Abstract
BACKGROUND: Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda.
METHODS: The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d.
RESULTS: The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1–176 min (mean 36.2, median 18.5).
CONCLUSIONS: The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials.
Footnotes
- Correspondence: Jim Black MBBS PhD MCommH, 8 French Avenue, Northcote, Victoria 3070, Australia. E-mail: jim{at}freo2.org.
This study was funded by a Grand Challenges Explorations grant from the Bill and Melinda Gates Foundation. Dr Moschovis has received research funding from the National Institutes of Health (Grant 5F32HL124951), the Thrasher Research Fund Early Career Award, and a KL2/Catalyst Medical Research Investigator Training award (an appointed KL2 award) from Harvard Catalyst: The Harvard Clinical and Translational Science Center (National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health Grant KL2 TR001100). The content is solely the responsibility of the authors and does not necessarily represent the official views of Harvard Catalyst, Harvard University and its affiliated academic health-care centers, or the National Institutes of Health. Drs Peake, Sobott, Black, and Rassool are members and/or directors of FREO2 Foundation Australia, which is a not-for-profit organization based in Melbourne, Australia. Drs Black and Peake are directors of FREO2 Pty Ltd, which controls the associated intellectual property. The other authors have disclosed no conflicts of interest.
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