Design and evaluation of a solar-aided autoclave to aid in the prevention of neonatal sepsis in Uganda

Abstract

In Uganda, approximately 81 babies die each day before reaching their first month. As of 2016, Uganda had a neonatal mortality rate of 21.4 deaths per 1000 live births and an under-five mortality rate of 53.0 deaths per 1000 live births. Sepsis, a systemic inflammatory response to an infection, is the third major cause of neonatal deaths in Uganda contributing to 18.2% of the total neonatal mortality. Autoclaves kill all infectious pathogens, including their endospores, and they are essential in achieving and maintaining a sterile environment. However, autoclaves require electricity to function but, few rural areas in sub-Saharan Africa have access to stable electricity. A low cost, solar-aided autoclave was designed to address the unique technical, behavioural and market challenges present in rural sub-Saharan Africa, particularly in Uganda. To achieve sterilization, water in an autoclave has to reach the required temperature of 121℃ at a pressure of 15psi for at least 30 minutes. The initial solar-aided autoclave prototype was tested to find out if it can achieve the standards recommended by the Centres of Disease Control and Prevention (CDC) on effective steam sterilization. Geobacillus stearothermophilus bacterial spores were also used as a biological indicator in a sterilization validation test. A thermal analysis simulation test was also performed using Autodesk Fusion 360 to determine the solar radiation energy output of the parabolic reflective dish. The water in the solar autoclave attained a steady-state temperature of 76.35℃ at a pressure of 172031Pa within 3 hours and 15 minutes. This temperature and pressure attained by the initial prototype did not reach the required standards for steam sterilization. Therefore, the team redesign the solar-aided autoclave with the aim of improving its efficiency in capturing solar radiation energy for use in sterilization. The redesigned prototype was tested and achieved steam temperature of 123.12℃ and autoclave chamber pressure of 201328.12 Pa within 2 hours.