title: Acetazolamide improves cerebral oxygenation during exercise at high altitude.
abstract: Vuyk, Jaap, Jan Van Den Bos, Kees Terhell, Rene De Bos, Ad Vletter, Pierre Valk, Martie Van Beuzekom, Jack Van Kleef, and Albert Dahan. Acetazolamide improves cerebral oxygenation during exercise at high altitude. High Alt. Med. Biol. 7:290-301, 2006.--Acute mountain sickness is thought to be triggered by cerebral hypoxemia and be prevented by acetazolamide (Actz). The effect of Actz on cerebral oxygenation at altitude remains unknown. In 16 members of the 2005 Dutch Cho Oyu (8201 m, Tibet) expedition, the influence of Actz and exercise (750 mg PO daily) on heart rate, peripheral and regional cerebral oxygen saturation (Sa(O(2) ) and rS(O(2) )), the Lake Louise score (LLS), and psychomotor function were studied at 0 m 14 days prior to the expedition, after arrival at 3700 m on day 3, after arrival at 5700 m on day 29, and again at 5700 m before the end of the expedition on day 51. After arrival at 3700 m, the LLS of the climbers taking Actz (n = 8) was significantly lower compared to those who did not take Actz (n = 8): 0.75 +/- 1.0 versus 2.9 +/- 2.0, p < 0.05 (ANOVA). High LLSs were associated with low rS(O(2) ) values in rest and exercise (p < 0.01 and p < 0.001). With altitude, resting Sa(O(2) ) and resting rS(O(2) ) decreased significantly (p < 0.001), irrespective of Actz use. Exercise at 3700 m and 5700 m reduced Sa(O(2) ) and rS(O(2) ) even further compared to rest (p < 0.001), although at 3700 m the rS(O(2) ) was preserved better in those who took Actz (55.3 +/- 4.3% versus 47.9 +/- 5.7%, p < 0.05). Irrespective of Actz use, with altitude, the percentage of omissions in the vigilance and tracking test increased while the climbers' scores on vigor decreased (p < 0.05). In conclusion, at altitude, exercise-induced reduction in cerebral oxygenation is less in climbers on Actz compared to climbers not taking Actz. This effect is nullified after several weeks at altitude due to acclimatization in climbers not taking Actz.
authors.affiliation: Department of Anesthesiology, Leiden University Medical Centre, Leiden, The Netherlands. j.vuyk@lumc.nl
authors.forename: Jaap
authors.initials: J
authors.lastname: Vuyk
authors.forename: Jan
authors.initials: J
authors.lastname: Van Den Bos
authors.forename: Kees
authors.initials: K
authors.lastname: Terhell
authors.forename: Rene
authors.initials: R
authors.lastname: De Bos
authors.forename: Ad
authors.initials: A
authors.lastname: Vletter
authors.forename: Pierre
authors.initials: P
authors.lastname: Valk
authors.forename: Martie
authors.initials: M
authors.lastname: Van Beuzekom
authors.forename: Jack
authors.initials: J
authors.lastname: Van Kleef
authors.forename: Albert
authors.initials: A
authors.lastname: Dahan
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage / Q000494:pharmacology*; D000208:Acute Disease; D000328:Adult; D000532:Altitude Sickness / Q000188:drug therapy / Q000378:metabolism / Q000517:prevention & control*; D000704:Analysis of Variance; D001921:Brain / Q000378:metabolism*; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects*; D012016:Reference Values
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide