suggested new prediction equation may be used to estimate, with some limitations, the ambient barometric pressure at latitudes below 47° and altitudes up to about 4,700 m.

Song Zhen, Anxin Zhang, Jie Luo, Guanghai Xiong, Haibo Peng, Rang Zhou, Yuanfeng Li, Hongqiang Xu, Zhen Li, Wei Zhao, and Haoxiang Zhang. Prevalence of high-altitude polycythemia and hyperuricemia and risk factors for hyperuricemia in high-altitude immigrants. High Alt Med Biol. 24:132-138, 2023. Background: Few studies have investigated the epidemiology of chronic mountain sickness (CMS) in high-altitude immigrants. This study evaluated the prevalence of polycythemia and hyperuricemia (HUA) and risk factors for HUA in high-altitude immigrants. Methods: A cross-sectional study was conducted with 7,070 immigrants 15-45 years of age living on the Tibetan Plateau between January and December 2021. Information from routine physical examinations was obtained from each participant. Binary logistic regression analysis was performed to determine the correlation of several risk factors for HUA. Results: The prevalence of high-altitude polycythemia (HAPC) and HUA was 25.8% (28.7% in males and 9.4% in females) and 54.2% (59.9% in males and 22.5% in females), respectively. The highest prevalence of HAPC in males and females was observed in participants 26-30 and 21-25 years of age, respectively. The highest prevalence of HUA in both males and females was observed in participants 26-30 years of age. Binary logistic regression analysis showed that age, sex, and hemoglobin (Hb) concentration were risk factors for HUA, among which age was a negative factor and male sex and Hb concentration were positive factors. Conclusions: Immigrants are more susceptible to HAPC and HUA. The high prevalence of CMS of immigrants may be associated with Hb concentration, age, and sex.

van Veelen, Michiel J., Giulia Roveri, Ivo B. Regli, Tomas Dal Cappello, Anna Vögele, Michela Masè, Marika Falla, and Giacomo Strapazzon. Personal protective equipment protocols lead to a delayed initiation of patient assessment in mountain rescue operations. High Alt Med Biol. 24:127-131, 2023. Introduction: Mountain rescue operations can be challenging in austere environmental conditions and remote settings. Airborne infection prevention measures include donning of personal protective equipment (PPE), potentially delaying the approach to a patient. We aimed to investigate the time delay caused by these prevention measures. Methods: This randomized crossover trial consisted of 24 rescue simulation trials intended to be as realistic as possible, performed by mountain rescue teams in difficult terrain. We analyzed the time needed to perform an airborne infection prevention protocol during the approach to a patient. Time delays in scenarios involving patients already wearing versus not wearing face masks and gloves were compared using a linear mixed model Results: The airborne infection prevention measures (i.e., screening questionnaire, hand antisepsis, and donning of PPE) resulted in a time delay of 98 ± 48 (26-214) seconds on initiation of patient assessment. There was a trend to a shorter time to perform infection prevention measures if the simulated patient was already wearing PPE consisting of face mask and gloves (p = 0.052). Conclusion: Airborne infection prevention measures may delay initiation of patient assessment in mountain rescue operations and could impair clinical outcomes in time-sensitive conditions. Trial registration number 0105095-BZ Ethics Committee review board of Bolzano.

Pühringer, Reinhard, Martina Muckenthaler, and Martin Burtscher. Association between ferritin levels and altitude-dependent cardiorespiratory fitness in mountain guides. High Alt Med Biol. 24:139-143, 2023. Background: Higher ferritin levels may be associated with lower cardiorespiratory fitness (CRF; i.e., maximal oxygen uptake, VO₂max) and may represent early markers of cardiovascular risk but may also support high-altitude acclimatization. To evaluate these potential associations, data recordings from a large sample of male mountain guides have been analyzed. Methods: A total of 154 data sets (including anthropometric data, VO₂max, blood lipids, hemoglobin, ferritin, and transferrin levels) of regularly physically active and well-acclimatized mountain guides were available for analyses. Participants performed equal incremental cycle ergometer tests to exhaustion at low (600 m) and (∼1 week later) at moderate altitude (2,000 m). Results: Ferritin levels were positively correlated with levels of hemoglobin (r = 0.29, p < 0.01), total cholesterol (r = 0.18, p < 0.05), triglycerides (r = 0.23, p < 0.01), and low-density lipoprotein (r = 0.22, p < 0.01), and negatively with high-density lipoprotein levels (r = -0.16, p < 0.05) and also with baseline (taken at low altitude) VO₂max values (r = -0.19, p < 0.05). In contrast, higher ferritin levels were associated with less VO₂max decline from low-to-moderate altitude (r = 0.26, p < 0.01). Conclusion: Higher ferritin levels in male mountain guides are weakly associated with lower CRF and higher prevalence of cardiovascular risk factors but with slightly less reduction in VO₂max when acutely exposed to moderate altitude. The clinical relevance of these observations needs further investigation.

Anderson, Paul J., Christina M. Wood-Wentz, Kent R. Bailey, and Bruce D. Johnson. Objective versus self-reported sleep quality at high altitude. High Alt Med Biol. 24:144-148, 2023. Background: Previous studies have found little relationship between polysomnography and a diagnosis of acute mountain sickness (AMS) using the Lake Louise Symptom Questionnaire (LLSQ). The correlation between sleep question responses on the LLSQ and polysomnography results has not been explored. We compared LLSQ sleep responses and polysomnography data from our previous study of workers rapidly transported to the South Pole. Methods: Sixty-three subjects completed a 3-hour flight from sea level to the South Pole (3200 m, 9800 ft). Participants completed limited overnight polysomnography on their first night and completed LLSQ upon awakening. We compared polysomnography results at the South Pole with sleep question responses on the LLSQ to assess their degree of correspondence. Results: Twenty-two (30%) individuals reported no sleep problems whereas 20 (32%) reported some problems and 20 (33%) individuals reported poor sleep and 1 reported no sleep (n = 1). Median sleep efficiency was (94%) among response groups and mean overnight oxygen saturation was 81%. Median apnea hypopnea index (AHI; events/hour) was 10.2 in those who reported no problems sleeping, 5.1 in those reporting some problems sleeping, and 13.7 in those who reported poor sleep. These differences were not statistically significant. Conclusion: Self-reported sleep quality varied but there were no associated significant differences in sleep efficiency, overnight oxygen saturation, nor AHI. Studies that explore the role of objective sleep quality in the development of AMS should remove the sleep question on the LLSQ from AMS scoring algorithms.

Libersa, Marie, Louis Marxer, Ken Zafren, Stephane Oggier, Lorenzo Pucci, and Mathieu Pasquier. Takotsubo cardiomyopathy following complete avalanche burial: a case report. High Alt Med Biol. 24:149-151, 2023.-Takotsubo cardiomyopathy is a transient left ventricular dyskinesia triggered by a stressful physical or emotional event. We report a case of mid-ventricular Takotsubo stress cardiomyopathy in an avalanche victim. The patient was a 41-year-old woman who was completely buried under 1.2 m of snow for 30 minutes. On arrival at the hospital, she was conscious and hypothermic (core temperature 33.7°C). Her ECG showed rapid atrial fibrillation (142 beats/min) that converted to sinus rhythm after rewarming and administration of crystalloids. Echocardiography showed akinesia of the left mid-ventricle with a left ventricular ejection fraction of 41%. At 48-hour follow-up, echocardiography showed an almost complete recovery. During her hospital stay the patient was diagnosed with an acute stress disorder with symptoms of dissociation. She was discharged home after 5 days. At 2-week follow-up echocardiography was normal. Psychological follow-up was normal at 7 months. The physical and psychological stress of the avalanche, as well as hypothermia, were all possible triggers of Takotsubo cardiomyopathy.