Closed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m).
AuthorsMcMorrow, R C N
Windsor, J S
Hart, N D
Rodway, G W
Ahuja, V Y
O'Dwyer, M J
Mythen, M G
Grocott, M P W
AffiliationUCL Centre for Altitude Space and Extreme Environment Medicine, UCL Institute of Child Health, University College London, London, UK. email@example.com
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CitationClosed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m). 2012, 67 (8):875-80 Anaesthesia
AbstractWe 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.
SponsorsJohn Caudwell, BOC Medical, Eli Lilly, The London Clinic, Smiths Medical, Micropore Inc, Analytical Industries Inc, Deltex Medical, The Rolex Foundation, The Association of Anaesthetists fo Great Britain and Ireland, The UK Intensive Care Foundation, and the Sir Halley Stewart Trust. Some of the work was undertaken at University College London Hospital - University College London, Comprehensive Biomedical Research, which received a proportion of funding from the UK Department of Health's National Institute for Health Research Biomedical Research Centres funding scheme.
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