The Development of a CO₂ Monitoring Device for the Early Detection of Sepsis

Bloodstream infections (BSIs) pose a significant threat to public health, particularly in developing countries with limited diagnostic facilities. Increased levels of carbon dioxide (CO₂) in blood samples indicate the presence of microorganisms, making CO₂ monitoring crucial for the early detection of blood infections like sepsis. Traditional blood culture methods are often expensive, time-consuming, and prone to contamination. The lack of cost-effective and efficient diagnostic tools hampers timely and accurate diagnosis, leading to delayed treatments and higher mortality rates. This study, therefore, addresses this critical gap by developing a semi-automated blood culture CO₂ monitoring device that is low-cost, efficient, and suitable for Low- or Middle-Income Countries (LMICs).

The semi-automated CO₂ monitoring device (SCMD) was developed using an MQ-2 gas sensor, powered by a 9V battery and a 5V regulator for the ATmega microcontroller. The device was tested with three positive and two negative sepsis samples in the University College Hospital (UCH) microbiology laboratory. Its performance was compared with traditional blood culture techniques, which are the gold standard, and the BACTEC blood culture bottle. The accuracy of the device and the testing time were evaluated.

The SCMD detected the increased CO₂ produced by the growth of microorganisms in infected blood samples with over 90% accuracy and substantially reduced the turnaround times for detecting bacterial growth, potentially enabling quicker diagnosis and treatment of sepsis, by displaying test results in less than five minutes. Additionally, the device demonstrated a running time of up to 24 hours on a single battery charge, making it suitable for continuous use in healthcare settings.

The semi-automated CO₂ monitoring device offers a prompt solution to improve diagnostic capabilities and patient outcomes in resource-constrained environments. Integrating this device into existing healthcare infrastructure could significantly enhance the timely detection and treatment of bloodstream infections, ultimately saving lives.