Sea-level Assessment of Dynamic Cerebral Autoregulation Predicts Susceptibility to Acute Mountain Sickness at High Altitude

Kevin Evans, Julien Brugniaux, Damian Bailey, Nicholas J Cochand, Michael Wild, Peter J Davies, Richard G Wise

Research output: Contribution to journalArticlepeer-review


Background and Purpose-Dynamic cerebral autoregulation is impaired in subjects who develop acute mountain sickness (AMS), a neurological disorder characterized by headache. The present study examined if the normoxic sea-level measurement of dynamic cerebral autoregulation would predict subsequent susceptibility to AMS during rapid ascent to terrestrial high altitude. Methods-A dynamic cerebral autoregulation index was determined in 18 subjects at sea level from continuous recordings of middle cerebral artery blood flow velocity (Doppler ultrasonography) and arterial blood pressure (finger photoplethysmography) after recovery from transiently induced hypotension. Six hours after passive ascent to 3800 m (Mt Elbrus, Russia), the Lake Louise and Environmental Symptoms Cerebral Symptoms questionnaires were used to assess AMS. Results-AMS scores increased markedly at high-altitude (Lake Louise: 32 points, P0.001 and Environmental Symptoms Cerebral Symptoms: 0.60.9 points, P0.0003 versus sea level). Inverse relationships were observed between the sea-level autoregulation index score and the high-altitude-induced increases in the Lake Louise (r0.62, P0.007) and Environmental Symptoms Cerebral Symptoms (r0.78, P0.01) scores. One subject with a history of high-altitude pulmonary and cerebral edema presented with the lowest sea-level autoregulation index score (3.7 versusgroup: 6.21.0 points) and later developed high-altitude cerebral edema at 4800 m during the summit bid. Conclusions-These findings suggest that a lower baseline autoregulation index may be considered a potential risk factor for AMS. This laboratory measurement may prove a useful screening tool for the expedition doctor when considering targeted pharmacological prophylaxis in individuals deemed “AMS-susceptible.”
Original languageEnglish
Pages (from-to)3628 - 3630
Number of pages2
JournalStroke - Journal of the American Heart Assocation
Publication statusPublished - 29 Sept 2011


  • acute mountain sickness
  • dynamic cerebral autoregulation
  • high altitude
  • individual susceptibility
  • vasogenic edema


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