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Closed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m)

Record type: Article

We present a randomised, controlled, crossover trial of the Caudwell Xtreme Everest (CXE) closed circuit breathing system vs an open circuit and ambient air control in six healthy, hypoxic volunteers at rest and exercise at Everest Base Camp, at 5300 m. Compared with control, arterial oxygen saturations were improved at rest with both circuits. There was no difference in the magnitude of this improvement as both circuits restored median (IQR [range]) saturation from 75%, (69.5-78.9 [68-80]%) to > 99.8% (p = 0.028). During exercise, the CXE closed circuit improved median (IQR [range]) saturation from a baseline of 70.8% (63.8-74.5 [57-76]%) to 98.8% (96.5-100 [95-100]%) vs the open circuit improvement to 87.5%, (84.1-88.6 [82-89]%; p = 0.028). These data demonstrate the inverse relationship between supply and demand with open circuits and suggest that ambulatory closed circuits may offer twin advantages of supplying higher inspired oxygen concentrations and/or economy of gas use for exercising hypoxic adults.

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McMorrow, R.C.N., Windsor, J.S., Hart, N.D., Richards, P., Rodway, G.W., Ahuja, V.Y., O'Dwyer, M.J., Mythen, M.G. and Grocott, M.P.W Caudwell Extreme Everest Research Group (2012) Closed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m) Anaesthesia, 67, (8), pp. 875-880. (doi:10.1111/j.1365-2044.2012.07152.x). (PMID:22519895).

More information

Published date: August 2012
Organisations: Human Development & Health


Local EPrints ID: 348863
ISSN: 0003-2409
PURE UUID: 766c4abe-1060-4fff-813a-bec012d8bfb0

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Date deposited: 20 Feb 2013 15:42
Last modified: 18 Jul 2017 04:47

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Author: R.C.N. McMorrow
Author: J.S. Windsor
Author: N.D. Hart
Author: P. Richards
Author: G.W. Rodway
Author: V.Y. Ahuja
Author: M.J. O'Dwyer
Author: M.G. Mythen
Author: M.P.W Grocott

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