Acupuncture effects on cerebral blood flow during normoxia and normobaric hypoxia: results from a prospective crossover pilot study

Cerebral blood flow (CBF) is significantly influenced by exposure to hypoxia, both hypobaric and normobaric. Alterations in cerebral blood flow can play a crucial role in the pathogenesis of acute mountain sickness (AMS) and its symptoms, especially headache, dizziness and nausea. Acupuncture has been proven to be effective in treating some cerebrovascular disorders and PC6 Nei Guan stimulation seems to enhance cerebral blood flow. Therefore we have hypothesized that PC6 Nei Guan stimulation could affect CBF in acute hypoxia and it could be used to contrast AMS symptoms. We evaluated blood flow in middle cerebral artery (MCA) in normoxia and after 15 minutes in normobaric hypoxia Fraction of Inspired Oxygen (FIO2) 14% corresponding to 3,600 m.a.s.l.) in basal conditions and after PC6 Nei Guan stimulation, both by needle and by pressure. No comparisons with other acupuncture points and sham acupuncture were done. PC6 stimulation seems to counteract the effect of acute normobaric hypoxia on end-diastolic velocity (EDV) in MCA, especially after acupuncture and reduces significantly systolic and diastolic blood pressure. A re-balance of CBF could control some AMS symptoms, but further studies are necessary.