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

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

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)875-880
Number of pages6
JournalAnaesthesia
Volume67
Issue number8
DOIs
StatePublished - Aug 2012
Externally publishedYes

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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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., & Grocott, M. P. W. (2012). Closed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m). Anaesthesia, 67(8), 875-880. https://doi.org/10.1111/j.1365-2044.2012.07152.x