A Metabolic Simulator for Unmanned Testing of Breathing Apparatuses in Hyperbaric Conditions
2014 (English)In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 85, no 11, 1139-1144 p.Article in journal (Refereed) Published
Background: A major part of testing of rebreather apparatuses for underwater diving focuses on the oxygen dosage system. Methods: A metabolic simulator for testing breathing apparatuses was built and evaluated. Oxygen consumption was achieved through catalytic combustion of propene. With an admixture of carbon dioxide in the propene fuel, the system allowed the respiratory exchange ratio to be set freely within human variability and also made it possible to increase test pressures above the condensation pressure of propene. The system was tested by breathing ambient air in a pressure chamber with oxygen uptake (VO2) ranging from 1-4 L.min(-1), tidal volume (V-T) from 1-3 L, breathing frequency (f) of 20 and 25 breaths/min, and chamber pressures from 100 to 670 kPa. Results: The measured end-tidal oxygen concentration (FO2) was compared to calculated end-tidal FO2. The largest average difference in end-tidal FO2 during atmospheric pressure conditions was 0.63%-points with a 0.28%-point average difference during the whole test. During hyperbaric conditions with pressures ranging from 100 to 670 kPa, the largest average difference in FO2 was 1.68%-points seen during compression from 100 kPa to 400 kPa and the average difference in FO2 during the whole test was 0.29%-points. Conclusion: In combination with a breathing simulator simulating tidal breathing, the system can be used for dynamic continuous testing of breathing equipment with changes in V-T, f, VO2, and pressure.
Place, publisher, year, edition, pages
2014. Vol. 85, no 11, 1139-1144 p.
respiratory measurement, machine testing, oxygen consumption
IdentifiersURN: urn:nbn:se:kth:diva-156103DOI: 10.3357/ASEM.4047.2014ISI: 000343642500012ScopusID: 2-s2.0-84910068714OAI: oai:DiVA.org:kth-156103DiVA: diva2:778234
QC 201501092015-01-092014-11-212015-09-03Bibliographically approved