Date Published: February 6, 2019
Publisher: Public Library of Science
Author(s): Ryan Calderon, Melissa C. Morgan, Mark Kuiper, Harriet Nambuya, Nicholas Wangwe, Akos Somoskovi, Daniel Lieberman, Long Wang.
Access to therapeutic oxygen remains a challenge in the effort to reduce pneumonia mortality among children in low- and middle-income countries. The use of oxygen concentrators is common, but their effectiveness in delivering uninterrupted oxygen is gated by reliability of the power grid. Often cylinders are employed to provide continuous coverage, but these can present other logistical challenges. In this study, we examined the use of a novel, low-pressure oxygen storage system to capture excess oxygen from a concentrator to be delivered to patients during an outage. A prototype was built and tested in a non-clinical trial in Jinja, Uganda. The trial was carried out at Jinja Regional Referral Hospital over a 75-day period. The flow rate of the unit was adjusted once per week between 0.5 and 5 liters per minute. Over the trial period, 1284 power failure episodes with a mean duration of 3.1 minutes (range 0.08 to 1720 minutes) were recorded. The low-pressure system was able to deliver oxygen over 56% of the 4,295 power outage minutes and cover over 99% of power outage events over the course of the study. These results demonstrate the technical feasibility of a method to extend oxygen availability and provide a basis for clinical trials.
Globally, lower respiratory tract infections, including pneumonia, are a leading cause of mortality in children, accounting for over 700,000 deaths in children under age 5 in 2015 . An estimated 120 million cases of childhood pneumonia, 14 million of which are severe, occur each year [2–9]. Oxygen is an essential therapy to treat hypoxemia , but remains under-utilized in many low-resource settings due in part to cost and implementation challenges . Many health facilities lack or are unable to maintain reliable access to oxygen and related supplies [11–13].
This study evaluated the technical performance of the LPR prototype in the laboratory and field settings. The data demonstrated that the prototype supplied oxygen to cover over half of the recorded power outage minutes over the flow rates set between 1–5 LPM.
The results of this study demonstrate the ability of a novel reservoir system to store and deliver oxygen from a concentrator during a power outage and, consequently, minimize health worker intervention typically required to switch to a back-up cylinder source. The low-pressure system was able to deliver oxygen in 56% of power outage minutes and cover over 99% of power outage events. These results demonstrate an alternative, relatively simple, low cost and accessible method to extend oxygen availability. Future work will aim to explore this system in a clinical study and to assess its health and economic impact.