Subudhi Andrew W, Fan Jui-Lin, Evero Oghenero, Bourdillon Nicolas, Kayser Bengt, Julian Colleen G, Lovering Andrew T, Panerai Ronney B, Roach Robert C
University of Colorado Altitude Research Center, Department of Emergency Medicine, Anschutz Medical Campus, Aurora, Colorado;
J Appl Physiol (1985). 2014 Apr 1;116(7):724-9. doi: 10.1152/japplphysiol.00880.2013. Epub 2013 Dec 26.
Cerebral autoregulation (CA) acts to maintain brain blood flow despite fluctuations in perfusion pressure. Acute hypoxia is thought to impair CA, but it is unclear if CA is affected by acclimatization or related to the development of acute mountain sickness (AMS). We assessed changes in CA using transfer function analysis of spontaneous fluctuations in radial artery blood pressure (indwelling catheter) and resulting changes in middle cerebral artery blood flow velocity (transcranial Doppler) in 21 active individuals at sea level upon arrival at 5,260 m (ALT1), after 16 days of acclimatization (ALT16), and upon re-exposure to 5,260 m after 7 days at 1,525 m (POST7). The Lake Louise Questionnaire was used to evaluate AMS symptom severity. CA was impaired upon arrival at ALT1 (P < 0.001) and did not change with acclimatization at ALT16 or upon re-exposure at POST7. CA was not associated with AMS symptoms (all R < 0.50, P > 0.05). These findings suggest that alterations in CA are an intrinsic consequence of hypoxia and are not directly related to the occurrence or severity of AMS.
脑自动调节（CA）的作用是在灌注压波动的情况下维持脑血流量。急性缺氧被认为会损害CA，但尚不清楚CA是否受适应过程的影响，或者是否与急性高原病（AMS）的发生有关。我们通过对21名活跃个体在海平面时、到达海拔5260米处（ALT1）、适应16天后（ALT16）以及在海拔1525米处停留7天后再次暴露于海拔5260米处（POST7）时，对桡动脉血压（留置导管）的自发波动进行传递函数分析，并由此评估大脑中动脉血流速度的变化（经颅多普勒），来评估CA的变化。使用路易斯湖问卷来评估AMS症状的严重程度。到达ALT1时CA受损（P < 0.001），在ALT16适应过程中或POST7再次暴露时CA没有变化。CA与AMS症状无关（所有R < 0.50，P > 0.05）。这些发现表明，CA的改变是缺氧的内在结果，与AMS的发生或严重程度没有直接关系。
