Early acclimatization to high-altitude is characterized by various respiratory, hematological, and cardiovascular adaptations that serve to restore oxygen delivery to tissue. However, less is understood about renal function and the role of renal oxygen delivery (RDO₂) during high-altitude acclimatization. We hypothesized that: 1) RDO₂ would be reduced after 12-hours of high-altitude exposure (high-altitude day1) but restored to sea-level values after one-week (high-altitude day7); and 2) RDO₂ would be associated with renal reactivity (RR), an index of acid-base compensation at high-altitude. Twenty-four healthy lowlander participants were tested at sea-level (344m; Kelowna, Canada), on day1 and day7 at high-altitude (4330m; Cerro de Pasco, Peru). Cardiac output, renal blood flow, arterial and venous blood sampling for renin-angiotensin-aldosterone-system hormones and NT pro-B type natriuretic peptides were collected at each time point. RR was calculated as: (Δ arterial bicarbonate)/(Δ partial pressure of arterial carbon dioxide) between sea-level and high-altitude day1, and sea-level and high-altitude day7. The main findings were: 1) RDO₂ was initially decreased at high-altitude compared to sea-level (ΔRDO₂: -22±17%, P<0.001), but was restored to sea-level values on high-altitude day7 (ΔRDO₂: -6±14%, P=0.36). The observed improvements in RDO₂ resulted from both changes in renal blood flow (Δ from high-altitude day1: +12±11%; P=0.008), and arterial oxygen content (Δ from high-altitude day1 +44.8±17.7%; P=0.006); and 2) RR was positively correlated with RDO₂ on high-altitude day7 (r=0.70; P<0.001), but not high-altitude day1 (r=0.26; P=0.29). These findings characterize the temporal responses of renal function during early high-altitude acclimatization, and the influence of RDO₂ in the regulation of acid-base.

中文翻译：

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2018年全球REACH法规：在早期适应过程中保持肾脏氧气输送至4330 m

早期适应高海拔的特点是各种呼吸，血液和心血管适应，可恢复向组织的氧气输送。然而，人们对高海拔适应过程中的肾功能和肾氧输送（RDO ₂）的作用了解甚少。我们假设：1）RDO ₂在高空暴露12小时后（高海拔第1天）将减少，但在一周后（高海拔第7天）恢复到海平面值；和2）RDO ₂会与肾反应性（RR）相关，肾反应性是高海拔地区酸碱补偿的指标。在第1天和第7天在高海拔（4330m；秘鲁塞罗德帕斯科）的海平面（344m；加拿大基洛纳）对二十四名健康的低地参与者进行了测试。在每个时间点收集心脏输出，肾血流量，肾素-血管紧张素-醛固酮系统激素和NT pro-B型利钠肽的动脉和静脉血样。RR的计算公式为：海平面与高海拔天1之间以及海平面与高海拔天7之间的（Δ动脉碳酸氢盐）/（Δ动脉二氧化碳分压）。的主要结论是：1）RDO ₂最初在高海拔的降低相比海平面（ΔRDO ₂：-22±17％，P <0.001），但恢复到高空DAY7海平面值（ΔRDO ₂：-6±14％，P = 0.36）。观察到的RDO ₂改善是由于肾脏血流量的变化（高海拔第1天的Δ：+ 12±11％； P = 0.008）和动脉血氧含量（高海拔第1天的Δ+ 44.8±17.7％；动脉血氧含量变化）引起的。 P = 0.006）；2）高海拔第7天RR与RDO ₂正相关（r = 0.70； P <0.001），而高海拔第1天RR与RDO ₂正相关（r = 0.26； P = 0.29）。这些发现表征了早期高海拔适应过程中肾功能的暂时反应，以及RDO ₂对酸碱调节的影响。