High altitude medicine & biology最新文献

Tu, Ke, Lei Tian, Qi Zhu, Kailian Bai, Lin Li, Mengmei Fu, Mengxia Wang, Lei Zhang, Zhuo Zhan, Haoxi Li, Xiaojun Li, Ruofan Yi, Cheng Jiang, Hua Huang, and Mingming Zhang. Intraoperative opioid-free anesthesia with dexmedetomidine and esketamine versus conventional general anesthesia in laparoscopic cholecystectomy at 3,600 m: A randomized trial on hemodynamic stability and postoperative recovery. High Alt Med Biol. 00:00-00, 2025. Background: Opioid-free anesthesia (OFA) is gaining attention as an alternative to opioid-based techniques. However, its hemodynamic and clinical characteristics at high altitudes, where hypoxia and resource limitations prevail, remain unclear. Methods: In this single-blind randomized trial, 48 patients undergoing laparoscopic cholecystectomy at 3,600 m were assigned to either a conventional general anesthesia (CGA) group (sevoflurane, sufentanil, remifentanil) or an OFA group (sevoflurane, dexmedetomidine, esketamine). The primary outcome was intraoperative mean arterial pressure (MAP); secondary outcomes included heart rate (HR), awakening time, sedation level, patient satisfaction, postoperative pain, postoperative nausea and vomiting (PONV), perioperative medication use, and adverse events. Results: Compared with CGA, the OFA group maintained higher intraoperative MAP, with significant differences after induction (OFA: 87.9 ± 12.3 vs. CGA: 77.2 ± 11.7 mmHg, p < 0.005) and 10 minutes after incision (OFA: 83.5 ± 14.9 vs. CGA: 72.5 ± 9.8 mmHg, p < 0.005). The CGA group exhibited a significant MAP decline at 10 minutes postincision (72.5 ± 9.8 vs. baseline: 83.0 ± 9.1 mmHg, p < 0.001), whereas the OFA group showed a transient MAP increase after intubation (96.1 ± 16.1 vs. baseline: 85.8 ± 7.8 mmHg, p < 0.01). HR trends paralleled MAP changes. Awakening time was significantly longer with OFA (OFA: 20.4 ± 7.5 min vs. CGA: 10.6 ± 8.2 min, p < 0.001), while pain scores at 6 and 12 hours were lower (p < 0.005). Sedation, satisfaction, PONV, and medication use were comparable. No severe adverse events occurred. Conclusions: At high altitudes, OFA with dexmedetomidine and esketamine exhibited distinct clinical characteristics compared with opioid-based anesthesia, maintaining blood pressure and postoperative analgesia but less effectively blunting intubation-induced pressor responses and prolonging awakening time. These factors should be weighed when selecting anesthesia strategies in resource-limited, high-altitude settings, particularly when managing large numbers of patients.

Danzeng, Zhuoga, Rui Zhang, Luobu Gesang, Jin Wang, Bai Ci, Zejuan Wang, Zhuoma Ciren, Quzhen Gesang, Yangzong Suona, Xiaona Liu, Quzong Zhaxi, Cuomu Baima, Binyun Liu, Zhuoga Baima, Wei Cong, and Qiangba Dingzeng. Efficacy and safety of extended-release acetazolamide capsules for the prevention of acute mountain sickness: a randomized, double-blind, placebo-controlled phase III trial. High Alt Med Biol. 00:00-00, 2025. Background: Acute mountain sickness (AMS) frequently affects individuals ascending rapidly to high altitudes. Data on acetazolamide prophylaxis in Asian populations remain limited. To evaluate the efficacy and safety of acetazolamide for the prevention of AMS in the Han Chinese population. Methods: In this multicenter, randomized, double-blind, placebo-controlled phase III trial, 288 healthy Chinese Han adults traveled from Peking (43.5 m) to Lhasa (3,670 m). Participants received either extended-release acetazolamide (500 mg once daily) or placebo, starting 2 days before ascent and continuing for 4 days postarrival. The primary endpoint was AMS incidence (Lake Louise Score [LLS] ≥3 with headache). Results: Among 284 completers, AMS incidence was significantly lower with acetazolamide (36.9% vs. 55.9%, p = 0.0013). Moderate/severe AMS (LLS > 5) was also reduced (9.9% vs. 24.5%, p = 0.0012). SpO₂ levels were consistently higher in the treatment group (p < 0.0001). Adverse events, including paresthesia and polyuria, were mild and self-limiting. Conclusion: Once-daily extended-release acetazolamide (500 mg) effectively prevents AMS and is well-tolerated in healthy Asian individuals. This regimen may enhance adherence and serve as a practical prophylactic option for high-altitude travelers.

McLaughlin, Kyle, Charley Shimanski, Ken Zafren, Ian Jackson, Gerold Biner, Maurizio Folini, Andreas Hermansky, Eric Ridington, Peter Hicks, Giacomo Strapazzon, Marika Falla, Alastair Hopper, Dave Weber, Ryan Jackson, and Hermann Brugger. Helicopter rescue at very high altitude: Recommendations of the International Commission for Mountain Emergency Medicine (ICAR MedCom) 2025. High Alt Med Biol. 00:00-00, 2025. Background: Helicopter mountain rescue is highly effective. However, air rescue operations at very high altitude (VHA), above 3500 m, are inherently hazardous because of challenging topography, dynamic weather, and hypobaric hypoxic environment. Currently, no established international guidelines exist for helicopter rescues at VHA. Methods: We conducted a narrative review of existing literature, supplemented by expert opinions from helicopter pilots, physicians, and rescuers actively engaged in VHA rescues. These recommendations were approved by the International Commission of Alpine Rescue (ICAR) Medical Commission and endorsed by the ICAR Air Rescue Commission. Discussion: We identified 19 key factors to consider, including operational parameters, ground site management, pilot and rescuer safety protocols, and psychological factors to assist air rescue programs in developing pre-mission, mission, and post-mission plans for helicopter rescue missions at VHA. Conclusions: By implementing the recommendations outlined in this article, helicopter rescue teams operating at VHA can improve response capabilities and minimize risks.

Background: A recent study of our group quantifying ¹³C-octanoate metabolism in HA (Capanna Margherita [MG]/4,559 m) showed that acute HA exposure might lead to an increase of the lipolytic and CO₂-producing pathways. Objective: To further test this hypothesis, we investigated intestinal biopsies from the same participants from simultaneously performed endoscopy studies for changes of mRNA-expression levels of the beta-oxidation enzymes and the decarboxylating tricarboxylic acid cycle (TCA) enzymes. Methods: Duodenal biopsies of 16 subjects exposed to HA were sampled via gastro-duodenoscopy at Zurich (baseline ZH, 490 m), on day 2 (MG2) and on day 4 at HA (MG4). After mRNA extraction, quantitative real-time polymerase chain reaction was performed to assess mRNAs expression of TCA cycle enzymes as well as beta-oxidation enzymes. Results: Aconitase mRNA levels increased early (MG2 vs. ZH, p < 0.05) and were still higher at day 4 compared with ZH (MG4 vs. ZH, p < 0.05). Isocitrate dehydrogenase (DH) levels increased with time spent at 4,559 m (MG4 vs. ZH, p < 0.01). The remaining TCA cycle and beta-oxidation enzymes investigated tended to higher values at HA but without reaching significance. Conclusion: We conclude that acute exposure to HA leads to increased transcription of aconitase and isocitrate DH in the duodenal mucosa due to hypobaric hypoxia exposure.

Liu, Zhen, Chao Nie, Lijia Yuan, Hui Jiang, Chuanchuan Liu, Yi Zhang, and Minghua Liu.Impact of Acute High-Altitude Exposure on the Timing of Tranexamic Acid Administration in Rabbits with Traumatic Hemorrhagic Shock. High Alt Med Biol. 00:00-00, 2025. Background: Acute exposure to high altitude (≤3 days)-induced physiological changes may shorten the therapeutic time window for tranexamic acid (TXA) administration after traumatic hemorrhagic shock (THS). This study aims to compare the differences in the TXA therapeutic time window between THS patients with acute high-altitude exposure and those in low-altitude regions. Methods: Forty-two anesthetized rabbits were divided into three groups: low-altitude THS (l-THS), high-altitude sham, and high-altitude THS. All h-THS groups were housed for 3 days in 10% oxygen chambers (simulating 5,000 m altitude) before experimentation. THS models were established by reducing mean arterial pressure from 105 to 55 mmHg through blood loss combined with left tibiofibular fracture. Animals received single-dose TXA (90 mg/kg) with the following subgroups: l-THS-2h and l-THS-3h (TXA administered 2 hours/3 hours post-THS), h-THS-1h, h-THS-2h, h-THS-3h and h-THS-4h (TXA administered 1 hours/2 hours/3 hours/4 hours post-THS). Comparative analyses included hemodynamic parameters, complete blood counts, coagulation-fibrinolysis function, endothelial injury markers, inflammatory cytokines, and pulmonary histopathological changes. Results: High-altitude exposure required less blood loss to achieve THS compared with low-altitude conditions (51.00 ± 2.45 ml vs. 59.60 ± 3.65 ml, p < 0.05). At 6 hours post-THS, compared to the l-THS-2h group [TIC risk (INR:1.34 ± 0.09), anaerobic oxidation levels, inflammatory response levels, and lung injury score (1.8 (1.0, 2.0))], the l-THS-3h group [INR:1.51 ± 0.08; 2.6 (2.0, 3.0)], h-THS-2h group [1.45 ± 0.06; 2.8 (2.0, 3.5)], h-THS-3h group [INR:1.75 ± 0.11; 5.6 (4.5, 6.5)], and h-THS-4h group [INR:1.99 ± 0.06; 6.2 (6.0, 6.5)] all showed significantly higher values. For the same observational indicators, compared with the l-THS-3h group, the h-THS-1h group had lower values, while the h-THS-3h and h-THS-4h groups showed higher values. No statistically significant differences were observed between the l-THS-2h and h-THS-1h groups, or between the l-THS-3h and h-THS-2h groups for all parameters. Conclusion: The optimal time window for TXA administration in traumatic hemorrhagic shock may be shorter at high altitude compared with low-altitude area. These findings could influence therapeutic guidelines for TXA administration at high altitudes in humans.

Shrestha, Suraj, Sanjeev Kharel, Suman Acharya, Gobi Basyal, and Sanjeeb S. Bhandari. A Retrospective Analysis of Altitude Illness at the Himalayan Rescue Association Aid Post Manang (2018-2023). High Alt Med Biol. 00:00-00, 2025. Introduction: The Himalayan Rescue Association (HRA) in Nepal has been operating high-altitude aid posts in the Himalayas to alleviate illnesses in hikers and locals with a focus on acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE), as well as other common medical problems. This study examines the altitude-related illnesses occurring between 2018 and 2023 at the HRA Manang aid post. Materials and Methods: A retrospective study analyzing the medical records of HRA Manang from 2018 to 2023 was conducted. Demographics and diagnoses were documented, and the Lake Louise Score (LLS) was calculated for AMS cases. The frequency of altitude-related illness was compared among trekkers with/without a good ascent profile. Results: During the study period, a total of 2,904 people visited the aid post, with 337 (11.6%) suffering from altitude-related illnesses, including 274 AMS, 40 HAPE, 11 HACE, and 12 concurrent HAPE with HACE, with 58.8% of cases seen in the fall season. Most were adults, non-Nepali (70.3%), of which only 4.5% comprised the pediatric population. The majority of AMS cases were mild (70.6%) (LLS ≤5), while 17.2% had moderate to severe AMS. Almost one-third (28.2%) of cases had rapid ascent (elevation >500/day above 2,500 m), with a majority of 67.4% being Nepali compared to non-Nepali (p < 0.05). The proportion of HACE and concurrent HAPE with HACE was significantly higher among those with rapid ascent profiles. About 36.20% of cases with altitude-related illness had taken prophylactic acetazolamide, which was considerably lower among Nepali patients (p < 0.001). Motor vehicle evacuation (86.7%), followed by helicopter evacuation (13.3%), was used for those requiring immediate descent. Conclusion: Altitude illness is a common problem among trekkers in the Annapurna region of Nepal. More effort should be focused on educating high-altitude travelers to reduce the risk of these problems.

Cornwell, William, Aaron L. Baggish, Christoph Dehnert, Benjamin D. Levine, and Andrew M. Luks. Clinical conundrum: climbing at the extremes of high elevation with nonischemic cardiomyopathy. High Alt Med Biol. 26:237-241, 2025.

Brazo-Sayavera, Javier, Alba Camacho-Cardenosa, Talita Morais Fernandes, Jamille Guedes Malta Argolo, Ana Paula Morais Fernandes, Carlos Arterio Sorgi, Elisângela Aparecida da Silva Lizzi, and Átila Alexandre Trapé. Effects of moderate-intensity cyclic normobaric hypoxic training on cardiovascular disease risk factors of patients recovered from COVID-19: The AEROBICOVID randomized controlled trial. High Alt Med Biol. 26:265-272, 2025. Objectives: The aim was to analyze the effects of a training program under hypoxic conditions compared with a control and normoxia training program on cardiovascular disease risk factors in patients recovered from COVID-19. Methods: A total of 67 patients were randomly assigned to the control group, training and recovery with hypoxia (T_H:R_H), training in normoxia (T_N) and recovery with hypoxia (R_H), and T_N and recovery in normoxia (R_N). Anthropometric, body composition, respiratory, and cardiometabolic risk factors were analyzed before and after intervention. Results: All intervention groups had positive effects on various health outcomes in patients recovered from COVID-19. The reduction in waist, hip, and waist/hip ratio, glycaemia, total cholesterol, and low-density lipoprotein-cholesterol indicates improvements in cardiovascular health. The increase in the forced expiratory volume in 1 second suggests improvements in respiratory health. In addition, the decrease in cardiovascular disease risk score indicates a reduction in overall cardiovascular disease risk. Conclusions: The study provides evidence to support the clinical benefits of moderate-intensity intermittent hypoxic training as a part of the treatment of patients recovered from COVID-19. It may also provide evidence on the efficacy and safety of intermittent hypoxic training in different health conditions. The study was registered at the Brazilian Clinical Trials Registry (RBR-5d7hkv).

Pirlot, Thibaud, Thibaud Mihailovic, Philippe Gimenez, Grégoire P. Millet, Franck Brocherie, Eric Fruchart, Gilles Ravier, Bertrand Baron, Romain Bouzigon, Sandrine Guirronnet, Emmanuel Brunet, and Alain Groslambert. Psychological, sleep, and heart rate variability responses during early- and middle-term acclimatization of "Living High-Training Low and High". High Alt Med Biol. 26:291-300, 2025. Background: This study investigated the relationships between psychological responses, sleep, and heart rate variability (HRV) before and during a "living high-training low and high" (LHTLH) camp. Methods: Ten elite female cyclists (mean ± SD, age = 17.3 ± 1.2 years, VO₂max = 54.9 ± 6.9 ml·min/kg) were monitored for 19 days divided into three periods: (1) normoxia (5 days preceding LHTLH), (2) early acclimatization period (days 1-4 of LHTLH), and (3) middle acclimatization period (days 5-14 of LHTLH) in normobaric hypoxic chambers set at a simulated altitude of 2,800 m. During the intervention, their training load (TL), sleep disturbance, psychological (stress, activation state, and perseverance) and physiological responses (sleep architecture, nocturnal peripheral oxygen saturation [SpO₂], and HRV) were monitored. Results: In normoxia, no significant correlations were observed between TL and any psychological and physiological responses. However, in the early acclimatization period, significant correlations were found between sleep disturbance and SpO₂ (r = -0.83, p < 0.005) and between achieving objectives and HRV (r = -0.91, p < 0.005). In the middle acclimatization period, significant correlations were found between the feeling during training and SpO₂ (r = 0.83; p < 0.005). Conclusion: This indicates that LHTLH exacerbates the psychophysiological interactions during the early acclimatization period that disappear during the middle acclimatization period while others appear.

Van Ochten, Natalie, Eric W. Rudofker, and William K. Cornwell. Altitude adversities: is it safe for people with cardiovascular disease to travel to moderate-high altitude? High Alt Med Biol. 26:328-334, 2025.-The risk of acute cardiac events increases following acute exposure to hypoxia associated with travel to moderate-high altitudes. Herein, we present seven illustrative cases among lowlanders who presented to our center (1,609 m, equivalent fraction of inspired oxygen [F_IO₂] ∼0.17) with acute cardiac emergencies during travel to moderate-high altitude. We also provide a concise, yet comprehensive, review of the relevant physiology pertaining to the impact of acute hypoxia on cardiovascular physiology and mechanisms by which altitude exposure may increase the risk of adverse events.