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A phage-based microfluidic platform for highly sensitive and rapid detection of E. coli in low-resource settings.

Introduction Pneumonia is the leading cause of death globally in children. Supplemental oxygen reduces mortality but is not available in many low-resource settings. Inadequate power supply to drive oxygen concentrators is a major contributor to this failure. The objectives of our study were to (a) assess the availability of therapeutic oxygen; (b) evaluate the reliability of the electrical supply; and (c) investigate the effects of suboptimal oxygen delivery on patient outcomes in selected healthcare facilities in rural Kenya. Materials and methods A cross-sectional descriptive study on oxygen availability and descriptive case series of Kenyan children and youth hospitalized with hypoxemia. Results Two of 11 facilities had no oxygen equipment and nine facilities had at least one concentrator or cylinder. Facilities had a median of seven power interruptions per week (range: 2-147). The median duration of the power outage was 17 minutes and the longest was more than 6 days. The median proportion of time without power was out 7% (range: 1%-58%). Fifty-seven patients hospitalized with hypoxemia (median oxygen saturation 85% [interquartile range {IQR}: 82-87]) were included in our case series. Patients received supplemental oxygen for a median duration of 4.6 hours (IQR: 3.0-7.8). Eighteen patients (32%) faced an oxygen interruption of the median duration of 11 minutes (IQR: 9-20). A back-up cylinder was used in 5/18 (28%) cases. The case fatality rate was 11/57 (19%). Conclusion Mortality due to hypoxemia remains unacceptably high in low-resource healthcare facilities and may be associated with oxygen insecurity, related to lack of equipment and/or reliable power.

Optical spectroscopic devices have historically been too expensive or not portable enough to take full advantage of their abilities to offer real-time, on-site, objective results, especially in the developing world. Recent advancements toward smaller and cheaper hardware, especially in the visible and near infrared (NIR) ranges, could enable widespread use in low resource settings, down to a rural health clinic or at the individual farm level. We recently designed and tested a spectroscopic device with these goals in mind. It is based on an initial commercial version of a low cost MEMS spectral detection chip operating in the NIR, or more properly short wave infrared (SWIR) region. Custom optics, electronics, and mechanical designs were created to produce a complete handheld system capable of operation in the lab or in the field. Initial lab testing indicated excellent reproducibility both within and between five different devices. We have verified desired performance (e.g. acceptable signal to noise for target integration times, spectral features equivalent to lab-grade devices, etc.) for applications including pharmaceutical analysis and for analyzing multiple agricultural materials, including soils, plants, fertilizers, and manures. We have also developed a custom mobile app to accompany the devices in upcoming field testing, which will validate their performance in realistic settings in sub-Saharan Africa.

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.